Engine cut out

partwerks · Posted: Mon Aug 25, 2014 9:13 pm Post subject: Engine cut out

Within the first 4 minutes of a cold engine, my 96 VW Jetta, has this thing where it will intermittently cuts out. If you happen to be stopped, one of two things, if you let it run it's course, then the idle will fluctuate up and down from about 700 to 900 for about 5 seconds, or there abouts, and then the idle goes high to about 1200, for about 5 seconds, and comes down to normal idle.

On the other hand, if you slam the pedal down, and let back up quck, it tends to clear it out, and everything is normal. Otherwise, it runs just fine once it has it's fit.

I've cleaned all the grounds that I know of, and replaced the coolant temp sensor, and throttle body, but not sure what is causing it??

I'm hoping someone might have an idea on what is causing it.

It would almost make me think that it is something that when it first warms up?

Any, thoughts, ideas, or suggestions?

Danwvw · Posted: Mon Aug 25, 2014 11:31 pm Post subject:

Almost sounds like a vacuum leak! Check those vacuum hoses on the manifold. Also it could need a new air cleaner. And Sometimes it's sparkplugs!
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1960 Beetle And 1679cc DP W-100 & Dual Zeniths!

partwerks · Posted: Tue Aug 26, 2014 5:05 am Post subject:

I'll check the hoses. I just put on new wires and plugs about 6 months ago, but have had the problem before that. New MAF sensor also.

Danwvw · Posted: Tue Aug 26, 2014 10:40 am Post subject:

My 924S started doing that after I changed the sparkplugs, then it just cleared up after a trip and using some stabilizer in the gas. Have you tried a fuel additive that will clean the injectors. Here is a resource http://www.pelicanparts.com/Volkswagen/index-SC.htm
_________________
1960 Beetle And 1679cc DP W-100 & Dual Zeniths!

partwerks · Posted: Fri Aug 29, 2014 8:00 pm Post subject:

Took it to the mechanic:

Ck codes17535, fuel trim bank 1, system too rich P1127, 16486 Mass air flow sensor signal too low PO102, found intake air hose off of throttle body, cleaned MAF sensor.

Only thing that didn't make sense, is if it is the hose that hooks to that brass fitting, as I recall, it was on there the first time I opened the hood to try and see what the whole ordeal was about. It doesn't pull off easy. Unless he was talking about some other hose, and/or was a bit loose or something, but runs good now...........

I don't see any other hose on the TB?

partwerks · Posted: Sat Sep 20, 2014 7:07 pm Post subject:

Got that problem fixed, but still has the original underlying problem, in the first few minutes, it has the fluctiating idle/cut out. Not sure what could be causing it. Doesn't happen all the time either. If you punch the pedal, it tends to clear it out.

ps2375 · Posted: Sun Sep 21, 2014 8:45 am Post subject:

Have you cleaned the TB?

partwerks · Posted: Sun Sep 21, 2014 9:10 am Post subject:

It was no more than a year ago I put on a new TB, but was an aftermarket one, but have had the issue, even when the original one was on. I could give it a cleaning as well.

ps2375 · Posted: Sun Sep 21, 2014 11:35 am Post subject:

If this is an OBDII motor, the TB has a little motor in it that controls the butterfly for idle control. If it is OBDI, there is an ISV valve on the manifold that controls idle. Sounds like one of those may have an issue, or you could still have a vacuum leak. The PVC valve on the VC and it's associated hoses would be the first things I'd inspect.

ps2375 · Posted: Sun Sep 21, 2014 6:05 pm Post subject:

VC= Valve Cover

If you have a silver cylinder with a hose going to it on the drivers side of manifold, that is the ISV. Try taking it off and cleaning it.

partwerks · Posted: Sun Sep 21, 2014 6:27 pm Post subject:

Whatever it is that is on the driver's side, looks like a pipe that is pressed into the manifold, and goes to the roundish brake thing by the brake reservoir, and on the opposite side, is a gizmo that screws into the manifold. I took it out, and is a bullet shaped piece. I don't know if it is made of plastic, but has a electrical connector that hooks to it.

I thought I read where the 96 does not have a ISV?

ps2375 · Posted: Sun Sep 21, 2014 8:11 pm Post subject:

The roundish thing by behind reservoir is the brake booster. The other "thing" with wires is the Intake Air Temp sensor. And OBDII should not have an ISV, but it seem you don't know what items under the hood are, so there is question as to what it is(at least to me).

How many wires are in the connector at the TB?

Do you have a service manual for this car? If you plan on doing your own work on it, I would highly recommend getting one.

partwerks · Posted: Mon Sep 22, 2014 6:04 am Post subject:

I counted 7 wires.

ps2375 · Posted: Mon Sep 22, 2014 8:03 am Post subject:

W/O looking in my manual, I would have to say your car is indeed OBDII. So, you don't/shouldn't have an ISV. I'm not sure if that TB needs an adaption procedure run on it to sync it with the ECU. I had best luck on those when they were cleaned well, any buildup of dirt/oil/carbon on the bore where the butterfly and bore meet can cause airflow issues that the TB has a harder time adjusting for.

partwerks · Posted: Mon Sep 22, 2014 5:56 pm Post subject:

I had put a new TB on, probably not even a year ago. I did clean that air temp sensor on the passenger side of the intake manifold, and for at least 2 cold starts, it has not acted up, so I don't know if that was part, or all of the problem? I cleaned it with mass air flow sensor cleaner. We'll see over a prolonged period of time what happens. I hope that was what the problem was?


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