Electrical Problem

[tooldude]

Scitzz, do you have any manuals? The Haynes manual recommends the easiest test, disconnect the coil positive wire and place an led test light in-line (like an ammeter), crank the engine and look for blinking from the light. The 1990 engine/emissions manual recommends disconnecting the ICM connector, jumper the GND and SPOUT terminals back in circuit, then jump the test light in-line between the IDM [which is labeled IGN(W) in the EVTM] terminals on the connector & ICM. That's the same test only more trouble because of the jumpers. In other words, the ICM can be tested by placing an led test light in-circuit (like an ammeter) anywhere in the circuit from the ignition switch (BK/W-supply voltage) up to the IGN connection at the module, because it's simply showing that voltage is being grounded and ungrounded by the ICM (BUT, in conjunction with a SPOUT signal). This test of the ICM is only valid if the ECA is functioning and PUTTING OUT that SPOUT signal. If you perform this test and it fails (no blinking light), it does not tell you the ICM is bad YET. You must next test for a SPOUT signal, and if that is functioning, then it proves a bad ICM. This is a good test since most of the time it's the ICM that fails, not the ECA and it's quick and easy, and a PASS is telling you both are good. all that said, I need to make another post about the ICM.

[scitzz]

Scitzz, do you have any manuals? The Haynes manual recommends the easiest test, disconnect the coil positive wire and place an led test light in-line (like an ammeter), crank the engine and look for blinking from the light. The 1990 engine/emissions manual recommends disconnecting the ICM connector, jumper the GND and SPOUT terminals back in circuit, then jump the test light in-line between the IDM [which is labeled IGN(W) in the EVTM] terminals on the connector & ICM. That's the same test only more trouble because of the jumpers. In other words, the ICM can be tested by placing an led test light in-circuit (like an ammeter) anywhere in the circuit from the ignition switch (BK/W-supply voltage) up to the IGN connection at the module, because it's simply showing that voltage is being grounded and ungrounded by the ICM (BUT, in conjunction with a SPOUT signal). This test of the ICM is only valid if the ECA is functioning and PUTTING OUT that SPOUT signal. If you perform this test and it fails (no blinking light), it does not tell you the ICM is bad YET. You must next test for a SPOUT signal, and if that is functioning, then it proves a bad ICM. This is a good test since most of the time it's the ICM that fails, not the ECA and it's quick and easy, and a PASS is telling you both are good. all that said, I need to make another post about the ICM.

I must have missed that test when I searched for it last year in the haynes. Huh. I even have the 89 service manual. Thanks dude, PM me when you post about the ICM!

[tooldude]

Is there someone out there who can scope the signal pattern at the SPOUT SIGNAL and post it? It would not be too hard to make a handheld tester for the ICM if we knew a little more about it. If anyone has any information about the electronics within the module or where to get I would like to know. I don't believe this is going to be in any shop manual as it's not necessary for repair. Here's my guess from looking at the circuitry: this is a very basic system so I believe it was done in the simplist way. That is, the SPOUT is a NEGATIVE signal; in other words, a ground connection made by the ECA in the same way ECM's are commonly used for ground control. This makes the most sense to me as the voltage coming to the ICM is POSITIVE and I believe that allows for the ICM to have the simplist, and therefore cheapest, circuitry. Another question whether the ICM is continually conducting current to ground under a key-on/engine-off condition. Can somone test this? Just disconnect either the positive or negative wire at the coil and connect your ammeter inline, also record the amperage reading. IF the circuit operates that way it will tell us two things: (1) you should not leave your key on with engine off for long periods as it will create more heat in the module than when it is operating with a duty cycle [not constantly on] & (2) under that condition the coil will be saturated and when the key is turned off there will be one spark generated from the coil - and an easy test for spark from the coil wire. However, I would like to get the current reading from the other test, if there is that condition.

[tooldude]

Test for the SPOUT signal: with the key off (as always, when connecting or disconnecting electronics) unplug the ICM connector. Connect an LED test light between VPWR and the SPOUT terminal on the disconnected ICM connector. Crank the engine and the light should flash (on & off). Note that these directions are for using a breakout box so it seems safe to assume VPWR is full battery voltage. You could hook to B+ at the battery or coil. However, I believe the test light may operate off the IGN (W) terminal on the ICM harness connector which will also test that voltage is reaching that terminal. I would caution anyone that doesn't know to be careful not to inject static electricity into that SPOUT terminal going to the ECA, especially this time of year. Now that I've gone back through this, I see this proves a NEGATIVE grounding control signal at the ICM. My only question is whether there is ever a positive signal on that terminal, but I am now pretty much convinced--NO. [WARNING: I once had a voltmeter destroyed when I was testing voltage on the coil terminals with the engine running. Spark came under the boot and down the coil tower to my voltmeter probe. For this test, though, spark is disabled] As a side note, these are tests (CPS-SPOUT) that I wanted to suggest when I was trying to help on the Burnt Toast case but didn't because I couldn't take a chance on MY calculations with someone else's computer. I have this from the factory manuals now so you can have confidence in these procedures.

[muleskinner]

I would go back and test the distributor, the Battery, & altenator. If all check out fine. Then test the coil. I would also check for a ground problem. Somethings can work ok but still have something wrong with it. Even check the piece the fusible link is in. Just a thought.

[jbrown]

Hey I fixed it. The LED spout signal checked out and I wanted to headbutt my car, but I gambled and got a ECM from my local PnP with like 15k (I will go back for trunk latch, determined that while I was there). Took apart my dash (less knuckle busting than I thought it would be) plugged it in and vroom. Timed it. And it was off to the races. This is a little off topic however last summer my seatbelts came on randomly and worked twice and then quit. Today with the new ECM my seatbelt light came on with all the seatbelts done up. My question is do those get any signal from the ECM? Is it worth trying to hook them back up?

[tooldude]

The passive restraint module is powered off the main fuse. It operates independently from the ECA and grounds the belt lamp (LG/Y wire). It's possible the ECA had bad terminal connections.

[scitzz]

Hey I fixed it. The LED spout signal checked out and I wanted to headbutt my car, but I gambled and got a ECM from my local PnP with like 15k (I will go back for trunk latch, determined that while I was there). Took apart my dash (less knuckle busting than I thought it would be) plugged it in and vroom. Timed it. And it was off to the races. This is a little off topic however last summer my seatbelts came on randomly and worked twice and then quit. Today with the new ECM my seatbelt light came on with all the seatbelts done up. My question is do those get any signal from the ECM? Is it worth trying to hook them back up?

That is my boy! WooT! WooT!

OK, here comes the tough part....

What fried it in the first place? Don't want to get stranded, ya know?

You can change the ECU by removing the driver side speaker grille, and speaker(if equipped) then undoing the two ten mm bolts. Reach under the dash, disco the 2 connectors, push up, pull out, then down.

[tooldude]

It might be a good idea to check the voltage output on the alternator.

[muleskinner]

I reiterate, get your alternator checked. Another symptom that I experienced was blown lights. All my dash lights were blown out, had to replace every bulb. One of my LED tag lights fried, my brake lights as well. If your alternator fails testing, five gets you ten you also fried your ECM.

Yes, check the alternator again. Looks like scitzz called it out earlier.

[jbrown]

When my aunt originally bought it the bought it from a farm with a rubber glove oil cap and two molded out seats. When I pulled it out there was moisture and corrosion all over it. Plus my dash lights werent blown my uncle was trying to avoid helping me. I also remember I was getting bad gas mileage. I drove 55 miles (had to get my timing light) and only pu a gallon and a half in. Wheeew. I also remember working on a old civic hatchback where the ECU did the same thing every couple of weeks. I think im going to try and get those belts to work.

[jbrown]

And I got my alternator tested at three different part stores all with a thumbs up. This forum has never failed me!