I've put my motor back in after a rebuild and picked up a new engine harness. The car will turn over fine but will not start.

I've bench tested the main relay and it appears to be good. Continuity between the right things, etc. I have noticed that the ecu light does not come on when I turn my key to the on position. The fuel pump will also not prime.

I've checked the ground on the thermostat housing. The fuses are also ok.

I'm figuring that the relay not getting power would keep the ecu from coming on or is it vice versa? I'm wondering if the ground in the harness I picked up could be messed up somewhere. Is it possible to cut the ground wire going to the relay and/or ecu and ground them inside the car?

Edit: Just checked to see if the main relay is getting voltage it is while off on 1 and 2 and with the ignition switch on it is good on 5 and 2.

What else should I check? All help would be appreciated. I'd love to hear my car start soon.

 

Is the CEL bulb burned out or have any of the CEL light wires been cut?

Do you also lack spark? If so, one of the three main relay fuses or wires is blown/bad, the ground on the thermostat housing is bad, or the ECU is bad.

 

Cel bulb is good. Worked when the motor was pulled. Ecu also worked before the motor was pulled which is leading me to thinking my new harness has a bad ground for the ecu.

Is it possible for me to cut the ground wires going to the ecu in the cabin and ground them to something local without messing something up?

 

What year Civic?

A better idea is to check whether the ground wires have continuity (=not open).

Why do you think that the non-working CEL isn't related?

 

1996 with an obd 1 conversion harness and ecu.

I've found the pinout for the ecu:

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

I'm guessing I need to connect one line to the ground part that hooks to the thermo housing and then go through each of the grounds on the ecu plug correct?

On my multimeter I set it to ohm 20k? Reads 1 when no continuity and 0 when there is (touched together). Just making sure I am doing it right I guess.

As for the non working cel it kinda meshes with the ecu having a bad ground which would keep the relay from working which keeps the fuel pump from priming (problem that tipped it all off)

Thanks for the help so far btw.

 

You lack fuel. Do you also lack spark?

Below shows how to troubleshoot the non-working CEL and likely your no-start problem.

 

No spark as well.

The chart is pretty handy.

I'm trying to figure out what it means by test for voltage between the body ground and terminnals A10 and A23 individually?

Do I test for voltage between the two? Or do I need to hook the ecu up and make a barespot on the wires and ground it to the body and look for voltage that way? It's late and I am extremely tired and frustrated so the good old brain isn't working 100%.

 

This is basically correct. You measure voltage for each wire individually to body ground. You can use your approach or back probe the ECU connector.

 

I tested between them and got zero. I also checked my mil light and swapped bulbs around so the bulb was good.

Thought the ecu was bad so my neighbor had a spare that we plugged in just to see and it did the exact same thing.

I am thinking that the ecu is not getting power for some reason. The fuse is good.

I turned the ignition to the "ON" positsion and in plug A checked pins 11 and 24 for voltage. Got 12v on 24 but nothing on 11. Could this be my problem? Just a bad wire?

 

If you mean here that you measured the voltage between ECU pins A10 and A23, then you did not do the test correctly. The test is done by setting the multimeter/voltmeter to measure voltage and then touching the + probe to the ECU A10 or A23 wire and the - probe to a convenient ground source, such as the metal framework under the dash.

Sorry, what are pins 11 and 24 and why did you test them?

Does the oil pressure light turn on with the key in ON(II)?

 

Yea the light does come on.

I did test each one individually. After it tested zero I swapped the ecu out and it still did the same thing. The other ecu is a known working one.

Pins 11 and 24 are IGP1 Power Source and IGP2 Powersource.

 

You have two separate problems - CEL not working and no start.

In the troubleshooting diagram, there is a yes/no choice made at the question "Does the engine start?". You should also do the tests on the YES side as the results will likely tell you why the CEL doesn't work. Once you get the CEL working, the trouble codes may help you diagnose the no-start problem.

Do you measure battery voltage at fuse 44 under the hood?

Do you measure battery voltage at fuse 13 and 31 under the dash with the key turned to ON(II)?

 

I don't have a fuse diagram with the fuse numbers. Just the one that tells you what it is.

Which fuses are 44 under the hood and the others inside the car?

 

You don't need a diagram for the under-dash fuses. They are numbered in the box.

Here's the under-hood fuse box numbering:

 

Just verifying your testing of the main relay connector:

With Key OFF: Only terminal 7 should have battery power.

With key in ON(II): Terminals 5 and 7 should have battery power.

With Key in ON(III) and clutch pedal pushed down: Terminals 2, 5, and 7 should have battery power.

When the key is turned to ON(II) or ON(III), do you measure battery voltage at the fuel pump connector for 2 seconds or constantly, respectively?

 

Based on the ECU pin out at the link you provided, IGP2 Power Source is A25. I could not find the IGP1 Power Source.

 

set your ohm meter to ohmsx1 or it's lowest setting to test continuity. should read 0.00 or 0.xx , where xx is the resistance of the meter wires, usually less than o.2 ohms.
Your readings from a good ground point to all ecu and wiring points should not be more than 1 ohm (ish)

 

Bind thin wire round your meter + probe with a sewing needle and pierce the insulation

 

We plugged the ecu into a friends car today and his pump primed and all that good stuff so I can for sure rule the ecu out.

I know this may be a really rare condition but could it possibly be my ignition switch? It will do everything but get power to the ecu and that main stuff when it is set to the on position?

 

If you get the test results described in post #15, then the ignition switch is fine.

 

Your ignition switch should be fine. Try a working main relay and see if the problem goes away.

 

Main relay is brand new. Old one bench tested fine as well (guess I have a spare now)

I popped open the ignition switch and found the contacts were worn and somewhat dirty but one of them was covered up with junk. Maybe this will do it.

 

Hey i have a 96 civic lx with a 95 gsr swap in it just done today. The motor turns over, the fuel pump is not priming, i tested the main relay its ok, i just got to this site and seen this guys problem, looks like same thing with me. Im going to do all the rest of the tests in the morning but b4 i do that, might b a noob thing but whats "CEL"?

 

CEL = check engine light

 

When you turn the key to ON (II) do your dash board lights light up? If so, your ignition switch is fine for now and your fuel pump should prime.

When you switch to ON (II) do you hear the main relay click?