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Puff of smoke when I mash on the accelerator (81 VW Caddy)
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I'm a bit new to the Caddys (1980, 1981 1.6L Non-Turbo) and small Diesel engines.

One thing I've started to notice is that when I push the pedal to the metal, I see a pretty gnarly puff of black smoke in my rear-view mirror.

I'm noticing it mostly on freeway onramps, but perhaps it is less obvious elsewhere.

I imagine it is partly my fault with upshifting too quickly, and not downshifting frequently enough.

However, I'm wondering if it is a fundamental flaw with the design of injected engines, and what has led to the stigma against small Diesel Engines in the USA.

I.E. With a carbureted gasoline engine, the fuel/air mixture is pretty much determined by the venturi, and the engine speed is regulated by the amount of the fuel/air mixture let into the cylinder.

In a traditional, mechanical injection Diesel engine,
The air intake is pretty much wide open, and unregulated (primarily varies with engine speed).
The amount of fuel injected varies with the accelerator.

So, with the gasoline engine, the venturi can handle a wide range of air flows, and can even handle a turbocharger/supercharger reasonably well.

With the traditional injected Diesel Engine, on the other hand, it is much harder to match the correct air/fuel mixture with the engine speed. Thus, one is often running either lean or rich.

I guess my question is what, if anything, can I do about it other than altering my driving style?

I was thinking of adding an electric turbocharger/supercharger wired into a feedback loop to maintain the optimum fuel/air mixture. But, I guess that is essentially what has been done with modern TDI engines.

So...
What years/engines have the proper feedback to burn cleanly under a variety of conditions, and under load?
 
Location: Oregon | Registered: October 17, 2007Reply With QuoteReport This Post
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I have a /87 1.6 turbo and can experience the same effect,I just don't mash it. When this starts to happen it's usally the injection pump going out of calabration. The turbo on mine has a hose from the intake to the injection pump so it can sense the boost and alter the amount of fuel going in to go with the higher charge of air.

Just boosting the air charge probably won't gain a lot of power but it could clean up the smoke. It might be cheeper to rebuild the Injection pump than install a turbo/supercharger. I can do mine for 700 bucks up here and I would also suggest changing the injectors as well if they have a lot of miles on them, they should be under 50 bucks apeice and I've heard as low as $30 and they're not hard to change. The turbo uses a different injector as well.

It's not a fundemental problem with the diesel but more of a wear problem. These engines were quite clean from the get go.


21 years off the grid and counting

 
Location: Muskoka, Ont, Can | Registered: March 23, 2003Reply With QuoteReport This Post
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Thanks for the reply.

I can buy VW Injector Cores for about $10 each, so that is probably my next order of business.

I'd like to build a "pop tester" in the next few weeks to help with testing and rebuilding my injectors.

The pickup does well when running light, as long as I'm careful with the accelerator.
But, it has serious problems with smoking when pulling a heavy load.
 
Location: Oregon | Registered: October 17, 2007Reply With QuoteReport This Post
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quote:
I'd like to build a "pop tester" in the next few weeks to help with testing and rebuilding my injectors.



Love to hear how that works out. What do you plan to use for the pump plunger?


21 years off the grid and counting

 
Location: Muskoka, Ont, Can | Registered: March 23, 2003Reply With QuoteReport This Post
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There's a 6 mm fuel adjustment bolt on the distributor head end of the pump that may help with the black smoke. Loosen the locknut first (I think it's 13 mm), ccw = less fuel, cw = more fuel.
 
Registered: May 08, 2005Reply With QuoteReport This Post
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quote:
Originally posted by 12voltdan:
quote:
I'd like to build a "pop tester" in the next few weeks to help with testing and rebuilding my injectors.
Love to hear how that works out. What do you plan to use for the pump plunger?
There are several design notes about making POP testers on the internet.

http://biodiesel.infopop.cc/ev...11024582&r=860105721
http://www.peachparts.com/shop...wthread.php?t=224334

I was just planning on getting a "hand hydraulic pump" as shown in the Biodiesel.infopop.cc page. However, I'm wondering if it would be "more fun" to try to rebuild a small jack as done on the peachparts page.

Reading the description by cornblatt, it sounds like there is an advantage of the jack based tester in that the jack cylinder acts like a reservoir to even out the pressure surges of hand pumping & release process. This may not be true of the hydraulic ram pumps.

Whew...
3000 psi to work with!!!!!!!!!
 
Location: Oregon | Registered: October 17, 2007Reply With QuoteReport This Post



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Your pump timing could be advanced. If your pump is not leaking don't consider rebuilding. I have 2 TDI Passats one with 402,000 and 307,000 miles original pumps, never off engine.
 
Location: Va. | Registered: June 25, 2005Reply With QuoteReport This Post
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quote:

I was just planning on getting a "hand hydraulic pump" as shown in the Biodiesel.infopop.cc page. However, I'm wondering if it would be "more fun" to try to rebuild a small jack as done on the peachparts page.



I never thought of using a port a power, cool

one thing I would add a manual valve between the pump and the gauge so you can check leak down.

The only tester I ever used was an old CAV unit that looked like it was made in the 50's

it worked just fine and I rebuilt a lot of injectors with it. It's still in use today but not by me, unfortunetly


21 years off the grid and counting

 
Location: Muskoka, Ont, Can | Registered: March 23, 2003Reply With QuoteReport This Post
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Thanks guys for the suggestions.
I haven't gotten the POP tester built yet. That is still on the agenda.

However, I checked the ignition timing.

According to the Bentley Manual... for the 81/82, they listed a "standard setting" and "Improved Performance" setting.

Measuring movement of the cam in the IP,

Standard Setting: .0327in to .0366in
Improved Performance: .0366in to .0406in

Mine was at .036in.

I found the chart on the internet:



Looking at the graph.
Advancing the ignition increases the NOX emissions, but also significantly reduces everything else (CO, Hydrocarbons, and Fuel Consumption). I linked to this on a Diesel site, I assume it is meant for Diesels.

So, I decided to set my timing slightly advanced, but within the "Improved Performance" range.

Also, as suggested above.

My IP had the throttle limiter bolt completely removed when I bought the pickup.
I went ahead and put that back in a few weeks ago (borrowing the idle limiter), with only helping the issues a bit.

According to Bentley, it should be set based on the no-load RPM's. But, I don't have a good tachometer for a Diesel.

Anyway, I've now got it set so that the only smoke I can see is a tiny puff when I mash on the pedal... from standstill, enough to squeak the tires in 1st gear... then everything else is fine. And, it still seems to have some get-up-and-go empty.

And, dropped the idle speed down a little bit too.

I'll need to do a little more testing, (like getting out on the freeway), as well as hooking up my trailer again.




The lathe looks small, but it is deceptively heavy. Enough that my Tractor didn't like carrying it at all. Note position of lathe, Left Rear in the air, and Right Front smashed to the rim.



We'll see how I do for now.

I'm still trying to decide if I wish to track down a 1.6 Turbo, 1.6 "Eco" Turbo, 1.9 Turbo, or a 2.0 Turbo to put in it.

There is a SWEET 2.0L Turbo on E-Bay right now...
Says it only has 7 Miles.
I'm trying to figure out if it was a crash-test vehicle, or managed to get totaled pulling out of the Dealership Parking Lot.

http://cgi.ebay.com/ebaymotors...fPartsQ5fAccessories

My only problem is that the 2009 Jettas and Golfs get worse fuel mileage than the '80-something Rabbits and Caddies.

I suppose for now, I should try to make the 1.6 work for me before trying any big changes.
 
Location: Oregon | Registered: October 17, 2007Reply With QuoteReport This Post
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I've set my car up to deliever black smoke on diesel fuel.Its less or none on grease.


126 diesels yahoo groups
83 SD straight exhaust 94 Cobra
Cold air,real cold.Cobra electric radiator fan,Monark nozzles,10 psi electric fuel pump.85 amp alternator 12" subs.23 psi boost, 30 micron filter,an 5 micron filter added
2 tank,wvo,boost guage ,line heaters,coolant heater Fattywagons customer. 99 S320 with 75 more hp.
 
Location: Bristol Tennessee | Registered: January 05, 2008Reply With QuoteReport This Post
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quote:
Originally posted by keelec:
I'm a bit new to the Caddys (1980, 1981 1.6L Non-Turbo) and small Diesel engines.

One thing I've started to notice is that when I push the pedal to the metal, I see a pretty gnarly puff of black smoke in my rear-view mirror.

I'm noticing it mostly on freeway onramps, but perhaps it is less obvious elsewhere.

I imagine it is partly my fault with upshifting too quickly, and not downshifting frequently enough.

However, I'm wondering if it is a fundamental flaw with the design of injected engines, and what has led to the stigma against small Diesel Engines in the USA.

I.E. With a carbureted gasoline engine, the fuel/air mixture is pretty much determined by the venturi, and the engine speed is regulated by the amount of the fuel/air mixture let into the cylinder.

In a traditional, mechanical injection Diesel engine,
The air intake is pretty much wide open, and unregulated (primarily varies with engine speed).
The amount of fuel injected varies with the accelerator.

So, with the gasoline engine, the venturi can handle a wide range of air flows, and can even handle a turbocharger/supercharger reasonably well.

With the traditional injected Diesel Engine, on the other hand, it is much harder to match the correct air/fuel mixture with the engine speed. Thus, one is often running either lean or rich.

I guess my question is what, if anything, can I do about it other than altering my driving style?

I was thinking of adding an electric turbocharger/supercharger wired into a feedback loop to maintain the optimum fuel/air mixture. But, I guess that is essentially what has been done with modern TDI engines.

So...
What years/engines have the proper feedback to burn cleanly under a variety of conditions, and under load?


Could this be considered as a diesel runaway?? A puff of smoke appeared and oil came out from the air intake and also the exhaust plus RPM surge up to 4k... From what I’ve known diesel engine runaway is a state wherein the engine loses its control, runs at high rpm while its consumes its own oil lubrication that causes it to get destroyed due to lack of lubrication (engine seizure) or mechanical failure.. Does the crankcase breather pipe really feeds into the air intake to vent the crankcase in most engines? How could traces of oil on the air intake pipes relate to this problem?

This message has been edited. Last edited by: AR,
 
Registered: March 15, 2011Reply With QuoteReport This Post
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