89 Coupe, it will start fine and drive as long as you want but once you cut it off it wont start again even with the engine turning over fine (not battery or alternator). You have to give it an hour or so before it will start again. And heat doesnt matter either. You can start it dead cold, run it for 1 minute, shut it off and it wont start again for 30 min to an hour. Any ideas? It just started it suddently one day.

 

Could be many things, but I would swap out the ignition module in the distributor to start. When they go bad, weird things happen.

 

Lets go to page 1 on any auto repair book! When the engine won't start, THAT is the time to start doing some diagnostics. Engines require three basic things to start and continue to run. They need a hot spark and spark at the right time, they need fuel and air and in the correct ratio, and they need cylinder compression to start and continue to run. Use your timing light to see if you have spark during cranking and if it is at the right time. Unplug a plug wire and bring a grounded wire close to the boot while someone cranks, you should have a snappy at least 1/2" spark. Spray starter fluid into the MAF and try to start the engine, if it starts and quits, you clearly have no fuel. Measure the fuel pressure on the shraeder valve on the end of the right fuel rail, it should be 35-42 psi and it should hold up for at least 1/2 hr after the ign sw is off or you have leaky injector/s or a defective check valve in the fuel pressure regulator. Connect a noid light (available at parts stores) across an injector plug on each cylinder bank and see if it pulses during cranking. If not, check the two inj fuses and measure if you are getting reference pulses on the prpl/wh wire on the distributor.
***** Nilly replacing of parts to see if that fixes your problem is the dumbest possible way to repair an automobile and it can become expensive too!

 

Had the same problem, the injectors were leaking. Changed them out and it ran perfect afterwards

 

I was hoping that it was a common problem that could easily be explained since I did not own a fuel pressure gauge and my timing light gave up the fight a few years ago. I did break down and bought both and found out the fuel pressure is not holding. It drops from 40 to 20 in less than a minute. I am assuming that is an injector problem because wouldnt the regulator check valve just dump fuel back into the tank and not prevent the engine from starting? Strange thing is the first time I did the testing the engine started and ran several times in a row even with the pressure dropping that quickly after shut off. But since then it has gone back to the original problem of not starting after the 1st time. Just dont understand why it did start several times in a row if it was dumping fuel into the cylinders and now it doesnt.

 

If you think you have an injector or injectors leaking down and flooding causing a no start hold the pedal to the floor while cranking this is the clear flood mode stops injector flow to clear a possible flooded engine.

 

I tried that and it still wont start.

 

You haven't said if you have verified a good spark while in the no start condition. If you haven't done this you need to. This is probably the most important thing to do as it is kind of the separation point between the fuel system and the ignition system. You can always put the timing light on any of the plug wires, tape the trigger closed, and aim the light towards the steering wheel. Then hit the key and see if the timing light flashes.

 

I have checked with a timing light during crank up and it does appear to have spark.

 

If you smell gas after trying to start it the second time, or if it is getting poor gas mileage, or if the engine idles ruff, it could be the injectors, which are an easy fix, but don't forget to check the temp gauge sensor. If it goes bad (loses ground) it will tell the engine it is -35 degrees, which will cause to dump in so much gas that the engine will not start when it is a little warm. but you should be able to smell it.

Good Luck,

Randy

 

Ohm the injectors as Jon shows in his video. Over half of mine ohmed bad in my 89 and it was doing the same thing you are describing. Call Jon at FIC for wonderful pricing and service.

 

In my case that's what happens after 2nd start and starts after but cranks so long, but, if I turn off the engine again and start it up, it starts quickly and without fuel smelling

 

Have you checked the FP regulator. And the check valve in the return line?

 

Thanks! That's a good one...But, do you know which is the best way to check them?

 

I don't remember how. But, there are several videos on the FP regulator and the return line. You need to clamp one side and if the pressure drops it is this if it doesn't drop it's that. Straight forward. I hope you resolve the issue.