My Wife's 92 RS with the stock 305 TBI is the vehicle in question. It has just over 151K on the clock and has always been reliable (note we have only had her for the last 12K). Anyways I have replaced the fuel filter a couple times as part of maintenance. Last night some friends and I replaced the fuel pump as well. The car turns over just fine, but with the air cleaner lid off it's very easy to see that the injectors are not letting out any fuel. I checked the injector fuses, the fuel pump fuse and relay, the pump primes great as I replaced it with a TPI pump. I really need some help as this is her daily driver. TIA

 

Have you checked for spark?

The ECM won't let the injectors fire if you're not getting any spark from the coil or the control module is not telling the coil to fire.

 

I am pretty sure I am getting spark, but I will make sure to try again. Maybe the coil is acting up or with my luck the ECM went out

 

Any chance you have the return and feed lines reversed at the tank? Or the electrical connection to the pump reversed?

RBob.

 

Likely No, Possbile yes, but I doubt it because changing the pump was a reactive measure to the car dying in a intersection, and then after attempting to jump it, and removing the air cleaner lid I saw that the injectors were not spraying. So unfortunately I guessed it was the fuel pump, because I couldn't hear it prime with the filler cap removed from the filler neck. I can definitely hear the pump prime now, but it's the same as before, the car turns over but just not getting any fuel to the injectors. Maybe it's the Spark Control Module in the Distributor?

 

I would say its either still a problem at the pump or the module could be bad. Without a 'scope or a DVM with a built-in scope feature theres no way to check the quality of the reference pulse signal the ecm is getting. Its also possible that the module was bad to start with adn thats what caused the car to die at the intersection. Try checking the pressure at the feed line in the engine compartment when you crank the car to make sure it has good pressure. You should also be able to kear the injectors fire, they make a pretty loud click each time they open. If you hear nothing from them then try another ign. module. Could be something else but those are probably the most likely culprits.

 

Thanks to all that replied. Just to post the results I changed the Ignition module (even though testing indicated it was good, but why replace a part that is over 11 years old) did a cap and rotor while I was there. But the real culprit was the Spark Control Module.

 

good job, and thank you for the info (on what the problem was).

RBob.

 

im pretty dense today so maybe someone can fill me in. How is it that the esc can cause a no injector pulse condition? It seems like the only signal it can send to the ecm is a varying signal indicating knock (or possible false knock)

 

I believe he was referring to the ignition module under the cap (Spark Control Module). You are correct about the ESC module, just reports knock to the ECM.

RBob.

 

oh, ok... looked like he was referring to the something else after he said he replaced the ign module. nvm...

 

That's OK.

No thanks needed.

 

I was referring to the Spark Control Module located on the firewall as opposed to the Ingition Control Module under cap. I had the ignition module tested and it came back good, but like I stated since it was as old as the car I decided to be proactive and replace it, as well as I could see it was rotor and cap time. I wasn't able to get fuel again until I replaced the spark control module on the firewall. Don't mean to contridict what anyone else has stated, if it shouldn't work that way don't blame me, I just wanted to get her running again and she is! :lala:

Thanks again for the help!

 

This is interesting. I recall a while back someone else mentioned the same. Replacing the ESC module allowed the engine to run. At that time too I thought that it was a mix up in terms.

I wonder what it is that causes the no fuel, no start problem. Hmmm, now I am going to have to go play and see if I can figure it out what it is that causes this.

Thanks again for the update,

RBob.

 

I was joking.

It's good to hear that it worked for you though.

I had my ICM checked at AutoZone, but it came back fine after 3 days of trial and error of a no-start.

I finally decided to change it after checking EVERYTHING ELSE, and that's what it turned out to be.

I guess it goes to show not every Corvette is red.

 

This did sound odd so I unpluged my SCM and the injectors didn't spray.

 

Id be willing to bet that it may have been jsut a possible bad connection at the FP relay when you went to replace the ESC behind it, or possibly the problem is intermittent and just happened to 'fix' itself at the same time. Hopefully its not an itermittent electrical problem since they can be a pita to fix. IIRC, i dont think there is really anything the esc could do to cause the injectors not to fire or the pump not to function

 

I checked the relay and fuses before I did the fuel pump