Quote:
Originally Posted by sweetbmxrider
S244, fuel level sensor and fuel pressure sensor are on the same circuit. there's your problem.
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My initial instinct is you are looking on the wrong side of the pcm for fuel gauge reading. that is the serial out of the PCM. I'm thinking you can tap the lead right off the sender. I'm not even sure why the pcm needs fuel level info for running the engine, but it does appear to impact emissions related items. I'd bet 99.9% of the conversions out there do not use fuel level in. You can't tell me that all the LS swaps in old cars use fuel level in.
From reading the 99 service manual it appears EVAP and fuel pressure sensor work in unison to some degree. Some EVAP codes need 15%-85% fuel level as a testing condition. EVAP issues may throw off fuel pressure readings, which is based on tank pressure, not line pressure as you’d think of it. So based on 30 minutes of reading DTC codes and looking at diagrams, I think you can make both work but I’d stay as close to OE as possible and your EVAP connections need to be spot on. And I see zero evidence of feed back from the gauges. EVAP and FP readings both go to the pcm 1st, then a serieal out for fuel level to the gagues. Why would they get a reading back?
I think this is a decent primer document:
http://www.gmperformanceparts.com/_r...44807E-ROD.pdf