99 GC 4.0 setting timing on new engine
Thread Starter
Seasoned Member
Joined: Dec 2010
Posts: 350
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From: Georgia, USA
Year: 1994
Model: Grand Cherokee
Engine: v8
Got the new engine in today, hooked up, and primed the oil.
How do you get the electronic ignition sensing wichery to know when to fire? It doesn't have a distributor.
How do you get the electronic ignition sensing wichery to know when to fire? It doesn't have a distributor.
CF Veteran
Joined: Apr 2008
Posts: 2,340
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From: Burlington, NC
Year: 1994...mostly...
Model: Cherokee (XJ)
Engine: 4.0L I6 HO, Lot's of Bolt Ons
CAM Shaft Position Sensor.
Looking at the front of the motor it is on the left side of the block.
Oil Pump Gear drivers the pulse ring for the sensor.
Need to set your motor at top dead center and then install the assembly.
Looking at the front of the motor it is on the left side of the block.
Oil Pump Gear drivers the pulse ring for the sensor.
Need to set your motor at top dead center and then install the assembly.
Thread Starter
Seasoned Member
Joined: Dec 2010
Posts: 350
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From: Georgia, USA
Year: 1994
Model: Grand Cherokee
Engine: v8
Yeah, that is what I was thinking. I just dropped it in there without setting the crank to TDC.
Will the computer "figure it out" from there? Or are there other steps involved?
Will the computer "figure it out" from there? Or are there other steps involved?
Old fart with a wrench
Joined: Nov 2010
Posts: 14,398
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From: Manlius, east of Syracuse, NY
Year: 2000 XJ Sport & WJ Laredo
Model: Grand Cherokee (WJ)
Engine: 4.0L
No, there is an involved installation procedure, however the Haynes manual explains it pretty well.
Thread Starter
Seasoned Member
Joined: Dec 2010
Posts: 350
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From: Georgia, USA
Year: 1994
Model: Grand Cherokee
Engine: v8
Thanks, I have a manual, either that one of Chiltons... maybe both.
I am on duty today, and wont have a chance to mess with it until tomorrow morning. I will report back.
I am on duty today, and wont have a chance to mess with it until tomorrow morning. I will report back.
Old fart with a wrench
Joined: Nov 2010
Posts: 14,398
Likes: 741
From: Manlius, east of Syracuse, NY
Year: 2000 XJ Sport & WJ Laredo
Model: Grand Cherokee (WJ)
Engine: 4.0L
It explains how to just change the sensor or install it if the gear has been removed. Changing just the sensor is simple. Just remove the two screws and install it. HOWEVER, IF the gear was removed, you must re-install it with the alignment pin installed and the sensor slot parallel with the block. It's a helical cut gear like a distributor gear on a GM car. If it runs ragged, it might need to be adjusted with a scan tool at a dealer.
Thread Starter
Seasoned Member
Joined: Dec 2010
Posts: 350
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From: Georgia, USA
Year: 1994
Model: Grand Cherokee
Engine: v8
Well, after a few tries... going back to basics... it worked.
The new engine ran like a sewing machine, for a few, stumbled, started back.... etc.
Not road worthy just yet, as I am chasing leaks and the computer is still "learning".
It shut down as soon as the fan activated. It started again, right away.
I have never had a "0 Miles" engine.
The new engine ran like a sewing machine, for a few, stumbled, started back.... etc.
Not road worthy just yet, as I am chasing leaks and the computer is still "learning".
It shut down as soon as the fan activated. It started again, right away.
I have never had a "0 Miles" engine.
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Old fart with a wrench
Joined: Nov 2010
Posts: 14,398
Likes: 741
From: Manlius, east of Syracuse, NY
Year: 2000 XJ Sport & WJ Laredo
Model: Grand Cherokee (WJ)
Engine: 4.0L
When I rebuilt my 392 Hemi, it overheated in the first 10 minutes. I shut it down and after cooling, it fired right up and ran flawlessly from that point on. It had to wear the high spots off the rings in that first 10 minutes. That was a .060" overbore with an Isky cam and 2 4bbl carbs. "Mr Nasty" my buddy called it.
Thread Starter
Seasoned Member
Joined: Dec 2010
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From: Georgia, USA
Year: 1994
Model: Grand Cherokee
Engine: v8
still running oddly. I have about 50 miles on it now, but it has been running "warm" and today flooded out at 9 miles down the road.
The local shop wants $170 to "flash" the PCM. Not really sure what that means, nor if it will fix the problem. Any thoughts?
The local shop wants $170 to "flash" the PCM. Not really sure what that means, nor if it will fix the problem. Any thoughts?
Thread Starter
Seasoned Member
Joined: Dec 2010
Posts: 350
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From: Georgia, USA
Year: 1994
Model: Grand Cherokee
Engine: v8
it's drinking coolant.
I thought the engine was "burping" when it was losing a quart everytime I ran in in the driveway the first few times.
Feels like a gut punch. Will see how the supplier deals with this. I believe it was faulty... somehow... from the crate.
I thought the engine was "burping" when it was losing a quart everytime I ran in in the driveway the first few times.
Feels like a gut punch. Will see how the supplier deals with this. I believe it was faulty... somehow... from the crate.
Old fart with a wrench
Joined: Nov 2010
Posts: 14,398
Likes: 741
From: Manlius, east of Syracuse, NY
Year: 2000 XJ Sport & WJ Laredo
Model: Grand Cherokee (WJ)
Engine: 4.0L
Was this a new crate engine or a rebuild? If the block is bad, you should be able to go back on the supplier.
Old fart with a wrench
Joined: Nov 2010
Posts: 14,398
Likes: 741
From: Manlius, east of Syracuse, NY
Year: 2000 XJ Sport & WJ Laredo
Model: Grand Cherokee (WJ)
Engine: 4.0L
This is sickening! How can a reputable company rebuild an engine without magnafluxing and inspecting the block first? With a backyard rebuild, it's a crap shoot, but done commercially your reputation is on the line! Any of the engines that I rebuilt were proven engines but worn out. We NEVER took a junkyard engine to rebuild without having the block tanked and inspected first.
My rant is over, but I feel your pain deeply.
My rant is over, but I feel your pain deeply.
Thread Starter
Seasoned Member
Joined: Dec 2010
Posts: 350
Likes: 0
From: Georgia, USA
Year: 1994
Model: Grand Cherokee
Engine: v8
This is sickening! How can a reputable company rebuild an engine without magnafluxing and inspecting the block first? With a backyard rebuild, it's a crap shoot, but done commercially your reputation is on the line! Any of the engines that I rebuilt were proven engines but worn out. We NEVER took a junkyard engine to rebuild without having the block tanked and inspected first.
My rant is over, but I feel your pain deeply.
My rant is over, but I feel your pain deeply.
How they handle this remains to be seen.
I am not naming the company at this time, as I will give them adequate time to rectify this.
What sucks for me is that I "had it running" on the 5th, and am still without the use of the vehicle. Not to mention the wasted hours that will need to be repeated, and the diagnostic time where it was assumed that the engine wasn't blown up upon installation.
I hope that they do right by me,


