At my wits end
03-17-2018, 10:23 PM
#1
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Model: Cherokee(SJ)
At my wits end
ok guys i really need help, i have a 92 4.0 it was just rebuilt, bored .30 over, but they added a cam for me, now heres my problem, the motor runs amazing above 2k rpm, but below is bad, really bad, it idles at like 250rpm and stalls alot, has bad misfiring when accelerating and has no power, soon as it hits 2k rpm it comes alive and screams with power. Now i have no check engine light, EVERY sensor has been replaced and tested, new ecu, new fuel pump, injectors, fuel pressure reg, literaly everything is new. I cant find the issue. I have even retimed the cam. Im beyond lost ill try to attach a video. Any idea will be greatly appreciated.
03-17-2018, 10:56 PM
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Year: 2000
.480, no that doesn't seem that big.
Next question would be timing, I only see a adjustment for 1984 to '86 though in my Haynes.
Any ideas what stock lift is on a '92 anyone?
Next question would be timing, I only see a adjustment for 1984 to '86 though in my Haynes.
Any ideas what stock lift is on a '92 anyone?
03-17-2018, 11:18 PM
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I googled it, where did you find that?, anyway.
Maybe something is a 180 degrees out of rotation.
I've had that problem before with issues like this, others too from what I've read on the internet.
The misfire would trigger the cel on a 96' and later.
Imo, check the crank/cam timing.
Maybe something is a 180 degrees out of rotation.
I've had that problem before with issues like this, others too from what I've read on the internet.
The misfire would trigger the cel on a 96' and later.
Imo, check the crank/cam timing.
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03-18-2018, 12:10 AM
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Im not firmiliar with cammed vacuum, usually vacuum leak increase idle, not sure how it would reapond on cam, but i know bigger cams cause lower vaccum, ill check tomorrow. Thank you
03-18-2018, 12:16 AM
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Vacuum, could be a issue.
That cam should run though, good to hear it runs well over 2k.
How are the brakes?
That cam should run though, good to hear it runs well over 2k.
How are the brakes?
Last edited by Transpoquick; 03-18-2018 at 12:20 AM.
03-18-2018, 12:21 AM
#11
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Yeah it runs awesome, alot of power, doesnt get hot, im getting to the point where if i cant figure it out ill have to pull that cam out. At tds this year going down hill it stalled out, super sketchy with hydro steering, thank you guys for the help ill keep you guys updated with anything i find in the morning.
03-18-2018, 02:28 AM
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Engine: 4.0/ 3.2
If it is a low vacuum issue I personally wouldn't change the cam. For 40.00 bucks you can buy a vacuum reserve canister from jegs or summit racing.
03-18-2018, 07:52 AM
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Double check the distributor indexing.
03-18-2018, 12:33 PM
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Going to check for vacuum leaks this morning, distributor index is perfect, cam toming marks perfect with crank, only thing im unsure of is on the cam card under centerline it says 2/up and im completely unsure what that means. Also im not sure how to turn the idle up because it has a IAC that keeps adjusting. When i start it, it goes high idle till it warms up then the issue starts.