Hi guys, I'm new and I'd appreciate any help you can offer. Here's my issue, I was gifted this Civic, it has had lots of mods that I have no way of knowing about. It has a VTEC head on it. It was an auto but was converted to 5 speed. It ran for years with no issues. A while back Rob went to start it and the fuel pump would not run. They replaced it. Nope. So it sat. He gave it to me because he said he was never going to mess with it again.

I got it home. Sure enough, fuel pump would not run. I replaced it because it had rusted up. Still would not run. Since it has a cold air intake it was easy to start it with starting fluid. Sounded fine.

At this point I take it to my brother who is a "real mechanic" (dealerships). There is no pulse to the injectors but they do have power, fuel pump still not running either. In the process of checking the fuel relay the damn pump turns on, the pulse comes back and the car starts. I drive it down the road and it's fine. So we "guess" it was the relay but it is now operating. I order a new one and we stick it on. Nope, no pulse, no pump again!!!!!

So we take the cover off the PCM and I see some leaking caps ( I am an electronics tech). I replaced them. Nope. Allen has chased down all the wires and grounds and can find no issue. After replacing the caps I have no spark, pulse or fuel pump now!!

Allen is pretty certain the PCM is done and this is where my questions come in.......
1 This pcm ran the car for years and I drove it with it...... 37820-P28_L01
2 Can I try and find another and just plug it in? Would it need "programming"?
3 If the last set of numbers is different will it still work, as in "run the engine"? Meaning not an "L01" We "think" the last numbers/letter would not matter since it is now a 5 speed.

Thanks guys, I really appreciate any help you can offer.
Ed

 

If there is no spark and no injector pulse then would assume the crank sensor is not working.
The check is to take out the sensor and back probe the connector signal wire and wave a screwdriver near the sensor
Look for changes in the meter reading.
Don't guess, test.

Note: Fuel pump will not run if there is no signal from crank sensor
It is a safety feature in case vehicle is in an accident

 

Thank you Avisitor for the reply. I'm pretty sure it's not the crank sensor. The pump should run for a couple seconds as soon as you turn the key on. At least all my other fuel injected cars do. When this one started the few times, which btw it seemed erratic, it did too, now it does not just like before, it does not come on for those first seconds. Please understand, I am greatly appreciative of any suggestion but Allen is a "master tech' with all ASE certs. He's worked at dealerships and I wish it were as simple as the crank sensor. The problem is we have no basic information. He is quite capable of chasing down a problem, replacing a wiring harness, all that with enough info. We have none. At this point since the caps in the pcm were bad, for sure, they leaked, and the car actually ran a couple times and then it stopped, something hard failed like it did when the thing died on Rob and the cap replacement did not fix it. We are led to believe it is in fact the pcm.

We do not know about compatibility or programming if needed. My questions are specific.........we need basic info. A pin out of the connectors on the pcm I have would be useful too, but I can't find one.

Again, I really do appreciate any and all advice.
Ed
edit**** make no mistake, I will question Allen about the crank sensor, just in case but I'm sure he's ruled it out. When the crank sensor on my Probe GT went out the fuel pump did come on the first couple seconds like normal but had no injector pulse or spark. This is different, pump not even coming on at all unless we force it. Thanks again for any and all suggestions!
edit #2.... keep in mind at one point we had spark, would run on starting fluid, but no fuel pump or injector pulse. Then it ran, then it stopped, replaced caps, no change except now no spark. It may have several issues obviously but the crank sensor was working even when we had no injector pulse so it seems.

 

Sure, the fuel pump should prime the fuel rail with the key first turned to the on position.

Did you make sure the wiring to and from the PCM is good?
If not then replacing the PCM will only bring you the same results.

 

Thanks again Avisitor but we are way ahead of all that. I build high end audio equipment for a living. I'm "ok" with a schematic. Allen is a factory trained mechanic. He can only understand if he has the information, same with me. We do not have and are having a hard time finding basic info. If this were a Chrysler it would have been fixed and we'd know the answers. We have a factory service manual but certain things are missing or may be assumed to be known.

The pcm had several caps that had leaked. No matter what, it has got to be replaced. What I need to know are the answers to the questions I originally asked.

1 This pcm ran the car for years and I drove it with it...... 37820-P28_L01
2 Can I try and find another and just plug it in? Would it need "programming"?
3 If the last set of numbers/letter are different will it still work, as in "run the engine"? Meaning not an "L01" We "think" the last numbers/letter would not matter since it is now a 5 speed. We are guessing based on all we could find.
4 #3 is the main one..............will a 37820-p28- "XXX" run the car given the fact a 37820-p28-L01 ran it for years.

Thank you again for the replies and I really appreciate any and all help. If you know the answers to the questions it would help a lot!
Ed

 

P28 : 92-95 OBD-1 Civic Si/Ex
EX AUTOMATIC:
37820-P28-A51
37820-P28-L51

EX MANUAL:
37820-P28-A01

Si MANUAL:

37820-P28-A01
37820-P28-L01

That is all I found.
P28 is the PCM for Civic
The first 0 after the Letter means manual
Second number is the software revision???

 

Thank you my friend. So, we are to assume any 'P28" will run the car and since I have a 5 speed that was converted from an auto and the car ran fine on the "L01" I have, the last letter/ number sequence will not matter, it just needs to be a "P28"?

Based on the leaking caps, the intermittent operation and having checked all wiring we're pretty sure it's the pcm but I sure don't want to buy one that won't actually run the engine. Finding the "L01" is proving difficult but if the others will work I think I'm ok.

Thanks again for the info. Every little bit helps.
Ed