https://xjjeeps.com/

Ive looked at the 93 fsm on here ( to match the engine timing chain specs)

It says if the deflection exceeds "112-inch" replace sprockets and chain. Doesn't make sense ? Typo?
Btw, did you want me to test cmp output again? You said it was to coarse, im not quite following you.



awg- if the ckps needs shimmer or moved, shouldn't it not start or run smooth?

 

It might just be 1/2 degree out, elongating the CPS holes is fairly quick & easy, shimming the CPS out a bit same

(maybe 2hrs)

I would also run a single dedicated wire to replace each wire from the CPS and Cam sensor to the PCM

(the old wires may have some conductivity thru the insulation (if wires are touching)

In my opinion, you are close to the end of the line after that, there are no other things to try that make economic sense...how much is it to but a similar condition XJ in your area?

If it is around $3K, like they are here, you may have to consider that path, if you can eventually fix yours, one can be sold, if not you have one for spares

The guy in the video that states he is a professional "diagnostic technician"...that is what you need, however someone like that always charges +$100ph

I know a guy paid over $1000 to get his Jag codes sorted by the dealer...they could not sort it. Our EE club member was needed.
He wont work on cars unless you pay him, its very difficult to find someone like that, he is the only one I know of in my area, over 500k population
(but he now works as an Aviation Engineer, so little car stuff)

have a read of this recent thread
https://www.cherokeeforum.com/f2/cps...cps-gap-89964/

 

Just to be clear are the sensors to be disconnected and new wires backprobed to the pcm?

 

what I am suggesting would be the very last step that I would take..extremely reluctantly, once you have performed every other suggested idea,
as your vehicle is working, and this will cause an issue down the track if not done to an exacting standard.

snip the wires close to the PCM and suspect sensors, eliminaing connectors, solder in new wires, it must be done to professional standard.

If it doesnt fix the problem, solder connectors & correct color wires back in

The harness/wires/connectors are the only common part, (apart from the flexplate)...its very hard to get away from that fact

If other poster suggest you dont go snipping wires, I would consider that advice seriously

 

Yeah I don't take to comfortably to that idea, last resort as you say, agreed.

As for the flexplate I can try unbolting the tc mostly and flexing on the plate more while looking for issues, any pictures I can provide I'm happy to try.


As for this again, call it if I'm off track here. The chain does not slack down any further. I was very careful to push the chain to it's stop in this picture.

.Do you guys disagree that an eyeballed deflection is maybe the same thickness as the chain?
.I have no real experience with timing chains here, it's one of the very few things I've never worked on, but by what you have all said, this seems to be in good shape, no?

I have had a mind to grab JY ckps,cmp, to try for the hell of it, even though the shop signals were "good". Without gutting the harness it would seem that continuity tests are good, pcm shows CEL on both replacement PCMs, some thing is still wrong!!!! Lol, but it starts, drives fine..... ????

I may call some ships and ask what they would price a scope at just to get pictures, not a diagnostic procedure.

The spare harness I have is in rough condition, definitely grounds with new wire and terminals needed, plus continuity test of whole harness, any further rebuilding would be needed. It doesn't seem the most practical option yet.



This has been a terrible life week for me, I need to go back and re read your guys suggestions fully so that I'm getting you the correct information for these checks I need to do.

Thank you greatly for your patience.

 

The shop got back to me and they were not interested in hooking up to a scope again and allowing me to get a couple pictures of the signal.
Or them.
I find this a bit odd because it's a very simple and quick probe, less than 15 minutes and we would be done.

As awg said thus may need a capable technician that can read a lab scope.
I'm taking their refund because this doesn't smell right to me.

 

You do need a experienced tech/mechanic who can use a scope. As I mentioned this may be hard to find.

Ex-military guys are usually well trained. They have mobile mechanics over here, ring and ask some ?

search for "automotive diagnostic technician"

Take their refund..who knows what they did..most mechanics avoid jobs like this like the plague as they are not profitable. They want to get rid of you, changing oil & brake pads is much more profitable

I am a qualified electronics technician, and worked for some years in various electo/mechanical/auto jobs

One of the main reason I got into doing most of my own auto work is when I was young & working long hours, I..or my Mrs, was taken advantage of by dishonest mechanics

 

Glad I didn't waste money on a book to read this summer.....

 

Right lol, this goose chase aint over, but we have narrowed down many things that are not typically checked on this code.

More to come.

Oh and hell yes I took the money back

 

Absolutely. Anyway, you're not looking at an FSM, that's a Haynes book. The real FSM says more than 12.7 mm (1/2 inch) replace it.

 

IIWM, and since a kit is only about 60 bucks, if I had gone to the trouble of tearing it down that far I would have just changed it out.

At this point, going back in would be the last resort. Electrical tape would be before that.

BTW how'd the chain guide look?

 

Well shoot a crappy Haynes manual would make sense, the other 99 manual I got from cruisers page. Is this a Haynes copy also?
Who sells reliable accurate FSMs
Chain guide looked like new before putting the engine in.

 

Well here's a plot twist.

I decided to scope my own engine to put up some examples of what to look for, and what finds it?



My crank sensor is a disaster!!

No codes and runs OK...

It is an AZ sensor tho.

Thought you'd enjoy the irony.

We now return to our regularly scheduled thread.

 

I would think now's not a good time to run cam/crank sync...

 

Dave what scope did you use? Cam signal looks nice and clean.