crispyflame

----Long story edition (Short story at bottom)---
I have a 94 del Sol S. Back a few months, I can't remember exactly when, she just cut out while driving and wouldn't start up. I went to class for a little more than an hour and then it started up fine. My mechanic told me about the main relays tending to cause intermittent problems like that, so I put in a new one. It went a long time without any incident, and then one morning on the way to work it died again. I rolled the key back and was able to start it again mid-roll. This happened around three times and then it seemed about dead for good. I read about the ignition coil and ICM (ignition control module) problems, so I popped open the distributor and just gave everything a look. The posts on the cap were obviously old so I brushed them off a bit and put everything back and she started up again. So that led me to believe that my problem (possibly disjoint from the original dying) was just ancient distributor cap and rotor. Unfortunately I was broke, so any time it started misbehaving I pulled the cap brushed off the posts and the rotor, and it would behave for quite a while. So finally I got a new cap a couple of weeks ago and it seemed pretty happy. There was a bit of a "chug" that disappeared. Then I got the new rotor in last Thursday. Friday I went to work, hopped home for lunch, went back to work, and then when I was leaving at the end of the day I got about 30 seconds out of the parking lot and bleh, dead again. No restarting while rolling this time. I fiddled with the distributor and plugs and it came back up. It died two or three more times on the way home with varying amounts of time and fiddling before it would start again. I left it for the night and all day Saturday. I checked on it Saturday night and managed to pull a code 0 out of it, so I fiddled around with the (brand new) main relay and the ECU fuse, and it didn't want to die any more. So we got up Sunday morning and just hoped for the best going to church. I had literally come to a stop in our parking place and it died. I got out and messed with everything and it came back. After church I pulled G101 and cleaned it up just for good measure. It ran plenty parked. Started driving for about 30 seconds and ded. I left her in the parking lot for a while and came back later. I was finally able to reliably recreate the behavior by pulling the ECU fuse (hadn't really checked what it did when I pulled it before), then managed to drive home without incident. Looked through the wiring diagrams and saw that the main relay was right in with that along with fuse 24, and of course pulling any of these three replicated the problem. Went out for a few errands without any incident. I figured everyone just wanted some attention and was happy now. Then I had another great dying time coming home from work today. It wouldn't start when I first got in, so I pulled the ECU fuse and put it back. No change. Same with fuse 24. No change. I unplugged/plugged the main relay without any change. I popped the cover off of the main relay and poked at the components, and it started up. I continued in this "mess with the main relay" method through around 3 more failures on the way home, but I'm starting to lean towards the "that was just a coincidence" train of thought. I've run down the flow charts in the tech manual, hitting the "plug in the test harness" step in both the main relay and the ECU (ECM) flow charts.
---Short Story edition---
94 del Sol S
Intermittent engine death during drive followed by various periods of no-start
ECL code 0
G101 is fine
Replaced main relay already, but removing the relay or either of fuses 24 or 31 perfectly replicates the failure behavior.

Can anyone help an extremely frustrated Sol owner out? I saw one post saying that a new ignition control module fixed something that sounds similar (https://honda-tech.com/forums/showpo...0&postcount=23). Thoughts?

fonkernuckle

iTrader: (5)

Have you noticed that the cel goes out as it should after a couple a seconds or does it stay on at the times when it does not start

crispyflame

When it's shot, the light stays on. No fuel pump noise. When it decides to come back it immediately changes to 2 seconds of CEL with fuel pump noise.

fonkernuckle

iTrader: (5)

yea I had the same issue and was going around in circles turned out to be the ecu.

crispyflame

Are there any tests besides "replace with a known good ECU"?

fonkernuckle

iTrader: (5)

yeah but you will have to search and find this for yourself

B_Swapped93

I don't see "replaced/try'd different" ECU ?

crispyflame

Yeah I don't know anyone else with a manual del Sol and I don't really have the money for a new one if it's not a definite fix, so I would like to exhaust any other possibility before going that route.

B_Swapped93

can you borrow one ? looks like you've tried ALOT and it's not uncommon for an ECU to go bad eventually.

also it doesn't have to be from a manual del sol.... what engine ?

crispyflame

Yes, I have indeed tried A LOT. My understanding is that places like Advance or AutoZone won't take back any electronics, so I don't see them letting me "borrow" a new ECU. Any suggestions on where I could borrow one from? Anyone in the Huntsville, AL area want to help me out?

B_Swapped93

Ok 1st I have NEVER heard of places like advance or auto zone selling ECU's and if they did I wouldn't trust it. 2nd what engine im guessing you're obd1 correct. as for ECU look on ebay a stock one(for your engine) should easily be under 100$. d16y8 right ?

you'd be looking for a p28(manual ECU) if i'm correct look at ebay or craig's list

crispyflame

D15B1. It's a P06-A02 ECU

B_Swapped93

here found one already. you can always re-sell it remember that. http://www.ebay.ca/itm/92-93-HONDA-C...14ce65&vxp=mtr

crispyflame

So can anyone tell me anything more technical about what might be happening in the ECU? I opened it up and everything is pristine.

B_Swapped93

it's an electronic device it CAN go bad over time can just be something that's loose or not visible.

crispyflame

The only "invisible" problems that could exist on a board like this would be a failure inside one of the ICs, and that would not be intermittent. Nothing is loose, and all of the solder joints look great, so I'm looking for someone who knows more about the ECU and problems that it may experience. I'm working on being able to get an ECU off of Ebay to see what that does, but I would just love to hear some more detailed information.

crispyflame

Here's another thought. Could a faulting ignition switch look anything like this, or does it cause different failure behavior?

angrysmileyface

It could also be defective Capacitors in the ECU, electronics do go bad after a while. Any rotten fish smell when you open it or smell of burnt electronics?

Former User

A faulty ignition switch would not throw code 0. However, it's possible that your car has more than one problem, for example a bad ECU and a bad igniter unit or coil.

crispyflame

No. I've done a lot of circuitry, and the only thing that strikes my eye is the lacquer or whatever it is they've put over everything to keep it weather proofed. It might as well have been manufactured yesterday. But I talked to my EE bosses and they said that the transistor walls in the ICs could very well be in a temperature-dependant damaged state. I'm still planning on trying a new ECU, just lgrasping for any more info

Former User

You definitely want to try swapping in a known good ECU. Also be prepared for the possibility that the coil and igniter unit may be on the way out.

crispyflame

Alright, we had a great yard sale this morning, so I'm ordering a new (used) ECU. Is there any way I can be sure to get one that won't just go dead in the next two weeks, or is it just a crap shoot?

Former User

Select a highly reputable seller who offers a 30 day or more guarantee.

beecee18

http://techauto.awardspace.com/ignitionswitch.html

Make sure ignition switch is not the culprit, Use this to troubleshoot and rule that out

gmac53

had unreliable starting my 93 del sol sometimes no spark and no fuel pump changed main relay didnt help cleaned the ground from ecu to thermostat cover and ground from battery to body I have had no more problems