Hey guys,

The other day I was checking my spark plugs for arcing, and sprayed a bit of water on them to aid in this. When I went to start it up, it sounded like my pump began to prime but then failed. Car wouldn't start until the next day.

It started fine for the next day or two, probably 5ish cranks. Now I'm having the same problem where the pump will not prime.

I can hear the relay click a few seconds after ignition is turned, and I even swapped them around to see if that was the problem. Also doesn't seem to be a VATS issue. In addition, I tried to run a wire from my battery to the red wire test terminal, no dice again, but I did this very quickly.

Seems like everything leads to the fuel pump being shot. I had heard that pumps usually crap out completely, so I figured the fact that it worked fine for a few starts intermediately pointed to something else.

Please help me diagnose this stuff before I drop the fuel tank and replace a part that may not solve the issue!

 

New pump time I suspect it if doesn't run with power on the test terminal.Could always check wiring from relay to pump to confirm not a wiring / connection problem before pulling tank
VATS doesn't affect fuel pump ; only injectors firing

 

i agree, sounds like a bad pump to me. while you have the tank out check the screen on the pickup, it could be clogged

 

Thanks for the input,

I was hoping it might be something else since it exactly coincided with the water in the engine bay. I also remembered something last night. My relay clicks on a few seconds after the ignition is turned to start. Maybe it is slow, or perhaps this is the relay turning off? I'm looking for any reason not to pull the tank!

 

It's worth pluging in a different relay first just so you can rule that out. Check the wires around the base of the plug to to make sure there is no corrosion in there. I would say more than likely your fuel pump is on the way out. From what I understand they don't always die all at once. If you are having intermittent problems with it you need to replace it though. It's only a matter of time until it leaves your *** stranded and it's much more pleasant to do this kind of work at home vs. some random parking lot/side of the road. Good luck.

 

ECM only runs pump for 2 sec to prime fuel rail , then turns it off until engine is cranked.
You have checked the fuel pump fuse haven't you?
That is on the power circuit to the pump ; not on the control circuit to relay

 

And if all the wiring checks out and its time to replace the fuel pump, you can pick up a TTA pump for later. Drops right in for TPI cars.

 

I've gone through the fuse block under my dash; nothing labeled FP. Some more details on where the fuse is would be fantastic, I just assumed there was none. I know it sounds obvious, but my Haynes manual has no info on this type of stuff.

 

Not sure where it is, not able to check on my car, but Vettoz's post I'd say just follow the wiring from the relay, cant be too far.

 

Looking at the fuse block with words right side up, it should be the second one from the left, top row. It's a 10 amp fuse and labeled "F.PUMP"

 

The driver side under dash fuse panel on my 1992 z28 does NOT have any blocks labeled FP or F PUMP. I am also trying to find info on where I can check it so if anyone knows where else to look it would be a great help. Please be specific if able.

 

This diagram for a '92 TPI shows a 20A inline fuse that is hot all the time which would indicate a fusible link on the wire rather than a fuse in the fuse box
http://www.austinthirdgen.org/mkport...ine_wiring.gif

Do you 12V on the heavy org wire going into the relay?

 

Thanks for the help vetteoz. I'm going to need to get looking.

 

Im having a similar problem as the op.

Usually when i turn my key to start i can hear the fuel pump prime. But today when i went to go start it, it didnt make that sound and the car wouldnt start. After turning it a few more times, it primed and started.

Driving down the road today, it would sometimes jerk hard on me as if it felt like the engine wasnt geting fuel.

Would this mean a bad fuel pump.
And isnt there another way to get to the pump instead of droping the tank?

 

Rent a fuel pressure tester and you'll know. I could barely tell my pump was going the car seemed to run fine, and would easily spin them off the line. However on the top end the car felt lackluster. I passed it off to being used heads/cammed LS1s making way more power.

However when I put a FP tester on it I discovered my fuel pressure was only about 25psi at WOT, when it should have been around 43 to 47psi.