TTA wont start when hot

[gethighracewear]

I'm just getting my TTA back on the road after sitting for almost 5 years. The car worked fine before I parked it. My car starts up fine when its cold, but after I drive it a few miles and it heats up to normal operating temperature (about 190) and I shut it off it wont restart till it cools down. It gets to the point where it cranks but wont fire, I verified I have fuel pressure and spark. I checked an injector with a noid tester and I'm getting no pulse. Looked at my crank sensor and it appears to be adjusted properly. Can crank sensors just go bad from sitting or could it be something else? Maybe the cam position sensor? I really don't know how to test either and didn't wanna just go buy one not knowing for sure.

Thanks, Gary

 

[No disintegrations]

The trick there is warm up the engine. Then when it won't start, cool down the crank sensor with a blast of brake cleaner. If it starts you have a bad sensor.

 

[gethighracewear]

Sounds good, I'll try it tomorrow
Thanks

 

[gethighracewear]

Started fine this morn. Let it warm up to 190. Shut it off and won't start now. Tried spraying crank sensor with brake cleaner. Still won't start. Checked for spark again and noticed it's weak and intermittent. Any ideas?

 

[Venus]

I would replace the crank sensor. Like anything electronic heat is the killer, so they get heat soaked after you warm it up and park it. You have the classic symptoms for a bad crank sensor.

 

[Nick Micale]

A couple weeks ago I had the same issue on a GN, no injector pulse, had cam and crank sensor pluse?

Simple fix was changing the 30 year old module/coil pack.

If you have spark, the crank sensor is good.

I have seen bad modules for over 25 years, our 115 degree temps is VERY bad on these components.

 

[Linewalker]

A weak starter can also cause this problem. Heat gets to it and has to cool before it will start again. Just something else to check.

 

[Pronto]

V8Killer chased that for months on his TTA. Injector harness looses volts as it heats up. Hot wired harness solved the issue. Do a search.

 

[gethighracewear]

Installed a new crank sensor today. Started right up while engine was cool. Let the car warm up to 190, shut it off and tried to restart. Just cranks. Won't fire up. I'm gonna look into the previous post about the injector harness.

 

[Nick Micale]

With the ignition on, there should be 12 volts on the injector connector.

The ECM via the module provides the ground to pulse the injector when cranking/running, see if there is 12v at the injector when it will not start?

If you have 12 volts at that point, it would seem logical the injectors are not receiving a ground pulse. I guess a harness wire issue like a open ground is also possible?

 

[gethighracewear]

Just tested voltage. Was at 11.2 volts per injector cold before start. Started and checked while running. Bumped up about a volt to 12.3 volts. Let car run till temp hit 190 and shut it off. As usual it will not restart. Just cranks. Checked voltage hot with obviously engine not running and was around 11.7 volts. Tried a noid light just now too and no flash when I crank it.

 

[John Larkin]

Spray more stuff with compressed air and cool it off, especially the module under the coil pack. In fact, separate the module from the coil pack and see if the potting material is solid or gooey.

 

[Nick Micale]

The simple thing to do is change the coil/module with a known good one.

If you cannot borrow one locally I will gladly loan you one to try it out before you spend a couple hundred dollars for a new one.

 

[gethighracewear]

Just removed coil from module. Looks like brand new still inside of both of them. It wasn't the original. I had replaced them both awhile back just to be safe.

 

[gethighracewear]

I'm not getting an injector pulse with a noid light when the cars hot. Is that still a coil / module issue?

 

[GNRick]

This happened to me and it was the module. My cel also came on while driving, although the code was not module related.

 

[Pronto]

Coil/module didn't cure V8Killers hot start issue. Same results with the noid lights too...

 

[gdsims231]

Heat different components up with a heat gun or even a hair dryer while engine is cold. The one you heat up and get the no start is your issue.

 

[LSTTYPE]

Started fine this morn. Let it warm up to 190. Shut it off and won't start now. Tried spraying crank sensor with brake cleaner. Still won't start. Checked for spark again and noticed it's weak and intermittent. Any ideas?

I had this problem and it was simply to much base fuel pressure. Turned it down a little bit and never had the problem again

 

[gethighracewear]

I had this problem and it was simply to much base fuel pressure. Turned it down a little bit and never had the problem again

I have a gauge mounted on the fuel rail. I think I had it set for around 42psi with the vacuum line off when idling. With the engine off I think it's reading close to 40 psi. How much should I lower it?