It's back, Car cranks, but no fuel pump prime, Troubleshooting help needed
 

2014 Update, it's back. See last post





Last week or so, my 93 civic ex has been cutting off while driving. After a few minutes, it would always start back up and be fine for while. Yesterday, on my 7 mile trip back home, it died 3 times. After sitting for a few minutes, pulling ECU fuses, and waiting, I got the car restarted and made it home. It died one last time pulling into the driveway and wont restart.

While I was sitting with the car dead on the side of the road, I jumped the connector to read the CEL's but got nothing. Had just a few minutes to look at it last night and realized right away that when I turned the key on, the fuel pump wouldn't prime. I unplugged the main relay, jumped the two pins in step 4, and the fuel pump ran.

http://i37.photobucket.com/albums/e9...elpumptest.jpg

Does that for sure mean the main relay is bad? Or do I need to do some more troubleshooting?

Re: Car randomly dies, now wont start. Main relay/Fuel
 

i have a similar problem too..it just that my main relay doesnt prime sometimes so im stuck for 5min switching my keys on n off till it does..it randomly happens or when i turn my car on than shut right it off than it wold prime no more.. anyhelp too?

Re: Car randomly dies, now wont start. Main relay/Fuel
 

All your steps are in there:
https://honda-tech.com/forums/honda-civic-del-sol-1992-2000-1/93-delsol-no-start-2801692/

Re: Car randomly dies, now wont start. Main relay/Fuel
 

Didn't catch that thread when i was searching yesterday.

One question, what is the proper way to test the ECU terminals/connections without the test harness? Do I disconnect the connector and probe the connector, or do I leave the connector plugged in and probe the back of the connector?

I stopped and got a new main relay yesterday just in case, but tried some more troubleshooting first. I checked hood fuses 31 (15A) and 32 (7.5A), and dash fuses 24 (15A) and 18 (7.5A). They all were fine. The ground at the thermostat housing looked good, but I removed it, cleaned the connections and reinstalled it. I re-soldered my old main relay (this helped me years ago on my 90 civic), but still wouldn't start. I tried the new main relay but it didn't start either.

I started troubleshooting this page:
http://i37.photobucket.com/albums/e9...dhsd/11-32.jpg
http://i37.photobucket.com/albums/e9...dhsd/11-33.jpg
http://i37.photobucket.com/albums/e9...dhsd/11-34.jpg

Following the flow chart down (assuming I did everything right), I need to try a new ECU. All the connectors looked fine as did the pins coming out of the ECU. There was a little oily liquid on the "D" connector, not sure what that is.

I ran out of time, so I plugged the ECU back in, and for shits and giggles, tried the key. Relay clicked, fuel pump primed, and it started. I drove it around the block, shut the car off, re-started it and made it back home. Tried the key a couple more times and got prime every time. This morning, however, car is back to not starting. It starts, runs for while, then dies and wont restart for a while.

Re: Car randomly dies, now wont start. Main relay/Fuel
 

Alright, back from some more troubleshooting.

I tested the main relay according to this page in the Helms, it tested OK.

http://i37.photobucket.com/albums/e9...d/11-116-1.jpg

I then followed the flowchart on the next pages. I got yes for all of them. Do I 100% need a new ECU, then?
http://i37.photobucket.com/albums/e9...d/11-117-1.jpg
http://i37.photobucket.com/albums/e9...d/11-118-1.jpg

One thing I noticed in this thread: https://honda-tech.com/forums/showthread.php?t=2801692 was that RonJ@HT suggests checking continuity from pins A26 and B2 to ground.

At the top of page 11-34 above, it says to test voltage between B2 and ground, and A26 to ground. Do these tests accomplish different things? Do I need to do the test RonJ suggests?

Re: Car randomly dies, now wont start. Main relay/Fuel
 

When the engine stalls while driving, do the cluster warning lights come on or are they off?

Re: Car randomly dies, now wont start. Main relay/Fuel
 

They all come on.

Forgot to mention,. halfway through the troubleshooting process today, (not sure what we did, it just did it) the relay clicked on, CEL went off, and the fuel pump primed. The battery had gotten too low to start the engine, though. By time I hooked up the jumper battery and tried it, the CEL came back on and the fuel pump wouldn't run.

Re: Car randomly dies, now wont start. Main relay/Fuel
 

When the fuel pump won't run and the engine won't start:

With the key in ON(II), does the CEL remain on steady and not turn off after 2 seconds? If so, when you then jump the service connector, does the CEL still remain on steady?

Have you also checked whether there is no spark at the plugs?

Re: Car randomly dies, now wont start. Main relay/Fuel
 

The CEL stays on. It also stays on when I jump the service connector.

Haven't bothered to check for spark since I realized the fuel pump wasnt running. I can run and do it once the battery charges up some.

Re: Car randomly dies, now wont start. Main relay/Fuel
 

I suspect that you will also lack spark, but you can verify that.

Your test results do point to a bad ECU, but I'd be more comfortable with this idea if the problem were not intermittent, which opens the possibility of a poor wire terminal connection. But at this point, it is definitely logical to swap in known good ECU to see whether the problem is solved. If not, then a poor wire terminal connection would be my guess.

Re: Car randomly dies, now wont start. Main relay/Fuel
 

The intermittent part is the worst part of the whole thing.

I'm gonna have a hell of a time finding a Civic ECU in rural eastern NC. Looks like I'll be ordering a used one online.

Thanks for your help.

Re: Car randomly dies, now wont start. Main relay/Fuel
 

Actually found an ECU locally, I couldn't believe it. Only difference is mine is a 93 (P28-A01) and the donor ECU is out of a 95 (P28-A02)

Preliminary testing shows the new ECU fixed the problem. I tried the old ECU one last time before I plugged up the new one. Still didn't work. Got fuel pump prime right away with the new one, but didn't have a chance to try to start it. Didn't want to start it for 10 seconds since I had to go back to work. Looking good so far.

Re: Car randomly dies, now wont start. Main relay/Fuel
 

check your alternator!!!

Re: Car randomly dies, now wont start. Main relay/Fuel
 

Re: Car randomly dies, now wont start. Main relay/Fuel
 

:thumbup:

Re: Car randomly dies, now wont start. Main relay/Fuel
 

I wanted to bring this back up. The new ECU had been working fine, until last week. I got in the car in the morning and cranked the car. It started, but immediately died along with all the lights in the dash. After another try, it started up and ran fine. It's done the same thing a few times since. It died while driving once as well, leaving a parking lot. I had to try at least 4 times for it would stay running. I pulled ECU out to take a look inside, but everything looks normal except one transistor solder point looks a little burnt. No caps are leaking or anything. The main relay also looks good, no sign of cold solder joints. I put them back in the car, and it has only died on me once since.

I posted a couple pics of the ECU circuit board on another forum, and I'll post them below as well.

https://i37.photobucket.com/albums/e...ps7e92b49a.jpg

https://i37.photobucket.com/albums/e...ps7e1915cb.jpg

Re: Car randomly dies, now wont start. Main relay/Fuel
 

This is not an ECU problem. It's different.

Test the ignition switch and clean and tighten the G1 battery ground connection to the chassis.

Re: Car randomly dies, now wont start. Main relay/Fuel
 

I tested the switch per the factory service manual and it tested OK. The G1 (that's the one directly off the battery, right?) ground looks fine. The problem is very intermittent right now, I tried to re-create the problem this morning, but was unable to do so. I guess I need to test it when the problem is actually happening.

Re: Car randomly dies, now wont start. Main relay/Fuel
 

This^

Re: Car randomly dies, now wont start. Main relay/Fuel
 

Does the whole ignition switch usually fail, or just the end where the wiring attaches? I've seen these parts like shown below.

https://i.ebayimg.com/22/!BkuSCZQCGk...ItCHQ~~_12.JPG

http://www.ebay.com/itm/92-93-94-95-...-/300318496717

Re: Car randomly dies, now wont start. Main relay/Fuel
 

Maybe the coil in the dizzy?

Re: Car randomly dies, now wont start. Main relay/Fuel
 

Any thoughts on this above?

The problem has happened a couple more times, and it's looking more and more like the ignition switch. It acts like it returns to the ACC position after it dies. The radio will stay on, but all the dash lights and climate control panel go dark.