electric update

[Teds89IROC]

notes: I've had an electrical problem for months (low volts, very slight miss in idle, ALDL cannot connect to ECM) battery, alternator all check fine.

I inspected more of my main harness going to the ECM as well as the wires at the ALDL connector and behind the radio/console; everything looks good. I found out that my ECM is remanufactured. So since everything looks good, I checked with my local auto parts store and I can have it rebuilt for $100. I explained to them how I can't connect through the ALDL and they think it sounds internal. I'm thinking of doing it, what do you guys think?



Also, while looking around I came across this...what is it?



it plugs into here:

[//<86TA>\\]

i dont see how a bad computer could cause a low voltage issue

how are the battery cables and chassis/block grounds?

dont know what the black thing is.

[sweetbmxrider]

Originally Posted by //<86TA>\\

i dont see how a bad computer could cause a low voltage issue

i have personally seen this. the computer regulated the alternator.

i have no idea what the black thing is. looks like its a gm number. i'll write it down and call tomorrow.

[Teds89IROC]

Originally Posted by //<86TA>\\

i dont see how a bad computer could cause a low voltage issue

how are the battery cables and chassis/block grounds?

I don't know either, maybe its shorting or something but regardless, it is part of the whole electrical mess that I have. I've been tracking this problem for months and I'm way past the simple grounds/battery cables etc. I know definitely that I cannot connect to the ECM through the ALDL, Josh couldn't either when I went to him for a tune. He checked the connector prongs and everything is fine there. Anything obvious or visual I've checked and I've found nothing.

[Teds89IROC]

Originally Posted by sweetbmxrider

i have personally seen this. the computer regulated the alternator.

i have no idea what the black thing is. looks like its a gm number. i'll write it down and call tomorrow.

that would be great, thanks man

[BonzoHansen]

that black thing is a box. LOL

Not sure yet, but there is a 7-pin something in this pic:

http://www.austinthirdgen.org/mkport...ody_wiring.gif

look at the bottom at the 7 pin deal - it appears to be related to lighting.


So you physically traced the ALDL link leads back to the ECM?

http://www.austinthirdgen.org/mkport...ine_wiring.gif

this says an orange wire and a wht/blk wire go to the aldl from the ecm

If that is good, this may sound dumb but check the ECM# and make sure it is for your car. I've seen wrong chips installed and the car runs. you may also want to see if the pins are physically ok, maybe one of them is bent/broken.

[Teds89IROC]

That must be it because it shows the two flashers near it. Another weird thing is that the "ARC radio" fuse on that panel was blown so I replaced it and there were no fuses in the other slots which are power seat and something else dumb but those functions still work.

Anyway, I physically traced as much of the wires from the ALDL to the ECM as best I could without going too crazy (taking the dash out). The wires intertwine with other groups of wires but I looked at as much as I could from under the dash as well as behind the center console..I took out HVAC controls and radio for access and everything I've seen looks good. I can feel the wires running from there up under and behind the dash along the passenger side down to the ECM and from what I can tell they are fine, just hanging loose wrapped up.

How can I check if it is the correct ECM..call GM? On tunerpro it shows the correct one to use for datalogging is 1227165_6e but I don't know about 310 written at the end of my ECM.

EDIT: all pins are good and harnesses are plugged in all the way

[BonzoHansen]

You physically unplugged the ECM from its harness and checked? You need to check the continuity of the leads with an ohm meter. One probe at the correct pin on the ECM connector the other at the ALDL. A good circuit will be closed (0 resistance). You also may need to check short to ground, one probe at the correct pin on the ECM connector the other to ground. Here you want open (no resistance).

You might want to ask Stevoone for some assistance, he’s a GM tech.

[Fast92RS]

That black thing looks like its from the convience center. IIRC that box makes the buzzing noise when you leave the key in the ingnition with the door open and the buzz noise with the lights on. Also controls the seat belt light.

[Teds89IROC]

Originally Posted by BonzoHansen

You physically unplugged the ECM from its harness and checked? You need to check the continuity of the leads with an ohm meter. One probe at the correct pin on the ECM connector the other at the ALDL. A good circuit will be closed (0 resistance). You also may need to check short to ground, one probe at the correct pin on the ECM connector the other to ground. Here you want open (no resistance).

You might want to ask Stevoone for some assistance, he’s a GM tech.

The ECM was physically unplugged and checked. I'll have to try the ohm meter tomorrow morning..I completely forgot about that test . I'll let you know what I find and contact stevoone. Thanks

[The Fixer]

Originally Posted by Fast92RS

That black thing looks like its from the convience center. IIRC that box makes the buzzing noise when you leave the key in the ingnition with the door open and the buzz noise with the lights on. Also controls the seat belt light.

I was going to say the same thing, I'm pretty sure that's what the 7-pin black box is. I pulled one out of the Monte I parted years ago, and that's what it was for.

Also Ted, I've never seen that ECM number used as a replacement for a '165 ECM, but that might be the issue. Make sure the guys at the parts store give you a '165 ECM when you trade the other bugger in.

Edit: The lower number printed on your tag has the 1227165 on it, so it most likely is already a 165 ECM, just with a different P/N.

[sweetbmxrider]

14034321 = Electric Spark Control Module

so what exactly was going on with the car again ted? i saw that there are 5 different amp ratings on alternators for these cars; 85, 100, 105, 108, and 120. there is a gm tool for testing the alternator.

someone mentioned that box controls the seatbelt light possibly? does that seatbelt light work? does your battery light on the dash work?

the ALCL connector goes like this....

| F | E | D | C | B | A |
| G | - | - | - | - | - |

A - ground
B - Diagnostic "Test Terminal"
C - A.I.R. (if used)
D - C.E. Lamp (CCC)
E - Serial Data
F - T.C.C. (If Used)
G - Fuel Pump

i also read that some control modules may have problems due to cracked solder joints on the circuit board. it can cause the module not to communicate with a scanner or some various intermittent driveability problems.

you can apply heat to the control module to simulate underhood temps. then tap on it with your finger to simulate vehicle vibrations. if the engine stumbles or stalls, there could be an internal problem with the module.

[V]

my 88 gta had all weird issues back in the day, would randomly stall, volts jump/drop, couldnt connect to ecm, got new ecm, fixed everything, not saying thats def the case for you, but was for me.

[Teds89IROC]

Originally Posted by BonzoHansen

You physically unplugged the ECM from its harness and checked? You need to check the continuity of the leads with an ohm meter. One probe at the correct pin on the ECM connector the other at the ALDL. A good circuit will be closed (0 resistance). You also may need to check short to ground, one probe at the correct pin on the ECM connector the other to ground. Here you want open (no resistance).

I checked continuity from ALDL to ECM and had zero ohm. I also checked short to ground and came up with the same thing..looks like it's ECM...

Originally Posted by sweetbmxrider

14034321 = Electric Spark Control Module

so what exactly was going on with the car again ted? i saw that there are 5 different amp ratings on alternators for these cars; 85, 100, 105, 108, and 120. there is a gm tool for testing the alternator.

someone mentioned that box controls the seatbelt light possibly? does that seatbelt light work? does your battery light on the dash work?

the ALCL connector goes like this....

| F | E | D | C | B | A |
| G | - | - | - | - | - |

A - ground
B - Diagnostic "Test Terminal"
C - A.I.R. (if used)
D - C.E. Lamp (CCC)
E - Serial Data
F - T.C.C. (If Used)
G - Fuel Pump

i also read that some control modules may have problems due to cracked solder joints on the circuit board. it can cause the module not to communicate with a scanner or some various intermittent driveability problems.

you can apply heat to the control module to simulate underhood temps. then tap on it with your finger to simulate vehicle vibrations. if the engine stumbles or stalls, there could be an internal problem with the module.

My problem started as a low voltage issue, I had the alternator checked and I had a new battery at the time. I checked all my wires and upgraded as well as scraped all my main grounds and made sure there was proper contact. Also, I've noticed a slight mis when the car is idling, just a slight drop in RPM then it picks right back up. Finally, I tried tuning the car and I wasn't able to connect through the ALDL.

I was just curious what the black box was, all my noises and dash lights work lol

I didn't try the heat test on the ECM but after checking continuity I'm pretty sure I need to have it rebuilt.

Originally Posted by SmokingSS

my 88 gta had all weird issues back in the day, would randomly stall, volts jump/drop, couldnt connect to ecm, got new ecm, fixed everything, not saying thats def the case for you, but was for me.

Sounds like it might work for me as well lol

[maroman88]

i also think the lil black thing is the door chime....

[Teds89IROC]

so whats the verdict, I'm thinking I'll have the ECM rebuilt, what do you guys think?

[Kat]

aftermarket chip?

[sweetbmxrider]

do they rebuild ecm's? i thought you buy a rebuilt and send in the core or buy new and keep your old one. all signs seem to point at the ecm so i would go that route.

[Fast92RS]

I would go for it or try and get one of ebay.

[Teds89IROC]

Originally Posted by Kat

aftermarket chip?

It's a custom chip/tune by Josh piggybacking the stock one because they couldn't connect through the ALDL.

Originally Posted by sweetbmxrider

do they rebuild ecm's? i thought you buy a rebuilt and send in the core or buy new and keep your old one. all signs seem to point at the ecm so i would go that route.

They told me they rebuild them but it is probably buying a rebuilt ECM and giving them my core.

[BonzoHansen]

My suggestion is verify you have the correct ECM part# now. Don't just order another one the same #. Order it for the application. Don't overlook a dealer part.

[Teds89IROC]

I verified the correct part # which it was and picked up a new (rebuilt) ECM. I don't have access to a laptop at this time but hopefully in the next couple weeks I will and see if I can connect through the ALDL. When I plugged the new ECM in and started the car I didn't notice any difference with volts but then again I'm sure it will take a little more than just starting it for a few minutes. When the snow/ice melts I'll go for a spin.

[HardcoreZ28]

The lack of connection between the ECM and a laptop shouldn't be part of your problem. I think that's a common issue with our computer. Prevost has had tons of issues with getting his software to link up with my ALDL over the past few years. We've tried 3 different ECM's with no luck so that's not a problem with the car per say.

[Teds89IROC]

I called Craig Moates and had him walk me through connecting, we tried a few things and he thought it was the ECM too. I couldn't even get it to read volts or anything with "dash display."