About 30 seconds after the warranty expired on my Autometer fuel pressure gauge my fuel pressure started reading low. Turn the key on and it would only show around 30psi, at idle around 18psi, and at WOT it might to up to 30 again. But my a/f was good so I didn't really pay much attention to it (other than it annoying the hell out of me). Pulled the sending unit out, cleaned it with some carb cleaner, put it back in, seemed to have fixed the issue.
Few months pass and it does it again. Tried the same cleaning idea, no difference. So I pulled the Zex adaptor off and got an adaptor with two fitting holes. Put the fuel pressure sending unit in one, and a mechanical gauge in the other. There is a good 10psi at idle and nearly 20psi at WOT difference between the two gauges. And no, I didn't run beside the car with the hood up and someone driving to look at it. I saw it during a dyno run. At least that confirmed that it was the gauge and not an actual lack of fuel pressure.
Zoom forward a few more months to today. Had some spare time so I decided to pull out the SOS pillar pod and install the SOS dash pod. After coming up with a couple of new cuss words while routing all the wiring through the defroster vents I plug in the gauges and turn on the key to make sure everything is working. The fuel pressure gauge cycled then went to 100psi. It has done this a couple of times in the past but usually turning the key off and back on would correct it. And if not it would correct itself within a mile or two of driving. But not this time. Damn thing goes right to 100psi and stays there. I triple checked all the wiring and with the exception of one question I see absolutely nothing wrong. That one question is which one of the two black wires goes to the sending unit and which one goes direct to ground. I am pretty sure I know by compairing the plug to the plug on my water temp gauge. It has 5 wires, the fuel pressure gauge has 6. And I am 99% certain that the "6th" wire is the one that goes to the sending unit.
Only reason this is even a question is because I had to cut the wiring to get it through the dash vent because the friggin plugs were too big to go through the vent. Both wires in question appear to be a ground so even if they were flipped I don't see it causing the gauge issue. But just to satasify my own curiosity I swapped them and it made no difference.
I fucked with this one stupid gauge for about 2 hours trying to figure out what I could have screwed up moving it and came up with nothing. Now for the REALLY jacked up part. Swap the fuel pressure gauge with the water temp gauge ( same pinout on the plug, just one extra black wire ) and turn the key on and the water temp gauge goes straight to 260 degrees. Basically does the same thing as the fuel pressure gauge. So I figure I would try the fuel pressure on the water temp harness. Yea... well that was pissin' in the wind. It still went straight to 100. Put the gauges back to their correct wiring harnesses and the water temp works as normal, fuel pressure is still maxed out.
One thing I did notice. If I unplug the sending unit, gauge does the same thing. So it is like it is not getting any signal at all after it's initial sweep. I don't know if the gauge just shit the bed or if the sending unit went south. Either way it doesn't matter. Can't buy the damn sending units from Autometer. I know, I tried. You can get them from Summit, couple of other aftermarket places, but not from Autometer. So it looks like I am out $100+ for another damn fuel pressure gauge sensor. Or possibly an entire new gauge setup.
Does anyone know if ALL Autometer digital gauges ( i.e. Cobalt, C2, Sport Comp ) have the same pinout configuration? I do have a buddy that has Sport Comps in his car. Might try my gauge in his car and/or his gauge in my car to see if I can at least narrow this horseshit down a little.
As a side note. The SOS dash pods look great. BUT... just say screw it and get the "drill" model instead of the no drill model. Getting the wiring down through the vents is a complete pain in the ass. I think if I had to do it all over again, or if I had helped someone else do theirs first, I wouldn't think twice about the version that you drill a hole in the dash and run the wires up through the hole instead of the version that you run the wiring through the defroster vents.
Few months pass and it does it again. Tried the same cleaning idea, no difference. So I pulled the Zex adaptor off and got an adaptor with two fitting holes. Put the fuel pressure sending unit in one, and a mechanical gauge in the other. There is a good 10psi at idle and nearly 20psi at WOT difference between the two gauges. And no, I didn't run beside the car with the hood up and someone driving to look at it. I saw it during a dyno run. At least that confirmed that it was the gauge and not an actual lack of fuel pressure.
Zoom forward a few more months to today. Had some spare time so I decided to pull out the SOS pillar pod and install the SOS dash pod. After coming up with a couple of new cuss words while routing all the wiring through the defroster vents I plug in the gauges and turn on the key to make sure everything is working. The fuel pressure gauge cycled then went to 100psi. It has done this a couple of times in the past but usually turning the key off and back on would correct it. And if not it would correct itself within a mile or two of driving. But not this time. Damn thing goes right to 100psi and stays there. I triple checked all the wiring and with the exception of one question I see absolutely nothing wrong. That one question is which one of the two black wires goes to the sending unit and which one goes direct to ground. I am pretty sure I know by compairing the plug to the plug on my water temp gauge. It has 5 wires, the fuel pressure gauge has 6. And I am 99% certain that the "6th" wire is the one that goes to the sending unit.
Only reason this is even a question is because I had to cut the wiring to get it through the dash vent because the friggin plugs were too big to go through the vent. Both wires in question appear to be a ground so even if they were flipped I don't see it causing the gauge issue. But just to satasify my own curiosity I swapped them and it made no difference.
I fucked with this one stupid gauge for about 2 hours trying to figure out what I could have screwed up moving it and came up with nothing. Now for the REALLY jacked up part. Swap the fuel pressure gauge with the water temp gauge ( same pinout on the plug, just one extra black wire ) and turn the key on and the water temp gauge goes straight to 260 degrees. Basically does the same thing as the fuel pressure gauge. So I figure I would try the fuel pressure on the water temp harness. Yea... well that was pissin' in the wind. It still went straight to 100. Put the gauges back to their correct wiring harnesses and the water temp works as normal, fuel pressure is still maxed out.
One thing I did notice. If I unplug the sending unit, gauge does the same thing. So it is like it is not getting any signal at all after it's initial sweep. I don't know if the gauge just shit the bed or if the sending unit went south. Either way it doesn't matter. Can't buy the damn sending units from Autometer. I know, I tried. You can get them from Summit, couple of other aftermarket places, but not from Autometer. So it looks like I am out $100+ for another damn fuel pressure gauge sensor. Or possibly an entire new gauge setup.
Does anyone know if ALL Autometer digital gauges ( i.e. Cobalt, C2, Sport Comp ) have the same pinout configuration? I do have a buddy that has Sport Comps in his car. Might try my gauge in his car and/or his gauge in my car to see if I can at least narrow this horseshit down a little.
As a side note. The SOS dash pods look great. BUT... just say screw it and get the "drill" model instead of the no drill model. Getting the wiring down through the vents is a complete pain in the ass. I think if I had to do it all over again, or if I had helped someone else do theirs first, I wouldn't think twice about the version that you drill a hole in the dash and run the wires up through the hole instead of the version that you run the wiring through the defroster vents.
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