ECMlink RESOLVED - Fuel pressure sensor reading 4.47v

[Yaakob]

Hey everyone. Kind of an odd question but maybe someone has dealt with something similar in the past. I picked up an AEM 0-100 psi fuel pressure sensor a few weeks back. Got it all wired up using this photo

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Set EGT to autometer 2246, have it displayed and such. However its only reading 4.47v and 99psi of fuel. Currently have it temporarily installed with a gm tps sensor connector, tried aem’s connector and no such luck. Hoping someone might have also come across this issue and was curious to know how they eventually solved it.

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[DSMPT]

It seems you are connecting the 5v power and ground oppositely.
The sensor's pigtail you are using has the wire color as below.
Black = 5V Power Input
White = Ground
Blue = Signal Output

 

[Yaakob]

It seems you are connecting the 5v power and ground oppositely.
The sensor's pigtail you are using has the wire color as below.
Black = 5V Power Input
White = Ground
Blue = Signal Output

In the photo I did actually have 5v power and ground flipped, I didnt realize it at the time because I was in a rush. But they've been corrected. Still no luck unfortunately.

 

[DSMPT]

Assuming now you have everything wired properly, remove the sensor from the FPR and block off the sensor port on the FPR, then turn the key on. The sensor should send approxi 0.5v. If it's still sending 4.5v instead of 0.5v, then you may have shorted the sensor internally.

 

[Yaakob]

Assuming now you have everything wired properly, remove the sensor from the FPR and block off the sensor port on the FPR, then turn the key on. The sensor should send approxi 0.5v. If it's still sending 4.5v instead of 0.5v, then you may have shorted the sensor internally.

Good idea! Ill have to try that in the morning!

 

[Yaakob]

Assuming now you have everything wired properly, remove the sensor from the FPR and block off the sensor port on the FPR, then turn the key on. The sensor should send approxi 0.5v. If it's still sending 4.5v instead of 0.5v, then you may have shorted the sensor internally.

So i pulled the sensor out and reinstalled my original analog gauge. Kicked the key on and activated the fuel pump via ECMLink. Was still showing 4.47v. Ill insert a picture and i can throw a quick log up of it

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Edit: just ended up screen shotting the datalog since i didnt see a reason to upload an entire 30 second log of nothing moving other then time

 

[1990TSIAWDTALON]

Mine reads 111 all the time, same issue. Make sure you haven't locked the EGR temp in ECMLink on the Misc tab, I believe.

 

[DSMPT]

Check the voltage with key on but engine off, between the black power wire and the white ground wire, the blue signal wire and the white ground by a voltmeter. If it reads 5v on the black wire and 0.5v on the blue wire, the sensor and wiring is fine. If it reads 4.5v on the blue wire, most likely you need to replace the sensor.

 

[Yaakob]

Mine reads 111 all the time, same issue. Make sure you haven't locked the EGR temp in ECMLink on the Misc tab, I believe.

Oh damn i didnt even think of that. I’ll go check that now

Edit: Just checked, EGT is unlocked. If only it was that easy

 

[1990TSIAWDTALON]

I was hoping......well check that off the list. Darn!

 

[Yaakob]

I was hoping......well check that off the list. Darn!

Check the voltage with key on but engine off, between the black power wire and the white ground wire, the blue signal wire and the white ground by a voltmeter. If it reads 5v on the black wire and 0.5v on the blue wire, the sensor and wiring is fine. If it reads 4.5v on the blue wire, most likely you need to replace the sensor.

Well i believe i have potentially sorted it out. I ran continuity from signal input to pin 15 and got nothing. So either theres another blue/yellow wire that i managed to tap into, or i have a break somewhere that i need to find this weekend

 

[1990TSIAWDTALON]

Don't feel alone in this. Mine started doing the same thing when I was beginning a tune with Kevin Jewer. It worked long enough for him to see that we were getting adequate fuel pressure and it quit reading about 2 weeks after I installed it. I bought another sensor and put it in but got the same thing......stuck at 111. If you find a break somewhere, post up where you found it. It may be the same thing that is wrong with mine. These are old cars so nothing really surprises me anymore.

 

[Yaakob]

Don't feel alone in this. Mine started doing the same thing when I was beginning a tune with Kevin Jewer. It worked long enough for him to see that we were getting adequate fuel pressure and it quit reading about 2 weeks after I installed it. I bought another sensor and put it in but got the same thing......stuck at 111. If you find a break somewhere, post up where you found it. It may be the same thing that is wrong with mine. These are old cars so nothing really surprises me anymore.

Thats actually the same situation I’m in too. Except mine didnt work from the start. Kevin and I have been trouble shooting it for about 2 weeks now. If i manage to find something ill let you know!

 

[1990TSIAWDTALON]

I finally went to a electrical pod mount gauge just to keep an eye on it and know I am not loosing pressure. We can't log it but I can verify it is working properly. Tell Kevin Marty says "hi"!

 

[Yaakob]

I finally went to a electrical pod mount gauge just to keep an eye on it and know I am not loosing pressure. We can't log it but I can verify it is working properly. Tell Kevin Marty says "hi"!

Sounds good! Hopefully we can figure it out soon so that way i can get back to trouble shooting the original reason i bought the sensor!

 

[1990TSIAWDTALON]

When you had your pump out, did you clean the sock? I had some fueling issues all last year and mine was from E85 jelling in my tank, making my sock suck itself closed resulting in dropping fuel pressure. I went thru 3 hellcat 525 pumps, 2 AFPR's, 2 MAP sensors, hell 2 of everything. I even got another ECU with link in it and the problem persisted. When I put my THIRD pump in (mind you, everytime I put a new pump in, the car would run GREAT, ONCE. After that it would loose fuel pressure) I reached into the tank and felt some of the metal in the tank and it was "slimey". You couldn't see it but it was like fish slime. It was coating my FP sock and then the sock would not pickup fuel so it couldn't deliver it. See HERE in one of my threads. It kept the car down a whole year.

 

[Vegas Smith]

Don't tap anything. It's easy to run 3 all-new wires to sensor. Just buy the correct crimping tool and some pins. Very easy. At least you will rule out any weird wiring issues.

 

[1990TSIAWDTALON]

While my ECU is sitting out I think that is something I should do. I do like to log FP and the ECU isnt mounted yet so its easily accessible.

 

[Yaakob]

When you had your pump out, did you clean the sock?

I did clean the sock when I had the pump out, it seemed alright. Didn't feel slimy. However the car hasn't run since I cleaned it, so I don't actually know if that could be the culprit just yet. I'm hoping its something simple. But I’m having similar issues as well. Right around 6k ish i loose a lot of fuel pressure and the car goes lean. So the sensor was initially going to be used to troubleshoot the drop in FP. Fingers crossed once this fps reads properly, finding the cause of the fuel pressure drop will come shortly after

Don't tap anything. It's easy to run 3 all-new wires to sensor. Just buy the correct crimping tool and some pins. Very easy. At least you will rule out any weird wiring issues.

That's the point where I'm at. This weekend ill probably just bypass the wire to pin 15 and replace it with a new one running straight to the fuel pressure sensor

 

[Yaakob]

Don't tap anything. It's easy to run 3 all-new wires to sensor.

Ended up doing what Vegas said and just ran a new wire straight to pin 15 for signal input, and wha-la, she reads fuel pressure now! So there must have been a break somewhere in the original wire.

 

[1990TSIAWDTALON]

I bet mine is that way also and I need to do the same!
Thanks for the solution!

 

[Yaakob]

I bet mine is that way also and I need to do the same!
Thanks for the solution!

Absolutely! Hopefully its your solution as well!

 

[1990TSIAWDTALON]

I ruled out everything except what you did too. My ECU is laying on the floor right now so now is the time to go ahead and rewire it direct. I wonder if any others have had an issue with the EGR temp wiring failing too.

 

[Yaakob]

I ruled out everything except what you did too. My ECU is laying on the floor right now so now is the time to go ahead and rewire it direct. I wonder if any others have had an issue with the EGR temp wiring failing too.

I had a strange feeling it was going to ultimately be my issue a few weeks ago. But i didnt want to just jump straight to chopping a wire at the ecu. But i guess it doesnt matter cause i had to do it in the end anyway

 

[1990TSIAWDTALON]

Gotta keep your tuner HAPPY!