badbiddy8

Long story short - car has been tuned at 15psi (waste gate pressure). While driving around the eBay 3 bar map sensor went out. Towed it home - purchased a Motec 3 bar map sensor, Hondata boost solenoid, and a fuel pressure gauge.

Installed new MAP sensor and fuel pressure gauge - start car and its acting very lean - yeah maybe MAP sensor isn't calibrated the exact same but fuel pressure gauge is registering 80psi at idle.

1995 Acura Integra

Motor Setup:
GSR Block
B16 Head
CP Pistons - 9.0.1
Eagle Rods
ACL Bearings
ARP headstuds
Crower Valvetrain
GSR Cams / Cam gears
Factory distributor

Turbo Setup:
STC Reaper turbo
Spoolin Performance quick 4 manifold
Tial BOV
Tial Wastegate


Fuel Setup:
Stock FPR
Stock fuel filter
braided feed/return fuel lines
Walbro 450
FIC 1100cc injectors
E85

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1. Installed AEM fuel rail and AEM FPR to rule out stock FPR / stock rail. Still around 80 psi when priming the car.

2. Disconnected the return line and ran it to a bucket - still high pressure

3. Inspected fuel pump - removed sock and attempted to prime without the sock - still high pressure.


I'm starting to run out of ideas to try here..... I do have a new fuel filter I can install to see if that fixes the issue. One thing we thought about was potentially the eBay MAP sensor vs the new Motec MAP sensor will be calibrated differently and would require a new tune however I don't think its causing the high fuel pressure.

What is also weird is that running 80+ psi fuel pressure the car is running super lean and not rich..... makes me think its getting air in the lines from somewhere.

Let me know if you can think of anything else.

Thanks!
Bad Biddy

B and B

iTrader: (3)

Shitty fuel pressure gauge?
Btw, how/where is it mounted?
Really shouldn't have tuned on an ebay MAP, imo...Gm is cheap at the Vatozone, mine is 7 yrs. old.

badbiddy8

I'm going to admit it may not be the highest quality - Marshall gauge. Reads up to 90psi.

We removed it and tested it with a air compressor... Was able to achieve the correct reading compared to the output of the air compressor.

It's starting to get to the point where I'm getting dissapointed in the car.... When it was running on 15psi of boost recently I was having the time of my life... This is my first turbo build.

LightningTeg

Put the AEM back on and tune it down to correct base pressure.

badbiddy8

AEM rail / AEM FPR is currently installed now. I have the FPR unscrewed almost all the way out.

LightningTeg

There is a restriction somewhere.

D-Rob

The AEM regulator comes with three flow control orifices in different diameters. You need to size it accordingly to your supply.

You likely have the smallest unit in the regulator right now. Step up to the next larger size, and try.

motoxxxman

remember guys, he said it was happening with the stock rail and stock fpr, and is STILL doing it after installing the aem rail and fpr.

my first thought was also a bad guage. I still think it's a bad guage even though you tested it on an air compressor. personally I'd be finding a way to test the guage a bit better, like on a stock car, or next to a fuel pressure test kit guage.

if the guage truly is accurate, the only way it can reach that high is if there's a restriction in the return line somewhere.

ignore the fact that it's running lean. fuel pressure wont affect fueling anywhere near as much as a map sensor with different calibrations. you'll need to have your map adjusted for the new map sensor. theoretically once the sensor is calibrated correctly, it should run exactly the same as before. in reality, that doesn't always happen and often needs some touchups to the actual tune to get it back on par. of course make sure to sort the fuel pressure issue first though.

Turbo-LS

iTrader: (4)

Stock regulator has very small outlet. And if he didn't change the size on the aem it comes standard with a very small outlet. I have the largest orifice in my arm and screwed all the way out and my base pressure with a Walbro 450 is 55 psi static

badbiddy8

Interesting! I will have to put the large orifice in and see if that helps with the issue some.

badbiddy8

Thank you for the information! I went from a eBay GM 3 bar map sensor to a Motec 3 bar sensor. Within my s300 on the old MAP sensor we tuned under the Motec sensor setting. Going to install larger AEM orifice and purchase another gauge.... Any recommendations? B&M?

LightningTeg

I wouldn't go with a new gauge just yet. Do the orifice change and see what happens. If you do both you won't know if it was gauge or orifice but you said you tested the gauge so in gonna guess it's fine

badbiddy8

True... too many variables working with. I got my fuel rail / FPR as a complete setup from a friend without the orifices. I just ordered through Amazon Prime a AEM FPR rebuild kit which comes with the orifices.

Last thing to replace would be the fuel filter.... but it wouldn't make sense it would be that.... but nonetheless I do have a new filter in my garage currently.

Turbo-LS

iTrader: (4)

Rule of thumb also, once fuel pressure is squared away. Whenever you change Map sensors you should retune or clean up the tune. You could put back to back same brand sensor and it'll change to some degree. I've never seen an example where changing map sensors and selecting a new one in the preferences resulted in the car running exactly the same and the tune be spot on. There is always variables in the way the transducer reacts etc..

badbiddy8

Thanks for the insight! New orifices came in the mail today! Hopefully will get to it today or tomorrow!

motoxxxman

that is going to be a problem, they run quite different signal patterns. you are going to need a complete retune.

badbiddy8

Yeah I figured I would need too.

badbiddy8

****Figured out the issue*****

Got my orifices in the other day.... Took the AEM FPR off and low and behold check out what I found.



The orifice was anodized or something too much. You can see in the next picture I had to literally chip the extra material off to even see through the hole. I installed the largest orifice anyways. Sitting at a nice adjustable 43PSI now! I'm thinking I might post on AEM's Facebook about this....