Another 454 Vortec Build Thread - Documenting, Q&A, Help

[Supercharged111]

The parts cannon is not the path to longevity, at least not anymore. Too high a failure rate from garbage parts.

 

[454cid]

Strangely it doesn’t have the AIR setup on the manifolds.

AIR is for CA emissions, not Federal.

I'd like to see the O2 sensors in the exhaust manifolds you mentioned earlier. All four should be in the pipes.

 

[Supercharged111]

AIR is for CA emissions, not Federal.

I'd like to see the O2 sensors in the exhaust manifolds you mentioned earlier. All four should be in the pipes.

My '88 C1500 was sold new off the lot in Fenton, MI and had an air pump.

 

[454cid]

My '88 C1500 was sold new off the lot in Fenton, MI and had an air pump.

I'm speaking of the L29, since that's what the OP has.

 

[Spareparts]

Just because a vehicle was not sold in CA does not mean it can't have CA emissions. The only way to know for sure is RPO codes.

 

[BeXtreme]

Strangely it doesn’t have the AIR setup on the manifolds. Based off this pic I’m feeling like I need to just replace the fuel pump, FPR, Injectors, and manifold gaskets. I know it’s crazy to just throw money at it, BUT, I’m the type who likes to replace EVERYTHING. Simply because I’m looking for longevity. I won’t replace low failure rate items but remember I’m doing heads and cam next year. Oil pressure gauge isn’t working so thinking oil pressure sensor should be replaced.

You will just end up chasing your tail and spend tons of money to potentially solve nothing like that. There have been lots of good advise on how to simply troubleshoot your problem and you seem to completely ignore it and instead laser focus on something that everyone is telling you IS NOT the problem.

There is no fuel pressure sensor on your truck. The Fuel TANK pressure sensor is only used for EVAP system testing when the truck is first turned on and is not used in your application... regardless of whether there is a sensor installed in your fuel sending unit. The fuel pump itself is the same for almost all GM trucks/SUV's from ~96-2003.

Put a fuel pressure sensor on the rail and then test the pressure(I know you already did this). Record the pressure key on/ engine off. Turn key off and record how fast the pressure drops(PSI/second). Then do what spareparts said and pinch off the return line. Record the key on/ engine off pressure. Turn key off and record how fast the pressure drops(PSI/second). If your pressure with the return line pinched off is over 60psi and it doesn't bleed off very fast after you pinch the return line closed, your entire problem is the FPR. Full stop.

 

[Bachert24]

You will just end up chasing your tail and spend tons of money to potentially solve nothing like that. There have been lots of good advise on how to simply troubleshoot your problem and you seem to completely ignore it and instead laser focus on something that everyone is telling you IS NOT the problem.

There is no fuel pressure sensor on your truck. The Fuel TANK pressure sensor is only used for EVAP system testing when the truck is first turned on and is not used in your application... regardless of whether there is a sensor installed in your fuel sending unit. The fuel pump itself is the same for almost all GM trucks/SUV's from ~96-2003.

Put a fuel pressure sensor on the rail and then test the pressure(I know you already did this). Record the pressure key on/ engine off. Turn key off and record how fast the pressure drops(PSI/second). Then do what spareparts said and pinch off the return line. Record the key on/ engine off pressure. Turn key off and record how fast the pressure drops(PSI/second). If your pressure with the return line pinched off is over 60psi and it doesn't bleed off very fast after you pinch the return line closed, your entire problem is the FPR. Full stop.

On it sir I’m not ignoring anyone, in 3 years nobody has gotten this thing to run and I have info that the injectors were never done. I’ll look for the spot for the return line and test I’ll have to see how to do that.

 

[Bachert24]

Here is what i would do.
Hook up a fuel pressure gauge. Pinch off the return line under the driver's door inside the frame rail. Turn the key on and if the pressure jumps over 80PSI, your pump is probably ok.
If the fuel pump can build that pressure then you have a bad/wrong FPR. The bleeding off of pressure is probably leaky injectors.
It seems like a real PITA to get to the FPR but really it's not that bad. I had my upper intake off so many times i could do the job im under 45 minutes.
If i remember right this one is said to work. I just can't remember if thats the one i used or an adjustable one.

More Information for DELPHI FP10021

Also from what i remember, The California emission equipped trucks will have the fuel tank pressure sensor. Federal emission trucks will not have that.

How do I pinch off the return line?

 

[BeXtreme]

On it sir I’m not ignoring anyone, in 3 years nobody has gotten this thing to run and I have info that the injectors were never done. I’ll look for the spot for the return line and test I’ll have to see how to do that.

This has no diagnostic value.

You have evidence that fuel pressure is not right. Focus on that until you find the culprit. Once you have fully diagnosed that issue, fix that problem and then re-test. Any part you replace that wasn't actually broken is another potential issue being introduced to an already messy situation. The quality of replacement parts right now is terrible and you could very well be replacing a good part with a bad part, or a bad part with a bad part... you just don't know if you haven't VERIFIED.

Replace the fuel filter and pinch the return line off right there where it goes from soft line to hard line(pinch it off after you have replaced the filter and run the key on/engine off fuel pressure test). That is a service part and should be replaced regularly anyways.

 

[BeXtreme]

How do I pinch off the return line?

https://www.harborfreight.com/4-pie...jKtFenWA5tL2pKzmSG9NPVV2B8XFYKeoaAopnEALw_wcB
or
https://www.harborfreight.com/line-...KgmqJcLMcmGGnru0k1EWwdFp5o0GXu_QaAucQEALw_wcB
or I've used needle nose vise grips with another piece of rubber hose over the line to protect it from damage.