Help me get rid of the PT Cruiser

This is a long story. The short version is that I need to fix a weird issue it has before I try to sell it. See this:

http://grassrootsmotorsports.com/forum/grm/obd2-scanners-not-code-readers/31738/page2/

Done? Cool. It still does it. Yes it was two years ago. yes, I drove it and didn't care. I may be selling it soon and need it to be right to get rid of it easily.

Essentially it's a 'rough idle'. In the cold especially, idle will oscillate and hunt for about ten-thirty seconds before settling in. When warm it's much better. You hardly notice it. If you drag your foot off the brake with a slight throttle input (very slight) you get a neat shudder.

I've probed and poked. The wires and plugs were done not too long ago, the intake and all rubber in the area looked great. I tried a new IAT, the scanner says it is getting close to needing a downstream O2 sensor, cleaned the IAC, and no dice.

And...

GO!

Sounds like it might be a temperature sensor problem. Sort of takes the place of the choke and manifold heat on a carburetor car.

iceracer wrote: Sounds like it might be a temperature sensor problem. Sort of takes the place of the choke and manifold heat on a carburetor car.

IAT = intake air temperature

The other one works the gauge, right? That one works fine if I can reliably tell by reading the gauge and seeing when the radiator fan comes on.

Typically there will be two separate engine temp sensors. One for the gauge, or possibly idiot light, and a separate one for the ecm.

Also, you said the sparkplugs were good, but what type are they? I know that a lot of modern engines are finicky about sparkplugs and often the oem plugs will be the only ones that they really like. I have no personal experience with Chrysler products and plugs, but I know that its true for SAABs and some Nissans.

Ever do the rear 02? They actually do control fuel trims on a chrysler. Rear should stay around 600mv. What year is it? And is the o2 your only code? But, the car ignores to o2s until they warm up, so....

HappyAndy wrote: Typically there will be two separate engine temp sensors. One for the gauge, or possibly idiot light, and a separate one for the ecm. Also, you said the sparkplugs were good, but what type are they? I know that a lot of modern engines are finicky about sparkplugs and often the oem plugs will be the only ones that they really like. I have no personal experience with Chrysler products and plugs, but I know that its true for SAABs and some Nissans.

OEM type, and the issue was consistent before and after the swap.

So I have to figure out which sensor is bad? I don't have any idiot lights on, the gauge is fine, the coolant sensor still turns on the fan at the right time, and the AIT didn't fix it. What else is there?

Jaxmadine wrote: Ever do the rear 02? They actually do control fuel trims on a chrysler. Rear should stay around 600mv. What year is it? And is the o2 your only code? But, the car ignores to o2s until they warm up, so....

2001, have not changed it.

no code on the rear O2, it just barely fails the mode 06 tests. Reading the data, it does work, it's just lazy.

You should see if there is a temp sensor just for the ECU. It should measure temp in the head. This is separate from the one that turns on the fan's or the gauge and from the AIT. I tells the ECU how to control the fuel mixture on cold start up.

dean1484 wrote: You should see if there is a temp sensor just for the ECU. It should measure temp in the head. This is separate from the one that turns on the fan's or the gauge and from the AIT. I tells the ECU how to control the fuel mixture on cold start up.

According to Rockauto (I know) it's got one for the overhead temeprature readout (works fine), one for the gauge (works fine) and one for the incoming air (replaced to no avail).

If I'm right, by 2000 or so the one for the gauge is the same as the one used by the ECU to determine if the engine is up to operating temp or not. The gauge will be getting its data from the ECU, not direct from the sender.

What are you running for spark plugs? I've seen weird problems that usually show up as misfires when running plugs other than Champs in Mopars. They don't always trip a code though.

tuna55 wrote:

iceracer wrote: Sounds like it might be a temperature sensor problem. Sort of takes the place of the choke and manifold heat on a carburetor car.

IAT = intake air temperature The other one works the gauge, right? That one works fine if I can reliably tell by reading the gauge and seeing when the radiator fan comes on.

There are two temperature SENSORS and on temperature SENDER. The sensors are coolant and air intake. these feed information to the ECU which then detremins proper fuel and ignition. The sender is for the temperature gauge, it has no effect on proper running.

Rob_Mopar wrote: If I'm right, by 2000 or so the one for the gauge is the same as the one used by the ECU to determine if the engine is up to operating temp or not. The gauge will be getting its data from the ECU, not direct from the sender. What are you running for spark plugs? I've seen weird problems that usually show up as misfires when running plugs other than Champs in Mopars. They don't always trip a code though.

Aww crap I was wrong, it has Bosch +4 spark plugs - I just checked my records. It was the Volvo that got Champs. I am pretty sure the problem existed beforehand, though. I guess it's cheap enough to try throwing them in - do have to pull the intake, though...

iceracer wrote:

tuna55 wrote:

iceracer wrote: Sounds like it might be a temperature sensor problem. Sort of takes the place of the choke and manifold heat on a carburetor car.

IAT = intake air temperature The other one works the gauge, right? That one works fine if I can reliably tell by reading the gauge and seeing when the radiator fan comes on.

There are two temperature SENSORS and on temperature SENDER. The sensors are coolant and air intake. these feed information to the ECU which then detremins proper fuel and ignition. The sender is for the temperature gauge, it has no effect on proper running.

Find me a part number - I think you may be mistaken.

How many miles are on it?

You want to get rid of just the one you own, not each and every one currently in existence, right? We're not talking about automotive genocide here, are we?

moparman76_69 wrote: How many miles are on it?

150k

1988RedT2 wrote: You want to get rid of just the one you own, not each and every one currently in existence, right? We're not talking about automotive genocide here, are we?

nah - it's uggo, for sure, but it's a very useful, very reliable and cargo-efficient (if not very fuel-efficient) ride.

Lose those Bosch plugs immediately if not sooner, those things have caused cold running problems in every brand of car I've ever worked with except Mercedes. The other thing: has the timing belt been replaced? If it hasn't do it quick. If it has, it's worth verifying the cams are timed properly in relation to each other.

tuna55 wrote:

1988RedT2 wrote: You want to get rid of just the one you own, not each and every one currently in existence, right? We're not talking about automotive genocide here, are we?

nah - it's uggo, for sure, but it's a very useful, very reliable and cargo-efficient (if not very fuel-efficient) ride.

Agree. I once had one as a loaner, and I felt that it was a kind of spiritual successor to the K-car wagon.

Curmudgeon wrote: Lose those Bosch plugs immediately if not sooner, those things have caused cold running problems in every brand of car I've ever worked with except Mercedes. The other thing: has the timing belt been replaced? If it hasn't do it quick. If it has, it's worth verifying the cams are timed properly in relation to each other.

Damn - ok. I'll do it.

Did the timing belt a few years back. Twice. I am pretty sure the timing is right as of the second time. Woohoo!

You just want rid right?

In reply to Adrian_Thompson:

Cannot see at work, but I see it's named "arson" - I'm not in for insurance fraud, and I need the few thou for other uses, so, if enough of you pitch in to see the resulting video, I'm in, but otherwise nah.

1988RedT2 wrote:

tuna55 wrote:

1988RedT2 wrote: You want to get rid of just the one you own, not each and every one currently in existence, right? We're not talking about automotive genocide here, are we?

nah - it's uggo, for sure, but it's a very useful, very reliable and cargo-efficient (if not very fuel-efficient) ride.

Agree. I once had one as a loaner, and I felt that it was a kind of spiritual successor to the K-car wagon.

It's better than that, is is a neon wagon!

tuna55 wrote:

moparman76_69 wrote: How many miles are on it?

150k

Was the timing belt done at 100k? If yes then maybe the timing is off if not is a ticking time bomb and you should look into doing the timing belt drive?

moparman76_69 wrote:

tuna55 wrote:

moparman76_69 wrote: How many miles are on it?

150k

Was the timing belt done at 100k? If yes then maybe the timing is off if not is a ticking time bomb and you should look into doing the timing belt drive?

Did it at 120k. Started it, it was wrong. Did it again, this time it was right.