Fuel pump will not prime sometimes

[BuickMike]

It seems like 50% of the time now my fuel pump fails to prime an of course the car won't start. After turning off / on the ignition it eventually primes and the car starts and runs just fine. Could this just be the fuel pump relay under the hood, or something else?

 

[groumoutis]

Is it not coming on or is it not priming? I'm confused.

 

[BuickMike]

You know how the pump runs for a moment when you turn the key to the on position? Mine doesn't always do that and the car won't start...or runs for a second until the fuel is gone. Once I get it to run I can start the car and it stays on.

 

[SHADOWII]

I think you'r correct, probably the relay. Turn the key to "on" w/no pump operation ck power to the coil to eliminate the the sw to coil wiring and isolate coil to pump wiring.

 

[BuickMike]

I replaced the fuel pump relay and it still happens. If I can get the car to start the fuel pump runs just fine. Its just that sometimes when I turn the key on it will not run for those 2 seconds to pressurize the system. Any ideas?

 

[~JM~]

Mine is doing somewhat the same thing. I've replaced the pump, filter, hotwire kit, regulater & the relay. I've found that if you turn the key on & the pump runs, then turn it off & cycle it back on right away the pump will not run. You must wait a few seconds in between cycles. Once the car finally starts, it will stop & start just fine all day. After it sits overnight or for several days it will not cold start. It seems to me that the priming cycle is not long enough.

Sorry... No answers here.

~JM~

 

[Roger]

Only time I had to prime my pump was when I installed it.

It's not recommended to allow the tank to run dry - the pump is lubed & cooled by fuel. I always start looking for fuel when it gets down to 1/2.

 

[BuickMike]

It's not that the tank is dry. It's that the pump is supposed to run for a moment when you turn the key to on and mine doesn't. I think I have narrowed it down to a possible issue coming from the ECM, One thing I did right before the problem started was put my ECM back into the kick panel. I took it out yesterday, unplugged the harness, and plugged it back in. Since then the pump has worked every time. I'm going to go back and check all the connections.

 

[forcedinduction]

im sorry to dig up this thread but im having the same problem with my car. sometimes it primes and sometimes it wont
I replaced:
pump
relay
ecm
fuse were good
oil pressure switch
for the time being I removed the hot wire so Its back to stock setup so I can figure this out.
when I turn on the ignition I do not get the 4 second prime signal at the relay.

and sometimes it primes and runs fine.

and here is the kicker!!!!! sometimes if its not starting or priming if I disconnect the relay all together it will start up. im lost if anyone can help please chime in.

 

[Shawn N]

Do either one of you have hot wire kits on the pump?

 

[Shawn N]

A little off topic Mike how did those GM t top seals work out for you?

 

[forcedinduction]

Do either one of you have hot wire kits on the pump?

Nope. I put it back to stock to figure out why this is happening.

 

[Shawn N]

What year TR and which hot wire kit?

 

[Shawn N]

Shit this is an old thread but I will try to figure it for you forced. Next time just start a new thread.

 

[forcedinduction]

What year TR and which hot wire kit?

It's an 86. And it had a homemade Hotwire setup on it when I got it. It does the same thing with or without the hotwire kit. I'm going to buy a real hotwire kit soon. But first I want to find out why I get no prime signal "sometimes" to the pump. And sometimes it works awesome and starts right up. Usually if I hear the pump prime when I turn the key then I'm good to go as long as I don't shut it off. But,,,,, if I turn the key and I do not hear the pump prime then It won't start.

I think the car has a mind of her own.

 

[forcedinduction]

Shit this is an old thread but I will try to figure it for you forced. Next time just start a new thread.

I'm sorry. I'm still a noob at this lol

 

[Shawn N]

Ah man one of those home hot wire jobs. Had one on my T when I bought it . Where does it start from and is it hacked into the relay?

 

[forcedinduction]

It ran from the the alternator to the rear. The relay was zip tied to the fuel pump harness. And the wires were hacked into the pump hanger harness. I replaced the entire hanger and added a walbro pump. So it's all cleaned up from that homemade Hotwire mess.
I also replaced the alternator because it was blown. Idk if that has anything to do with it.

 

[Shawn N]

Don't think it ruined the alt for it likely croaked from old age. Most the homemade kits I have dealt with are connected to the alt stud and goes to the pass side fuel pump relay. And then the pink wire it pulled out and replaced with the lead from the alt stud. A second hot lead wire is ran down the pass side frame rail to the pump harness and is either connected by a butt connection or the 12v wire on the pump side of the harness. Most of them don't have relays at the tank itself. My first thought would be the relay got wet inside and is corroded. Second I see a lot of problems with the OEM relay just totally junked up with dried up dielectric grease from the factory. I see you replaced the relay itself but the bottom harness that it plugs into may be the problem. Third is poking a multi meter into the wires and track it to the problem from there. Having local TR buddies are a value when problems like this pop up so you can look at things or swap parts out. What city/state are you located?

 

[forcedinduction]

I'm in ny. Dave h has been helping me but I cannot take the risk of breaking down on the way to him. His shop is at least 20 miles from me. I just broke down today pulling out of my driveway. It was running fine I let it idle for about 10 minutes and it died at the first traffic light (no fuel pressure). $115. To tow me 30 feet. Fml.