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Author Topic: '98 Jetta misfire on cold start, lacking power when cold  (Read 3527 times)

November 27, 2013, 07:56:42 am

CrazyAndy

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'98 Jetta misfire on cold start, lacking power when cold
« on: November 27, 2013, 07:56:42 am »
Hi all,

So I finally broke down and bought a modern car, a 1998 Jetta TDI.  Some history on the car:  Guy bought it w/ broken timing belt, bought rebuilt head, new injectors and glow plugs, and head gasket (I asked him about the notches, he said original HG was 2-notch, and that is what's on the car now).  It needs a new starter switch, and the PO before him, installed a remote button to get it started.  Also, for some reason, installed an Audi radio of comparable vintage.  Got it home 98 miles, and the very next morning started having a misfiring issue when starting cold (16 deg F).  It is repeatable, happening every time it starts after sitting for over 5-6 hours.  The first 2-3 starts it dies after stumbling for about 5 seconds, with blue/white smoke coming from the tailpipe.  After eventually getting it to start and idle, attempting to accelerate, either from a stand still or while moving, causes it to stumble and die again.  Once I let it run for a bit I am able to accelerate without it bogging down, but feels gutless until about 2400 rpm, with smoke front he tailpipe and sometimes feeling like the turbo is not spooling.

Checked so far:
-Pump cog and cam timing (OK)
-Pump internal timing w/ VAG-COM (over advanced, readjusted; problem still persists)
-Will install fuel filter today

What the hey could be causing this issue?  Could the PO have botched the head job (what I'm leaning towards)?  Could I have air getting into the pump (saw some bubbles from filter feed line; tightened clamp and diminished; hope internals aren't cavitated)?  Is there a sensor that can go bad, causing this to happen?  Ignition switch causing this, or K-wire feedback due to wrong radio?  I know this thing can run good, It's done it before.  Any ideas would be appreciated.

Thanks!




Reply #1November 27, 2013, 08:03:40 am

RabbitJockey

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Re: '98 Jetta misfire on cold start, lacking power when cold
« Reply #1 on: November 27, 2013, 08:03:40 am »
more than likely, it is just air in the line.
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Reply #2November 27, 2013, 08:05:48 am

CrazyAndy

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Re: '98 Jetta misfire on cold start, lacking power when cold
« Reply #2 on: November 27, 2013, 08:05:48 am »
Or a seal in the pump letting it in, an unlikely but possible alternative.  I'll update after fuel filter install.  Are there any parts of the MK3 fuel system besides the pump inlet and return lines that like to leak?  Injector return lines?


Reply #3November 27, 2013, 09:00:24 am

theman53

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Re: '98 Jetta misfire on cold start, lacking power when cold
« Reply #3 on: November 27, 2013, 09:00:24 am »
I would guess the air in the pump would help starting. It maybe that the compression is down and after their head work they decided to get rid of it? I would pull the injectors once you have it hot and do a check. It won't hurt anything. Definitely fix your air.

Also as a side note when they did the head, did they used new nozzles in the injectors? If not I would say it is due.

Reply #4November 27, 2013, 09:28:24 am

libbydiesel

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Re: '98 Jetta misfire on cold start, lacking power when cold
« Reply #4 on: November 27, 2013, 09:28:24 am »
So I finally broke down and bought a modern car, a 1998 Jetta TDI.

Ha ha, that's funny.  15 years old isn't exactly modern.  It's more than halfway to being an antique car!
Use, abuse or ignorance of any information is at your own risk, confirmation or refutation is your own responsibility, no further 'proof' will be given, take it or leave it, YMMV,terms subject to change without notice, avoid contact with eyes or skin, contents known to cause cancer in California

Reply #5November 27, 2013, 09:31:11 am

theman53

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Re: '98 Jetta misfire on cold start, lacking power when cold
« Reply #5 on: November 27, 2013, 09:31:11 am »
So I finally broke down and bought a modern car, a 1998 Jetta TDI.

Ha ha, that's funny.  15 years old isn't exactly modern.  It's more than halfway to being an antique car!

funny but that is the way I see it too, anything newer than 90 seems pretty new to me

Reply #6November 27, 2013, 10:36:39 am

libbydiesel

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Re: '98 Jetta misfire on cold start, lacking power when cold
« Reply #6 on: November 27, 2013, 10:36:39 am »
I remember when I was a kid, when my folk's car was 10 years old it was OLD.  Now my '02 Jetta wagon seems like a spaceship.
Use, abuse or ignorance of any information is at your own risk, confirmation or refutation is your own responsibility, no further 'proof' will be given, take it or leave it, YMMV,terms subject to change without notice, avoid contact with eyes or skin, contents known to cause cancer in California

Reply #7November 27, 2013, 12:46:29 pm

CrazyAndy

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Re: '98 Jetta misfire on cold start, lacking power when cold
« Reply #7 on: November 27, 2013, 12:46:29 pm »
So I finally broke down and bought a modern car, a 1998 Jetta TDI.

Ha ha, that's funny.  15 years old isn't exactly modern.  It's more than halfway to being an antique car!

I DROVE an antique before this.  This has heat, power steering, a radiator, an ECM, A/C, and a radio that has more than 2 speakers.  It's modern (enough). :)


Reply #8November 27, 2013, 03:17:41 pm

ORCoaster

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Re: '98 Jetta misfire on cold start, lacking power when cold
« Reply #8 on: November 27, 2013, 03:17:41 pm »
Sounds like classic fuel filter plug creating a vacuum on run then when it sits air leaks back into pump causing start/run issues.

You could bottle feed it a while and see if that keeps it going or runs without the lag. 
Now Own 1981 Caddy as the NEW DISTRACTION to all that is around me.  Project Away!

Reply #9November 27, 2013, 06:14:21 pm

CrazyAndy

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Re: '98 Jetta misfire on cold start, lacking power when cold
« Reply #9 on: November 27, 2013, 06:14:21 pm »
Update on runing concern:

R and R fuel filter; concern persists.  Tested flow before and after fuel filter replacement; low flow in both tests.  R and R pressure line to ECM for fault '65535 - Internal Control Module Memory Error' as per http://www.myturbodiesel.com/1000q/a3b4/ecu-hose-chip-tdi-65535.htm (pretty nice 1000q); concern persists.  Visually inspected body fuel supply lines from filter to fuel pickup tube; no external damage present.  Next diagnosis step is bottle feed test as per ORCoaster recommendation, and in-tank fuel pickup flow test.


Reply #10November 27, 2013, 06:25:18 pm

dieseljunkie69

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Re: '98 Jetta misfire on cold start, lacking power when cold
« Reply #10 on: November 27, 2013, 06:25:18 pm »
Next diagnosis step is bottle feed test as per ORCoaster recommendation, and in-tank fuel pickup flow test.

It has been ten minutes.

How did this workout?  ;D
I'm That Guy.

Reply #11November 27, 2013, 07:55:52 pm

745 turbogreasel

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Re: '98 Jetta misfire on cold start, lacking power when cold
« Reply #11 on: November 27, 2013, 07:55:52 pm »
Isn't that car supposed to have an electric lift pump?

Reply #12November 27, 2013, 10:46:51 pm

CrazyAndy

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Re: '98 Jetta misfire on cold start, lacking power when cold
« Reply #12 on: November 27, 2013, 10:46:51 pm »
Next diagnosis step is bottle feed test as per ORCoaster recommendation, and in-tank fuel pickup flow test.

It has been ten minutes.

How did this workout?  ;D

Ran out of time, temperature, and daylight.  I'll try Friday and/or Saturday, as tomorrow I have Thanksgiving family crap to do.

Isn't that car supposed to have an electric lift pump?

Nope, that's Mk4's, Mk3 and B3/4 TDIs still relied on the pump's own internal vacuum to draw fuel.  Sucks, don't it?  I could install a lift pump, but that is dependent on if the pickup filter is clogged or not obviously.

P.S.:  Anyone got a lead on new or good used Mk3 TDI Jetta fuel sender assemblies?  I have a bad feeling these things are NLA, as google searches on the part number just turn up Chinese copies.  No tank you.


Reply #13November 28, 2013, 01:12:26 am

745 turbogreasel

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Re: '98 Jetta misfire on cold start, lacking power when cold
« Reply #13 on: November 28, 2013, 01:12:26 am »
If you have a lift pump, I'd install it temporarily  as a fast way to do a leak check

Reply #14November 28, 2013, 06:40:50 am

CRSMP5

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Re: '98 Jetta misfire on cold start, lacking power when cold
« Reply #14 on: November 28, 2013, 06:40:50 am »
 ::)

bad glow harness... kicks on light.. one or 2 plugs dead.. so colder then others an dmisses makes smoke..

 

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