Six months ago I bought a beautiful 84 Vette with only 13k miles.

I drove it 2k miles to California. On the second half of the trip it was stalling every time I let go of the gas pedal, so I had to continuously hold down the pedal a little bit even when i was braking.

Brought it to the shop; they adjusted the tps sensor which fixed the stalling issue.

Car drove fine for a few months. Then the auto trans went out. Got the trans rebuilt. Car back on the road driving better than ever.

Then the trouble starts right after that. Car starts to stall about once per 30 min drive after the car has warmed up. Usually happens when coming to a stop. Then coming home one day three weeks ago it stalled and wouldn’t start up again.

Since then I replaced the ECM, adjusted tps sensor, replaced spark plugs and wires, looked inside distributor cap. Everything looked fine. Car still wouldn’t start.

Buddy came over and noticed fuel pump wasn’t turning on anymore. We replaced what was the sketchiest fuel pump relay i have ever seen and then the car started up!!

We high-fived and he left. Few hours later decide to take a test drive. Car starts right up INSTANTLY. As soon as I start to go up the ramp to leave my underground garage, the car stalls out. I let it roll backwards then started the car again on flat ground. Again the car stalls when i hit the ramp and start going inclined.

Now the car will not start anymore. Turns over but won’t start. And i cannot hear the fuel pump turning on anymore last time i checked.

 

Check the basics when it's acting up, fuel pressure, fuel inj. pulse, and spark.

 

firing order +

 

Check your fuel pressure. You have all the tell tale signs of low pressure. Put in an 85-89 spec unit. It is higher pressure and your L83 will love it. Advance the timing for a little more boost afterward.

 

Bill, the ECM wont override the added timing?

 

Nope. The L83 engine is a "Tweener" as in "in between" old school mechanical and full on digital. While the engine monitoring soft ware is "modern-ish" the timing is strictly old school. The distributor cap is manually adjustable just like the old days and you can twist it to advance or retard timing using the timing mark off the balancer.

 

Awesome! Thank you!

 

Followed your advice. Currently in my garage installing a new ac delco ‘85 pump but I am now stumped because the electrical connections are different. Please let me know what to do


Pics attached. First pic is old pump and other pics are new pump

Old pump

Connectors that came with new pump

New pump

 

Update: local mechanic helped me with the electrical connections. Came home and installed the assembly with new ‘85 pump. Turn key to on position…. Still no sound of pump starting and no start.

 

By the way, last time the car was running I checked out the fuel injectors and they were spraying out a healthy looking cone.

Since I can’t hear the fuel pump starting up I am convinced there is something preventing the fuel pump from getting electrical power and that is causing my no start issue.

Any tips would be much appreciated.

 

I took these measurements with my multimeter. Hopefully they can help troubleshoot the problem.

Connector to fuel pump assembly:

• With the key at the on position i have 10.43v on the middle (pink) pin and .27v on the blue pin

Connector to fuel pump relay:

• orange pin has steady .048v when key is on
• Steady .006v at single red pin when key is on
• Middle pin (blue with white stripe) when turning key to on position it will have a short blip of energy then it goes down to steady .003v
• Reads .27v where two red wires are connected

 

Update: Fortunately the problem has been solved. The main culprits were the oil pressure switch and a fried fusable link that visually looked fine but actually wasn’t.

Car is running and my girlfriend and I are using it as our second daily driver once again.

Next I need to replace the coolant temperature sensor and also rebalance the throttle bodies a little bit more precisely by using a manometer.

hopefully this thread helps others.

 

If you need help on the TB balancing, go to my site and watch the two vids under FAQ #22, click FAQ link. Very good vids on how it's done. The vids were done by a local Phoenix valley guy I know. GL and Enjoy your 84. FAQ

 

Hey man! Thanks for responding to my thread. I’m already a customer of yours and huge fan of your website. I’ve already seen your video and that’s what I’ll be using as my reference.

I’m already running one of your ECM’s in this car which is a great product and I’ve got your keychain on my keys. Only issue with the ECM I have is getting the housing to fit in the slot properly because it’s shaped for the 1982 vette, not the ‘84. Do you have any advice on that? For example should i use the housing from my old ecm or should i pad the slot or modify the ECM housing?

By the way I always try to remember to check your site regularly so I can get my hands on an ‘84 fuel pressure guage and a renegade manifold when they become available.

 

Thank you for your support. The 84 cases can be tricky and may take a little creativeness to mount them and as you know, the EBL works great as a replacement ECM. The issue is that the EBL will not work/fit in a stock 82 or 84 ECM case, I wish it did. It is best that you contact Bob at Dynamic EFI on this and they may be able to help you out with a better solution. There are other 84 owners that are running the EBL here, maybe they can help you on the mounting as well on a 84. The 82 seems to work OK. bobr@dynamicefi.com