My 89 350 Iroc cold starts fine, with 2 cranks. Once the engine comes up to operating temperature, after driving it a few miles, I shut it off. Take care of whatever business I have to, then return to the car. Turn the key & nothing. Fuel pump pressurizes the lines & that's all. Replaced the battery & starter. That was fun. Still doin the same thing. Once hot, no start. After about 3 hours, with the hood closed, it fires right up & runs fine. I'm sure that if I opened the hood, it would cool faster. Took it to a local shop & they couldn't find anything. Anybody here have any ideas? 49k mile car.

 

Sounds like you need to ohm injectors warm or could be icm breaking down. Need to test for spark fuel pressure and injector pulse warm.

 

Nothing as in no crank, or nothing as in it just spins with no combustion?

My hot start issue was bad injectors. It's pretty common, I'd start by ohming them cold and hot.

 

Forgot to mention that the first thing I did was replace all the injectors, as 3 of them were hella clogged.

 

Clogged with what ? Rust and junk from
the tank ?

 

Rust. Replaced the fuel filter, drained the fuel tank & scoped it. Tank was amazingly clean for being 31 years old.

 

Have you tried using starter fluid when the no start happens ? The rust in fuel system is a concern hopefully not a repeat of previous injectors.

 

[QUOTE=Komet;6454775]Nothing as in no crank, or nothing as in it just spins with no combustion?

When I turn the key, nothing happens. It's like there's no engine under the hood. Total silence, outside of the fuel pump pressurizing the lines.

 

That sounds like a VATS problem maybe. Do you still use the key with the pellet in it? Do you have another key? Not sure what the hot start would have to do with it but seem like you've tried the usual stuff.

 

1

 

Yes, I still have the factory keys with the black chip in them.

 

Thanks for the suggestion & the link. I'm running out of ideas.

 

Well, you can test if it's VATS by bypassing the start enable relay in the driver's footwell. Make a jumper out of thick wire and two male spade terminals. If it goes from no cranking to cranking after the bypass, you know that relay isn't being energized by VATS.

edit: VATS also disables the injectors so don't crank it forever this way if it does crank, this is just for testing.

I'd also recommend closely inspecting battery cables and all wiring going to the starter area for burns, breaks, splits, etc.

 

So now it’s a no crank or crank no start ?

 

Just replaced the original starter & I did check all of the cables for breaks. All were solid & in good shape.

 

It starts fine when it's cold, as in cold start. When it gets up to operating temperature & I turn it off, that's when it fails to do anything. Turn the key & nothing.

 

It's not my daily driver, so I can only work on it on weekends. I work long days & do not feel like beating my head against the car on week nights.

 

Easy check when hot and no start. Turn headlights on, try the starter. If the lights go out and stay out you have a bad battery cable or connection. The high current draw of the starter opens the circuit, the current draw of the headlights keeps it open. Heat and resistance deal.

 

I think the first thing to do would be to see if you are getting voltage to the starter / solenoid when you turn the key.

 

which injectors did you replace them with?

 

this

 

I Had the same problem and change out the starter and it fix my maybe this will help you

 

Starter has been replaced. Did not fix the problem.

 

I'll check my records when I get home later tonight I keep extremely detailed records for everything I do to all of my cars. Takes the uncertainty out of the equation.