nelsonvazquez

Hi all
my corvette 1984 (crossfire) runs for a while good an hour or so,suddenly stalls and shut off,start cranking but not fuel on injectors, let it set for a while 15 minutes or so and start again with some issues but later no problem,change almost everything



please let me know

ex-x-fire

Check to see if you are missing spark too. The Ecm needs to see a tach signal from the distributor to fire the injectors.

nelsonvazquez

this happens in the middle of the road,wait 15 minutes or so and keep running again,I will check next time it happens,the tach is working properly.

nelsonvazquez

I forgot to mention that when this happens I take off the air cleaner and see the showers pulsing gas but not full just when the motors cranks,also the fuel pump fuse is very hot close to melt.

corvettenorway

go get a new fuel pump !

nelsonvazquez

I did already,also changed oxigen sensor,egr valve and sensor,tps sensor,coolant sensor,oil sensor,oil pressure sensor,temperature sensor and others.

1984Z51auto

I have seen problems like this caused by a bad ignition module and also by a bad fuel tank cap. The ignition module can fail intermittently when it gets hot, no spark or no engine turning (Tach) signal so no fuel from injectors. There is a test light for those injectors that you can plug into each pigtail and see if the ECM is commanding a pulse. Also, a plugged up fuel tank cap can result in a vacuum in the tank that the fuel pump can not move fuel against. Next time it quits open the tank and see if you get a woosh of ingoing air then try re-starting right away.

My bet is bad module in the distributor or no thermal (heat sink) grease when the current one was put in. Good luck!

nelsonvazquez

I will check the cap next time,but meanwhile will work with the grease on the module,it is any specific one? where it is applied?

thanks 1984z51auto
will let you know any news

ToniJ1960

No way the fuse should be hot check the fuse connector and make sure its nice clean metal.

Electrical resistance will cause heat like that.

nelsonvazquez

Thanks I will verify and let you all know what I found

1984Z51auto

The grease I was talking about is a heat sink compound that should go between the module base and the body of the distributor body when the module is installed. I think that auto parts stores have it in tubes as di-electric grease. The purpose is to improve the heat transfer from the module to the distributor body so the module stays cooler. New modules usually have a little packet with a daub of it included. Hope I didn't cause more confusion than I relieved.

ToniJ1960

Get a new fuse make sure the fuse socket is clean and its not loose fitting.

Poor electrical contact causes resistance, resistance with current passing through causes heat by lost voltage. The voltage times the current equals power in watts. Power is dissipated as heat. That heat means you are losing voltage to the load (the fuel pump).

When it cools down car runs again?

Wont hurt to use some electrical cleaner for switches and contacts on that socket. If its very bad from the heat already it might take serious cleaning or replacing.

nelsonvazquez

Hi All
past week (thursday)I got the grease and applied, yesterday (saturday) took it for a spin 1 1/2 hour more or less with out any hesitation (finally) but getting close to home the motor start failing and I thought that could be the spark plugs put it in the garage until next day (today) and crank it and start again with out any problem runs like 1/2 hour with out any problem and stop for another hour or so,when crank to start it did not send gas again on the showers,check the gas cap and no "Swoosh" sound on it like vacuum,pull out the fuses (inj 1 and 2, ECM and fuel pump) to reset but nothing,keep cranking until start but failing like spark plugs or poor gas, let it for a while iddle and not shutting it off,until it went off, let it for a while 1/2 or so and crank again start failing and trembling but running, I keep it gas and brake for a while until finishing stopping,I got home with gas and brake and the motor failing and stumble.

any thoughts?

ex-x-fire

Stuck open egr valve.

1984Z51auto

I didn't think of that angle... my Cross-Fire had a Weiand EGR Block Off Plate - Part# 9007 in place of the valve and I never missed the darn thing!

You can actually make that valve move manually by squeezing the diaphragm up from the bottom by hand when its cold or by using a vacuum pump on the fitting on the valve, assuming the valve is good. Not sure that one sticking open would kill the engine... might make it run really poorly however??

stevedude2

As the Ignition Control Module gets worn, a typical symptom is car will stall and not be able to start for 30 to 45 minutes of cooling. Then will restart like nothing ever happened.

I replaced mine with an AC Delco or BWD from Oreillys recently <$30 and are in stock there. Do add the grease under module and a tad on contacts.

That should do the trick.

nelsonvazquez

Ok
I will get a new module during the weekend and will try,I have a question do the resistor on the pump could be worn out or burn?because the main problem is no fuel when it is hot,this time the temperature runs on the 180s or 190s all the time.

whalepirot

Check for spark with a no-start before throwing parts at it.

1984Z51auto

Yeah, what he said.

nelsonvazquez

Hi All
today started and runs great changed the Ignition module put grease and clean contacts, took it for a spin and in less than fifteen minutes start failing again, motor shuts off and no gas on the showers, took off the injectors, ecm and fuel pump fuses and start again but failing, took it home and let it in the garage, tomorrow will check fuel pump, but anyone has any idea what could be happening?