: 93 Eldorado T.C ignition issues



jrcougars
04-16-06, 10:46 PM
I need help please!! We have a 93 touring Coup w/ 83K. Last week it began
stumbling before it reached operating temp. Now it stumbles all the time.
It starts fine and has never failed to start and has never died. It will start to
miss then even out and run fine for a min. or 2 then miss badly again then
recover.
it will idle flawlessly from cold start to about 150 degrees then start to stutter.
It has 4 codes that keep re-occuring. They are..
23- EST problem- ignition control
25- 24X signal low
30- Idle speed contorl
and 83- one book has this one no crank signal a or b
another has this one 24x signal high.....
There is no miss past idle or WOT.
I am sure the ISC code is due to the inability to maintain a constant idle.
The ISCM is working itself to death...
We have replaced.. Plugs, wires, ICM, and cam sensor as well as all 4 coils.
the car has not been serviced prior to this issue, so I am ruling out tampering.
Very interested in anyone's ideas....
Thanks
jim:confused:

eldorado1
04-16-06, 11:06 PM
I need help please!! We have a 93 touring Coup w/ 83K. Last week it began
stumbling before it reached operating temp. Now it stumbles all the time.
It starts fine and has never failed to start and has never died. It will start to
miss then even out and run fine for a min. or 2 then miss badly again then
recover.
it will idle flawlessly from cold start to about 150 degrees then start to stutter.
It has 4 codes that keep re-occuring. They are..
23- EST problem- ignition control
25- 24X signal low
30- Idle speed contorl
and 83- one book has this one no crank signal a or b
another has this one 24x signal high.....
There is no miss past idle or WOT.
I am sure the ISC code is due to the inability to maintain a constant idle.
The ISCM is working itself to death...
We have replaced.. Plugs, wires, ICM, and cam sensor as well as all 4 coils.
the car has not been serviced prior to this issue, so I am ruling out tampering.
Very interested in anyone's ideas....
Thanks
jim:confused:

Hmm.... You likely have more than one problem, possibly an intermittant problem as well. For sure, you probably have one bad crank sensor. You can test for which it is by disconnecting one, trying to start it, and then repeating (with the other one plugged back in). Whichever crank sensor allows you to stay running is the good one. ;) (it could also be the wiring to the "bad" sensor, keep that in mind)

You may also have an intermittant short or open in your wiring. That's going to take a bit of work to find.

jrcougars
04-17-06, 09:23 PM
Thanks for the tip. I'll check it out.

jrcougars
04-18-06, 09:29 PM
I tried the sensor test.. no luck. it ran the same w/ either sensor conected....
and that was poorly, but it ran...So it is back to the drawing board....

peteski
04-19-06, 01:01 AM
24X signal is generated by the ICM and received by PCM. If it constantly comes up "low", and you replaced the ICM, then either the wiring harness or possibly the PCM could be defective.

What you need it the HELM Factory Service Manual. It has diagnostic charts for troubleshooting error codes. That would help you in this case.

Peteski

eldorado1
04-19-06, 10:20 AM
The next thing you need to do is verify whether the 24x signal is making it to the PCM. What you have to do is backprobe the blue PCM connector, pin F1, and check with your voltmeter set to frequency (hopefully you've got one that does, otherwise it becomes more difficult)

Should be light blue/black. The PCM is probably located in some terrible location, like underneath the dash. It may require a lot of work to get to it.

jrcougars
04-19-06, 06:28 PM
yuck, this is getting ugly.... I would like to have one of those service manuals.
ideas on where to score one. I don't have a G.M. buddy...

eldorado1
04-19-06, 07:16 PM
www.helminc.com

jrcougars
04-19-06, 10:16 PM
Thanks for the link!!

parts68
04-19-06, 10:20 PM
try ebay for a used one
normally under $50

zonie77
04-19-06, 11:19 PM
Depending on where you live the library may have Alldata available. In Phoenix and in San Diego it's available. You may have to go to the library to access it though.

eldorado1
04-20-06, 12:12 AM
yeah, they come up on ebay every so often. If you've got the time to wait... you can save about $80.

jrcougars
04-20-06, 08:11 AM
Thanks for the tips. I am going to dust off the old library card and see what happens..i think I will have better luck w/ e-bay though.. :-)

jrcougars
04-20-06, 08:50 AM
just found a pair of the GM service manuals on e-bay.They are on the way.
Thanks. I will keep you all updated.
I have to ask though, I am having a rough time with the car just devoloping
wiring issues.. Is this a common problem?? I understand component failure, I can even stretch and go for a PCM failure out of the blue. But this car's hood
has been up I swear only about 4 or 5 times in the last 6 years. i just changed
the original serp. belt a year or so ago.... It is just not driven very often.
The only time it gets wet is when it is washed.. (not my idea BTW)...LOL

Rob_M
04-20-06, 03:43 PM
I just had an issue where my TRACTION DISABLED light came on and off plus it would hesitate, had a loss of power(especially on the freeway at 45-65mph) and stall intermitently. I replaced everything under the sun: battery cables, isc motor,crank and cam sensors, igniton switch, icm, map sensor, fuel pump, 2 EBTCM's. Nothing worked eventhough my codes and the trouble tree pointed to the EBTCM. It would run great for up to a day or so then would have the problems all over. I ended up swapping the previous j-yard EBTCM for a new PCM at the junkyard for $100. Put it in and it hasn't skipped a beat. The moral of the story is that I spent close to 3 grand trying to chase the problem and it turns out to be the PCM. Plus, for our year, there was a TSB (http://www.alldata.com/TSB/08/93080232.html) about surging/loss of power/and hesitaion and they came out with a newer PCM fixing the problem..... Hope that might help.

parts68
04-20-06, 08:50 PM
chances are an upgraded memcal would have solved that problem

Rob_M
04-20-06, 09:40 PM
I didn't hear you mention any codes.

jrcougars
04-26-06, 05:55 PM
Ok folks, I have spent some quality time with the manuals. not looking to good for the PCM. any ideas on reman units/brands? Does GM offer reman'd
PCMs? So far I have checked out the wires going from the new ICM back to the PCM. no shorts or opens there. I reset the codes and it still says there is
no 24X signal from the ICM and the wiring seems in tact.

parts68
04-26-06, 06:43 PM
How have you narrowed it down to PCM?
I have a spare but its missing memcal which is out for dissection.

jrcougars
04-26-06, 08:33 PM
one of the trouble codes, 25 I think is 24X signbal low. I found that wire as
it came out of the ICM, found the other end @ the PCM it checks out good.
no opens or shorts. That coupled with the code 23 and 83 all of which should
add up to a no start I don't think there could be much else. But I am new at fighting the wire monster I might have missed something though. I welcome
other thoughts...
:-)

eldorado1
04-26-06, 08:38 PM
You can get a used PCM from www.car-part.com

It's not new, but they rarely go bad. You can probably pick one up for about $50 if you're willing to drive a bit.

jrcougars
04-27-06, 08:39 PM
Thanks for the tip. I checked out a few other connections tonight from the ICM to the PCM connectors. The wires checked out good. Am I missing anything..?

Loose screw
04-30-06, 02:40 AM
Since your problem changes with temperature I would doubt it is a wire problem but rather a (crank) sensor that warms up with engine heat, or the computer that warms up with electrical current - Try cooling down the computer after the car has warmed up and then restart. The engine will stay warm for a long time. Use a ice bag or blue ice in a flexible bag or something else that will make good contact on both side of the unit. (the ICM comes out and can be plugged in in just a couple minutes once you get it out once. If you get a change in operating replace ICM.

jrcougars
04-30-06, 07:35 PM
good idea, Thanks

jrcougars
05-02-06, 10:10 PM
I replaced the PCM today. I used the prom from my unit. went thru the learn
sequence for a p080 code and what do ya know.. the car runs great!!!
Thanks for the tips, links and ideas. This is a terrific site!!! As long as I have the car, This site will head up my FAVORITE PLACES!!
Thanks again!!