Check eng light on

[Infinitiace1992]

Any advice on diagnosing codes on OBD 1 cars? I don’t drive my 91 Q45 much. A few weeks ago I started it and drove it and the check engine light was on but ran fine. Today, it started fine and idled smooth (a bit higher rpm than normal) I backed it out of the garage and it seemed to be running rich (dark exhaust from tail pipe) when I revved it a bit it seemed to choke out. When I put it in gear (under a load) it kept stalling out. This happened about 6 times pulling it back in the garage. Any advice is greatly appreciated.

[3Q Jay]

Hi Ace- did you actually pull the code? WAG is MAF connector.

[Infinitiace1992]

I have an OBD II decoder but I don’t have one for OBD 1 so I cant pull the codes

[3Q Jay]

Although unpleasant, you can always get the OBD-i code right from the ECU if you pull the pass side kick panel undo the 3 philips screws, and gently reposition the ECU so you can get at the mode screw. be gentle with the screw if you are unfamiliar with the procedure. You have to turn it to the stops, but don't gorilla it...

[Infinitiace1992]

I totally appreciate your help but that might be above my skill set. I’ll check eBay for an obd 1 scan tool seems easier and safer for me

[3Q Jay]

finding a Consult1? That would be sweet, my understanding is that they don't come up often. The laptop (even tablet) type interfaces are not too expensive. Mostly it's the dongle to the 14-pin connector that will make or break your success-so consider spending a few $ extra for one with good reviews. I'd steer clear of an OBD-i to OBD-ii "jumper harness". Those are typically junk.

[dnudelman]

Consult software and cable
Here is the rabbit hole:
https://www.z1motorsports.com/electroni ... 9b47b9db2f
https://www.conzult.com/index.htm

[Ryantzer]

The factory service manual has step by step instructions on how to pull codes, and also has diagnostic procedures for every code you might encounter. o reason not to locate one if you're planning on working on your own vehicle. Pretty sure there are links to download the FSMs somewhere here on NICO.