I have a 89 Honda CRX DX with a B18C1 swap. I converted to OBD-1 and run a P28 Crome chipped ECU. As I was cruising on the freeway, the check engine light randomly appears. I stopped at the nearest gas station and tried to see if any connections might of came loose. Everything was in place so I pulled the ECU & Hazard fuse from the engine bay fuse-box in hopes to reset the code. Once I started the car, the check engine light appeared again within 5 seconds. I managed to make it back home and called it a night.

The next morning, I used a wire to jump the connector to retrieve codes. When I did that, the gauge cluster indicated that there were no codes to be found. I removed the wire and proceeded to start the car. The main relay clicks and the check engine light appears on the number 2 key position then goes off like it's supposed to. Once I cranked the car over and it started, the CEL comes back on and remains on until the engine is shut off again.

It's becoming really frustrating because there are no codes that indicate any sensor malfunction. The car drives normal but I'd rather be safe and keep out of the VTEC range until I get this issue resolved. How is it possible for the system to show no codes but yet when the car is started the CEL appears? Any assistance would be greatly appreciated. Thanks guys.

 

Bump for some help. Thanks.

 

Having troubles myself but, when you say it has no codes do you mean when jumped the CEL does not come on or does not flash because mine does not go off and i would like to know if this means no codes or a code 0??

 

That means you don't have any codes if the jumper wire is connected and the check engine light does not turn off. The problem with mine is that regardless if the jumper wire is there or not, it still acts as if there were no codes. I already tried 3 different ECU's and the same thing happens. This leads me to believe that the ECU is not the culprit here. I've never experienced anything like this before and it's becoming a nuisance. Anyone else?

 

Anyone ever experienced this problem before?

 

Please help. Thanks.

 

bump same problem here.

 

By chance did you ever get that figured out I’m having same problem myself like u said checked everything no codes just solid cel light when jumped just gets brighter but does not blink at all… car runs great n also gsr motor only difference is mine in eh2 hatch

 

Your problem is likely a bad ECU. Test using a known good ECU and see if your problem goes away.

There are potential issues caused by either a loose/bad main engine ground OR a "Phantom Code" caused by a incongruity in a custom chip program and the foundational ECU in which it is installed in. If this problem is recent, then the latter is not possible.

 

hopefully I can get my hands on one buddy said he might have an extra laying around gonna try it this week when brings it by I was think ground on ecu just because it does run good

 

Usually, if the engine runs "good" as you described, and it is a "chipped" ECU... there is an incongruity in the ECU type/foundation and the programming. A good example would be a non-VTEC ECU (and not converted to VTEC) with a chip installed that is programmed for VTEC. The programming is looking for VTEC parts, but the ECU doesn't know that they are missing and doesn't have the basic codes internalized to identify the problem. These are called "Phantom Codes" by those in the Industry.

 

got my hands on another ecu same as this p72 just solid light both ecu are virgin ecus … so problem must be on car?

 

Maybe... but trying an ECU that is "Just Laying Around" isn't what I call a "KNOWN GOOD" one. So, try the P72 in your buddy's car, and if it cranks and the MIL goes out (or creates codes that are due to incongruities in the programming/engine sensors that can be obviously ignored... for example, no Knock Sensor or no VTP switch), then you can call it "Known Good".