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Unread 07-06-2013, 07:59 PM   #1
Winners97TJ
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Please, if you want to flame me.... go elsewhere. I know. I know. Lots of other people have posted about a bouncing or erratic idle. I am having the same issue. Yes, i searched but the suggestions haven't fixed the problem. I replaced my IAC, no change. New Battery, no change. (It started after the jeep sat for about 2 weeks and the battery had died. Recharged battery and issue was there. Battery slowly discharging itself so it needed to be swapped out regardless.) Pull the plug on the TPS and the idle shoots up to about 1200rpm and still bouncing. I have not REPLACED my TPS yet. That is next on the list. TPS DOES test like it should though. Smooth voltage change from closed to WOT. If I don't have to spend an extra $100 on a TPS, I'd rather not. I took a video of the start and idle. Check it out. Any input or help would be appreciated. Thanks everyone in advance.



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Unread 07-06-2013, 11:23 PM   #2
1982cj8
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Look at the tps voltage while at idle, if it is steady then the tps is not the problem, it is moves even a little it can cause idle fluctuation.
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Unread 07-07-2013, 04:22 PM   #3
Winners97TJ
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Quote:
Originally Posted by 1982cj8
Look at the tps voltage while at idle, if it is steady then the tps is not the problem, it is moves even a little it can cause idle fluctuation.
The idle is still bouncing, the voltage is remaining at .79 during bouncing idle. Any other thoughts?!
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Unread 07-07-2013, 04:33 PM   #4
MattJeep
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Voltage is at .79 with a scanner in the port or multimeter on the TPS? I had to change mine couple years ago after getting it wet washing the engine bay down. It would idle super high though, not erratically if I remember correctly. Vacuum leak?
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Unread 07-07-2013, 04:49 PM   #5
Winners97TJ
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Quote:
Originally Posted by MattJeep
Voltage is at .79 with a scanner in the port or multimeter on the TPS? I had to change mine couple years ago after getting it wet washing the engine bay down. It would idle super high though, not erratically if I remember correctly. Vacuum leak?
Multimeter at the TPS.

It's just very odd that there was no idle issue until after the 2 weeks of it sitting and the battery died.
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Unread 07-07-2013, 04:52 PM   #6
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Added note:

Smells like its running a little rich too. It usually has an added "fuel smell" due to the stroker and the straight-pipe-cat but this is a little stronger. Also has a VEEERY faint smoke out of the exhaust when the rpm are dropping. Then clears up as rpm rise back up again.
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Unread 07-07-2013, 04:56 PM   #7
MattJeep
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O2 sensor? Mine ran stupid rich and crappy when front O2 was bad. Worse than what a bad O2 sensor should do. But its a Jeep so.
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Unread 07-07-2013, 05:35 PM   #8
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Quote:
Originally Posted by MattJeep
O2 sensor? Mine ran stupid rich and crappy when front O2 was bad. Worse than what a bad O2 sensor should do. But its a Jeep so.
Replaced both O2s recently....
Within last 12months (@5k miles)
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Unread 07-15-2013, 04:29 PM   #9
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So I replaced TPS. No change.

Put stock TPS back in, and took it around the block.
If I'm at a "cruising" throttle position, it seems as if it has a "miss" and wants to die. I was in 2nd gear around 2k rpm and it was VERY evident. Any other thoughts or ideas?? I'm about to the point to find the nearest cliff..... :
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Unread 07-22-2013, 05:37 AM   #10
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UPDATE:

After my brother came over and started staring at the engine bay with me for a little bit, he started playing with the injectors and connections. (OEM Ford injectors to fuel the stroker) He thought it was the injectors or the wiring where I soldered the new plugs to the wiring harness. Every time he started to move one of them, the idle would start to straighten out. I took the Jeep to work the other day, and when I started it up before I left, the idle was bouncing. I tried the same thing and no dice. Fast forward to Saturday; I was looking at the connectors again and started moving them around while it was bouncing and it started to have a consistent bad miss. FINALLY a check engine code came up. P0202. Open Circuit on Injector #2. So I started looking at the wiring. Pulled the Ford injectors and connectors and re-installed all of the OEM Jeep connectors and injectors. When I finished, I tested the Ohms between the two wires on each injector. No open connection between any of the wires (positive to negative) on any of the injectors besides #2. Traced the wires all the way to the PCM. If you disconnected the PCM wiring harness, the connection between the wires disappeared. I tested the ohm rating between the wires at the PCM plug to make sure I hadn't "passed" the short in the wire and the wires tested out fine. I checked pin-outs on the PCM between all 6 injectors, and the #2 was the only one that showed a slight short. A little short is all it takes! Had the ohm meter set at the 20k mark and it was showing a 330 on the screen. I assume that would be a 330k ohm resistance, correct? Either way, its got a connection and that ain't supposed to be there!

Long story short, I think I found my issue. I just hope the $300 PCM replacement will fix it! (That's a $169 remanufactured PCM from autocomputerexchange.com PLUS the $100 lifetime warranty) I'll be calling them in the next few hours to get the order placed, and I hope, by the end of the week I'll have a GOOD NEWS update to post up here. Thanks for all of you guys/gals help on this. I appreciate all the input and thoughts.
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| WJ Seat Swap into a TJ WITH FORWARD TILT!!



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Unread 07-26-2013, 02:37 PM   #11
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Alright, received the refurbished PCM today. After the install..... EVERYTHING is working as it should!! Thanks everyone for the thoughts. The PCM has been replaced and the beast can get back on the road and trails again.
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| WJ Seat Swap into a TJ WITH FORWARD TILT!!



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