Author Topic: smokey exhaust+rough starting  (Read 4842 times)

August 28, 2009, 03:15:47 pm

dieseldubber

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smokey exhaust+rough starting
« on: August 28, 2009, 03:15:47 pm »
Hi everyone,
My problems are smokey exhaust and rough starting. I recently installed brand new glow plugs and rebuilt injectors hoping to solve these problems. Checked the plugs with the injectors out and they all lit up. When I first started the engine after installing the injectors it coughed out a pile of carbon literally speaking. The smoke seemed to have reduced greatly until a week or two after and its back. The car starts and runs rough when cold even in hot weather. When the engine is warm it runs great. Pulling the cold start handle helps but I shouldn't have to in summertime! If I run it, park it and start it warm it fires right up perfectly but if I run it and let it sit for a while it seems to crank over a couple times before firing. I'm starting to think maybe pump timing is off? I will replace fuel and air filter as they are due and go from there.
As always your help is greatly appreciated.
Thanks,
Jay
'85 1.6TD JettaGL

Reply #1August 28, 2009, 04:21:45 pm

burn_your_money

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Re: smokey exhaust+rough starting
« Reply #1 on: August 28, 2009, 04:21:45 pm »
It's normal to have to pull out the cold start even in the summer time. Your timing could be a bit retarded though, it doesn't hurt to check.
Tyler

Reply #2August 28, 2009, 05:03:36 pm

dieseldubber

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Re: smokey exhaust+rough starting
« Reply #2 on: August 28, 2009, 05:03:36 pm »
never had to pull it out before in anything warmer than full on winter.
'85 1.6TD JettaGL

Reply #3August 28, 2009, 08:41:06 pm

8v-of-fury

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Re: smokey exhaust+rough starting
« Reply #3 on: August 28, 2009, 08:41:06 pm »
well how do you justify when you have to pull it out?  Diesel fuel needs really high temperatures to Combust fully.. like 400F or something like that. When you start it cold on a hot day at even say 110F its nowhere near optimal temperatures for a full burn on the fuel. Hence why you get plumes of grey smoke.. grey smoke is half burnt fuel coming out your tailpipe.

Whistler.. what's your elevation there? Maybe the air is too thin, and you are literally choking the car?

Reply #4August 28, 2009, 08:59:09 pm

burn_your_money

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Re: smokey exhaust+rough starting
« Reply #4 on: August 28, 2009, 08:59:09 pm »
It probably wouldn't hurt to check your GPs again. If they are put in too tight they just crap out
Tyler

Reply #5August 29, 2009, 01:14:26 am

rabbitman

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Re: smokey exhaust+rough starting
« Reply #5 on: August 29, 2009, 01:14:26 am »
My rabbit will crank slower if I pull the cold start out, if it's cold enough out I start the engine and then pull the knob, usually I don't pull it in the summer. If your knob helps some then you could get away from using it by advancing the timing but that might not be the correct fix.
'82 Rabbit, I put on a euro vnt-15, 2.25" DP, 2.5" exhaust, the result.....it whistled.

I removed the turbo, made a toilet bowl 2.5" DP, the result....it was deafening. Now it has a homemade muffler up front and a thrush in the rear, the result.....less loud.
Watch: AGENDA, GRINDING AMERICA DOWN

Reply #6August 29, 2009, 06:56:18 am

theman53

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Re: smokey exhaust+rough starting
« Reply #6 on: August 29, 2009, 06:56:18 am »
What year pump? My 81 you didn't have to do anything with the CS knob, but just get it to start the knob made no difference. My 86 I couldn't start in the summer without pulling it. Maybe had something to do with the advance springs??? I don't know, but I figure whatever the car wants thats what I give it.

Reply #7August 29, 2009, 12:51:27 pm

dieseldubber

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Re: smokey exhaust+rough starting
« Reply #7 on: August 29, 2009, 12:51:27 pm »
ok, the car is an '85 so no altitude adjustment feature. Whistler is at 2140ft. is that high enough to matter? I will check the glow plugs again but I dont think thats it. I know something is not right because I never used to have to pull that handle unless it was cold outside and it always fired right up, no cranking over a couple times like it does now. Its a little mysterious to me but I'll have to dig a little deeper. Thanks.
'85 1.6TD JettaGL

Reply #8August 29, 2009, 01:21:05 pm

burn_your_money

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Re: smokey exhaust+rough starting
« Reply #8 on: August 29, 2009, 01:21:05 pm »
You could have a fuel leak that is bleeding a bit of fuel out of the pump which causes the extra cranking. It would also cause rough running at startup
Tyler

Reply #9August 29, 2009, 06:30:06 pm

8v-of-fury

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Re: smokey exhaust+rough starting
« Reply #9 on: August 29, 2009, 06:30:06 pm »
You could have a fuel leak that is bleeding a bit of fuel out of the pump which causes the extra cranking. It would also cause rough running at startup

Werd. It will have to work the air out of the system.. and that will also cause the smoke. its probably just a small leak.

Reply #10August 29, 2009, 08:20:02 pm

dieseldubber

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Re: smokey exhaust+rough starting
« Reply #10 on: August 29, 2009, 08:20:02 pm »
You could have a fuel leak that is bleeding a bit of fuel out of the pump which causes the extra cranking. It would also cause rough running at startup
Ya, that could be it for sure. The BMW TD I owned briefly had a leaky pump and I experienced the same issues when starting but it was much worse and it was really leaking. I cant see any leaks here though...hmm?
'85 1.6TD JettaGL

Reply #11August 30, 2009, 04:48:24 am

smutts

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Re: smokey exhaust+rough starting
« Reply #11 on: August 30, 2009, 04:48:24 am »
Watch for bubbles as it first starts, I have a theory that if there is an air leak the diesel drains back to the tank when the car is left overnight. Also thinking about the fuel temperature thingy on the filter,  the diesel that is in the pump with the camplate and governer flailing about at 2000rpm gets warmed by this stirring. If the fuel temperature valve on the filter is warm, it sends the fuel and bubbles back to the tank. If it is cold, the valve sends the warmed fuel and bubbles back to the injector pump. This does bad things to the injection timing and spray. I have sorted the fuel pipes out on my red GTD and starting is much better. Air can get in through all the joints on the fuel filter and pump, but also through the spill pipes on the injectors. Good luck. ;D