b18b1 swap, p75 ecu no power to fuel pump

[spooky12k]

Recently bought a 95 Honda Civic with a full 94 Integra LS front end (b18b1 with 5 speed, power steering, a/c, custom integra/civic fenders, integra bumper)
The guy I bought it from did all the work himself, with the help of his cousin or brother cant remember, none of which is done very professional at all. Anyway, I don't know what extent of wiring modification he went to, only wiring I know for sure is custom is for all the lights on the front of the car.

However, just last week after taking it for inspection it died on the highway (lost spark). After getting it towed back to my house, I replaced the whole distributor, now it runs and drives again. However in that process while I was on the highway I decided to take a paper clip and get the code for the CEL that has been on since I bought the car, and it was throwing one code, code 19 (A/T Lock up solenoid or something like that)

So I figured that just means I needed to get a manual transmission ecu, since the ecu that was in the car was for the original engine and transmission. That being said I went ahead and picked up a P75-A01 ECU off of eBay, assuming it would work fine, except when I plugged it in and went to start the car there was only one issue. There was no fuel delivery at all. No sound of the fuel pump priming so I cant get the car to actually start with the P75 ECU. All it would do is crank, no start. Was able to get the car to start for about half a second on starting fluid, but just dies instantly. The CEL goes out, so it doesn't throw any codes. I'm kind of at a loss right now because I don't even know where to begin to figure out why the ecu doesn't send any power to the fuel pump.

Like I said, with the Civic ECU the fuel pump primes and fires right up so I know the pump is good, I tested spark so I know its got spark.

I don't own a multi meter, which I should probably invest in one, but even if I did I still wouldn't know what to look for. If anybody could point me in the right direction, I would greatly appreciate it.

Civic ECU P06-A52

 

[nd4sped]

If you put the old ECU back in, everything works fine, just with the 19 CEL?

Buy a multimeter and test the operation of your main relay with the P06 ECU installed to get a baseline voltage measurement. Then repeat the tests with the P72.

 

[nd4sped]

You can download the service manual off my website, link in signature.

 

[spooky12k]

If you put the old ECU back in, everything works fine, just with the 19 CEL?

Buy a multimeter and test the operation of your main relay with the P06 ECU installed to get a baseline voltage measurement. Then repeat the tests with the P72.

Correct, everything works fine with the old ECU.

But okay will do that, will go buy a multi meter this afternoon. Do i check voltage with the car off or do i turn the key to ignition?

 

[nd4sped]

Correct, everything works fine with the old ECU.

But okay will do that, will go buy a multi meter this afternoon. Do i check voltage with the car off or do i turn the key to ignition?

Download the service manual from my website for the 92-95 Civic and follow the diagnostic steps in the HSM.

 

[spooky12k]

Thanks will do, will check back in a couple days with what i figure out when i can get my other car out of garage from all the rain

 

[nd4sped]

Thanks will do, will check back in a couple days with what i figure out when i can get my other car out of garage from all the rain

Sweet, post any questions you have in the meantime. We are here to help. Post videos and pictures to help with your questions

 

[spooky12k]

So yesterday i was finally able to get around to probe the main relay harness, i didn't get all the voltages for the P06 ecu, because i had a bit of a hard time finding a good ground, but the blk continuity read about 1.3 ohms, and with the P75 the blk wire continuity read anywhere from like 2.3 to about 3.3 ohms, and when testing voltage for the other wires on the P75 they all had normal volts, all around 12. It was at that point that i moved over to the ecu harness like the service manual suggested and gave up after the first grn/ylw wire trying to back probe since i don't have a test harness, but being over there i did see electrical tape and some of the wires look spliced. So im thinking the person that did the engine swap, monkeyd with the wires to make something with the civic ecu work, because the ecu itself on the inside does not look modified. Also neither did the main relay harness. With that in mind do you think i would be better off getting a manual P06 ecu instead of the integra ecu that i bought to get rid of the code 19? At this point i don't want to spend any more money than i have to. I would like to be able to use the integra ecu so that the engine is getting the right air/fuel mix but i don't know the first thing about wiring.

 

[nd4sped]

I would like to be able to use the Integra ecu so that the engine is getting the right air/fuel mix but i don't know the first thing about wiring.

Regardless of OE ecu you use it should run, albeit with codes if its automatic or not. Sounds like you should make those repairs to the harness and then plug in whatever ECU you want to use.

Note depends on the model ecu you do use will effect what functions work, IE: P06 has no VTEC but it would still run like a non-vtec B18 or D15/16.

 

[spooky12k]

So I have another question, so like i said when the p75 is plugged in and i switch the key to ignition the CEL goes out after about 2-3 seconds. With a paper clip in the obd port to read codes, the CEL stays solid. Is it supposed to do that if theres no codes? I know code 0 is for a faulty ecu, if thats the case it confuses me why the CEL goes out without the obd jumped.

 

[nd4sped]

No flash, no codes.

 

[spooky12k]

Do you understand whats going on here, because i don’t. I’ve attached videos of both ecus with me turning the key to ignition, as well as where the wires look spliced on the ecu harness and shock tower harness

http://imgur.com/a/XGQsxXZ

 

[nd4sped]

No telling what was previously spliced in. Most likely spliced to piggyback signals to feed input on aftermarket gauges. Best thing you can do is inspect the wires to make sure they are not cut. If they are, start soldering them back together.

 

[spooky12k]

Gotcha, i may have to just see if theres any shops or something around me that can figure this out because its honestly beyond me at this point LOL

 

[nd4sped]

Gotcha, i may have to just see if theres any shops or something around me that can figure this out because its honestly beyond me at this point LOL

Its really not beyond you. If there is continuity then the connection is good. If the pin is in the correct location on the plug, then you should be able to plug virtually any ecu in and call it a day.

Since you just have a stock B18B non-vtec then any P06 should work just fine.

 

[mian8790]

It sounds like the issue is with the P75 ECU being for an automatic transmission (A/T). Your car has a manual transmission, and the A/T ECU might not be sending the proper signal to the fuel pump, which is why it’s not priming.

To fix this, you’ll need to use an ECU for a manual transmission, like a P06 or P28. The wiring for the fuel pump seems fine since it works with the original ECU, so switching to a manual ECU should solve the issue. Also, if you don’t have a multimeter, it’s worth getting one to check the fuel pump relay and wiring.

 

[spooky12k]

It sounds like the issue is with the P75 ECU being for an automatic transmission (A/T). Your car has a manual transmission, and the A/T ECU might not be sending the proper signal to the fuel pump, which is why it’s not priming.

To fix this, you’ll need to use an ECU for a manual transmission, like a P06 or P28. The wiring for the fuel pump seems fine since it works with the original ECU, so switching to a manual ECU should solve the issue. Also, if you don’t have a multimeter, it’s worth getting one to check the fuel pump relay and wiring.

The P75 i have is for a manual integra, the P06 thats in the car is for an automatic civic. And after doing some reasearch on the vin, i found out the car is originally a manual so im not sure why theres been an automatic ECU put in. Though i do have a hunch that the P75 is bad, i still havent been able to test it thoroughly, but seeing as the P06 works just fine i would have no reason to believe the P75 wouldnt as well unless the ECU itself was bad.

 

[nd4sped]

Sounds like a bad ecu homie.

It sounds like the issue is with the P75 ECU being for an automatic transmission (A/T). Your car has a manual transmission, and the A/T ECU might not be sending the proper signal to the fuel pump, which is why it’s not priming.

If there was a manual to automatic swap that was conducted then you need to check the A/T park connector and install a 0 ohm resistor (jumper wire). If this is not jumped or the pin fell out this will cause the fuel pump not to prime as you can see in the circuit.

Additionally check and see if they installed a clutch switch. Most wont to save time and simply will just jump the A/T Park connector.