Boo383

I have a starting problem with my 84. Sometimes it will fire right up and other times it takes cranking and cranking and it will usually start on about the 3rd attempt, but on rare occasion it won't start at all.. I am thinking it could be the fuel pump relay and was wondering if the relay is the same on an 84 as it is on an 85?? Any suggestions?? The 84 is my daily driver so I need it to start dependably! TIA! I was thinking of swapping the relay from the 85 to the 84 just to see if that is the problem?

JonM

1When is the last time you changed the fuel filter?
2You may want to check the fuel pressure...13psi for an 84
3You may also want to remove the sock on the fuel pump...may be old and clogged.
4Your return lines to the charcoal canister may be clogged.
5The two injectors also have a screen on each that may be old and dirty.
6Remove the wires to the two injectors, crank it over...you should get NO gas at all.
7How old is the O2 and temp sensors?

85shark

I have an 85 with similar starting problems.

So far I've changed:
Fuel Pump & Sock Filter
Fuel Filter
Fuel Pump Relay
Blew out line from tank to cansiter
Replaced O2 and temp sensors

The two injectors you referenced, are these found on the 85?

Thanks

JonM

No...84 has a crossfire injection system...two injectors mounted on top of the manifold...kinda like two carbs

vettmech

The fuel pump relay is on the firewall near the wiper motor. Not sure if the two years are the same but here's a test that I am successful with on my 85: unplug the relay and using a jumper wire connect the OUTER two wires in the connector. This will force the pump to run. Give it a few secs , you will hear the fuel system pressurize, then crank it trying to start it. If it starts then leave it running and you can remove the jumper wire. it will keep running because now the oil pressure switch is running the pump. It will only start without this jumper if you can build instant oil pressure to the switch to get the pump to run. I am DRIVING my car this week waiting for payday so I can get a new relay. (divorce court sucks) Oh BTW ..... don't DRIVE the car with the jumper in place because if you wreck the car the pump will still be running .......... good luck ....... let me know if I can help any more :seeya

85shark

I tried your suggestion with the jumper on my 85 and it worked. I just replaced the relay this last weekend.

When I first installed the relay I do remember the pump coming on when I turned the key on, then it stoped coming on by the next day.

Any thoughts? :confused:

Boo383

I replaced the relay and the battery today. The battery was pretty well dead. I'm not sure how old it was exactly, but I've had the car almost 2 years and it was the one it came with. I know the battery isn't gonna solve the problem, BUT so far so good. I haven't taken the car out because I didn't have to go anywhere today, but I started it a few times and it is working great so far, but like I said the problem is intermittent. So I will know if it is fixed in the next couple of days! :chevy