I decided to tackle my first wire tuck and ran into some road blocks.

Background:
OBD1 P72
OBD2 Engine harness

Prior to tuck car ran fine.

Troubleshooting Steps:

https://honda-tech.com/forums/honda-civic-del-sol-1992-2000-1/92-civic-fuel-pump-wont-prime-no-spark-after-wire-tuck-3013475/

All fuses checked good in accordance with above post.

http://marketplace.honda-tech.com/sh....php?t=2952478

I have checked the main relay wiring in accordance with the above thread. The 2 black wires did not have continuity with the chassis. I verified that these 2 wires have continuity with the ECU. I have also verified that the ECU ground (brwn/blck or LG1) is good at the thermostat.

I have a question in regards to the grounding of the main relay. According to the schematic in the haynes manual PG1 & PG2 ground at the thermostat. However the only 2 wires that trace back to the ECU from the thermostat are a (brwn/blck & blue/rd). Is the ground to the main relay and the thermostat within the ECU?

If not what else could be causing the grounding issue?

 

If the 2 black wires from the main relay do not have continuity with the chassis what could cause this?

As stated before I have tested all wires from main relay plug:

Blck-not grounded (Is this ground provided electronically through ECU?)
Yellow/Grn-No power in on position (When jumped pump turns on when key is in on poistion)
Yellow/Wht- Hot all the time
Yellow/Blck- Hot in run & start
Blue/White- Hot during cranking only

Main relay clicks once when key is turned to on position.

ECU ground at thermostat checks good.

If more informations is needed I would gladly fill in any blanks, any help would be appreciated.

 

Of the 2 black leads going to the PGM-FI Main Relay, [same terminal] one of them is the ground lead, the other is a "daisy chain", [parallel connection] ground to, [in your case the ECU/ECM] another load,

Regardless, that terminal with the 2 black leads at the PGM-FI Main Relay MUST have full continuity to chassis ground.

The one click you hear/feel from the PGM-FI Main Relay is more then likely the fuel injector relay turning on and off again instantly, the 12V+ "trigger" supplied to the fuel injector relays coil is from ign, [yellow/black] the relays coil should have a constant ground, [black].

If the fuel injector relay does not stay on, the fuel injectors have no power, either does IGP1 and IGP2 at the ECU/ECM, so no fuel pump relay control or distributors, [ICM] ign. input signal.

Add a "jumper" ground to that terminal, you can just "stuff" some stripped wire, [same gauge or thicker then the blacks there] into the back of the plug at the black wire terminal, [wire end] and ground the other end and see what happens.

If if works, make the jumper permanent, [proper connections] a load, [in your case, the relays coil] does not care one bit where it gets it's ground, in fact adding the ground will have absolutely no other effect other then grounding the PGM-FI Main Relay, [and whatever the daisy chain ground is for].

Or if your real **** about it, you can spend the time and effort finding the connection you missed, [ground point for the black lead(s)] hummm, what would I do, and I am pretty **** about wiring, naa. I would make the jumper permanent. 94

 

Thank you for all of the info! For some reason I think that I tried jumpering the 2 black to a chassis ground and nothing changed. However taking into consideration I am not 100% certain I tried that, I will give it a shot when I get home and post my findings.

 

Jumped main relay to ground no change. Main relay clicks on and remains on while key is in the on position.

Yellow/blk at the ecu has 12 volts when key is in the on position.

 

With the key on use a jumper to supply a ground to the ECU/ECM control lead running to the PGM-FI Main Relay, [to fuel pump relays coil]. 94

 

After I jumped the main relay to ground, I checked the black wires that run from the ecu to the main relay at the ecu and they were grounded, but I am still having the same symptoms.

 

However if the black wires at the ecu are not the ones you are referencing, I will locate the wire you are talking about on my schematic at home and follow the procedure you stated.

 

What exactly is your "Eg6" MM&Y and trim level?

What Haynes are you looking at, 42025? 94

 

93 Honda Civic Cx

I have Haynes 42024 & 42025.

 

U have a crank sensog in the dizzy,also check ur power and ground wires going there.if the ecu doesnt sence the motor is turningit will kill spark and fuel. I would start here if you have ruled out ur main relay and connections to the computer. Get a test light and verify u have power to fuel pump at the connection at the pump. If it lights up fro 3sec that's good and main really is good. U can have fuel pressure but bad crank sensor wiring will not allow injectors to open or the coil to fire

 

If the black lead at the PGM-FI Main Relay is gerounded and there is power on the black/yellow when ign. is turned on, the fuel injector relay will turn on, [one click].

If that is not happening, [one click from relay] then either the ground is bad, the black/ yellow is not powering up, or the PGM-FI Main Relay is bad, it can not be anything else

Not getting that one, [first] click from the PGM-FI Main Relay, [fuel injector relay turning on] will have absolutly nothing to do with the crank sensor or anything else in the distributor, in fact anything else in the car.

If only the black ground and the black/yellow ign. lead were the only leads connected to the PGM-FI Main Relay, the fuel injector relay would still turn on.

If the fuel injector relay does not turn on , there is no output on the yellow/black and the fuel injectors will not have power, [so can not pulse and spray fuel into the cylinders].

There will be no power to the fuel pump relays coil, internal, [fuel pump relay can not turn on, [2nd click], there also will be no power to IGP1(A25) and IGP2(B1) also yellow/ blacks, along with no power to the Purge Control Solenoid and EACV solenoid.

IF IGP1&2 do not get power, there will be no ground output from ECU/ECM, [FLR1(A7) and FLR2(A8)] to the fuel pump relays coil, [green/white] fuel pump relay can not turn on, [no 2nd click].

The only two black leads at the ECU/ECM, [PG1(A23) and PG2(A24)] are common grounds with the black at the PGM-FI Main Relay and the VSS ground and thermostat grounds, they are ECU/ECM grounds. 94

 

Thanks for all the help thus far. I have to take a break on the honda this week to put my subi back together before I get anymore snow. I will then get back to the grind on the honda and update my findings.

 

IGP1&2 have 12v.
Jumped fuel pump relay to ground pump turned on with key in on position

So is it safe to say that the ECU is bad since IGP1&2 have power but isn't providing a ground output to fuel pump relay coils?

 

I purchased a new ecu and that did not solve the problem either. Any other suggestions out there?

 

Then I would check all grounds/powers to the ECU/ECM.

As long as ECU/ECM is working, all it needs is power to the IGP1&2 inputs, [supplied by the fuel injector relay in the PGM-FI Main Relay] to supply a ground to the fuel pump relays coil.

If this is not happening the problem must be either the ECU/ECM itself, or ground/powers going to it. 94

 

"If the fuel injector relay does not turn on , there is no output on the yellow/black and the fuel injectors will not have power, [so can not pulse and spray fuel into the cylinders]." fcm

Black/Yellow has 12v
The Yellow/black only has 1.5 volts.

My initial thought was a bad main relay but I have a spare from the dealer and it didn't change anything.

I bought the spare a while back, I believe its for a obd2 integra, but from what I have read it should work, but I could be wrong.

"There will be no power to the fuel pump relays coil, internal, [fuel pump relay can not turn on, [2nd click], there also will be no power to IGP1(A25) and IGP2(B1) also yellow/ blacks, along with no power to the Purge Control Solenoid and EACV solenoid." fcm

IGP1&2 have power
Also checked FLR1&2 both have 12v
ECU ground is good.
Main relay ground is good.

 

With the ecu unplugged; yellow/blck @ PGM-FI, IGP1&2 has 12.5 volts

With ecu plugged in; yellow/blck @ PGM-FI, IGP1&2 has 1.5 volts

 

Can any body help 929 fuel pump not priming last year servo went as they do I replace with 04 blade that fits and work last week went for mot passed put bike away for a week when I went to go out on it it felt like a block in the exhaust 1 mile up the road turned off engine. will not start pump not priming but not fi light flashing like before

 

I found the problem a while back figured I would post the problem since many others may have had the same symptoms. After pulling the ecu plugs and check each wire I found many wires seemed to be in the wrong spot. Come to find out when I bundled the harness up I switched two plugs which were identical.

I think I have pics of the two plugs if needed but after swapping them back and changing a 15amp fuse that blew since the plugs were switched the car fired right up.