98 T/C..car starts but shuts off

[nomiezvr4]

Hey guys I have a 98 Town and Country with a 3.8L with about 90k miles on it.

The other day I was sitting at a stoplight and the car just shut off. When I cranked it, its started right up but it turned off after a second or two. If I start it and dont give it gas, it turns off. If I give it gas it stays running.

I did a little searching and I found that the throttle body gets dirty over time. So I removed it and cleaned it with carb cleaner. I also slightly sprayed some into what I believe was the IAC. There are only 2 sensors..one is the Throttle Position sensor so Im guessing the other is the IAC. Everything seemed to be working OK for a day or two but now its doing the same thing again. The problem is more prevalent on cold starts in the morning. My mom says that when the car is warmed up it tends not to shut off, though when it does or doesn't is still random.

FYI no check engine light.

Anyone have any ideas?

Thanks

Nomie

[nomiezvr4]

bump

[Rawtorque]

This could be a number of things; TPS, IAC, EGR stuck slightly open, worn out spark plugs, even a clogged fuel injector. You can check the TPS with an ohmeter by watching the resistance as you open the throttle (engine off!), it must have no glitches.

[nomiezvr4]

Originally Posted by Rawtorque

This could be a number of things; TPS, IAC, EGR stuck slightly open, worn out spark plugs, even a clogged fuel injector. You can check the TPS with an ohmeter by watching the resistance as you open the throttle (engine off!), it must have no glitches.

The spark plugs and wires are under 1k miles old. Ill check the resistance of the TPS and get back to everyone..thanks

Nomie

[nomiezvr4]

Well..I have narrowed down the problem somewhat.

Here is the thing. This is a specifically a cold start problem. When the car is warm it starts up fine w/out any trouble. I checked the fuel pressure at cold start up, it is solid at 47psi which is completely within spec. Im hoping that eliminates the clogged fuel injector/filter problem.

I also unplugged the connector for the IAC, didn't change a thing. Only the CE light came on. Car still wanted to shut off.

I know when the car is cold it requires a little more fuel at startup, different timing maps, spark advance, etc...so I changed the coolant temp sensor, unfortunatly it didn't help too much. What else plays a factor on cold start up? Any ideas?

Thanks

Nomie

[Rawtorque]

This could also be a vacuum leak. Also, a fuel pressure gauge won't tell you if you have a clogged injector. Get some Techron or other good fuel system cleaner & use it. It' worth the peace of mind when trouble shooting.

The Mass air flow (MAF) sensor might also be to blame, although it should cause stumbling hot & cold. One way to see if it's bad is to knok it with a screwdriver handle when it's idling. If it dies, the MAF is bad.

[nomiezvr4]

From what I understand these cars dont have a MAF they have a map sensor. I have already looked around for vacumn leaks and found none.
Anything else?

[Stretch58]

Originally Posted by nomiezvr4

Well..I have narrowed down the problem somewhat.

Here is the thing. This is a specifically a cold start problem. When the car is warm it starts up fine w/out any trouble. I checked the fuel pressure at cold start up, it is solid at 47psi which is completely within spec. Im hoping that eliminates the clogged fuel injector/filter problem.

I also unplugged the connector for the IAC, didn't change a thing. Only the CE light came on. Car still wanted to shut off.

I know when the car is cold it requires a little more fuel at startup, different timing maps, spark advance, etc...so I changed the coolant temp sensor, unfortunatly it didn't help too much. What else plays a factor on cold start up? Any ideas?

Thanks

Nomie

Some of the others may have additional ideas, but if you disconnect the IAC and nothing changes other than a CE light, that would tell me it is not doing much at idle and might be a good place to start.

[1thunder]

it is a good suggestion from stretch but with then engine warmed up and at idle with no accessories on the ais motor normally just sits at whatever step or position the pcm designated it to be at to maintain idle rpm and it usually wont change the idle speed when disconnecting it i have viewed and monitored this many times with my DRB3 scan tooland also tried this also i'm not contradicting stretch's suggestion and you could have a bad ais motor .Remember if you do replace it make sure the throttle body is clean around the throttle plate bore and disconnect the battery for at least 1 hour in order to reset all the addaptive memories and make sure you have a good battery and charging system