If you mean the shop put a scope on the engine such as the Pico scope, this is hands down the best of the best diagnostic for verifying all of the engine parameters. I would love to find a deal on one of these setups, they are pricey. However they are absolutely invaluable, in the right hands. You can look at the current waveform for the injectors and tell how they are firing. You can look at the current waveform for the starter while it's cranking, and tell how the compression in the cylinders is. I myself have an AAS (and a BSEET) ELT from a real accredited school and worked in the industry at military and civilian places where I used scopes all day. When you can look simultaneously on the same time base at the CPS and the CKPS waveforms you can see if they are in sync or not pretty easily IF you know what you're doing. The PICO scopes do that all automatically and are specifically set up for autos. The top of the line ones have specific VEHICLES pre programmed in and can almost do the work for you.
No, the pcm cannot be flash updated, as per my previous post, save for maybe the skim code and the vin and mileage. Nothing to do with the engine operation.
If you are satisfied with the conclusion of the tech who did the scope out, it might be worth it buy one from say Autozone or somewhere that you have some immediate recourse should you get a bad one. They are not that pricey either, I would guess in the 150 range.

 

A pcm is 150?

Yes it was lab scoped, the engine has upwards of 30000 on it, timing chain is good, signals Are synced.

 

I show Advanced as having a Cardone reman for a 99 cherokee xj 4.0 at $87.50. I bought one for my 97 zj a month ago and was quite pleased, though it was more like 150. Mine was plug and play, you would have to give your mileage and vin.. If you buy it online with a card and pick it up in the store, I get a pop up with a 25% discount on top of that.= $66 bux. $60 core, but bring yours in when you pick up the new one and they waive it.

what is the original problem again? rough running? with that mileage you could be looking at cam, chain, compression,.oil fouled plugs....not sure the tests would show that. But those wouldn't set the code you have. if you never changed the pcm, that;s pretty cheap..

 

[QUOTE=awg;3560745]would not be surprised if you have chain stretch (depending on miles)

If the chain was stretched, which they all are to some degree, the tech should see that by comparing the cps to the ckps signals. If they wander in comparison to each other that is the chain. So might be, they all are to some degree..his tech should have looked at that on the scope.

 

[QUOTE=4x4jeepmanthing;3560661]Sorry, "they" the shop I got to run the diagnostic, suggested having the dealer try updating my 99 PCM.

If you diagnostic shop suggested this, I would not have high confidence in your diagnostic shop. Dealers cannot update your pcm.

 

Do you have knowledge or an opinion on the Hantek Automotive scopes at around $200, seems like an affordable tool ?

I agree with you (as I mentioned earlier), replacing the PCM with a used or reman would be the cheapest, easiest, and most logical next thing to do

As I understand it, the OP vehicle has no actual symptoms ?...but needs "no codes" to pass an inspection ?

 

[QUOTE=97grand4.0;3560772]It wasn't an option given in high confidence, but more so they suggested it as a Maybe option after suggesting i ask the dealer. They can't work on Chrysler pcm so it was a thought they figured might be worth asking about before buying a new pcm. These are older vetran mechanics as well, they simply are only familiar with computers than cam work on, Chevy, gm....

Also I've heard the computer numbers have to match, how is this accomplished buying a pcm from az or such?

 

[QUOTE=4x4jeepmanthing;3560804]Year make and model and go from there. Numbers weren't an issue when I got mine. Would you like us to buy it for you and install it also? Lol.

 

Yeah Hantek seems to be the only alternative to Pico, and is about 5x less expensive Chinese? version. No opinion, have never used either, which you also have to have a laptop to use either one so there's another expense. But I would entertain buying one just to see.

 

How about all the wiring?

IMO if you're going to shoot the parts cannon shoot it at the crank sensor.

Or if it's running fine use the Piece of Black Electrical Tape Method.

 

[QUOTE=97grand4.0;3560806]While i bet thatd be nice, your the first I've heard say the numbers don't need to match, just trying to get the right part.

Dave51, as 97 grand said, the scope is a solid way of showing whether or not the sensors are working. With a square wave signal overlay, cam and crank signal, makes it extremely easy to see if something is wrong. The diagnostic with the scope came back good.
.Signal is getting to the PCM and reading properly from the sensors
.I've gone through wiring multiple times with a multimeter, digital and analog. Wiring is good.
. Distributor new, ignition coil new, alternator new



Diagnostic testing points to everything working up until it gets to the PCM. With this knowledge it's not firing the parts canon, why would I even think of buying another sensor when it's been shown to work?
Furthermore with no symptoms of a ckps issue and a CEL that doesn't quit, isnt that a fairly logical progression, suggesting a pcm issue.

Please correct me if I'm wrong here guys, but this woulkd explain quite well why this issue hasn't been resolved yet, and why after all the troubleshooting ive done, this persists.

Pcm is the only component that can't be verified without replacing right?

 

It showed it was working at the moment it was being tested.

Were diagnostics being monitored at the moment a CEL appeared?

 

But I'll stick in a however:

Was that literally and predictably, every second start?

 

BTW, did you try the Old Wives Tale adaptive memory reset with the headlights thing?

 

Do you have the link on that? Those things list at $336.99, so I'm going to buy up all of them and sell 'em on eBay.