PCM Diagnostics & Tuning HP Tuners | Holley | Diablo

What is my problem?

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Old Jun 6, 2006 | 07:06 PM
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Default What is my problem?

I think I have a bad ground or messed up wiring on my car.(its not tuning) My car started to hestitate real bad off idle to 2000rpms a couple months ago, I knew it was the maf, I put a new maf on and it solved it for about 3 weeks and now it's happening all over again. I know if I put another good maf it will solve it temporarily only to destroy another maf. Something is causing my maf to go bad. Any ideas? If it is a bad ground or wiring, what can be done? What is my worse case scenario? Could this be an expensive problem?
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Old Jun 6, 2006 | 07:16 PM
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When you say it's not tuning you mean no codes?
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Old Jun 6, 2006 | 07:29 PM
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Originally Posted by 2001NBMZ28
When you say it's not tuning you mean no codes?
Yes, no codes, my tuner has checked it and said it can't be. Is there something i may have done when working on the car to short something out or mess up a ground?
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Old Jun 6, 2006 | 08:43 PM
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Do you have a Oiled air filter? Too much oil and not enough time to dry will foul the MAF senor components. You can carefully clean it with electronics cleaner.
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Old Jun 7, 2006 | 06:24 AM
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I have done that and it did not help, I'm pretty sure it is not my air filter.
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Old Jun 7, 2006 | 07:30 AM
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Consider an SD tune, its not a fix, but a work around.
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Old Jun 7, 2006 | 07:18 PM
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Really don't want an sd tune b/c of the sensitivity to weather conditions. If I really did fry a ground or wire, what would I have to do to fix this? Would I have to replace the whole engine wiring harness? Why do my mafs keep burning out after three weeks?
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Old Jun 7, 2006 | 08:29 PM
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If the MAF is really bad you should see a code. The MAF
has only a little influence down around idle and tip-in is
ignoring the MAF entirely (unsteady MAP). I don't know
why swapping MAFs would make a temporary difference.

The main wiring sensitivity a MAF would have, is electrical
noise (EMI) messing up the frequency as read by the PCM,
or a gross supply/ground fault that cuts its power or the
output pullup. It could be in the connector (having to do
with the swap temporarily improving things) perhaps; pins
do push out.

'98s do have that knock sensor problem and this could be
where the hesitation comes in (perhaps following some
light ping on tip-in, from whatever source).

What this situation really needs is some street logging
to find the relevant symptoms as the PCM sees things.
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Old Jun 7, 2006 | 08:30 PM
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Sounds like the start of a failing o2 sensor to me.
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Old Jun 7, 2006 | 08:44 PM
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Originally Posted by keliente
Sounds like the start of a failing o2 sensor to me.
Just replaced precat o2s and the aftercat o2s are shut off.
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Old Jun 7, 2006 | 08:51 PM
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Two weeks after this hesitatio started, the code PO103 came up for bad maf and i reset it, a week later it came back, cleared it again, a week later, i replaced the maf, good for three weeks and now it is hesitating again but the ses has not come on yet, but i'm waiting.
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Old Jun 13, 2006 | 03:02 PM
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I cleaned my maf and the connectors put it back on and is good for now but for how long I do not know. Did this to my old maf and it was only a temp. fix. Does it have to do with the maf wiring connector that plugs into the maf?
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Old Jun 14, 2006 | 08:13 PM
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yeah, the hesitation is still there. Wasn't the temp sensor, my fuel pressure is good. Would having Hp tuners hooked up while this is hesitation clear things up? I think it has something to do with the maf even though there are no codes. It is such a mystery, would having the car dyno-tuned again solve my problem?
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Old Jun 14, 2006 | 10:23 PM
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IMHO, no on the dyno tune-Most likely at what you will get charged to simply run the car on the dyno trying to find a bug like this won't be economical-unless your best friend just happens to own a dyno. In btw MAF changes did you ever pull the battery? Or in anyway did the fuel trims get reset?? Did the Dyno tuner reset your fuel trims? Bad wiring should manifest it'self in a code in pretty short order-most of the time. Unfortuneatly, without a street scan it's going to be hard to nail this down. First of all a street scan will A)Tell you where your fuel trims are at B) Tell you if you are in fact in Closed Loop fueling, i.e. the pcm is taking the MAF's input, as in Open Loop it is not. Need to find out what your pcm is thinking / seeing.
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Old Sep 16, 2006 | 05:01 PM
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98camarols1 did you ever find out what the problem was. i'm having very similar issues and about to just go with a SD tune. i know it has to do with the maf though. unplug your maf and drive the car a little. i did this and the hesitation went away, which told me it was the maf. unfortunetly we can't leave it unplugged because it screws with WOT.
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Old Sep 16, 2006 | 05:12 PM
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Driving in the rain ruined mine
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Old Sep 16, 2006 | 05:26 PM
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i got a tune from EPP and the car ran perfect for about a week. then i drove through a bad storm and car started hesitating bad. it's been doing it ever since, but the thing is...i cleaned mine, same thing, i swapped it with my brothers which works fine on his car...same thing. i unplugged it and car ran like a dream again, plug it back in and car runs like ****. wtf?
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Old Sep 18, 2006 | 12:46 AM
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Check for vacuum leaks as well.
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