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Raw fuel on my 89 IROC TPI, need help

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Old 02-21-2016, 05:45 PM
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Raw fuel on my 89 IROC TPI, need help

I replaced a set of 23lbs Accel injectors back in the summer. It ran fine for 2 weeks until I noticed a distinctive smell of fuel when starting. I thought it might of been running too rich but it was raw fuel coming out of the tailpipe. shut it down right away then de-flooded all of the cylinders as it hydro-locked with so much fuel. Took the injectors and exchanged them with a new set. Still same problem. Then I remembered the exact same issue almost 10 years ago and I replaced the ECM. so I did that too, same problem. Anybody know what's causing all this? Checked fuel pressure on the rail and vacuum on the regulator. Any thoughts?
Old 02-21-2016, 06:44 PM
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Re: Raw fuel on my 89 IROC TPI, need help

I forget if the injectors are ground side switched or not, but you could pull a bank off and ohm it out to ground and make sure it's not shorted somewhere causing the injectors to always be on?
Old 02-23-2016, 12:55 PM
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Re: Raw fuel on my 89 IROC TPI, need help

I had a very similar problem on a Pontiac Ferro with the 2.8. Raw fuel from static injectors. The car would run and run well in the higher RPMs. I made the 150 miles home, but did not get the best mileage! The problem ended up being a bad ESC. It was causing one bank of injectors to stay open when ever the car was running. It was replace and the car ran great. Might be worth looking at.
Old 02-24-2016, 08:28 PM
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Re: Raw fuel on my 89 IROC TPI, need help

you might want to check the diaphragm on your regulator and your O2 sensor
Old 02-27-2016, 09:48 PM
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Re: Raw fuel on my 89 IROC TPI, need help

Also check that your MAP sensor didn't get disconnected when you were taking things apart.
Old 01-22-2017, 08:06 PM
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Re: Raw fuel on my 89 IROC TPI, need help

Replaced the fuel pressure regulator as the diaphragm was completely ruptured. Ran for a day and then it ran very rich and this time it stayed running but no raw fuel from the tailpipe. Took everything apart again and inspected the diaphragm on the new regulator that was replaced and it was starting to tear again. This time I removed the fuel line that crosses between the fuel rail and the fuel regulator to take a closer look. Found something in the line that was blocking the return line and the secondary line that feeds into the fuel rails. Not sure what the substance is as it looked like a calcium build up but nor corrosion. Tried to blow air pressure through my compressor and wouldn't come out. Had to source out new fuel rails and lines from a local guy that had one for a 90 Vette. Replace the new regulator under warranty (didn't tell them about the plugged fuel rail) and now it running normal. But still don't know what that white calcium or whatever that is. One suggested it's sugar but it should of screwed up the fuel pump first before reaching the injectors. The only thing I can think of is that I used teflon tape around the flex lines on the fittings for both the main and return line. Do you think this might of chemically broken up and caused the plug up on the rails? Any thoughts?
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