Hoping someone can give me some guidance on a strange problem I'm having with my fuel pump circuit. The trucks an 88 with a 3vze I bought it not running needed head gaskets which I replaced but since I got everything back together I haven't been able to get the truck running for more than a second. I know I have fuel pressure I don't know the exact psi but I've checked all the fuses and VAF I can hear the pump run when I move the vane but when I jumper FP and B+ the fuel pump does not come on. I've checked for 12 volts at FP in the diag port and that's fine but not sure what else I'm missing.

 

Start here if you haven’t run through these steps yet.

https://www.yotatech.com/forums/f116...-quits-312747/

 

Thanks but yes I did see this post and did the checks on that post and everything checked out fine other than when I jump out the B+ and fuel pump in the diagnostic port my fuel pump doesn't come on

 

And your CEL is illuminated when you turn the key on to jump Fp and B+? Is this a manual or automatic? 4Runner or pickup?

 

Yes CEL is on when I turn the key with the Fp and B+ jumped out it's a manual pickup

 

I don’t know how easy it is to hear the fuel pump on a pickup, but if you hold the key to start without the clutch cancel or pressing the clutch, you should hear the COR click and pump run. Do you?

 

Yes I actually had a problem with my ignition and the starter wasn't engaging but I could hear the fuel pump coming on but now I've replaced the ignition so the starter engages every time now but I don't hear the pump while it's starting but as far as the COR relay i can't hear it click while starting

 

You probably wouldn’t be able to hear the COR or the pump over the engine cranking, maybe you can, but I can’t. The steps I was saying was to not engage the clutch cancel button or the clutch pedal and just hold the key to start. When you do this, the starter won’t engage and you’ll be able to better hear the relay and the pump if they both energize.

 

do what @mholme is describing. do not push the clutch start cancel button, do not press down on the clutch pedal, do turn the key to the "start" position. this should prevent the starter from cranking while at the same time cause the Fp to run for as long as you hold the key in the "start" position.

 

Sorry for the late response but yes I can hear the relay click and fuel pump kick on when I turn the key without the clutch start cancel or clutch pedal pushed in.

 

It seems like the COR is doing what it’s supposed to from the ignition and VAFM. Did you verify fuel at the rail when you open the air flow meter door or when you’re holding the key down in the start position? Just replace the return hose off the FPR with clear vinyl tubing of the same diameter. You’ll be able to see it from under the hood for the airflow meter door test, but you’ll need a buddy or a camera setup to see it during the start position test.

You said you had 12v at Fp, did you mean B+?

Are you sure you have the jumper wire or paper clip seated making good contact during the B+ to Fp bridge test? What does your CEL do when you jumper TE and E1 terminals in the diagnostic port? Key On. Do you get a rapid “all clear” flash or a slow flash which would indicate a code stored.

 

I know I've got fuel pressure coming into the rail previous owner cut the fuel line right by the rail and I spliced it back together. I haven't checked yet to see if there's fuel in the line on the fuel pressure regulator. When I jumper TE and E1 my check engine doesn't flash but maybe I just didn't get a good enough connection last time I tried.