So here is my problem. I am getting a cel 4 on an all stock 1991 civic si
pm6 ecu all stock. i have replaced the distributor and still the same prob. will not go above 3200rpm. i have tried just about everything to my knowledge and even been looking online for days.
anyone had this problem? or can anyone help? thanks alot

 

Here is a troubleshooting guide from the Factory Service Manual.

Grab yourself a multimeter and just follow the flow chart and you will find your issue. I fought with this code for about 6 months before figuring out what the issue was. Mine happened to be a swapped car and the wire for the Crank sensor came unhooked... simple, I know lol.

Good luck.

 

Thanx alot man!!
will be doing some troubleshootin now!
will keep ya posted...

 

okat so after narrowing it down i have a dead wire somewhere.. no resistance
between B10 and B12 (orng/wht). so before i just go ahead and run a new wire i would like to know if anyone has done this before and maybe knows a good way to go about??
I did try another good ECM and the same prob. occured. so should i run the new wires directly to the male pins on ECM or just connect it to the existing orn/wht wires.?
thnx again for the help

 

So you are getting resistance at the distributor but not at the ECU?

 

i just checked and no. nothing at dis. or at the ecu.
it is a brand new dis. and i als have the used one which does the exact same thing. and both ecu's creact the same except my old one keeps the oil light on for some reason... the other one comes on and goes away properly.dont know if tht has anything to do with it but.
anyway what would you advise as a next step? and this car did have a b16t previously but i dont think it was obd1.. no signs of any wiring mods.
and one more thng, a little up the harness there is a ground wire which runs from the crank angle to t.stat ground i believe.?? if i rewire it will that be needed to work properly..
thnaks

 

There should be resistance on the actual distributor plug if it is brand new. If not, I would be returning it to the place you got it from because if that distributor doesn't have the resistance between those 2 pins you checked then it's the distributor. Do you have it set on the resistance setting on the multimeter? I would double check to make sure it is before trying to return the distributor.

 

no no i was talking about the harness AT the dis. lol
the dis. itself does give proper reading becuase it is powered by the icm..
but the harness does not so to attepmt to rewire it staright to the computer will i need to run that ground also (the one i mentioned prev.)?? and should i run to the ecu or the wires on the "B" clip??

 

And just to be clear to myself, you aren't getting the 350-550 ohm resistance at the ECU from the wires in b10 and b12? Are you getting low resistance or none?

 

none...

 

Alright, well if I were you I would just be very careful and make sure you clip the correct wires on the distributor run some new wire from the cut wires, make sure to do it correctly with solder and heat shrink to eliminate the possibility of the wires coming undone or bad contact.

Just make sure you leave enough wire incase you have to put the wires back for whatever reason.

 

okay thanks.what are the possibilities of two bad ecus?

 

Okay so tht kinda back-fired. cel stays on and it wont strt now.
can anybody give me some help here?? tried just about every way possible to wire it and i tried it both with and without the ground i had previously mentioned. thnx

 

Anyone!?!?
dephtone u got any input...

 

Okay so after i put it all bak to the way it was the cel is still constantly illuminated and it has no codes at all!! im sure i just messed messed tht little ground up a little but this is getting ridiculous! anyone..

 

Okay well obvously no body tht has seen this has any idea..
but i figured out why the cel was staying on so know im back to the original prob. Code 4 (crank angle sensor) i have replaced the sensor, and even the whole distributor. as well as the ECM, and have ran new wires directly to the ECM and i still am gettig the same prob... only revs to approx. 3200rpm idle like ****... can ANYBODY help??

 

hey dephtone.. since ur the only one who seems to know what theyre talkin bout lol..
it specified in the chart you gave me tht the two Crank Andle wires (orange and white), should have between 350 and 550 ohms. both of my distributors are reading at 370. is tht a low reading?? or..

 

No it's not low, it's just within tolerance of the specifications. Mine was roughly the same way ~390ish or so and that was with a brand new distributor from Rywire so no worries on that.

Are you using the same gauge wire that the originals are? If not that may have something to do with it lowering the resistance over the circuit.

So when you ran the new wires and plugged in the distributor do you have the 370 ohms of resistance coming through those wires?

And if you did, when you hooked them up to the ECU that's when the car wouldn't start?

 

just had this problem last night.

depin your b10 and b12 from the ecu plug, (orange and white) and crimp the female ends so they grab onto the ecu pins better. I had code 4 and limp mode, etc, and that was the problem

 

Found the problem ofr future ref. to anyone tht may have a similar problem.
i fully went through and resoldered every clip with diferent ones ( junk yard ones) AND EVERYTHING was perfect...370 ohms at EVERY point.. so tht was the prob.. purrs like a kitten thnx dephtone for your help..!!

 

No problem man, glad you got everything worked out. It seems like whenever an EF has a distributor issue it takes forever to find it. Great work though!

 

haha yeah really! but thats why i love em'!!
oh yeah and for future ref.. the way i really narrrowed it down was with dephtone's link AND i disconnected the main ecu harness from the engine bay one and tested the orn/wht wires and there was nothing but there WAS 370 @ the ecu ( with a wire straight from the CAS to the ecu) i just added a straight wire as well as the original ones. so i could see exactly where it was thnx again H-T.

 

OH ya but now i have a perfect cond. OBD0 B16 distributor if anyone needs.. located in the 909-951 area..