WMohrCHS

Can I reset the computer in my 1984 myself or do I have to go to the Corvette place? Battery was disconnected for 6 weeks, is now freshly charged. Engine fires instantly BUT only when fuel is dumped into the injectors. Fuel pump does not work IN the car, but works on my workbench. Connections, cables, fuses are fine. New fuel pump relay is installed.

StealthLT4

Hmm. May want to check the connections? Removing the battery for 30 minutes should do all the resetting necessary, if its needed.

staugur

Don't know much about '84's except it's the same set up on a truck of the same vintage.I tried to help a neighbor with a similar problem as yours on his truck to no avail.he did get it running eventually after a trip to the dealer and told me it was a computer problem and related to the injectors.Someone else probably knows more.

vinnies87

You only need to disconnect the battery for about 1 minute to reset, no need to go for 30 minutes as jwalker87 posted...

RRT vette

Yep, disconnecting the battery for ~30 seconds should reset the ECM. Connect a fuel pressure gauge and see if any fuel is getting to the injectors (12 psi). If it is, your injectors may not be firing due to an electrical problem. You will need a noid light for the CFI injector connectors to diagnose that.

WMohrCHS

I tried all of this already to no avail. A makeshift connection to the ALCL made the pump work, but the engine started and ran only (after I disconnected the ALCL) for several seconds until the fuel in the bowls was used up. Sigh... Seems the only thing will be to tow my good old car to the Vette Man.
Thank you guys for your ideas!
Best,
Wolfgang in North Charleston, SC

staugur

on later(87) cars there is an oil pressure sender and an oil switch located just below and behind the distributer.If the oil switch goes bad it wont energise the fuel pump on start up.

flannel_man

something like that happened on my '84 once, check the electrical connectors going to the distributor cap, the plastic connectors are old and brittle, one may not be making contact

RRT vette

Run a hot wire to terminal G and see if you are getting battery voltage at the fuel pump connector. Make sure the ground at the connector is good. If both are good and your fuel pressure gauge shows no fuel pressure, pull the fuel pump assembly and check the wiring to and from the fuel pump to the connector at the tank. If it checks out good, replace the fuel pump.

As a side note, and before pulling the fuel pump, you might want to remove the fuel feed line (top line going to the right). With the line removed and the fuel pump connector connected, hot wire terminal G and see if any fuel comes out of the metal line. Have something handy to catch fuel if it does come out and have someone handy to pull the hot wire from terminal G. If fuel comes out, check for restrictions in the lines. This could also be done by turning the key "on" but the fuel pump will only be energized for 2 seconds as long as the fuel pump relay, fuse, wiring and connections are good.

The oil pressure switch is a back up for the fuel pump relay. If the switch is bad the relay will still send the 12v to the fuel pump after the engine is running.

sweetbaboon

Is there a fuel cut off relay other than ecm? Just wondering

RRT vette

No fuel cut off relay. Once the key is in the "on" position the ECM will energize the fuel pump relay for 2 seconds. After that you will have to crank the engine and build up 4 psi of oil pressure and close the circuit of the oil pressure switch to send voltage to the fuel pump. If the oil pressure switch fails, the fuel pump relay and ciruitry will send voltage to the fuel pump. If the fuel pump relay or ciruitry fails and the oil pressure switch fails...no voltage will be sent to the fuel pump.