Ive got an 89 iroc 350tpi , it will start up when cold, but wont start when hot. Its not Vats related since i took that out and have never had a problem with it. I have changed the comp, and the dist just to check, but still does the same thing. anybody have any ideas?

 

Does it turn over? If not, change the starter. Been there done that! Heat soak is a common problem.

 

cranks but no start

 

You replaced the whole distributor and it still won't start when hot? That's strange because the ignition module controls spark and fuel while cranking, not the computer. That's usually fixes no start 99% of the time. Do you happen to have a MSD or other aftermarket ignition management box installed? If so disconnect it or bypass it during a time when it won't start.

You'll have to start a little troubleshooting otherwise to see what you're missing, spark or fuel. To test fuel disconnect any injector connector, using a test light across both wires see if the light will flash while cranking engine. Do not ground the test light, go across the two wires on the injector connector.

 

Dirty or worn/ leaking injectors, try some GM injector cleaner, part #: 12345515

Try flooring the gaspedal when starting hot, if this helps, your injectors are worn.

 

Test your fuel pressure. You just might have a fuel pump thats about to go out.

 

The car will crank, and has spark, and when its hot it will start if u spray with starting fluid, and then continue to run, other then that it wont start again. untill you shoot more starting fluid. What should the fuel pressure be at idle?noid light on injector blinks bright, car will start, noid light after hot blinks dim, car wont start

 

Swap just the ignition module under the distributor cap. It is heating up and failing to fire the injectors when hot when cranking. The module fires the injectors only during cranking under 300 rpm, after that the computer takes over. Be sure to use the special greese under the module when you change it.

Stay away from parts store ignition modules, they are junk. Use only AC Delco ignition modules and you will be much happier.

 

It sounds like a fuel deliver problem to me--sounds like U have spark, but I would make sure it is "as it should be". Any car, computer or not, U have to determine if U have fuel and spark--sounds like U have spark--now figure out why there is no fuel, cause if you are manually supplying the fuel (starter fluid) that a BIG clue right there about what's going on!!!

I think fuel pressure should be around 40 + or -. If this were a non computer car, I would be suspecting low fuel pressure and when it warms up , it could be vapor locking--the starter fluid makes that go away, and will continue to run, but when U shut it off, it vapor locks again.

 

john- i put in a brand new dist, still did it

zap- fuel injected cars cant vapor lock, but im gonna check the fuel pressure as stated. thinkin maybe the pump is on the way out

 

keep us posted
Rob

 

I just had that EXACT SAME PROBLEM! The car would start when its cold but will not crank when hot. I got a new distributer, battery, starter, new coil, plugs and wires. An it still wouldn't crank when hot. Then my uncle suggested get a stronger ground cable. So I went to autozone paid 9.99 for a 2G ground cable, stock cables are 4G. Once I replaced it the car will fire right up everytime hot or cold!

Now I just got to find out why it wont stay cranked when I put it in drive!!

 

Not even close to his problem. His car won't start when hot, it cranks just fine.

 

Where did you get this "brand new distributor", the local parts store? If so I wouldn't doubt it's bad out of the box. I did say parts store ignition modules are junk. Some last 12 months, others last 12 minutes.
You don't need to change the whole distributor either to replace the ignition module, it is easily replaced with distributor in.

EFI cars can't vapor lock. Your pump could be going bad but I doubt it from your description. Since the noid light was nice and bright when cold and very dim when hot that leads directly to the distributor and it's module. Remember about the heat compound grease I told you about under the module? It's CRITICAL to the life of the module. Without the grease even a good module will fail immediately.
If the fuel pump was bad it wouldn't continue to run after "jump starting" it with starting fluid.

 

Did you check the resistance on your injectors?

My '89 5.7, would start up cold, as soon as i got somewhere would just refuse to start. Little shot of fluid, start right up and act like nothing was wrong. Actually.. this is how i got the car.. guy couldn't figure out how to keep it running. I did a little sleuthing, and checked the injectors with my digital multi-meter... found that two of the injectors were bad. Put some new SVO injectors in, and a adjustable fuel pressure reg (did the reg just because i was there), all better. Car ran ok with the new injectors, but i had a chip burned for the new ones to get past NJ emissions at the time.

IF i remember correctly... bad injectors are common on the '89 cars.

Something to think about...

 

Off topic--I know!

Hey Rob--U gonna make the Hou. Summer Meet?