DTC 33 Map Sensor signal high low vacuum
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DTC 33 Map Sensor signal high low vacuum
Ok guys i'm tired of racking my brain over this one.
The car is currently throwing DTC 33. I've swapped a million things and tried a million others. Swapped MAP, map seal, map pigtail, check all voltages, signals, made sure it was grounded, just the whole 9 yards.
The car is a 95 TA M6 w/ 383 ported LT4 goodies and custom grind cam. The car has no AC, and I believe it used to throw the DTC 33 along with the AC pressure sensor off. I put the sensor back on and tucked it away and the PSI for the AC pressure sensor reads 5.2 which is on the positive side so it shouldn' throw the DTC 61 code (or at least I havn't seen it on Datamaster) but it used to before I hooked the sensor back up.
The car runs fine (so far as I know) it currently has a mail order tune keeping the engine alive thats still running pig rich. It starts good, w/ no miss, runs good w/ no miss, but heres where it gets troublesome. Whenever I go to stop at operating temperatures (like to turn around or at a stop light) the cars idle will drop from 950 (where its tuned at) to 550-600 and sound horrible untill i blip the throttle, but as soon as I let off it drops a few times again. It has a new MSD opti w/ maybe 1500 miles on it, new MSD wires, new fuel filter, new plugs, new coil, and about to install a MSD digital 6. The idle problem is getting progressivly worse, its doing it all the time now where it'd once do it once out of ever 5 times. The one thing I did forget to do was to put some loctite on the rotor bolts and this is for some reason what i'm leaning towards.
Can anybody help me out. Anymore information that you'll need feel free to ask for i'm sure that I left some information out. Thanks for your help in advance.
The car is currently throwing DTC 33. I've swapped a million things and tried a million others. Swapped MAP, map seal, map pigtail, check all voltages, signals, made sure it was grounded, just the whole 9 yards.
The car is a 95 TA M6 w/ 383 ported LT4 goodies and custom grind cam. The car has no AC, and I believe it used to throw the DTC 33 along with the AC pressure sensor off. I put the sensor back on and tucked it away and the PSI for the AC pressure sensor reads 5.2 which is on the positive side so it shouldn' throw the DTC 61 code (or at least I havn't seen it on Datamaster) but it used to before I hooked the sensor back up.
The car runs fine (so far as I know) it currently has a mail order tune keeping the engine alive thats still running pig rich. It starts good, w/ no miss, runs good w/ no miss, but heres where it gets troublesome. Whenever I go to stop at operating temperatures (like to turn around or at a stop light) the cars idle will drop from 950 (where its tuned at) to 550-600 and sound horrible untill i blip the throttle, but as soon as I let off it drops a few times again. It has a new MSD opti w/ maybe 1500 miles on it, new MSD wires, new fuel filter, new plugs, new coil, and about to install a MSD digital 6. The idle problem is getting progressivly worse, its doing it all the time now where it'd once do it once out of ever 5 times. The one thing I did forget to do was to put some loctite on the rotor bolts and this is for some reason what i'm leaning towards.
Can anybody help me out. Anymore information that you'll need feel free to ask for i'm sure that I left some information out. Thanks for your help in advance.
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Joined: Nov 1998
Posts: 71,094
From: Hell was full so they sent me to NJ
Can we assume your "custom grind cam" has a lot of overlap? That will cause it to idle rich, split BLM's, erratic idle, and have low vacuum (high MAP). Have you measured the MAP or vacuum at idle? Anything above 68kPa MAP will set DTC 33. Have you used a scanner to watch the IAC respond to the incorrect idle speed?
Sounds like it needs more than "mail order tune keeping the engine alive"
Sounds like it needs more than "mail order tune keeping the engine alive"
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