Herman K

In your earlier post you said hat the fans failed to shut down. In my case when I turned on the ignition the fans would be on right away instead of coming on after the engine would be at working temperature. On a cold start all seamed OK but ones at temperature the control unit would act up and I got the same symptoms as you’re describing in your post. I had a spare control on hand and ones it was popped in all was OK a 15 minute fix. I also found some post that described on how to fix the control unit in case you don’t have an extra.

Good luck

1994 GTS

Bill Ball

Yes, the plug is labeled. 3 and 5 are the outputs. 1 is ignition power (15 on the relay). So, string these plug connectors together.

Bill Ball

However, since it runs poorly BEFORE the relay trips, you already know you still have something else bad going on. Bypass it anyway, then get on with trying to work on the issue. I just think it is notable that the ignition monitoring system started to trip right after your plug and wires. You say you have spark at each plug, but it doesn't sound right.

John Speake

QUOTE :Looking at the wiring diagram, AL goes to pin 6 of the cooling element, which I am assuming is the finned box on the right front in front of the radiator. It looks like it's also tied in with the LH pin 28, and the manual calls for a continuity check from AL to LH 28, and I do have continuity between them.
END QUOTE

They are talking about the CODING element, which is the 8 way rectangular connector block mounted on the plate that holds the LH & EZK ECUs....... the finned box you were looking at was the radiator fan controller box.....

But, as Bill and others have said, it looks as though you have an igntion lead or similar issue here. Or it may be an injector connector issue.

derporsche928

Bill,
I think it may have tripped before, but I didn't look for or notice the LED, and I've had the battery disconnected several times in between starts, etc., which likely erased any codes.
I know today when I checked the plug wires again, they were all good, however, while I was checking them the relay tripped twice.... once green, and once red...... don't remember specifically which plugs were disconnected for each, but this would seem to indicate somewhat proper function.....
I also was able to read the fault code 1131 again....
I'm thinking your right that I have a couple things going on..... Read on.... Do you think there could be a correlation here?

Herman,
After I read your last post, I looked for, and couldn't find your thread related to it, but thought it sounded plausible, so I went out and quickly swapped one from my S4, and it didn't seem to help the running..... The fan symptoms you describe match mine exactly and I thought this might be the fix.... I'm still intrigued by this and the fact the two problems started on he same night, and the ignition monitoring relay circuit is tied to this....

Thanks again, .....Must sleep zzzzzzzzz
Greg

daveo90s4

9203
Subject: Diagnosing Ignition Monitoring System
ATTENTION:
Service Manager/Service Technician
Models Affected: 928 S4/GT/GTS >From 1989 Models ->
Concern:
Checking of components after activation of the ignition monitoring system (injection circuit switched off fault codes 1131 of 1231). Activation may be caused by the following:
- Damaged or defective exhaust gas temperature sensors.
- Possible damage to the ignition coil wire left side (in driving direction) between the ignition coil and distributor cap.
- Poor grounding of the mounting plate for the ignition final stages.
- Poor physical connection of the electrical plugs on the ignition final stages.
Parts Information: New version temperature sensor Part Number 928 606 155 02 New coil wire with hose covering Part Number 928 602 040 01 (for left side)
Repair Information:
1. Check the left side ignition coil wire. Be certain the coil wire is routed freely and not under tension. If damaged, replace with new version (see parts information).
2. Check all ignition components and connectors for corrosion, tightness, correct connection and damage. Repair or replace as necessary. If an ignition circuit has malfunctioned, an LED indication will be given by the ignition monitor relay located on the L-H control unit mounting plate. Ignition circuit I (cyl. 1-7-6-4) Red diode Ignition circuit II (cyl. 3-2-5-8) Green diode
3. Before replacing temperature sensors, check the voltage difference of both temperature sensors as per step 4 of this bulletin. Sensors are located in the exhaust ports: Model '89-'90, cyl. 4 and 8 Model '91 cyl. 3 and 7 The function of the ignition circuits and light diodes located in the ignition monitor relay remains unchanged. It is not possible to determine from the LED display of the ignition monitor relay if one or both temperature sensors are defective or which temperature sensor has failed. When installing temperature sensors, coat the sensor adapter threads with molykote paste HTP (white) and torque sensors to 10 N-m.
4. The voltage difference of the temperature sensors must be checked in order to ensure proper operation of the ignition monitor system.
Checking sensor voltage difference:
- Start engine and bring to operating temperature.
- Loosen the mounting bolt for the ignition monitor relay and pivot the relay up to gain access to the plug terminals Do not disconnect the relay plug.
- Set volt meter to the millivolt range and connect leads between E1 and E2 of ignition monitor relay (Figure 3, white wires). A digital volt meter must be used. Polarity is not important.
- Measure voltage with the engine idling and again at approximately 2000 RPM. A maximum difference of +2.5 mV or -2.5 mV (depending on polarity) is permitted. If the voltage difference is above 2.5 mV, stop the engine, loosen and rotate one temperature sensor. Retighten sensor and check voltage difference. If the difference is above 2.5 mV, stop the engine and rotate the other sensor. If after rotating the sensors to different positions, the voltage difference is too high (above 2.5 mV) the temperature sensors are defective and must be replaced.

derporsche928

Thanks John,
Yep, it does say CODING element.....
Didn't have my reading glasses in the garage........
Glad I asked for clarification on this..... and Sorry for the confusion.....
Best,
Greg

derporsche928

Thanks a lot Dave!
Just got your post..... (frame 36) This will be instrumental info for tomorrow....
Must go to bed,
G-nite
Greg

Bill Ball

When you pull a sparkplug to check for firing and are running the car, no doubt the ignition monitoring system will trip.

As to Dave's ignition monitoring diagnostics, bypass the relay plug and focus on steps 1 and 2. The other steps are aimed at identifying problems with the system itself. With it bypassed you can skip those for now, since you have other problems you must find.

As John mentioned, an injector or two not firing would cause the same problem as a plug not firing. You can check for injector firing by putting a mechanic's stethoscope or dowel rod against the injector body and your ear and listen for the solenoid click. You could use the Spanner's injector diagnostic test that will fire all the injectors once a second to help you do this test. That way the engine does not have to be running. I use an injector probe tool, but the dowel rod or mechanics stethoscope will accomplish the same thing. Anyway, that will tell you whether all the injectors are firing - remember to have the ignition monitoring bypassed for this.

If you find any injectors that are not clicking, you need to determine if there is a problem with the electrical signal to fire. The only way I know to determine if all the injectors are getting the electrical signal to fire is with a a noid light (short of using an oscilloscope). These cheap little tools plug into the harness plug for an injector and flash when the fire signal (ground on one side) is detected. These aren't foolproof, as they aren't the same resistance as the injector (you can get false positives - says it's firing when it isn't), but if the noid says any one of the injectors are NOT getting the signal, that would be very important. The noid light I have is GM PFI. Pepboys will loan you a set of noid lights. Check there or Autozone. Local store availability may vary.

derporsche928

Well Fellas, I can't thank you enough for the support....... Thank you, Thank you, Thank you,..........
She's back.....! Today was a good day......
I could not see anything obvious on the coil wires and they ohm'd at 2k, but sure enough, the left one had some leakage I could see when I shut off the garage lights. I replaced it with another shielded one that ohm'd good and didn't leak. NEW ignition wires will be ordered Tuesday....
Bill, I was able to just use a long 1/4" dowel to hear the injectors firing.......
Found one connector was askew on drivers side under the throttle cable bracket assembly........ I had given these a precursory look before, as I'd had the injector rail covers off both before and then again when removing the intake to repair the throttle position sensor. The drivers side rail cover is rather difficult to slide back past the wiring and vacuum lines and under the throttle bracket assembly, and I apparently knocked this connector loose.
I also replaced the temperature sensor on top of the intake to cure my fan running continuously problem......
The good news is now it's idle is good, and it runs without any hesitation or missing......
It also reads 90mpg when I'm off the gas, indicating proper TPS repair......(It now consistently able to flash code with the accelerator, which was flaky before.)
I also believe the hall sensor repair I'd mentioned before must be okay, because power seems fine as well......
The bonus is, I learned more about the car, and specifically about the function of the ignition monitoring system, and for that, I owe you guys.
Peace,
Greg

AO

So, I take it this means you'll be at SITM? I sure would like to witness another field sobriety test!

Bill Ball

Excellent!

daveo90s4

Good stuff, well done

ErnestSw

Greg,
Ya think it's worth a membership?

worf928

Great Greg! See ya at SITM