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Jeep LS swap for the LJ

85CUCVKRAWLER

85CUCVKRAWLER

Active Member
Location
Tooele
glockman said:
What 3 things are needed to start an engine?
Don't assume anything.
The butterfly in the throttle body was stuck. Missing air!
Makes sense why it never dies, only would not restart.
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I was about to post for you to spray some starting fluid in the air intake. If it didnt fire you have an air problem. Since you clearly found out it had fuel and spark.
 
glockman

glockman

I hate Jeep trucks
Location
Pleasant Grove
RockChucker said:
Bizarre. So new throttle body is in order? Or just the sensor on the side?
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I'm not sure what the actual failing mechanism is. It could be a notch worn in the throttle body or since it's drive by wire, it could be the motor or whatever moves the plate. I didn't pull the cover on the side to see what the root cause was. I'm also not sure if there is some TAC module component, I didn't touch anything on those plugs or wires though so I'd say low probability.
85CUCVKRAWLER said:
I was about to post for you to spray some starting fluid in the air intake. If it didnt fire you have an air problem. Since you clearly found out it had fuel and spark.
Click to expand...

I pulled the old Crank and cam sensors out and they both had 5x the resistance from low ref to the signal pin compared to the new parts. The new sensors were 1.5 M ohms, the old were 5 M ohms. So I figured they were old, oil soaked and more resistance equals more voltage drop and could be limiting the threshold so the ECU didn't see a toggle in voltage state. So I replaced them both, no change.

So for S&G's I decided to try some starting fluid. I pulled the air filter and went to push the plate open to shoot some starting fluid in and it was stuck, then popped open. I hit the key and it fired right up.

The old KISS rule wins again.
 
glockman

glockman

I hate Jeep trucks
Location
Pleasant Grove
So the jeep did great through all of EJS (with some drivetrain noises still unidentified). It still has some starting issues that I think are tuning. I've been playing with HP Tuners and have improved it but still have some more to go.
Around May it started misfiring on cylinder 6 badly. It would barely run. I swapped coil packs, plug wires and plugs. It stayed on cylinder 6. I figured a broken wire between the PCM and the coil pack. I checked it and had continuity. At this point, I had lost my will to work on this thing anymore, so I took it to Just 4 Fun in Lindon since they have done a bunch of LS swapped TJ's. They found a broken wire in the harness. It took them some time and it was intermittent but they found and fixed it.
I picked it up Tuesday and after not driving it for a couple months, it was pretty awesome to have it back and driving.

Back in May before the misfire I tried to get the emissions done but had an issue with the Emission test machine not communicating. I found pin 4 and 5 in the OBD port are both grounds, 4 is used by all OBD readers I've used and 5 is used for the Emissions test machine and only that in my experience. I checked my OBD part and I had not connected pin 5 to ground so I spliced it into the ground on pin 4, did some fiddling in HP Tuners with some sensors and took it to my emissions guy. He plugged it in, it showed all monitors ready and the only issue was a VIN mismatch that was no big deal, he was able to check boxes and I now have a Utah County Emissions certified LS Swapped Jeep!!!

I've been rodding it around all day and man, all Jeeps should come with V8's.
 
jeeper

jeeper

I live my life 1 dumpster at a time
Location
So Jo, Ut
Does the ticking come and go with the clutch? Always clicking when foot is off the clutch? Clicking in neutral? Clicking while stopped or only rolling?
 
glockman

glockman

I hate Jeep trucks
Location
Pleasant Grove
OCNORB said:
Sounds flexplate-y. Are the bolts tight, maybe a crack?? Just a guess.
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That's a good guess. I was thi king torque converter bolts but they are all torqued to spec.
jeeper said:
Does the ticking come and go with the clutch? Always clicking when foot is off the clutch? Clicking in neutral? Clicking while stopped or only rolling?
Click to expand...
Auto, but I can hear it in first or second gear and it seems to be tied to rpm. Flex plate would make sense for that too.

I'm going to check the starter tomorrow. It only happens when accelerating or climbing. If the bendix is lose and sliding back making contact with the flywheel that would explain it.
 
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UNSTUCK

UNSTUCK

But stuck more often.
Sounds like an exhaust leak to me (my speakers aren't the best). Only leaks under load. Easy to check your connections for a black soot mark...before pulling the starter or transmission.
 
glockman

glockman

I hate Jeep trucks
Location
Pleasant Grove
UNSTUCK said:
Sounds like an exhaust leak to me (my speakers aren't the best). Only leaks under load. Easy to check your connections for a black soot mark...before pulling the starter or transmission.
Click to expand...
I thought it was a chunk of cat floating around. Pulled the entire exhaust last week and they were in tact.

Pulled the starter this morning.

Looks like it's the starter. I get it replaced today and verify. Oh happy day, my sanity may be saved.
 
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