so i just put my 1994 accord back together. had to replace the head since the cam snapped from what i can only assume was oil starvation. after the head replacement and cleanout the car had a rough idle. i thought maybe timing so i redid the belt... 3 times. and the same symptom. low and erratic idle. i decided since i had time i'd pull the motor and check the head since i suspected a tans fluid leak also. long story short, nothing was wrong with either. i reset the belt and put all new gaskets in. checked compression and all timing marks. put the motor and trans back in the car after i changed the fuel filter since it was super easy to get to here. and it still won't idle. i checked injector resistance, voltage, coil voltage and resistance. tps voltage. the only thing i have seem to stumble across is if i unplug #4 injector connector it appears to idle almost normal. a little high and a CEL does pop up for injector. but with everything plugged in it runs awful. and there is no CEL. there are new injector O-RINGS installed with the overhaul and i'm genuinely stumped. i swapped #1 and #4 injectors to see if the issue followed the solenoid and it did not. it stayed on CONNECTOR #4. checked the injector resistor. and swapped MAIN RELAYS. same condition

DIAGNOSTIC CHECKLIST THAT'S BEEN DONE.
injector resistance. all within FSM ranges
IAC resistance
tps voltage
injector voltage to ground at RED/BLK wires (no shorts 12.6v on all with nothing on the pulse ground)
coil resistance on primary and secondary. all within FSM ranges
injector resistor OHMS. all good.
injector resistor voltage to body ground. good.
swapped MAIN relays. no change
swapped injectors

 

for anyone curious, i just took the ECU out and it's fried. so just a word to the wise, even if you aren't sure. sometimes its worth just smelling these ECU's lol good luck to anyone who has electrical gremlins.

 

Hopefully you can get another one from a junkyard for under $100.

Depending on your soldering skills and the condition of the board, you could see if you can repair it by looking at the burnt parts and replacing them. I've only had so-so luck myself.

 

I just googled the ECU number since its a 5 speed non vtec motor. Found one on ebay for $50. Worth a shot. Just playing the waiting game now. Hopefully the thing runs like a Ferrari when it gets buttoned up. Lol

 

well i put the new ECU in and it's literally the same exact condition. lol i'm stumped. if anyone has any experience i'm open to anything at this point

 

Since it seems to stay on injector 4 , can you get a replacement wiring harness and replace that part of the harness? Or are you able to pull it off and see if the wiring is damaged, but not so much that maybe you can repair it? Does it look melted or anything?

 

me and my dad talked it out this afternoon. i've been chasing my tail on this one, but looks like it is going to be the head i bought. guy had receipts for the machine work done and all. but i did a leak down test tonight and i put 70psi in and got something like 45psi across the board. so either the valve guides are bad or the seat job was garbage. either way, im pulling the head off this week and sending it off. hoping this is the issue, but compression test was good, it just looks like it isn't HOLDING compression. this car has been a nightmare lol. but i DID go to the junkyard and pull an entire new fuel rail off a 97 that has the 12mm service port on the return side. it was a nice little upgrade for future tests if i need it. new injectors and new clips. all same issue. so i'm sold it isnt fuel. especially after the pressure was 40psi on the rail. and the leakdown results. cheers. i'll update in a week or 2 once it's back together.

 

It does sound like you are onto something. 40psi is very low and would produce the effect you are seeing. Can you throw a head on from the junkyard (that you've tested while it was in the junkyard and seems ok)?

Thanks for the update.

 

so the head is at the machine shop and the only issue my guy found was he said the valve guides were some of the worst he's seen in a while. so he's putting new guides and seals and regrinding the valve seats. i'm suspecting that the valve rotation in the worn guides has been causing a "no seat" condition and dumping the compression. so getting the head back this weekend and hoping all is well. lol that's my update.

 

well got the head installed this weekend. and everything fired up... but it's doing the same thing. so i guess i'm going to trace some grounds. this is ridiculous. thanks guys.

 

just an update. i finally figured out 100% what was causing the car to stall. it took a LOT of checking and rechecking but i just happened to be outside and was trying to run the car to set the idle screw, thinking MAYBE the procedure was wrong. well long story short, i put a new coil, distributor, MAP, TPS EGR valve. fuel rail. and then i got to thinking about the FSM test on the egr. where you pull vacuum on the egr and if the car dies it's working. well there are 2 small vacuum lines on the driver side fender that control the solenoid signal and the vacuum control to the egr. BASICALLY i had them backwards. so long story short, as i've been driving the car, it's been "testing" the egr. hense the stalling at idle. long story short. this was my bad. i'll know on my 33 mile trip to work tomorrow, but i have a strong feeling that's the case. cheers and good luck to anyone who reads this and needs it.

 

Hey, at least you figured it out!