randall L

Replaced the CPS, Ignition coil, & today the TPS. Got it adjusted.

I can drive her 5 miles, switch it off & she won't start. Wait till she cools a little & fires right up.

Drive back 5 miles to the house, switch her off.......no start. Till she cools down. Runs perfect when running.

I'm lost

BlueRidgeMark

Been fighting a similar problem.


First, warm it up so that it won't start. Now check to see if you get any spark when you try to start it.

If you have spark, start looking at fuel system issues. If no spark, start looking at ignition issues.

Here's the fancy specialized tool you you need to isolate the problem: A big bag of ice.

1. Take the ice with you.
2. Drive it until it's warm.
3. Park someplace safe.
4. Verify it's not starting.
5. Now ice the suspect component. Ice it good.
6. Try to start.
7. If it starts, repeat the test to make sure. Do it a few times.
8. If it doesn't start, repeat the test, but ice a different component.

I used this method to isolate my problem to my PCM. Haven't had time to fix it yet, because it's fine in cold weather. Yours is worse, obviously.

VTJeep

What about using a can of compressed air (upside down) to cool it off? Too rapid?

randall L

Would a bad cat. converter have anything to do with a warmed no start?

Cherockee

A clogged cat could cause a simular symptom as to what you are seeing. But usually a clogged cat will cause a drop in preformance until the point it shuts the engine down. Once pressure is released from the exhaust system (usually by just letting it sit a while) it will start back up and run okay for a bit and then do the same thing again. How badly it's clogged will determine how long it will run fine, so the fact you can do short trips may not be telling the whole story.

As mentioned, a faulty sensor can cause these symptoms too. Most noteably the CPS. I know you said you replaced it, was the orginal one bad or did you replace it trying to fix this problem? Is it genuine Mopar part? If not you may want to replace it with one that is.

randall L

I replaced the TPS with a Mopar. The new TPS didn't help. I have noticed the cat. conv. rattling & getting louder so I need to check & see if it's just loose or a larger issue there.

BlueRidgeMark

Probably won't get it cool enough. There's an aerosol product you can get at some electronics supply houses that is made for cooling circuits to test for thermal faults, which might work, but again, I'm not sure you'd get it cool enough. You are talking about a lot more mass than with bare circuit boards.





Random parts swapping might eventually fix the problem, but it's sure the long and expensive way to a solution. Too bad it seems to be the preferred method on these forums.

Thinking it through and TESTING your way to a solution is more certain and much, much cheaper. For some reason it's not very popular.

cruiser54

Injectors may be leaking down when shut off. Have you done a fuel pressure test to see how well they hold pressure after shut-off?

Your PM said it runs rough on starting warm, correct?

The Rooster

He changed it because it was 23 years old not because he thought it was part of the problem he did it for peace of mind.. Read more carefully.. Please ...we tell people not to replace random parts have a great day and we are not the masses...

Turbo X_J

"she won't start.
switch her off.......no start"
I'm lost

So I'm I......
Either:
1) your trying to say the starter will not turn the engine over.
2) your trying to say the engine has no fuel.
3) your trying to say the engine has no spark.
Communication is the key to this, so whats missing?

randall L

Right on rooster. I'm not throwing parts. I bought this thing June on last year & have been slowly restoring her.
Some parts have been replaced because of age(piece of mind) & some cause of mal-function.
New tires,brakes,headliner,all bulbs & lights,in dash stereo & speakers, weatherstripping,window tint & paint job.
Under the hood.......pulled engine & replaced all freeze plugs,rear main, timing chain seal,valve cover gasket,plugs,wires,dizzy,rotor,fuel filter,radiator,thermostat,tension pulley,heater hoses,front & rear vacumn harness,AC comp,fuel regulator,new BOSCH injectors cause 2 were leaking,CPS & the list goes on.
This weekend the cat. converter comes off.
All of Cruisers ground re-fresh has been done as well as cleaned all connectors.
Right now my largest issue is this dang "drive 5 miles thermal issue".

Turbo X_J

Whoa, did the vehicle have this issue before it was torn apart and put back together? That changes things a lot.

randall L

what's missing is the difference between CRANK & START when it's at normal operating temp vs cool.
Communication is the key........I said START

randall L

Always been there. Slowly became worse. It's been on both sides of the injector change. When I got her it would be just now & then. It's constant now. Even after a 5 or 5o minute drive.

Turbo X_J

So if it has fuel, spark, and little good ole O2, it will "start" right up, whats the problem?