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Old 06-04-2014, 08:45 AM
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2000 wj 4.7 p0108

My GC has started running a bit rough and P0108 is the code that is stored. I disconnected the battery, pulled the throttle body, cleaned it and the IAC, and cleaned the connectors for the MAP, IAC, and TPS. The IAC looks newish, a bit of a crescent of silver on the tip. The jeep ran ok for a couple days, then choked, CEL came on, and the code set again.

The symptoms all seem to be at low speed. Most take offs choke and then the RPMs jump to where they should be and no issues until the next take off. When coming to a stop, the RPMs seem to step down once I stop, 900, 750ish, and finally settle at 650. It can choke and stumble a bit when at low speed, ~25mph. If I stop when its doing this, she will most likely die, but will fire right back up. What should I look at next? Could it be as simple as replacing the IAC? Or do I need to figure out to get that MAP sensor out of there?
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Old 06-04-2014, 04:44 PM
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Re: 2000 wj 4.7 p0108

Welcome to the garage.
The P0108 code is a MAP sensor voltage too high. (Too low of a vacuum as seen by the PCM. This could be a vacuum leak at the intake, a fault of the MAP sensor, a worn engine or the PCM. If you have a scanner with live data, then you could check the MAP with engine off. At sea level it should be around the 1.5V. You could check the value while moving the wiring and see if there is any change. If voltage with engine off is far from 1.5V, then probably the MAP sensor is fault or the ground connection is bad (corroded ground lug connection.) I will see which ground is used and let you know.
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Old 06-04-2014, 05:04 PM
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Re: 2000 wj 4.7 p0108

Ground for the MAP sensor comes via the PCM, but there is a splice close to injector #7. Check the MAP voltage with engine off while wiggling the splice. If you get a voltage change, then most probably the splice is bad.
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Old 06-05-2014, 06:21 AM
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Re: 2000 wj 4.7 p0108

Excellent info. I will attempt to tackle it this weekend. Would a bluetooth dongle and the Torque app be good enough for a live data scanner?
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Old 06-05-2014, 06:58 AM
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Re: 2000 wj 4.7 p0108

Torque has the possibility to show barometric pressure and inlet pressure, i only donīt remember if it was available on my jeep. Will try it out and let you know. It is at least a good idea to get a bluetooth dongle and the torque app, because it can be of great use in the future.
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Old 06-05-2014, 07:02 AM
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Re: 2000 wj 4.7 p0108

Do you have a dongle that you recommend? The longer I have the GC, the more I realize I should pick up some of these nifty tools. That and I never want to own a Mopar product again haha.
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Old 06-05-2014, 07:58 AM
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Re: 2000 wj 4.7 p0108

I did buy a cheap bluetooth dongle direct from China. (www.dealextream.com) Took one month to arrive, but cheap and no shipping. It allways worked well, but today it will not show any data on Torque
Hooked up my normal scanner and the MAP was around 93 kPa for both my cars (engine off) and 29 kPa for the jeep with engine running. My scanner doesnīt show the voltage.
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Old 06-20-2014, 06:24 AM
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Re: 2000 wj 4.7 p0108

Got the volt meter and did some testing with a buddy that is much better with electricity than I am. Turns out the MAP had ate itself, quick swap and everything is happy now. Thanks for the help man. My OBD2 scanner is still out in the shipping ether though ><
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Old 06-20-2014, 07:25 AM
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Re: 2000 wj 4.7 p0108

Good to hear, happy jeeping.
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