CJM: Ultimate 370z Fuel Pump Thread

[phunk]

I do have a complete replacement fuel pump module for the 370z coming out as soon as some suppliers on a few of the components new to my inventory follow through on their end. This new module will not use any components at all from the factory fuel pump module, so you wouldnt needed the stock pieces. But it will require a return system to use it, and it also will not be released for quite possibly several weeks yet at this point.

[Jayhovah]

Awesome! Thanks!

Looks like the JB weld product "AutoWeld" is made for repairing gas tanks... there is a reviewer on amazon that successfully used it on a plastic tank... hopefully it will bond to the plastic the black venturi piece is made of. O'Reilly carries it, so I can try it out tomorrow if drilling the regulator solves the idle pressure.

I think I'll probably shop for a replacement assembly anyway... There is a member here parting out his car so I posted to his thread..

[Jayhovah]

Originally Posted by phunk

I do have a complete replacement fuel pump module for the 370z coming out as soon as some suppliers on a few of the components new to my inventory follow through on their end. This new module will not use any components at all from the factory fuel pump module, so you wouldnt needed the stock pieces. But it will require a return system to use it, and it also will not be released for quite possibly several weeks yet at this point.

Good to know! I am still mulling over if I want to go E85 with a return setup in the future... my Z is my primary driver and I worry that going up to 650+whp I may start compromising the longevity of the motor and drivetrain. I go back and forth thinking about it..

[ChaseZ]

Originally Posted by Jayhovah

650+whp

That has such a nice ring to it

Just rolls off your tongue so nicely!

[Jayhovah]

One more question! Perhaps the one I should have led with! Could high idle pressure result in a wobbly idle? It only seems to happen with the car warm and the AC off.

Originally Posted by ChaseZ

That has such a nice ring to it

Just rolls off your tongue so nicely!

I know..... I know......

[phunk]

If the A/F is clean at the moment it is happening, than it is unlikely related to the fuel pressure. The o2 sensor feedback system will typically adjust for a fuel pressure spike at idle with ease so long as it is not outside its range of allowed correction. If your car has a custom tune that was generated on your car while the fuel pressure had the same profile, its even less likely related.

[Jayhovah]

Originally Posted by phunk

If the A/F is clean at the moment it is happening, than it is unlikely related to the fuel pressure. The o2 sensor feedback system will typically adjust for a fuel pressure spike at idle with ease so long as it is not outside its range of allowed correction. If your car has a custom tune that was generated on your car while the fuel pressure had the same profile, its even less likely related.

Ahhh.. I REALLY should have asked you before embarking on this lol.

The good news is, I was able to get an assembly from a wrecked Z for cheap so I will just replace the small venturi piece and call it a day... I would experiment with drilling the regulator, but the assembly I picked up is not 100% as the accident the car was in snapped the rods connecting the hat to the bucket... If i was completely functional, I would experiment till the cow's came home since I could just pop in the replacement.

Based on this feedback, it looks like I should just restore the state to the way it was before since I was tuned that way anyway and it is not likely to be the source of my wandering idle. The search continues!

Thanks a lot for your guidance on this phunk! You are the gold standard for vendors around here.

PS - I'll post a FS thread soon to part out the extra assembly. Should save some headache for anyone else that just needs a small piece.

[Jayhovah]

Swapped out the unmodified venturi piece from my salvage pump assembly.

My idle pressure with it is 65psi... So it looks like it was lowered ~5psi from drilling the venturi just to 5/64...but then nothing gained after that (even after I drilled the whole thing accidentally). I think to start, the venturi system was the bottleneck, but not far after the regulator became the bottleneck... I would speculate that I'd need to drill both the venturi piece and the regulator as directed in the Stillen instructions to get a more normal idle pressure.

But as phunk pointed out - my car was tuned with the idle pressure like this.. so I have decided to leave it alone.

Fuel pressure now:

[phunk]

Originally Posted by Jayhovah

Swapped out the unmodified venturi piece from my salvage pump assembly.

My idle pressure with it is 65psi... So it looks like it was lowered ~5psi from drilling the venturi just to 5/64...but then nothing gained after that (even after I drilled the whole thing accidentally). I think to start, the venturi system was the bottleneck, but not far after the regulator became the bottleneck... I would speculate that I'd need to drill both the venturi piece and the regulator as directed in the Stillen instructions to get a more normal idle pressure.

But as phunk pointed out - my car was tuned with the idle pressure like this.. so I have decided to leave it alone.

Fuel pressure now:

I would try reving the engine and seeing if the pressure falls down. If the regulator needed to be drilled to flow better on its outlet, pressure should fall down when fuel consumption increases.

[Jayhovah]

Originally Posted by phunk

I would try reving the engine and seeing if the pressure falls down. If the regulator needed to be drilled to flow better on its outlet, pressure should fall down when fuel consumption increases.

I'll give it a shot and take a little video... though it will have to wait at the moment as I am in the middle of a diff bushings/cover upgrade... Hopefully I'll have it back together tomorrow evening!

[ChaseZ]

I swapped on the Aero 340 I got from Charles and drilled the Venturi as instructed. I was reviewing the Stillen instruction book after my install to make sure I didn't miss anything and noticed they call for drilling out the regulator as well, but I don't recall seeing that in the. JM fuel pump,swap instructions. Though there is a lot of "if you have this, do this step, or not" and vice versa, so it's possible I just missed it.

Can someone confirm if I need to drill the regulator in the stock basket assembly with the Aero 340 or not?

Thanks in advance

[Jayhovah]

Originally Posted by ChaseZ

I swapped on the Aero 340 I got from Charles and drilled the Venturi as instructed. I was reviewing the Stillen instruction book after my install to make sure I didn't miss anything and noticed they call for drilling out the regulator as well, but I don't recall seeing that in the. JM fuel pump,swap instructions. Though there is a lot of "if you have this, do this step, or not" and vice versa, so it's possible I just missed it.

Can someone confirm if I need to drill the regulator in the stock basket assembly with the Aero 340 or not?

Thanks in advance

The speculation through my fuel pump fiasco is that I probably needed to drill the regulator since I took the black venturi piece out completely and it still did not lower my fuel pressure very much. Since I decided to leave it the way it was and since it probably is not the source of my wobbly idle I ended up putting everything back the way it was... unfortunately all I can offer is speculation =)

[ChaseZ]

Originally Posted by Jayhovah

The speculation through my fuel pump fiasco is that I probably needed to drill the regulator since I took the black venturi piece out completely and it still did not lower my fuel pressure very much. Since I decided to leave it the way it was and since it probably is not the source of my wobbly idle I ended up putting everything back the way it was... unfortunately all I can offer is speculation =)

I don't have a gauge on it yet since I couldn't fit CJ's tap at the dampener so not sure what psi it is idling at. Actually running around trying to find one locally that will work today.

I was getting spikes/surging when I first started it up with a base tune but that has gone away after Seb revised the tune a couple times. I'm still idling a touch high by maybe 100rpm or so but can't do the Ecutek idle learn with SD tuning, it just doesn't work.

Hopefully I can get a gauge on there today and see where things are at. I suppose that is what will actually dictate if I need to drill the regulator out or not.

[ChaseZ]

What is the target fuel pressure anyhow? I've just assumed it was around 55-60psi...

[Jayhovah]

Originally Posted by ChaseZ

What is the target fuel pressure anyhow? I've just assumed it was around 55-60psi...

52psi is stock.