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6.5L Injection Pump Optical Sensor
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Kevin:

An ongoing problem with the Stanadyne design is the fact that the pumping elements (high pressure plungers) are free floating. In other words, they are just sliding in and out in their bores. Transfer pump pressure and centrifugal force moves them out and the rotor cams force them in (pressure stroke).

Since the days of the original DB2 pumps, and it looks like the DS4 still suffers from this problem, if any crud does get by the filters or if any varnish build up happens on the cylinder walls, these free pistons hang up in the bore, and don't move at all (no fuel = no start). There have been many trys to fix the problem but the situation does still happen. The piston to bore clearances are very tight so any added heat just makes the matter worse.

From day one, I have always kept a liter or two of cool water in my car. If I experience a hot no start, I just carefully pour some water on the pump to cool it down. If this fixes it then I know it is time for a double dose of Stanadyne additive (still the best lubricant for these pumps).

Another thing to look at is the glow plug circuit. Especially in the summer months, there is a temperature disable switch (135F I think) built into the controller. Depending on the engine (my 6.2 always wants it's plugs) 135 may not be hot enough to start without glow.

Anyways, give these a try before changing out the IP or PMD.

Bill


91 Buick Roadmaster wagon, GM 6.2 diesel conversion (gone but not forgotten
89 GMC 6.2 (Just got rid of the last pieces)
84 Mercedes 300D (gone to the great autobahn in the sky)
94 Cadillac Fleetwood (Sold before I could convert it)
 
Location: Manotick, Ontario Canada | Registered: July 02, 2002Reply With QuoteReport This Post
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Bill, very interesting comments. I've read about the cold water trick to get a 6.5 that won't hot-start going. I've considered it to be a stop-gap trick to get a bit more life out of the IP but that it would have to be replaced as it further degraded. If you are able to restore its hot-start ability by using extra additive that would be a huge savings.


'97 GMC Suburban 2500 - 6.5 turbodiesel - 203,000 miles
2-Tank WVO conversion
 
Location: NH | Registered: August 24, 2008Reply With QuoteReport This Post
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Dave:

If Kevin is getting good cold starts and when the engine is running, there is no power loss, then there is no reason to suspect a bad IP. When these pumps go south, they do so slowly, usually over a 2 to 3 thousand mile period with the power slowly decreasing and any starts getting hard. Eventually they either simply refuse to start or there is no power left.

Interestingly there is normally not much wear on the plungers or bore but the advance piston tends to ream out it's aluminum bore, causing transfer pump pressure to drop and the pump to go too far advanced. There is a fix that uses a pressed in SS sleave and a re-sized advance piston. Don't know if this is the situation in the DS4s but it has been the case in all of the DB series pumps.

The Mercedes guys use a treatment called Diesel Purge that does a great job in cleaning out the system. One of the vendors on the Mercedes site sells it for about 25 bucks

http://mercedessource.com/node/791

Can't say if it is safe for all the electronic sensors in the DS4 but it can't do much damage as it is only exposed to the stuff for a short period of time. Works great on the DB2s.

Bill


91 Buick Roadmaster wagon, GM 6.2 diesel conversion (gone but not forgotten
89 GMC 6.2 (Just got rid of the last pieces)
84 Mercedes 300D (gone to the great autobahn in the sky)
94 Cadillac Fleetwood (Sold before I could convert it)
 
Location: Manotick, Ontario Canada | Registered: July 02, 2002Reply With QuoteReport This Post
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quote:
getting good cold starts and when the engine is running, there is no power loss, then there is no reason to suspect a bad IP.


I'm not sure I agree. In my case, I had good cold starts (though it went from instant start after just a few revolutions to maybe another 2 seconds of cranking). I had good power, no indication at highway speeds or climbing hills that anything was wrong. Hot start went from some extra cranking to having to go through 2 or 3 15 second crank cyles to get going, last time wouldn't start at all. Then when told to do that ramp up and down rpm test I found I couldn't do it, and became convinced my pump was toast.

I'm not saying you are wrong, maybe an additive could have restored my pump function, but too late now for me to find out. I'd certainly encourage Kevin to give it a try, but I have to admit I'm still thinking the IP is gone.


'97 GMC Suburban 2500 - 6.5 turbodiesel - 203,000 miles
2-Tank WVO conversion
 
Location: NH | Registered: August 24, 2008Reply With QuoteReport This Post
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Dave:

As I said, my experience with the DS4 is limited but it is the same basic design. Perhaps the electronics were masking a number of the early symptoms, but from what you are saying, your pump was exhibiting the symptoms of a pump hanging up. ie. hard hot starts etc. Even when they are on their way out, the Stanadyne will operate pretty well unless you really load them up. At part throttle the computer can do alot of compensation for poor output and mask alot of the early symptoms.

Would love to have seen the insides of your old pump. Way too often these pumps are just sent off to the re-builders with nothing mechanically wrong with them. For years GM had a policy of replacing the whole pump when the only thing wrong was the PMD, Lots of perfectly good DS4s hanging around the back shops of GM dealers. See them on Ebay alot.

Bill


91 Buick Roadmaster wagon, GM 6.2 diesel conversion (gone but not forgotten
89 GMC 6.2 (Just got rid of the last pieces)
84 Mercedes 300D (gone to the great autobahn in the sky)
94 Cadillac Fleetwood (Sold before I could convert it)
 
Location: Manotick, Ontario Canada | Registered: July 02, 2002Reply With QuoteReport This Post
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Any Ideas on How to clean/purge the IP?
I still am having a hard time conceding that my IP that I personally installed is bad after only 2000 miles.

I gave it some time and am going back to work on it again and I am going to do the test wiht the voltmeter:

PMD connector
red probe on A and black probe on ground - 1.2V and with 5 revolutions of crank and read should be 1.8V

Test light Probe to C and clip to positive - light should come on

Clip to neg terminal and probe to "D" with key in the on position - light should come on.

All 3 OK - IP problem
picture: Image of wiring diagram
........................................
Any idea of how to start to work on this. I was thinking to remove the plenum and get to the IP and open it up at the optic sensor and suck out all fuel with a vac. Then take out the optic sensor (I don't think it is the OP sensor because no fuel at injectors even when unplugged) and cleaning it with (what??)
I have fuel at the fuel shutoff solenoid. I will also see if I have an inlet screen but I think that is ruled out because of the fuel at the FShutoff. Any Ideas about purging or cleaning a blockage??
 
Registered: September 06, 2008Reply With QuoteReport This Post



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Image on this thread

Sorry that link is not working. Try link above and scroll down a couple of posts
 
Registered: September 06, 2008Reply With QuoteReport This Post
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Lost, I can get you the pages from the service manual if you want them. Flow charts on how to diagnose all the problems. You need a Tech II, however.
Were you blind, but now see? Wink


Blessings. Joe 1999 Chevy Suburban w/new optimizer 6500 TD and 1995 Chevy Cube van 6.5L. WWW.RillaBioFuels.com
WWW.RillaBioFuels.com
 
Location: Sterling Hts. Michigan USA | Registered: October 18, 2001Reply With QuoteReport This Post
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Hey Joe
Yep I was blind, but now I see. I just can't see clear to the purchase of another Ip at 2000 miles. Since I used veggy, my warranty is nil. I was wondering if anybody has gotten in there and cleaned an IP out. I think I am going to isolate this tomorrow as the IP. Last codes were:
P0370 -- Timing Reference High Resolution
P0251 Injection Pump Fuel Metering Control "A" Ma

Nope-Tech II is out of my pay scale
 
Registered: September 06, 2008Reply With QuoteReport This Post
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Any help appreciated. I set out today to test the terminals on the FSD/PMD and I got bad reading on pin A. I was not sure as to how to use the probe, so I unplugged the connection and turned on key, etc. N/G Then I plugged it bag in and shaved just a little insulation off the wire to test it plugged in and still no good. I only got a .002V at best which is nothing.

ANy ideas?
 
Registered: September 06, 2008Reply With QuoteReport This Post
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Prior OBII reading before the total shutdown had to do with the "manufacturer computer and outputs." At that time I traded an ECM from a runner and it did not work. I also traded a PMD, etc. All this to no avail, but now the runner is doing the same thing as the truck in question. Same test with voltmeter yeilded same thing on that truck?????????
 
Registered: September 06, 2008Reply With QuoteReport This Post
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quote:
Originally posted by losthenfound:
Hey Joe
Yep I was blind, but now I see.....


That's amazing! LOL
Anyway, here are the flow charts for your two codes, if they transfer well.
DTC P0251 Injection Pump Cam Sensor Circuit



Circuit Description

The optical sensor provides a pump cam signal to the PCM by counting pulses on the sensor disk located in the injection pump. The pump cam is one of the most important inputs by the PCM for fuel control and timing. This test monitors the number of crankshaft position pulses that have occurred since the last cam pulse. The physical one to one correspondence between the pump cam and the crankshaft implies if more crank pulses are detected than cam pulses, cam pulses have been missed.

Conditions for Running the DTC

• The PCM performs this DTC diagnostic continuously.
• The engine is operating.

Conditions for Setting the DTC

• The number of consecutive missing cam pulses is more than or equal to 8.
• All diagnostic set conditions met for 2 seconds.

Action Taken When the DTC Sets

• The PCM illuminates the malfunction indicator lamp (MIL) on the first consecutive drive trip that the diagnostic runs and fails.
• The Freeze Frame records the operating conditions at the time of failure and updates the Failure Records.
• The PCM will activate Back Up fuel.

Conditions for Clearing the MIL/DTC

• The PCM will turn the MIL off after three consecutive trips without a fault condition.
• A History DTC clears after forty consecutive warm-up cycles, if this or any other emission related diagnostic does not report any failures
• The use of a scan tool.

Diagnostic Aids

Intermittent DTCs (P0251, P0370 and P1216) may be caused by air entering the fuel system when fuel levels get below 1/8 of a tank while performing hard acceleration or turning maneuvers. It's also possible that a P0251, P0370 and P1216 will set the if vehicle has run out of fuel. Customer driving habits should be checked to determine if the vehicle has been performing in these manners. If the vehicle has been performing in these conditions, bleed the fuel system of all air and test drive the vehicle.
When the PCM is in backup fuel, fast idle and poor performance problems will exist.
An intermittent condition can be caused by the following:
• Poor connections.
• Rubbed through wire insulation.
• Broken wire inside the insulation.

Test Description

Number(s) below refer to the step number(s) on the Diagnostic Table.
3. This step will determine if this is a hard or intermittent DTC.
5. This step will determine if there is a 5 volt reference.
7. This step will check to see if the sensor is sending a signal back to the PCM.
11. The PCM supplies 5 volts on the signal circuit. This step determines if that voltage is present, not present, or too much voltage is present.
16. This step determines if the signal circuit is shorted to 5V. A normal CAM signal circuit will have 3-5 mA. Any reading over 50 mA indicates a short to 5V.
Step Action Value(s) Yes No
1 Important: Before clearing the DTCs, use the scan tool Capture Info to save the Freeze Frame and failure records for reference. The control module's data is deleted once the Clear Info function is used.
Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? -- Go to Step 2
Go to Powertrain On Board Diagnostic (OBD) System Check

2 Is the DTC P0370 set also? -- Go to DTC P0370 Timing Reference High Resolution System Performance
Go to Step 3

3
1. Start and idle the engine.
2. With the throttle closed, observe the CAM Ref Missed display on the scan tool.
Does scan tool display the specified value? 8 Go to Step 5
Go to Step 4

4 The DTC is intermittent. If no additional DTCs are stored, refer to Diagnostic Aids. If additional DTCs were stored refer to the applicable DTC table(s) first.
Are any additional DTCs stored? -- Go to the Applicable DTC Table Go to Diagnostic Aids
5
1. Turn the ignition OFF.
2. Disconnect the Optical/Fuel temperature sensor electrical connector.
3. Turn the ignition ON leaving the engine OFF.
4. Using a J 39200 , measure the voltage between the Optical sensor 5 volt reference circuit at the harness connector and chassis ground .
Is the voltage within the specified value? 4.8-5.2V Go to Step 6
Go to Step 8

6 Probe the sensor ground circuit with a test light connected to B+ at the harness connector.
Is the test light ON? -- Go to Step 7
Go to Step 9

7
1. Reconnect the Optical/Fuel temperature sensor electrical connector.
2. Start and idle the engine.
3. With a scan tool, command 900 RPM.
4. With J 39200 on Hertz (Hz) scale, back probe the Pump CAM signal circuit at the PCM.
Is the Hertz reading at the specified value? 60 Hz
(± 3 Hz) Go to Step 15
Go to Step 11

8 1. Turn the ignition OFF.
2. Disconnect the PCM and check the Optical sensor 5 volts reference circuit for an open, short to ground, or short to the sensor ground circuit.
3. If the Optical sensor 5 volt reference circuit is open or shorted to ground, repair it as necessary.
Was the Optical sensor 5 volt reference circuit open or shorted to ground? -- Go to Step 21
Go to Step 10

9 1. Check for an open or a proper sensor ground terminal connection at the PCM.
2. If a problem is found, repair as necessary.
Did you perform a repair? -- Go to Step 21
Go to Step 20

10 Check the Optical/Fuel temperature 5 volt reference circuit for a proper connection at the PCM and replace terminal if necessary.
Did the terminal require replacement? -- Go to Step 21
Go to Step 20

11
1. Turn the ignition ON leaving the engine OFF.
2. Disconnect the Optical/Fuel temperature sensor electrical connector.
3. With a J 39200 connected to ground, probe the CAM signal circuit.
Is the voltage within the specified value? 4.8-5.2V Go to Step 16
Go to Step 12

12 Is the voltage greater than the specified value? 4.8-5.2V Go to Step 13
Go to Step 14

13 Repair the short to battery/ignition voltage on the CAM signal circuit.
Is the action complete? -- Go to Step 21
--
14 1. Turn the ignition OFF.
2. Check the Cam signal circuit for an open or short to ground.
3. If the CAM signal circuit is open or shorted to ground, repair the circuit as necessary.
Was the CAM signal circuit open or shorted to ground? -- Go to Step 21
Go to Step 15

15 Check for a proper connection at the PCM harness terminal and replace the terminal if necessary.
Did the terminal require replacement? -- Go to Step 21
Go to Step 20

16
With a DMM J 39200 set to the mA scale, measure the current between the CAM signal circuit and the ground circuit at the Optical/Fuel temperature sensor electrical connector.
Is the current less than the specified value? 50 mA Go to Step 18
Go to Step 17

17 Repair the short to reference voltage on the CAM signal circuit.
Is the action complete? -- Go to Step 21
--
18 1. Check for a proper connection at the injection pump.
2. If a problem is found, repair the problem as necessary.
Was a problem found? -- Go to Step 21
Go to Step 19

19 Replace the injection pump. Refer to Fuel Injection Pump Replacement .
Important: The new injection pump must be timed. Refer to Fuel Injection Pump Timing Adjustment .
Is the action complete? -- Go to Step 21
--
20 Replace the PCM.
Important: The new PCM must be programmed. Refer to Powertrain Control Module Replacement/Programming .
Is the action complete? -- Go to Step 21
--
21 1. Using the scan tool, clear the DTCs.
2. Start the engine.
3. Allow the engine to idle at normal operating temperature.
4. Select DTC and the Specific DTC function.
5. Enter the DTC number which was set.
6. Operate the vehicle, with the Condition for Setting this DTC, until the scan tool indicates the diagnostic Ran.
Does the scan tool indicate the diagnostic Passed? -- Go to Step 22
Go to Step 2

22 Does the scan tool display any additional undiagnosed DTCs? -- Go to the Applicable DTC Table System OK


DTC P0370 Timing Reference High Resolution System Performance



Circuit Description

The optical sensor provides a high resolution signal to the PCM by counting pulses on the sensor disk located in the injection pump. The high resolution is one of the most important inputs by the PCM for fuel control and timing. This test monitors the number of high resolution pulses which have been missed (not detected). It's based on a comparison between the number of pulses that were detected since the last pump cam pulse and the number of the pulses that should have occurred. There are approximately 64 high resolution pulses for every cam pulse.

Conditions for Running the DTC

The engine is operating.

Conditions for Setting the DTC

A number of high resolution pulses missing (internal to PCM (64 to 1 ratio) per every 8 cam reference pulses.

Action Taken When the DTC Sets

• The PCM illuminates the malfunction indicator lamp (MIL) on the first consecutive drive trip that the diagnostic runs and fails.
• The Freeze Frame records the operating conditions at the time of failure and updates the Failure Records.
• The PCM will activate back up fuel.

Conditions for Clearing the MIL/DTC

• The PCM will turn the MIL off after three consecutive trips without a fault condition.
• A History DTC clears after forty consecutive warm-up cycles, if this or any other emission related diagnostic does not report any failures
• The use of a scan tool.

Diagnostic Aids

Intermittent DTCs (P0251, P0370 and P1216) may be caused by air entering the fuel system when fuel levels get below 1/8 of a tank while performing hard acceleration or turning maneuvers. It's also possible that a P0251, P0370 and P1216 will set if the vehicle has run out of fuel. Customer driving habits should be checked to determine if the vehicle has been performing in these manners. If the vehicle has been performing in these conditions, bleed the fuel system of all air and test drive the vehicle.
When PCM is in backup fuel, fast idle and poor performance problems will exist. If P0251 is also stored, the snap shot mode on the scan tool should be used to properly identify the fault. DTCs P0335, P1216, and P1217 may set along with this DTC.
The least likely cause of failure is the PCM.

Test Description

Number(s) below refer to the step number(s) on the Diagnostic Table.
2. This step will determine if the 5 volt reference is present.
3. This step checks the ground circuit.
4. This step determines if the problem is currently active by the scan tool displaying Last Test Failed. Do not proceed any further with this table if the scan tool does not display the term Last Test Failed. Duplicating the conditions in Freeze Frame and Failure Records can help create an active fault.
5. This step determines if a High Res signal is being sent to the PCM. Refer to the RPM vs Hertz table to compare the Hertz readings at different RPMs. Using Freeze Frame and Failure Records will help identify the RPM the problem occurs.
9. The PCM supplies 5 volts on the signal circuit. This step determines if that voltage is present, not present, or too much voltage is present.
13. This step determines if the signal circuit is shorted to 5V. A normal high res signal circuit will have 3-5mA. Any reading over 50 mA indicates a short to 5V.
Step Action Value(s) Yes No
1 Important: Before clearing any DTCs, use the scan tool Capture Info to save freeze frame and failure records for reference, as the scan tool loses data when using the Clear Info function.
Was the Powertrain On-Board Diagnostic (OBD) System Check performed? -- Go to Step 2
Go to Powertrain On Board Diagnostic (OBD) System Check

2
1. Turn the ignition OFF.
2. Disconnect the Optical/Fuel temperature sensor electrical connector.
3. Turn the ignition ON leaving the engine OFF.
4. Using a DMM J 39200 , measure the voltage between the Optical sensor 5 volt reference circuit at the harness connector and chassis ground.
Is the voltage at specified value? 4.8-5.2V Go to Step 3
Go to Step 6

3
1. Verify the Optical/Fuel temperature sensor electrical connector is still disconnected.
2. Probe the sensor ground circuit with a test light connected to B+ at the harness connector.
Is the test light ON? -- Go to Step 4
Go to Step 7

4
1. Reconnect the Optical/Fuel Temperature sensor electrical connector.
2. Start and operate the engine as close to the conditions saved in the Freeze Frame/Failure Records.
3. Using the Scan Tool, select DTC, specific and then enter the DTC number.
Does the scan tool display the term Last Test Failed? -- Go to Step 5
Go to Diagnostic Aids
5
Important: The scan tool must display Last Test Failed (under DTC, Specific). This ensures the fault is active while performing this test.
1. Maintain the engine speed at the point of failure (per conditions saved in the Freeze Frame/Failure Records).
2. With the DMM J 39200 on the Hertz (Hz) scale, backprobe the high resolution signal circuit at the PCM.
Referring to the RPM vs Hertz (Hz) table, does the Hertz reading in the table correspond (±100 Hz) with the Hertz reading on the DMM at the designated RPM? -- Go to Step 16
Go to Step 9

6 1. Turn the ignition OFF.
2. Disconnect the PCM, and check the Optical sensor 5 volt reference circuit for an open, short to ground, or short to the sensor ground circuit.
3. If the Optical sensor 5 volt reference circuit is open or shorted to ground, repair the circuit as necessary.
Was the Optical sensor 5 volt reference circuit open or shorted to ground? -- Go to Step 19
Go to Step 8

7 1. Check for an open or a proper sensor ground terminal connection at the PCM.
2. If a problem is found, repair as necessary.
Was a repair performed? -- Go to Step 19
Go to Step 18

8 Check the Optical sensor 5 volt reference circuit for a proper connection at the PCM and replace the terminal if necessary.
Did the terminal require replacement? -- Go to Step 19
Go to Step 18

9
1. Disconnect the Optical/Fuel temperature sensor electrical connector.
2. Turn the ignition ON leaving the engine OFF.
3. With a DMM J 39200 connected to ground, probe the high resolution signal circuit at the harness connector.
Is the voltage within the specified value? 4.8-5.2V Go to Step 13
Go to Step 10

10 Is the voltage greater than the specified value? 4.8-5.2V Go to Step 11
Go to Step 12

11 Repair the short to battery/ignition voltage on the high resolution signal circuit.
Is the action complete? -- Go to Step 17
--
12 1. Turn the ignition OFF.
2. Disconnect the PCM, and check the high resolution signal circuit for an open, short to ground, or short to the sensor ground circuit.
3. If a problem is found, repair the problem as necessary.
Was a repair made? -- Go to Step 19
Go to Step 16

13
With a DMM J 39200 set to the mA scale, measure the current between the High Res signal circuit and the ground circuit at the Optical/Fuel temperature sensor electrical connector.
Is the current less than the specified value? 25 mA Go to Step 15
Go to Step 14

14 Repair the short to reference voltage on the high resolution signal circuit.
Is the action complete? -- Go to Step 19
--
15 1. Check the high resolution signal circuit for a proper connection at the injection pump.
2. If a problem is found, repair the problem as necessary.
Was a problem found? -- Go to Step 19
Go to Step 17

16 1. Turn the ignition OFF.
2. Disconnect the PCM, and check the high resolution signal circuit for a proper connection at the PCM.
3. If a problem is found, repair the problem as necessary.
Was a problem found? -- Go to Step 19
Go to Step 18

17 Replace the injection pump. Refer to Fuel Injection Pump Replacement
Important: The new injection pump must be timed. Refer to Fuel Injection Pump Timing Adjustment .
Is the action complete? -- Go to Step 19
--
18 Replace the PCM.
Important: The new PCM must be programmed. Refer to Powertrain Control Module Replacement/Programming .
Is the action complete? -- Go to Step 19
--
19 1. Using the Scan Tool, clear the DTCs.
2. Start the engine and idle at normal operating temperature.
3. Select DTC, Specific, then enter the DTC number which was set.
4. Operate the vehicle, within the Conditions for Setting this DTC, until the Scan Tool indicates the diagnostic Ran.
Does the Scan Tool indicate the diagnostic Passed? -- Go to Step 20
Go to Step 2

20 Does the Scan Tool display any additional undiagnosed DTCs? -- Go to the Applicable DTC Table System OK


OK, well the table format didn't transfer, but it's still legible. HTH


Blessings. Joe 1999 Chevy Suburban w/new optimizer 6500 TD and 1995 Chevy Cube van 6.5L. WWW.RillaBioFuels.com
WWW.RillaBioFuels.com
 
Location: Sterling Hts. Michigan USA | Registered: October 18, 2001Reply With QuoteReport This Post



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Interesting subject.
Hi, Joe. Good to have you around, for sure.

Now I'm really discouraged. I bought this truck at a good price...$2,500, 1/4 million miles, had to rebuild the front end, all good now.

It runs like a champ on D2 or B20, even red ag diesel.
It starts fine, runs well, here lately, it does take a little more revs to start, but not much.

My FSD is on a heatsink above the plenum, had problems with it at first. After opening PMD box and retorquing the little nuts on the 'units?', that problem stopped.


My lift pump still wont puge the filter cup when I change filters, yet still runs fine everytime.

I drive it everyday, sometimes far from home.

I've been stockpiling WVO that titrates @ 0.9 NaOH. My processor is nearly ready to brew 35 gallon batches, and I have access to Cognis QTA spectrometer.

BUT, now I feel like I got the wrong truck. Chevy's are all I know. Never had anything else.

I would be satisfied to run B50+ year round.
I cant spend any more money on hi-dollar parts, plus I have a small loan against it. If it craps out, I'll have to drive the '76 one ton gasser. 7-10 MPG.

I'd like to fix the filter purging thing, but, Joe, tell me I'll be fine to run 50/50 at least.

Discouraged.
Brian


1996 K2500 4x4 6.5TD
 
Location: Southern Indiana USA | Registered: June 20, 2008Reply With QuoteReport This Post
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Brian,
You bet! I run B100 in mine in warm weather, B50 when it gets cold. Did you buy that PMD cooler? Very expensive for what it is and leaving it under the hood, right on top of the manifold isn't much better than leaving it on the pump. Mine is behind the grille, on a large finned heat sink from a power supply that cost me next to nothing. The lift pump times out. You need to cycle the key MANY times to purge the system when changing filters. Or hook up a Tech II and command the fuel pump on, or run a wire down to the pump to keep it running. When the pump begins to fail, it can't keep up supply, especially when pumping through a partially plugged filter. Fortunately, they aren't very expensive at Auto Zone. HTH Smile


Blessings. Joe 1999 Chevy Suburban w/new optimizer 6500 TD and 1995 Chevy Cube van 6.5L. WWW.RillaBioFuels.com
WWW.RillaBioFuels.com
 
Location: Sterling Hts. Michigan USA | Registered: October 18, 2001Reply With QuoteReport This Post
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Thanks Joe,
I think you or someone else here told me that I may also have a finicky IP.
I guess for it's age, the IP may or may not go soon anyway. I can justify that repair, I just hope it aint too soon.

The PMD was there when I got it. I did raise it all I could with short aluminum tubing.
Tell me gauge of the wire and colors, and I'll solder and shrink tube a splice in the harness to move it up front.

For some reason, maybe because I let it drip back into the bowl all I can, It starts right up after a filter change. I'll remember to cycle the key if I need to. Thanks again for the reply.!!!!! Big Grin

Less Discouraged, now.
Brian


1996 K2500 4x4 6.5TD
 
Location: Southern Indiana USA | Registered: June 20, 2008Reply With QuoteReport This Post
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Brian,

I just moved my PMD to the front bumper on my 99 Sierra. The wires are 18 awg. There are two red wires, two black wires, one green wire, and one pink with black stripe. Don't mix up the blacks and reds.

Tom
 
Location: Sunrise, Florida | Registered: April 16, 2003Reply With QuoteReport This Post
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Thanks Tsquare,
Got it---Will do.

Brian


1996 K2500 4x4 6.5TD
 
Location: Southern Indiana USA | Registered: June 20, 2008Reply With QuoteReport This Post
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I am a little new to the diesel world. i have a 95 6.5 yukon going straight WVO. Filtering with 3450 RPM centrifuge heated to 150 +.

This optical sensor thing has me worried. Where is the lift pump? The PMD has been relo'd. I know where the inline pump is but where is the lift pump? I like the re-wire idea, is it possible to hook up an intertia cut off like the new gas fuel pumps in case of a wreck?
Just wire the fuel pump relay to a hot at igninition source and you'll be good.

For things like this I've found the GM-Diesel.com site very good. Hanging there a lot too...

Paul[/QUOTE]
 
Registered: August 20, 2008Reply With QuoteReport This Post



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The lift pump is on the frame rail under the driver's seat. Just look underneath, follow the fuel line up and you'll see a small metal cannister that the fuel line goes in and out of, and two wires going to it. At least that's where it is on my Suburban.

When you say "going straight wvo" do you mean you have a 2 tank system? If not, if you try to burn straight wvo from the diesel tank you'll kill your injection pump after just a few miles.


'97 GMC Suburban 2500 - 6.5 turbodiesel - 203,000 miles
2-Tank WVO conversion
 
Location: NH | Registered: August 24, 2008Reply With QuoteReport This Post
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Anyone know where i can get a new optical sensor? Ive heard of people replacing just the sensor, but im not sure where to get it.


Jon

1995 GMC Sierra k2500 6.5 TD

http://bayareabiodieselsupply.com/
 
Registered: April 25, 2007Reply With QuoteReport This Post
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