24TEN

iTrader: (2)

I noticed maybe a month ago that a couple of a times while trying to start my car it wouldn't start on the first try. It would on the second try and I never thought twice about it. Last week I was trying to leave for class and my car wouldn't start at all. I tried three times and it just wouldn't fire up. I turned the key to the on or 1 position (I think that's the position) and listened. I could here the main relay click but no fuel pump priming sound. I figured it was done so I left the car and drove another. I tried again over the weekend and it fired up without any hesitation. I drove it through the weekend without incident. Then today same thing before class, it wouldn't fire up, no fuel pump priming sound. I gave it a couple of tries and this time it sounded like the battery almost died. On the last crank I heard a "gurgle" sound come from the exhaust so I figured fuel got through. I turned the key again and it fired up. Made it to school. After class I get in my car and same thing won't start. Cranked it a few times and this time it sounded like the battery did actually go completely dead (held the key turned and it cranked for about 2 seconds and stopped on it's own). So I let go of the key thinking I'm stuck. Figured I'd try to listen for the pump just to make sure. So I turn the key once more and listen...this time no main relay or pump, but after a couple of seconds I suddenly hear the relay click followed by a brief pause AND THEN the fuel pump primes. Car started after that and made it home without incident. SO...

Any thoughts or advice on what the culprit can be? I'll be checking into the FSM to look for a diagnosis procedure but was hoping someone could shed some light for me. If at all possible I'd like to hear/read "educated" responses meaning a reason for the problem with an explanation. I hope that's not too much to ask.

Former User

Sounds like a bad main relay, which can be fixed by resoldering. Also make sure the ground attached to the thermostat housing is tight and clean. Any CEL codes?

24TEN

iTrader: (2)

None. No CEL.

Might be worth mentioning (or not) that this is a 1994 CX with original motor and no mods. It's my daily so having it not reliable is not cool. It has been rebuilt by me personally with all OEM parts minus the pistons/rings/bearings. Block was overbored .5mm but otherwise is stock. It has accumulated 17k miles since the rebuild so I'm fairly confident the physical motor isn't a problem. Also, weather/temp doesn't seem to affect it because last week was reasonably warm and today is cold and rainy. The car only seems to have trouble starting at random times, it's never had a problem while the car is already running.

Former User

Does the CEL work? Otherwise, my advice remains the same.

24TEN

iTrader: (2)

Yep still works like normal when you turn the key.

Pothole987

could also be the fuel pump ground. when you get in and out of your car if the ground is loose your foot may move the carpet a little knocking it off the body for good ground.
or the main relay is sticking ( seen a 91 with the same problem hit it with something works right away [go figure]) the ground is attached to where the front seat rail bolts to the floor, lift the carpet up and its right there

24TEN

iTrader: (2)

I will check into that as well, thanks for the input. I really appreciate it.

24TEN

iTrader: (2)

Just a small update

Started the car when I was leaving for my evening class and same thing, cranked for about 2 seconds and slowly came to a stop with the key fully turned. Pulled key, put it back to 1 position and heard the main relay click and fuel pump prime. Proceeded to start it and it fired up just fine. After class was done, I went to my car and listened this time. I put the key in and on the 1 position and could hear the main relay click but no fuel pump priming. I sat there for about 15 seconds before removing the key and trying again. On the second attempt I could hear the relay click followed by a couple seconds of silence followed by the fuel pump priming and then I was able to start it. Tomorrow I'll be checking the grounds and the main relay. Hope this is a quick fix.

itsnotfast

I'm leaning towards the main relay as well.

24TEN

iTrader: (2)

Well I just found the diagnostic procedure in the FSM but there is a note in there that says "NOTE: If the car starts and continues to run the main relay is OK." I'll still do the full diagnostic for the relay itself just to be sure. If that checks out fine, hopefully it's just the ground on the pump.

Former User

Regardless of the statement in the FSM, main relay problems are notoriously intermittent. Just resolder it as detailed at the link and then go from there.

Also clean and tighten the ground attached to the thermostat housing. This grounds the ECU, which provides ground for the main relay.

24TEN

iTrader: (2)

I had a chance to take the main relay out but noticed on the last couple of start ups I could here a normal click but it was (and is currently) followed by two faint clicks. Is that normal?

Here's the relay circuit board side:



I've taken a soldering class about a year ago and as far as I can tell all the joints look good with the exception of about 2-3 joints where it looks like the flux/rosin core flowed to much or overheated/burned. I cleaned those up and resoldered the two worst looking ones which are soldered to the end of #8 pin which according to the diagram in the FSM is attached to the coil/inductor on the secondary half of the circuit (or second relay) and is responsible for starter switch and fuel pump.

I reinstalled the unit and although it's only been a day, so far so good I guess. I didn't get to actually do the diagnostic procedure yet because I wasn't sure I was understanding the procedure correctly. It specifically states to attach the "battery positive terminal" and "battery negative terminal" to specific pins. Am I correct in assuming I am supposed to depin the plug for the relay and remove the battery pos/neg wires and attach those as required per the instructions?

24TEN

iTrader: (2)

So the solder job I did seemed to fix it for the past couple of days. Then last night the problem returned and now today the car won't start at all. Relay no longer clicks and the fuel pump will not prime. Last night, it did the same thing but both came on after about 20 seconds or so.

24TEN

iTrader: (2)

Just a quick update...

I haven't posted for a bit because the problem happens just every now and then but only for a few seconds (and then the car will start up just fine) . Well, I managed to pick up a second main relay and switched it out. I tested the relay per the FSM and all was good. The car ran fine for two days and the problem came back. It happened again today and it stayed inoperative this time. Just by chance I left the multimeter in the car so I quickly took a reading just to make sure it was actually getting power which it was (12.3 or so if I remember correctly). I had to go so I left it at that knowing that the relay itself is getting power.

So to sum it up
-Problem occurs, main relay IS receiving power but the fuel pump is not receiving power
-ECU CEL stays lit while the problem occurs which [I believe] indicates that there is a problem with the relay sending power to the ECU.


Also maybe worth mentioning, although I never had an actual CEL I decided to jump the connector by the ECU just to check and I have no flashes to count form the CEL but the SRS light flashes.

Former User

Is the red text saying that the starter stopped cranking the engine with the key in ON(III)? If so, you may be having problems with the ignition switch.

Former User

accord2civic2prelude

could be your ignition! Just a thought, cause everytime you move the key or position it a different, the relay/fuel pump comes on. just a quick throw in.

when you get in, try starting it normally, if nothing, try wiggling the key while cranking.

24TEN

iTrader: (2)

Thanks to both of you guys for responding

RonJ@HT-

For the red text, yes the starter itself stopped cranking the engine and the dash lights noticeably went dim for half a second. I'd let go and then the dash lights went back up to normal brightness and then I'd start the car again with no problem. This particular scenario only happened two or three times. Hasn't happened in about two weeks.

For the blue text, starter is cranking the engine but it will not start. Fuel pump not coming on nor can I hear the main relay click. I checked for voltage directly off the black and white/yellow wires coming off the the connector to the main relay itself (1 and 2 as illustrated in the FSM). I'll look into the circuits you stated (if you know where in the FSM it's located that would be appreciated). I did inspect the ground off the thermostat visually (clean, not dirty in way) but I'll pull it off and sand accordingly.

SRS-Shoot if it ain't working then it's time to go aftermarket steering wheel j/p I'll worry about that later if it's not related to the car not starting.

accord2civic2prelude-I'll try doing that as well.

EDIT-I see #31 in the wiring diagram, is that the one located in the engine bay fuse panel? If so, I'll double check to see if that one is getting voltage next time the issue occurs (at the moment, the car is operational again...go figure).

24TEN

iTrader: (2)

Another small update-

Since the problem is inconsistent I only use the car once in a while now and for the most part it doesn't give me any trouble. When it does I quickly grab the multimeter (I leave it in there now) to see if I can get any readings on certain things. Usually the car will run after a few seconds so I haven't had any luck taking any readings until tonight. The car won't start, the CEL is on constant (ECU not getting power, please correct me if I'm wrong) and the fuel pump is not getting power (main relay not clicking) and this time it stayed this way, or at least long enough for me to check a couple of things.

On the relay:

Key Off Engine Off
Multimeter connected to 1 and 3 (1st relay), circuit closed (0.00 Ohms) and reading 12.65v
Key On Engine Off
Multimeter connected to 1 and 3 (1st relay), circuit open (1--- Ohms) and reading 0v

Key Off Engine Off
Multimeter connected to 5 and 7 (2nd relay), circuit open (1--- Ohms) and reading 0v
Key On Engine Off
Multimeter connected to 5 and 7 (2nd relay), circuit closed (0.00 Ohms) and reading 12.13v

So far, this confirms that the Main Relay is not providing power to the ECU. The weird thing is that the Main Relay does have an immediate click when I turn the key to the on position and clicks again when I turn the key to the off position. By the readings I've taken it's the second relay itself activating but what confuses me is that according to the FSM the first relay is what provides power for the second relay but the first relay isn't even activated. I'll be going over the wiring diagrams again to see if I can make sense of any of this.

Former User

None of your voltage tests tell you that the ECU fails to get power.

I can conclude from your tests that the main relay is getting power from hood fuse 31 and from dash fuse 24 via the ignition switch and that both voltages are getting grounded by the ECU.

Have you cleaned and tightened the ground on the thermostat housing?

Have you directly tested the main relay?

24TEN

iTrader: (2)

Directly tested the main relay yes (direct power to each relay and checked for an open on each, 0.00 Ohms each time with power, 1--- without power), ground on thermostat housing no. Reason is I've been waiting for the issue to occur so that I can clean it on the spot and see if it has a direct result/fix for the issue (I actually have a piece of sandpaper sitting underneath the filter and a 10mm in the car ready to be used but usually the car fixes itself before I have a chance to try that).

It's currently raining at the moment and will be for the next few days but when it lets up I'll go out there and just clean/sand the connection. If it works, then I get to drive it to school tonight. It sucks having to drive my other car, no heat or working defogger, hatch leaks water, etc and it's RWD so it's tricky in the rain.


-Doesn't the CEL on constant with the key on indicate that there is no power going to the ECU? When it works, the CEL turns off at the same time as the fuel pump is done priming and at the same you'd hear the relay click.

-My next thing I was going to check was the power wire to the ECU itself, still checking the wiring diagram. If I'm not mistaken A25 is where I would check? Also, if you notice in the previous post the Relay is actually reading voltage before I turn the key and the relay is reading 0.00 Ohms but loses both when I turn the key to the ON position. Is it supposed to be reading anything before I turn the key? I thought the circuit wouldn't be closed until the key is turned to the ON position.

Former User

CEL code 0 generally indicates a problem with power or ground for the ECU.

24TEN

iTrader: (2)

Cool, rain just let up so I'm going outside to mess with the ground.

24TEN

iTrader: (2)

Update-

Sanded/cleaned the thermostat ground, no change. Then I remembered I had stuck my spare P28 behind my seat to try out the next time the issue occured so I swapped the two of them, turned the key to the ON position and the fuel pump turned on immediately. Just to be sure I put the stock ECU back in and no power to the pump, put the P28 and power to the pump, back to the stock ECU and fiddled with the key and the wires to the ECU with no change, back again to the P28 and powers back. I repeatedly turned the key to the ON/OFF position with both ECUs and only had power to the pump with the P28 in place. Is it safe to assume that the ECU is the culprit? LOL

24TEN

iTrader: (2)

Just adding a link...

https://honda-tech.com/forums/honda-civic-del-sol-1992-2000-1/no-start-solid-cel-heres-what-i-did-tons-pics-2458280/

Same situation, basically the same car, turned out to be the same problem.