Topic: I am stumped; please help!

[sharpxmen]

It happens under load, but it is not tied to RPM.  I have had it happen when off the line, or when driving (always below 4K RPM, but the point in the RPM range varies).

what i am asking is to tell us if the RPM indicator dies right off when this happens (as in going to zero) although the engine is still at 2000 or 3000 rpm (carried by the Jeep weight) or maybe dropping some or becoming erratic - I'm trying to figure out if you have a crank signal issue and when this happens there is none or less or maybe you have a PCM general voltage or ground failure.

EDIT: just occured to me, could be an ASD relay or wiring issue also, might want to swap it out (you might be able to use the horn one for testing) and see if it improves at all

[jfrabat]

what i am asking is to tell us if the RPM indicator dies right off when this happens (as in going to zero) although the engine is still at 2000 or 3000 rpm (carried by the Jeep weight) or maybe dropping some or becoming erratic - I'm trying to figure out if you have a crank signal issue and when this happens there is none or less or maybe you have a PCM general voltage or ground failure.

EDIT: just occurred to me, could be an ASD relay or wiring issue also, might want to swap it out (you might be able to use the horn one for testing) and see if it improves at all

No, the Tach shows the correct RPM, so there the ignition switch should not be the cause...  If it were, the tach should show 0 RPM (as in when you shut down the engine).  I also asked the mechanic to swap the horn and ASD relays; I did this when Neale_RS commented on the relay possibility.

[neale_rs]

If it's not the relays, you could try running the engine and then moving wires by hand to try to provoke the problem. 

[sharpxmen]

No, the Tach shows the correct RPM, so there the ignition switch should not be the cause...  If it were, the tach should show 0 RPM (as in when you shut down the engine).  I also asked the mechanic to swap the horn and ASD relays; I did this when Neale_RS commented on the relay possibility.

the rpm eliminates the crank signal (i think) and the power to the PCM (main and run). Since you tested the ASD (probably I got that idea from reading neale's post) only thing i can think of is spark related (cap, rotor, dist, coil), if you find a cheap tach with an inductive probe that goes on a plug wire it could be a good tool to check for misses to the plugs. Unless it cuts out the fuel but by what you describe that's not the issue

[neale_rs]

Bad wiring to the coil is my best guess at this point.

[sharpxmen]

have they tried running it with a scanner connected, that should show what the parameters are (as in output from MAP, TPS, O2, crank signal, etc), if any of those are out of whack when is doing it could be a good starting point unless you can track a problem to the ignition path (i don't think the scanner will show that, it won't actually).

[grumpygy]

Bad wiring to the coil is my best guess at this point.

With all the problems he has had with coils in the past that would be a very good start.

[jfrabat]

have they tried running it with a scanner connected, that should show what the parameters are (as in output from MAP, TPS, O2, crank signal, etc), if any of those are out of whack when is doing it could be a good starting point unless you can track a problem to the ignition path (i don't think the scanner will show that, it won't actually).

As far as I know, that can only be done with OBDII, right?  Mine is OBDI...

[sharpxmen]

As far as I know, that can only be done with OBDII, right?  Mine is OBDI...

difference between OBDII and OBDI is that the former uses a common standard so any OBDII scanner can be used to connect to any vehicle, with OBDI you'd need a scanner compatible or that can support that specific vehicle but you can still monitor and display them (and even logging on some advanced ones).

[aw12345]

Go on Ebay and find a used OTC scanner with Chrysler software that's up 91 or 92  or something equivalent. That will give you data stream so you can see fuel trim, knock sensor, map, tps, timing advance all pretty close to real time. Will also show how well the O2 sensor toggles lean and rich

[sharpxmen]

if I knew Spanish i would have gotten this one, works for both obd 1&2 and has adapters for Chrysler, Ford and GM for OBD1
http://www.ebay.com/itm/231033525017?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649
send him a message, its the second time he has it listed and didn't sell (i'm sure it's the Spanish exclusive language that kept it from selling, on Amazon is $170 brand new).

[jfrabat]

I have an OBDI scanner; I just dont know if it will stream...  It's an Auto X-Ray one.

[sharpxmen]

i'm pretty sure it will

[jfrabat]

The tool I have is the AutoXray Codescout 2500.  Looking at the specs, it does not mention real time reading, though...

The good news about all this issues I am having is that I am finding ALL the little problems the Jeep had.  Yesterday, some cracked fuel hoses were replaced, and the ASD relay was swapped with the horn relay (to rule that out).  They are taking the jeep out for a test run today; I am crossing my fingers!!!

[sharpxmen]

its a code reader not a scanner so you're right, it won't work.