Can't retrieve CEL. Won't rev over 3000

We may earn a small commission from affiliate links and paid advertisements. Terms

jjsJDM

New Member
So, I'm looking for some details or advice here. I have an 89 CRX with a B16A, y1 trans, Crane external coil kit, and HI-6s Ignition, and a PR3 computer.

I have a check engine light, but from what I've read I should just have to turn the key on and the CEL codes will display for the PR3 because it's OBD0, right?

Second, the damn thing won't rev over 3k, I've read about the distributer wiring causing this "safety" condition from the ECU which makes me suspect the hack-wiring job my counsin's buddy did before I got the car.

A kid i was pullin parts with at the junk yard was saying that cars won't rev over 3k if they're cold, so that suggests the possibility of a ECT sensor... The guage does work, and I saw pin C6 listed as being for a coolent temp sensor, does this car have 2, one for the guage and one for the ECU? is that even a feature that the PR3 supports?

Like I said, I think the codes are supposed to just show when the key is turned to the "ON"position, but nothing happens, the LED comes on but never blinks at all. It's just constant. I looked for a 2 pin connecter like the 92-later OBD1 systems just to humor myself and found nothing.

I've invested some time reading diagrams, but some words from an experience swapper and trouble shooter might help me zone in on where to spend my time looking.
 
Its in limp mode, pull the hazard fuse to reset the ECU and then see if its still got a 3K rev-limiter.
 
reset

Yeah, I take the battery off every night... that should reset the ECU, right?

I need to figure out why it won't let me retrieve the codes... Start with the codes, see what's malfunctioning then address those issues.

Then reset... Makes sense to me.
 
Like I said, I think the codes are supposed to just show when the key is turned to the "ON"position, but nothing happens, the LED comes on but never blinks at all. It's just constant.
solid LED usually means bad ECU or a wiring problem - this is from the service manual:

ECUcode2.jpg
 
I checked and fixed some wires running to the Distributer last night. The TDC+ was broken I don't remember which pin that was...

But I still have Pin B20 that is "Ignition Timing Adjust" where the hell does the other end go? I'm assuming that it would go to the distributer, but I can't find full diagram that shows a chassis or engine wiring. I might have to go buy a manual with diagrams...

if any of these bad spices he had in here shorted to the firewall it could have burned up part of my ECU... I hope not, I'd rather not try and find another chipped PR3.
 
But I still have Pin B20 that is "Ignition Timing Adjust" where the hell does the other end go? I'm assuming that it would go to the distributer, but I can't find full diagram that shows a chassis or engine wiring. I might have to go buy a manual with diagrams...
the ignition timing adjustment jumper connection is located under the hood next to the driver's side strut tower - has 2 wires, one brown which goes to ECU pin B20 and one green/white (ground) which connects in the harness to a lot of other green/white ground wires for sensors and ends up at ECU pin C12

timingjumper2.jpg
 
Last edited:
the ignition timing adjustment jumper connection is located under the hood next to the driver's side strut tower - has 2 wires, one brown which goes to ECU pin B20 and one green/white (ground) which connects in the harness to a lot of other green/white ground wires for sensors and ends up at ECU pin C12

Awesome... So that's a good start for me. They tucked all the stock wiring inside under the dash, the fuse box that is usually on the strut tower and probably this as well. I can say for sure that the brown wire coming off pin B20 is about 3 inches long and ends at a butt-spice that's been pulled apart. Just find that jumper and the other wire and I'm golden... I hope.

I'll look for that connector tomorrow night after work in the mess of shit they crammed under the dash. If I can get this working as-is then I'm going to trim up this harness and get it to fit under there right. This is nuts. Want to make sure it works first.

Thanks for the pic bro. Gotta give ya some rep for a detailed answer like that... We'll see what I face tomorrow.

Wish I wasn't working 60+ hrs a week and taking night classes, this thing might get done alot faster
 
Wait, so what's this thing's function? Is it just used when adjusting the base timing on the distributer? If that's all that shouldn't be affecting my CEL or the Safety Mode that's holdin me back...

I was reading about how to check the tdc/cylinder position sensers in the distributer... I'll check those out when I get a chance and eliminate that as a possibility...
 
How can I Test my ECU?

So rather than come back with more stupid questions I spent alot of time workin on this bastard and doin more research.

I re-pinned all the bad wires that were at the ecu, I tugged on one and realized the idiot didn't have any pins from a wire harness and just jammed the new wires into the back of the plug until it contacted the pin and called it good. So I hacked some wires and their pins from an old accord and pinned and spliced them in.

I did some ohms testing on all the sensers and it looks like my o2 senser is bad. Yes, just one single wire on an obd0 car... it's chipped so, maybe they programed it to run with only one? either way it's bad, so I'm getting a new one soon. I don't think that would cause it to run in limp mode, would it?

Still having the solid CEL problem, I have eliminated any possible shorts or other wiring problems, and tested the harness to be sure... So I guess now I need another ecu...

Can i power the ECU out side the car just to see if there is anything it's reading through the car that is causing a solid CEL?
 
Fixed

After living on PGMFI.ORG with every free minute of my time... I realized that the horrendous wiring wasn't to blame. It was ugly and is now fixed, but the solid CEL is a hardware issue inside the ECU.

So that was right up my ally. I found that the solder job on this "chipped" ecu was a discrace to electronics, fixed that, only took a few seconds really...

My solid CEL is gone, the car sounds much better and it will rev over 4k (quickly). It's late tonight, so tomorrow right after work we're going for a ride!!
 
Last edited:
Back
Top