Another Gremlin... Time to move on?

[PlayingWithTBI]

The OP has an 88... how useful will a fancy scan tool be?

You can see all the sensors and other stuff. Here's a snapshot from TunerPro RT on my 88

You must be registered for see images attach

Verify timing as well, have to pull the diagnostic wire, in 88, is that behind the dash?

The EST bypass wire is in the main loom behind the engine on the passenger side.

You must be registered for see images attach

OP - when you replaced the ICM did you replace the coil too? A bad coil can/will take out an ICM fast.

 

[pmndlt]

Thanks @Schurkey - Sounds like quite the unit. I think I'd be looking for something a bit cheaper/simpler. @LC2NLS6 I have checked and set timing, as @PlayingWithTBI mentioned my disconnect was in the loom on firewall. I was actually thinking of advancing timing as a possible carryover for the time being until I figure out if I can get some funds to dig further.

I pulled the ICM from my 88 Iroc (OEM GM one) but I did not replace the coil at that time. Ill add it to the list lol.

 

[Schurkey]

The OP has an 88... how useful will a fancy scan tool be?

ENORMOUSLY useful.

I don't know how the rumor got started that "OBD-I" vehicles don't provide useful info on the data stream got started, but it's fairly common and entirely wrong. How do you think OBD-I vehicles got fixed when they were new, and new-ish? GM OBD-I vehicles back to 1980 1/2 provide info on the data stream, if you've got a scan tool that can talk to them. It is true that the older the vehicle, the less info there is--but all the basics like sensor info are there. I can get throttle position, O2 voltage, rich/lean, open loop/closed loop, knock sensor, MAP sensor data, etc, all the way back.

I had a long conversation on another forum about this exact issue. The whole conversation is interesting, with back-story about the effectiveness of scan tools on OBD-I vehicles, but the important part for the purposes of this thread are Posts 14 and 15; and just by coincidence, they involve an '88 K1500.

94 k2500 no low end power and horrible fuel mileage - Automotive Forums .com Car Chat

94 k2500 no low end power and horrible fuel mileage C/K

www.automotiveforums.com

 

[Erik the Awful]

I don't know how the rumor got started that "OBD-I" vehicles don't provide useful info on the data stream got started, but it's fairly common and entirely wrong.

Because these trucks came out in 1988, but the Tech2 didn't come out until 1995, and that was only if you worked in a GM dealership. Everybody else had to play winky-light diagnostics.

 

[Schurkey]

Because these trucks came out in 1988, but the Tech2 didn't come out until 1995, and that was only if you worked in a GM dealership. Everybody else had to play winky-light diagnostics.

Do you suppose that there was a Tech 1 years before there was a Tech 2? I'd have to dig into my W-body service manual, but it's either calling for the Tech 1, or--I thought--the Tech 2. I think the Tech 2 came out before '95.

I don't know when the MT2500 "Red Brick" showed up, but it would have been in the mid-'80s sometime. The Snap-On guy walked in the shop with one, for the then-outrageous price of...$700--$800.

The Red Brick was miles ahead of the OTC Monitor series, (Monitor 2000, Monitor 4000) which came out years before the 'Brick.

Yes, we did "play winky-light diagnostics" because there was only one OTC Monitor in the (independent) shop, we techs had to share the stupid thing. And the big deal back then was that all the companies making scan tools wanted to play "trade-in" games, to get the other scan tools out of the shops. They'd deliberately jack-up the retail price of the tool, then give you a bigass credit when you handed-in your Monitor 2000 for a Monitor 4000, or when you handed in the Monitor 4000 for the Snappy. The point I'm trying to make in post after post after post, is that "winky-light diagnostics" is a piss-poor way of doing things. The winky-light gives you codes with the engine off, and rich/lean and open-loop/closed loop with the engine running. It's almost but not quite useless.

Scan tools go back to the early '80s.

 

[454cid]

Do you suppose that there was a Tech 1 years before there was a Tech 2? I'd have to dig into my W-body service manual, but it's either calling for the Tech 1, or--I thought--the Tech 2. I think the Tech 2 came out before '95.

I don't know when the MT2500 "Red Brick" showed up, but it would have been in the mid-'80s sometime. The Snap-On guy walked in the shop with one, for the then-outrageous price of...$700--$800.

The Red Brick was miles ahead of the OTC Monitor series, (Monitor 2000, Monitor 4000) which came out years before the 'Brick.

Scan tools go back to the early '80s.

Only professional mechanics had scan tools back then.

Mine is an OTC Monitor Elite.... I hate using it. The interface is so archaic, and it's so slow. I need to get something else for actually looking at DATA.

 

[1997]

Seems a few of us members have this unit
actron 9690, for OBD1, lot of YouTube vids on using it.
I’m still figuring it out, was about $220 cdn, iirc.
might be worth investing since it does OBD2 stuff also.

 

[PlayingWithTBI]

The interface is so archaic, and it's so slow. I need to get something else for actually looking at DATA.

Yeah, keep in mind the early (87 - 92 IIRC) ECMs ran on a baud rate of 160 where the newer ones (93+) jumped up to 8192, much faster with larger data tables.

 

[Schurkey]

the early (87 - 92 IIRC) ECMs ran on a baud rate of 160 where the newer ones (93+) jumped up to 8192, much faster with larger data tables.

You're making me feel old. '87 isn't "early" to me.

I remember that there was a big-deal in...'86 (?) where the computers were said to be four times as powerful as the older ones.

Some years of the Chevy Chevette used a system called "Min-T" (Minimum function, "T-body") The computer was so prehistoric that if the Check Engine light came on, you were supposed to drive immediately to a GM dealer and DON'T SHUT OFF THE ENGINE because if you shut it off, the codes were erased--there was no memory with the ignition off. The Chevy dealer had to pull codes from your running Chevette or they were GONE.

 

[kenh]

$70 ish for a OBD1 cable and free software for your laptop and you have a great scan tool. I'm just now finding that out. If you are handy electronically you can build your own cable for much less.

Ken