Augh! My jeep is in a coma..

Well, after changing my injectors to those from an LS1, my jeep started up much smoother and ran (seemingly) normally for the first 40 miles or so.

Notably, I *thought* I had a distributor making noise, but apaprently that was all in my head.

Then, on the way back from the advanced auto to pick up a new idler pulley, I notice, on the highway, that it is running cool - 185deg if you believe the gauge. 5 deg below where is usually sits - not worrisome - I chalked it up to better fuel flow (injectors).

Came up the exit ramp, and pulled to a stop at the light, and POOF the jeep dies. No sputtering, coughing or warning. In fact, I would swear it shut down smoother than when I turn off the ignition.

The battery is strong, and the engine turns over quickly, it just doesn't catch.

I didn't have any tools, but did check that there was pressure to the fuel rail (there was)

Thinking there was a possibility I had flooded the engine, I tried ignition with pedal to the floor, but no dice.

I tried several times to pull trouble codes with the ON-OFF-ON method, but had no luck, although the idiot lights did light with the ignition. Not sure if I'm a spaz or that's a sign of something wrong.

I know I'm probably a XXXXXXXX for posting this when the obvious answer is check spark, check fuel ..

When I go back, I will try it after letting it sit for hours (flooding), then try disconnecting the battery and reconnecting (reset the ECU), and if that fails, check spark and fuel.

I'll bring along my old injectors and spare coil, too, it looks like

Basically, I know what I have to do next, just thought I'd run a post off and see if anyone had run into a problem like this specifically related to changing out injectors. Probably not LS1 injectors since that was my bright idea :banghead: but anyway ..

Also, as an update on the injectors - the jeep seems to run smoother and definitely starts smoother (not as much roughness and shake on ignition), but as langer1 correctly noted it would, it did not fix the knocking on 87 octane problem.

Does anyone know if the injectors get cycled back by the ECU based on the O2 sensor (not under WOT), or have I been slowly flooding my engine by using these? It just seems odd that they would work for 40 miles ..

Year?

96, sorry

I was going to ride my back back to my jeep, but now I can't find my bike pump. Sure hope my shoe doesn't blow out

Once the check engine light comes on it takes about 20 seconds or longer for it to start flashing codes.

Okay, an update ..

I tried pulling codes again with no luck. The check engine light just stays solid.

I disconnected/reconnected the battery cables but nothing magically fixed itself. (The check engine light goes away now, though I still can't get it to blink - is the correct procedure ON-OFF-ON-OFF-ON-OFF-ON ?)

I am not getting spark at the plugs or the coil, and I tried a spare coil with the same result.

Per the FSM, I read the voltage into the coil (assuming I did it right) and while it moved slightly on cranking, it never broke 0.8v

While poking around, I noticed that the wire to the O2 sensor had come loose and the sleeve had melted on my header.

I would like this to be the problem, of course, but while the sleeve was melted through, the wires looked fine. Additionally, according to the FSM, the O2 sensor has no bearing on engine startup. Does anyone know for sure whether bad O2 wires would prevent spark?

I haven't swapped the old injectors back yet, even thought that's probably still a possibility. I would like to avoid switching them out unless necessary, and at least as I can tell from the FSM, bad injectors would not prevent spark. Does anyone know whether this is correct?

Appreciate any help I can get
Thanks!

ON-OFF-ON-OFF-ON Three on's

Sounds like the classic CPS dead. Code 11. You must get the codes before disconecting the battery or you loose the codes.

btw, also posted at JU, sorry if you read it there too, but knowledgeable guys at both and didn't want to miss any

Update:

Symptom is: No Spark. The ECU does not provide full voltage to coil (<0.8v)

Fuel pressure at rail is 40psi at priming.

I have replaced the

CPS, MAP, and CTS

I tried starting with the Cam position sensor unplugged, as I thought I had read that this will allow rough running if the sesor has failed. I do not know if this is correct. In any case, it did not work.

Two things of note: The cruise control light on my steering wheel seems to blink erratically when ignition is turned on or off. I don't know if it did this before.

I can NOT retrieve any blink codes from the On-Off-On-Off-On procedure. Even if I had no problems stored, I should still receive a 55, correct? I have retrieved codes from the jeep before without problem, so I suspect this may be significant (unless no error codes = no blink at all)


The only options I have left, to my knowledge, are to replace the injectors (since that was the last thing I did before this problem), and to replace the distributor - actually the Cam PS, but a remanned distributor from NAPA is cheaper than a Cam PS from the dealer.

Can you guys offer any other suggestions?
Thanks!

What year was it?

You better get a scanner tool from autozone, if all fuses and ground wires are O.K. maybe your ECU is dead. Did you check the ECU fuse and connectors??

And don't forget to check the Check Engine bulb.

Hey, thanks for the replies. And for langer, it is a '96 XJ

I'm not really sure what exactly went wrong and when, but this morning when I was checking the ASD relay, I noticed that the ASD relay fuse (30A fuse #20 in the PDC) was blown. This fuse supplies power to the PCM, coil, and injectors, so it's almost certain this was the cause of my problem - and also explains why I was unable to retrieve codes. Figuring out why it blew or why things don't run well now that I've put in a new one may take a little work though.

I replaced the fuse, and the engine started! It died out unless I gave it gas, but more importantly, it was now throwing codes 12, 14, and 42

It was idling too rich in open-loop mode and would die out after a minute if just left on its own, but I limped it into work.

Unfortunately, I also tore up the O2 sensor wire on the front pinion yoke on the way in, and melted the loom to the header (again). So I was also throwing a 21.

I went to Pep Boys, bucking every so often, and shifting into N at stops and giving it gas so it wouldn't die. Azzholes wanted $19.88 to pull codes (to verify the 21 was the front O2 sensor) so I resolved never to return to Pep Boys and bought a new O2 sensor at Napa and installed it, but still getting jerking/hesitation and dying at idle.

I pulled the battery pos. wire to clear any codes that were lingering from resolved problems and will see what my drive home brings up.

It looks like I'm going to have to change the injectors back to stock. I really don't see how that could be the problem since it ran smoother than ever for 50 miles (until it died), but unless the new MAP sensor is bad, I can't think of anything else that could be the problem. If I damaged the O2 wiring, I would think it would still run fine in open-loop.