Saddles4388

91 Honda Accord. I just purchased vehicle - car was running great when I bought it. Occasionally the originally owner told me - the car would not start, but always did within 4-5 minutes of sitting.

I drove car around a bit and one day after driving and parking the car would not restart. I had removed the ECU/TCU and repaired a leaking capacitor on the TCU in attempt to fix issue with S light flashing, but had driven and started and restarted car a few times since installation of repaired TCU - I did notice that S light would still flash occasionally and that speedometer which was previously not working now showed 10 mph at all times key was advanced - I am guessing that the repair failed or there are other issues here.

I have verified no spark at plugs. Rotor does turn on distributor. I have verified power to ICM and Coil. I verified no trigger signal from ignitor. I verified that I did have pulse from ECM - however, pulse was apparent on grn/yel wire and car sputtered and almost started. Pulse became weaker but still noticable and car would only crank. I replaced entire distributor. Car still will not start.

With key advanced - CEL comes on and stays on - does not go off after 2 seconds. With service connector jumped S light flashes codes while CEL stays lit solid - no flashes. I have visually inspected inside of ECU for damage and did not see any burns.

I will also mention that if a sensor is causing this weakend pulse from ECM I would like to know what sensors TDC, Cam and Crank? sensors are required for spark pulse. The valve cover is leaking quite a bit of oil and I wonder if this may have damaged cam sensor. It is also worth mentioning that car will constantly crank if allowed to but ignition switch does have apparent problems with sticking removing key without turning ignition etc. Is ignition switch still possibility if car still crank without stopping or other loss of power?

Positive battery cable on car is loose and battery has drained in car. I did not ask but I wonder if previous owner had this loose to easily remove because of a parasitic drain, perhaps in one of the computers ECU/TCU or a sensor or?

Any insight appreciated. I need to rerun through diagnostic with new distributor installed. I am using a test light to test for power and a test light I have modified with an LED and resistor to look for pulse.

siavosh

Try taking out the main relay under the dash. The soldering was apparently pretty bad on the original main relays for the 90-93 accord. A bad main relay will definitely not allow the fuel pump to come on and you will also not have spark (the S will also flash but D on mine). I had the same issue and this fixed it. I took it out and noticed there was very little solder, and the little solder that was there had hairline cracks (not very noticeable but i could see them). I just added more solder and I have not had a problem since.

I also read about the bad capacitor issue on the ECU (cheap capacitors used) and was going that route if the main relay didn't fix it.

siavosh

Try this link. It explains this issue very well

http://techauto.tripod.com/

Saddles4388

Thank you for your advice!

I have double checked all fuses. I was using booster cables to diagnose car and have charged the battery up and repeated diagnostics with charged battery with same results.

I located the main relay and it is secured firmly under the dash (I know they're a pain to get to, I've had 3-4 hondas and if they've been replaced I've never seen them mounted back correctly, this one looks original.) I banged on the dash some and did not have any more luck.

I have ordered a main relay to put in the tool box since I like to tinker on these cars anyway and will be giving that a shot. I'll pull the old one and check it, I found the guide before to check for continuity.

My main issue right now is my GF was in an accident and its hard to get a helper to crank while I test!

I will update this post with any information I gain.

I understand that if the CEL does not blink with service connector jumped, stays on solid, this is known as Code 0? And means dead ECU? But I understand a bad ground at the thermostat housing can cause similar issue?

Appreciate all the info!

siavosh

Sorry to hear about your GF. I hope it's nothing serious. Here is a link to a remote starter. They are very handy (and cheap) and you can use them with any car.

http://www.tooltopia.com/kd-tools-12...aign=nextag_r1

It's called a remote crank/starter switch in case you want to look it up locally. It's very useful with diagnostics if you don't have anybody nearby that can help or if you want to control the crank start/stop by yourself.

Don't worry about the CEL for now until you test the main relay. A bad connection at that relay will cause a code 0 as well

Yeah, banging on the dash didn't do anything for me either. If the connection is really bad that won't help.

Saddles4388

Thank you. She is getting better, all done with surgeries now.

That is handy! Never knew that existed. I am going to get one ordered whether I use it on the honda or not. Good little tool.

I got the main relay pulled out tonight and discovered my meter is dead...must of left it on last time or turned on in my bag. Anyway...I dropped it fiddling with it taking it out of the case...discovered my meter was dead...put it back, and the car almost started a couple of times, backfired etc. After that, checked and still no spark. Think we might be on to something here.

I will get a 9v for my meter and let you know what I find!

Thanks for your help.

siavosh

Cool. Good luck. I hope that's it.

Saddles4388

Been pretty busy with the 4th etc. Found my tool box main relay had come in so I swapped them out to see what would happen.

Still no start...car cranks over and almost catches but wont fire up. Seems like fire is coming and going, though I havent checked that. Its been 105 degrees here lately.

Anyway...back to the drawing board! CEL behavior did not change.

Guess its time to recheck for fire and then clean up some grounds, at T stat housing and others?

gary95H22Accord

Make sure you are jumping the ecu correctly. The paper clip goes in the top part of the blue connector pin

Saddles4388

Good suggestion. I am inserting the clip in the portion with the little metal tabs. I am pretty sure I am doing this correctly as the S light begins flashing with the paper clip in place (actual codes, not just flashing) but the CEL does not change behaviour.

Saddles4388

Welp did some more testing. Had a friend come over with another 91, we swapped in his ECU and still no start.

All original parts - CEL would come on and not go off. I swapped in my spare main relay the other day and CEL still would not go off. I played with this a bit more and realized i had service conector jumped. I have confirmed with certainty that with the original main relay, CEL does not go off after 2 seconds, whether connector is jumped or not.

With replacement main relay, CEL does go off after 2 seconds, with service connector jumped light is on solid no codes. I do have fire now and it appears strong. However, car would still not start.

Not sure...guess I need to look at fuel pressure next...hmmm this is proving to be a bad investment

Hope I haven't jumped time.

Saddles4388

Got it running!

Original issue was main relay. That is why CEL began going off after I replaced main relay. ECU was not receiving power to send pulse to distributor. I had swapped on another older distributor that I thought was good and had tested...and was receiving fire out of it.

Today, I swapped in the original distributor with the replacement main relay and the car started up no problems!

Whew....getting there! Thanks everyone for help.

Sloppy troubleshooting on my part...

ankyg

Ok I am having same problem as many of you...1990 accord cranks & cranks does not start. Car has been sitting for about 4 months. Was running great then. So far I check all spark plugs, all are firing, replaced main relay, and now I replaced the fuel filter. When doing that a very milky colored gas came from the old filter on the firewall side of filter. It just seems like its not getting gas...where should I go from here?!


Thanks for any help!!!!

beord11

its the fuel pump. or can be fuel relay

Hondaguy83

Crank sendor