Sensor circuit commons.. SD vs MAF
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From: Honolulu, Hawaii
Sensor circuit commons.. SD vs MAF
Working on tuning my new acquisition. I've modified the "basics" to get it to run (changed tune for injectors, took out 3 degrees of spark advance across the board, fan speeds, EGR/AIR delete). I need several sensors that I know of for sure... most notably a new MAF (old Granatelli reads 471g/sec in both cars), and a new MAP (reads fine but is visibly broken on top of manifold). The car is running and somewhat driveable right now. I have an idle issue where it has a hard time staying idling off throttle and coming to a stop. I'm also currently running speed density mode due to the MAF being bad. So here's the "main" problem:
I tried to connect my working MAF from my other car, and enable MAF control. Even with the "good" MAF, I get a MAF system failure, a low and high res distributor failure, and an ECT failure. None seem "permanent", they come in momentarily and don't come back in for a bit. Sometimes not in long enough to even illuminate the SES. The WEIRD thing is, if the MAF is disconnected and I'm running SD, NONE of these codes come in at ALL. I can see where there are some splices that aren't well done in the engine bay, they appear to be in the same loom as the MAF sensor. Is the opti, ECT, and MAF all on a common loom, and perhaps share a ground? It seems weird that the only difference is the MAF and yet ALL those codes come in one way vs. the other.
For the idle problem.... at initial startup, IAC counts read 160 and the car BARELY idles... set at 800 all temperatures and conditions and initially runs at 575-625, as it warms up the IAC counts start to fall. Last night it settled out at a steady 800 rpm idle with IAC at 80. Off throttle as described above, the counts initially go to 40 or so, then rapidly climb to about 120-130. A few times it has stalled if I let it, but usually it will pick itself back up.
Additional issues: both O2's seem to be failing (perhaps because the shop that installed the headers spliced normal wiring into the sensor looms with NO protection). Car is fairly modified (see sig car #2) and running on a mostly stock program.
Any help appreciated.
Jonota
I tried to connect my working MAF from my other car, and enable MAF control. Even with the "good" MAF, I get a MAF system failure, a low and high res distributor failure, and an ECT failure. None seem "permanent", they come in momentarily and don't come back in for a bit. Sometimes not in long enough to even illuminate the SES. The WEIRD thing is, if the MAF is disconnected and I'm running SD, NONE of these codes come in at ALL. I can see where there are some splices that aren't well done in the engine bay, they appear to be in the same loom as the MAF sensor. Is the opti, ECT, and MAF all on a common loom, and perhaps share a ground? It seems weird that the only difference is the MAF and yet ALL those codes come in one way vs. the other.
For the idle problem.... at initial startup, IAC counts read 160 and the car BARELY idles... set at 800 all temperatures and conditions and initially runs at 575-625, as it warms up the IAC counts start to fall. Last night it settled out at a steady 800 rpm idle with IAC at 80. Off throttle as described above, the counts initially go to 40 or so, then rapidly climb to about 120-130. A few times it has stalled if I let it, but usually it will pick itself back up.
Additional issues: both O2's seem to be failing (perhaps because the shop that installed the headers spliced normal wiring into the sensor looms with NO protection). Car is fairly modified (see sig car #2) and running on a mostly stock program.
Any help appreciated.
Jonota
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