Auto PCM in manual? Hard starts, been sitting for a while

thuddles

thuddles

TJ Enthusiast
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Joined
Apr 24, 2020
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162
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CA
(sorry for the lengthy post just wanted to give all the details) Jeep was running fine, parked and installed a stereo system. Replaced battery cables, took out PCM and it was filled with motor oil. Put everything back together and i had it would crank but no power to fuel, no gas gauge, no battery gauge ect. so i figured I needed a new PCM since everything was in working order when i parked it. Fast forward 6 month i finally ordered one from Flagship 1.

I installed the PCM today. Upon turning the key I had all my gauges working on my cluster and it even seemed brighter. I went to crank and it wanted to start but was having a tough time. I barely had any fuel in it so i went and got some starting fluid and a couple of gallons of gas. It started and fizzed out a couple of times, finally i get the thing idling!!! HALLELUJAH IT LIVES. It idled by itself for 5-10 minutes. Power-steering pump sounded empty so i put some fluid in that and it quieted down a bit.

Go to put it in first gear to pull it up a few feet, let out of the clutch and nothing.. reverse, nothing. I can literally put it into first gear without putting the clutch in (with no grinding) So then I turned it off and tried to start it without the clutch in. It would not turn over do to the fail safe. Pushed the clutch in and it turns over and now i can't get the damn thing to start again even with starting fluid.

Do you think they programmed the PCM wrong? If it was for an automatic transmission would this make sense?

I do have the multi-switch disconnected because i'm waiting on a new one.

theres about a quarter tank of fuel in it and I can hear the fuel pump relay clicking. Do you think the little bit of fuel may have clogged up my fuel pump? but it was idling fine after fueling today..
 
Yeah got an email said it would be delivered on the 23rd, then one that said it was shipped the 28th finally got it today. I was wondering why they were cheaper then the other places and didn't require a core...
 
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Sounds like a dirty or loose ground connection.
Check the ground wires on the block near the oil filter, beneath the dash panel on drivers and passengers side, remove the dash board speaker grills on passenger and drivers side to check the grounds wires that are beneath the fasteners for the speakers.
Check the (3) 32 pin ECU harness connectors for oxidation and firmly snap the harness connectors into the ECU receptacles.
 
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CharlesHS said:
Sounds like a dirty or loose ground connection.
Check the ground wires on the block near the oil filter, beneath the dash panel on drivers and passengers side, remove the dash board speaker grills on passenger and drivers side to check the grounds wires that are beneath the fasteners for the speakers.
Check the (3) 32 pin ECU harness connectors for oxidation and firmly snap the harness connectors into the ECU receptacles.
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I just finished changing all battery cables to 2AWG cables fresh grounds everywhere, so everything is as it should be. I guess i'll double check though. I sprayed contact cleaner wiped, and then put some dielectric grease to keep out the water so my connections should be solid.
 
Lou said:
Sounds like multiple issues.
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There where no issues before I did the upgrades. And i did everything textbook. The only complication was the fact that I found my original PCM filled with motor oil.
 
thuddles said:
There where no issues before I did the upgrades. And i did everything textbook. The only complication was the fact that I found my original PCM filled with motor oil. I also replaced the oil pressure sender with a MOPAR OE sensor
Click to expand...
 
thuddles said:
There where no issues before I did the upgrades. And i did everything textbook. The only complication was the fact that I found my original PCM filled with motor oil.
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Does it run with the old pcm?

mid you put the jeep in gear with the engine off, will the jeep roll?
 
Jerry Bransford said:
So far as being able to shift into 1st gear without stepping on the clutch pedal that sounds like your transfer case shifter has the transfer case in Neutral.
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You know i didn’t even think about that i just took out my interior it might have been in N, i’ll check when i get home it was probably my oversight 🙄😂
CharlesHS said:
The question that should be asked is.... How did motor oil end up in the computer ?
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Everyone’s best guess is that the oil pressure sensor went bad and pushed oil through the wire into the pcm ... but who knows.
 
Lou said:
Did you use red cables for your grounds and black cables for the positives?
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i used red cables for all of it and painted ends of the ground wires black. used copper connectors on all + and tin on all -
 
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