Kilgore_Trout

First time poster on here, newcomer to Hondas. I’ve got a problem I’ve been troubleshooting and am stuck (other than slowly dismantling the harness).

Background: Bone stock 1993 Civic VX 120,000 miles. Bought it last year, drove it for a few days and parked it in the shop to do some extensive body work (MN car). Disconnected and removed battery as soon as it was in the shop before doing a lot of welding, grinding etc. Removed gauge cluster to clean it. Re-installed cluster without issue (added factory clock to dash). Didn’t touch anything in engine bay or under dash.

When I got the car all back together it would crank and crank and wouldn’t start.
I checked spark on all cylinders (good, strong).
When keyed on (not cranking) I realized the fuel pump was only coming on for a split second. Should be two seconds. Checked voltage at fuel pump connection, it gets a momentary 12v spike and goes back to zero.

Did some research and looks like the PGM-FI relay could be at fault (this is my first Honda). While still connected to the harness, I held the relay in my hand when I turned the key to feel for it clicking. By rotating/moving the relay around in my hand, the relays inside started clicking like crazy (15+ clicks) making the fuel pump come on and off.

I had another new relay that came with the car so I installed that, there is one click when I turn the key (not cranking) and that is it. The fuel pump does not come on with the new relay. Plugged the old “suspect” relay back in and it clicked inconsistently based on how I tweaked it, fuel pump coming on and off (same as before).

Jumped pins 1-7 on the harness, fuel pump comes on fine with key on.
Jumped pins 5-7 on the harness, fuel pump comes on fine with key on.

Did a bench test on the new relay according to section 11-128 of the 1993 FSM. Relay checked out fine.

Checked ground wire (Pin 2) on relay harness plug. No continuity between terminal 2 and chassis ground. Checked multiple “good” grounds including the negative battery terminal and still no continuity.

Tested fuse 18 and 24 under the dash and 31 under the hood (and every other fuse in both panels while I was at it). Checked by testing continuity across each fuse. All fuses were good.

Checked G101 on the thermostat housing. Looked slightly corroded, had continuity between ring terminal and battery negative, but I cleaned it up, wire-brushed and soldered on new ring terminals anyway.

Checked the front ground strap (Ground Cable A), it was fine, but replaced it for good measure. Checked passenger side ground strap (Ground Cable B) also had good continuity, but replaced it for good measure).

I’m at a loss. There is no continuity between Pin 2 on the relay harness and G101, or any chassis ground for that matter. I’ve removed the first few inches of wire loom on each end of the respective harnesses and haven’t seen anything fishy. I could probably just run a separate ground off of the relay connector, but I want to figure this out. I can’t think of any body work I did that would've affected this.

I’m having difficulty chasing the ground wire back from G101. It would appear that it has to go through one of the engine bay connectors C101, C102, C103, or C129 (which connect to C214, C213, C212, and C211 on the respectively) but I cannot see where the ground would pass through any of these connectors. Maybe I’m missing it?

Any suggestions or help would be greatly appreciated. I’m sure I’m missing something obvious. Are there other tests I could be doing at the relay connector that can tell me something?

Thanks.

Kilgore_Trout

I've seen pictures on here of what look to be pages of service manuals that list what wires go through each connector, as well as the connector color and location. I have the 1993 FSM for this car, but I'm not seeing anything that descriptive in there. Does anyone know where these are from?

I'm looking for the following connectors for a D15Z1

C101 - C214
C102 - C213
C103 - C212
C129 - C211

I'm trying to trace the ground wire from the G101 to C437 (PGM-FI) and I believe it has to go through one of the above three connectors. I could be wrong though.

TomCat39

The companion to the FSM is the ETM (Electrical Troubleshooting Manual).

If I have some time tonight I can dig those pages up and post them as I have the 93 ETM at home.

Also of note, I recall someone else once replaced the transmission to chassic ground wire with a battery cable and the extra length caused the car not to start. Once the length was reduced the car worked fine.

You may want to keep the ground straps you replaced handy as the stock ones may work while your new ones may cause issue. Might not, but then again, could be one of those ghost problems that just don't make sense but cause you a **** ton of grief.

TomCat39

Kilgore_Trout

Great! Thanks so much. Didn't know that existed. Might have to pick up a copy if I can find one.

I'll let you know what I find.

I did save the factory ground straps in case I needed to go back to them. You're right, you never know.

TomCat39

You can get all the shop manuals at helminc.com including the bodywork manual.

Helm Incorporated: Search Results

Kilgore_Trout

I got it running. It's a Band-Aid for now. I determined the break to be between G101 and C126/C304. This is the length of the engine wire harness that runs under the intake plenum. For now I ran a new ground from Pin 9 on C126 to a ring terminal on G101. I soldered it in on both ends to the original ground wire so if/when I have the intake off and feel ambitious I can try to find exactly where the break is. I wouldn't say this is solved, but it's working.

Thanks for the help.

TomCat39

That's interesting as there is a TSB about that section of harness for the 96-00.

Didn't think it applied to 92-95.

http://www.tegger.com/hondafaq/tsb/civic/x99-029e.pdf

The connector numbers are different as the TSB is about the 6th gen and your car is the 5th gen, but as you can see, it's in the same vicinity.

Glad you got it running.

Kilgore_Trout

Hmm…bizarre. Good to know. I’ll look out for that next time I have the intake off or am under the car. I’d be surprised if this was my problem as I assume the ground wire in question is bundled in the corrugated loom and if it wore through the tape/loom and my ground wire, it likely wore through other wires. But you never know. This has been a mystery.

Thanks for the info!