Tombomb661

I, personally habe an integra but my father drives a 1995 civic dx. today is his day off and im trying to see what we can do about his car


it seems that whenever it rains, something shorts out. when the key is turned to the on position, you cant hear the fuel [ump and the check engine light does not come one. sometimes after minutes of waiting or however long, it somehow kicks o and the light turns on and then the car will finally start... doesnt make much sense to me because a while ago i check the ecu and it was not damp.

its a 95 dx with around 380,000 miles (he drives 100 miles each way to work haha)

Former User

It does not sound like a short, but rather a poor power or ground connection. Check the G101 ground on the thermostat housing (see FAQ sticky). It should be clean and tight. Also check whether hood fuse 31 or dash fuse 24 is loose (see FAQ sticky for fuse box diagrams).

QwkD16

^^ you need to add "check G101" to your sig Ron. Lol

Tombomb661

I messed up guys. Same symPtoms but the check engine light stays on until the fuel pump kicks on! I'm sitting in it now waiting for the fuel pump to kick on so I can put it in my garage to look at it. It's been like ten minute now

Former User

Same answers.

Tombomb661

Ok I got it in the garage finally. It primed. But I don't understand how virtually no movement will complete the circuit. I tried it again and it kicked on within a minute. This is ridiculous

Former User

The higher temp of the garage probably improved a poor power or ground connection that I mentioned. And the fuel pump should do a 2-second prime almost immediately after the key is turned from OFF to ON(II).

Tombomb661

so i checked that groud. it was tight and everything. i took it off and cleaned it anyway. underhood fuses looked ok... i didnt wait very long but the fuel pump didnt prime very quick. and this only happens when its fairly rainy... thats what i do no understand. do you have any more ideas ron? or anyone? please!!! and thank you!

Former User

Does your dad drive a 95 or 96 DX? I'll assume it's a 95 DX.

When the CEL remains ON and the fuel pump won't prime, it generally indicates that the ECU is not receiving proper power from the main relay or ground from the thermostat housing. Therefore, you should check fuses 31 and 24, the wires from fuse 31 and 24 to the main relay, the wires from the main relay to the ECU, and the wires from the ECU to the thermostat housing.

In the diagram below, 5 = fuse 31 and 6 = fuse 24.

ECU A26 and B2 (LG1 and LG2) ground the ECU to the thermostat housing.

Tombomb661

i cant see a diagram??

also, i just did a "k-test" and i wasnt sure which wire for the clip to the MAP sensor so i di the two end ones, im getting 3.something on one and almost 5 on the other

where is the main relay located?

Tombomb661

i see the diagram now. sorry boss. where is this located in the car?


its a 95 im sure. thanks for you hekp man. i just want to get this fixed for my dad because he has to drive A LOT and the last thing that needs to happen is his car fail on him. My integra is lowered so its not a super smooth ride anymore haha so id rather his car be rolling.

Former User

Lots of good info in the FAQ sticky, like this:

Tombomb661

what do you mean when you say faq sticky?

are those relays accessibly from under the dash or are you supposed to take off a side cover?

after anopther 10-15 min or so, it primed again. im letting the motor run for a bit. that first diagram i cant understand man. are fuse 24 & 31 under the hood or dash?

and why would rain cause this? because it only happens when its fairly rainy...

Former User

Tombomb661

ok ron, thank you very much man! im done for now. my dads probably gotta be up bye 3 or 4 or whatever. so im gonna stop. the last ten tries, the pump primed almost immediately or within like ten seconds. this is so stupid haha.

so far, i ran a "k-test" and the ecu is fine, ive taken off the ecu ground and cleaned it. ive looked at some wires and jiggled, all to no avail. the master relay was replaced earlier this year i think. i found it and it clicks as soon as the fuel pump starts.

so with all that, the last thing to do would ne to run the length of the wires and thats it??

Former User

Use a multimeter to check the resistance of the wires. You often can't spot a bad wire or connection.

If I remember correctly, the K-test only checks the ECU to supply reference voltage to the MAP sensor, so you can't necessarily rule out a bad ECU as it has many other functions, many of which can't be tested.

Tombomb661

resistance? like check the ohms? continuity? what would it read?

Former User

Yes, 100 Ohms or less of resistance should be fine.

Some multimeters have a continuity setting that beeps when there is good continuity.

sorta2

I don't mean to hijack this thread or anything, but I have been having the same problem for a while now also. I'm driving a 94 dx hatch from canada. I've posted a couple times and read a few like threads.

Now my ability level when it comes to wiring is not that great, but I think I know the fundamental stuff. I checked fuses 24 and 31 they are both good, I checked resistance from fuses 24 and 31 to the main PGI-FM relay they were both fine ( both 00.5). Now checking from the relay to the ECU I'm getting confused.
Ron- In the diagram I'm assuming that A26, B2 and all that are positions on the ECU wire plugs. When I check the resistance from the relay to the ECU my meter just reads 1, I'm thinking that I'm not getting the right wires. I cross referenced the numbers in your diagram to the wiring diagram I have in my chilton's manual of the ECU not sure if that's right or not.

I'm thinking I got some of it right cause I also tested resistance from the ECU(A26 is the one I tested Blk/Red) to the thermostat ground, and that read 00.6.

Another thing I noticed I don't know if this is what is screwing me up or what but the numbers on the relay aren't in the same order/ configuration as on your diagram.

Former User

sorta2

I tested B2 (Blu/Grn) to the thermostat ground and my meter just reads 1 . Its the same as if I just turned it on the the Ohm setting.

When I try to test from the relay to the ECU I was testing at positions 5 Blk/Yel & 6 Blu/Wht on the relay and B1 & B5 on the ECU, not sure if that is right I'm assuming not cause I wasn't getting a reading for anything.

I'm seeing that on your diagram that it looks like positions B1, B9, A7, A8, A23, A24, A25 on the ECU all tie into the main relay should I be checking all of these? I guess I'm not sure how I should be checking from the relay to the ECU.

Former User

B2 in ECU connector B pins to a Brn/Blk wire not a Blu/Grn wire.

http://www.phearable.net/tech/wiring...schematics.gif

Tests to do:

Measure resistance/continuity between these points,

1) MR connector terminal 3 and ECU connector terminals A25 and B1.
2) MR connector terminal 2 and ECU connector terminals A23 and A24.
3) MR connector terminal 8 and ECU connector terminals A7 and A8.
-------------------
4) Also measure continuity to body ground at ECU connector A26 and B2.

sorta2

ok in my chilton book it has B2 as a Grn/Blu wire. I tested the Brn/Blk on connector B to the thermo ground and it was .7

I tested terminal 8 and didn't get a reading on A7 or 8, in my book it has A7 as Grn/Org and A8 as Blk/Red

I tested terminal 2 and same thing no reading my book has A23 as Red and A24 as Red/Grn

I tested terminal 3 and didn't get a reading for A25 which my book has as Blk and when I tested to B1 Yel/Blk it was .3

I did all this before I saw your post so I also tested terminal 6 to what my book says is B9 Brn/Blk and got .7 but when I came in to type this up and saw your post I went back out and tested that Brn/Blk wire to the thermo ground and I got the same .7. I was starting to think I was figuring this out but now I think I'm just as confused.

Wow didn't notice the link in your post either that is awsome

Former User

Post the diagrams from your manual. You may be misreading them.

The Grn/Blu wire from the MAP sensor pins to ECU D21. Click the Phearable link in my last post.

A Grn/Yel wire pins to both A7 and A8.

A Blk wire pins to both A23 and A24.

A Yel/Blk wire pins to both A25 and B1.

sorta2

here's a pic of the diagram in my book. I just used the link you posted and went back thru. Everything tested out ok all .5 to .3 on my harness A8 is empty but
term 8 to A7 was .3
term 2 to A23 was .3 A24 was .4
term 3 to A25 was .5 B1 was .3

So I'm still confused about the problem from fuse 24 and 31 to the relay is good from the relay to the ECU is good and the ECU to the thermo ground is good.