1990 5.0L LTC Hot Engine Will Not Start

[Borman]

One of my friends with '90 LTC has a problem now.

Cold engine starts perfectly.
When engine is hot, at normal operating temp., it works, but if turned off then it will not start, until cooled down.
While this condition occurs, sparks are present at spark plugs, gas pressure is OK, but there is no pulses on all fuel injectors!
Apparently ECM does not output those pulses for somehow.
At the very same time KOEO diagnostic only reads a single trouble code, related to TPS, which was recently replaced, but that does not seem to be the reason here. No any other codes were stored in memory.

Does anyone ahve any ideas what that might be?

 

[LincMark_7&8]

Have you checked the power relay for the computer or the fuel pump relay?

 

[Borman]

Look, we're not that damn .
Fuel pump and power are fully fine.

Again, sparks are there and fuel pump is on, gas pressure is ok.

 

[LincMark_7&8]

Does it just crank and wont start?

 

[thamarkman]

I had a friend with a chevy truck that wouldn't start when it was hot. He said it was because the starter gets hot and won't work. Just an idea.

 

[Redwingvksm]

...
At the very same time KOEO diagnostic only reads a single trouble code, related to TPS, which was recently replaced, but that does not seem to be the reason here. No any other codes were stored in memory...

That's probally your problem right there.

Rember - on fuel injected vehicles when you hold the pedal down to the floor that will SHUT OFF the injector flow to get rid of flooding or anything like that.

With that TPS sensor being bad and all - when cold/cool the resistance is enough - but when warmed up it changes the resistance and thus it won't start. The computer is seeing it as bad - but it still doesn't ignore the full throttle command for saftey purposes.

Replace the TPS and see what happens... Hope this helps!!