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Discussion Starter · #1 ·
Ok I swapped to another P28 and now the plugs are firing. I'm definitely getting fuel too. I think I may have the firing order wrong. I know it's 1342, but where does #1 go? I know on the A6 it was the bottom left, but the dizzy was upright, but on the Y8 the dizzy is tilted. So is it relative to the dizzy or the head?
 

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Look at the top of the cap... somewhere on there is an imprinted "C" in a circle... or something like that.. anyway, the post it is next to is #1... everything else is relative from there 8)
 

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downest said:
Oh yeah, and if my ECU is dead, shouldn't I get a solid CEL?
Not necisarily. If you look at your ECU as you turn the key to start, you should see it give a single red flash.

BTW, I had to replace my ECU recently because the fuel injector circuit on it apparently fried... all the other systems still worked, but I didn't get to the root of the problem until i started going throught the codes and breaking out the multimeter.
 

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Discussion Starter · #6 ·
Ok well... we tested for fuel using an extra Si manifold. There is definitely fuel pressure, but the injectors don't seem to be firing. I checked the resistor box and it's fine, I also checked for continuity between the injectors and their respective plugs on the ECU. I'm kind of stumped now, it's apparently getting no fuel, but I don't know why.
 

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Sounds like you're getting pretty close to solving the problem. How's the fuel filter? Which side of the fuel filter did you test for fuel pressure? Is there voltage going to the injectors when you try to start the car?
 

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"Is there voltage going to the injectors when you try to start the car?"

Grab a 'noid light' at Autozone.... very cheap, and you can plug them into your injector plugs to check for the ECU actually sending a signal... its not feasible to check this signal with a voltmeter (Fluke has some that can, but a 'normal' one isn't fast enough), and not a big enough of a signal for a normal test light, but the noid light is a great way to test it.
 

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downest said:
I checked the resistor box and it's fine
How do you know it's fine?

Also, that stirs up a question - Are you using obd1 injectors? If so, the problem is because you are using the resistor box. obd0 injectors are low impedence so you need a resistor box to cut down the voltage or amperage (I'm electrically illijamet) before it hits the injectors. obd1 injectors are high impedence, resistor box not required. If you are using obd1 injectors in conjuction with a resistor box, there's not enough signal to fire the injectors.

Disclaimer: above info subject to correction and confirmation. Sometimes I can't remember what day of the week it is.
 

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You are mixing and matching obd0 and obd1 parts. I think this could be where your problem is. Your p28 is sending a signal that isn't supposed to be cut down by a resistor box then it is going to obd0 injectors that require a different signal than what your 0bd1 p28 is sending.
 

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what tom is doing definitely works. Ive ran at least 2 cars personally with obd 0 injectors + resistor box on obd0+ cars.

thats also how everyone uses those DSM 450's on newer cars :)

[email protected]
 

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Without physically being there to see the car and what it's doing it's kinda hard to imagine what's going on. Since I'm at a loss for a new lead, how if any did you rearrange the vacuum hosing for the map sensor?

First things first though - confirm that there is signal at the injectors. Oh, have you tried starting fluid? If it starts with it then dies soon thereafter the starting fluid supply runs out, it's definitely a fuel issue. Beyond that it can still be wiring, spark, or computer control problems.

continues thinking....
 

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Discussion Starter · #15 ·
MAP is on the throttle body, it's a Z6 manifold I've been using for a few months. The injectors get 12V with the key on. We are using a speaker to test them for opening, I don't have a noid light or whatever but the speaker has worked before, it has a frequency response that covers the injectors pulse frequency.

Right now I'm thinking the dizzy is wired wrong, since I assume that sends pulse to the ECU/injectors. I'm trying to find a RELIABLE OBD0-OBD2 list, preferably OBD0-1-2 so I can check it against the ECU as well. If anyone has one I would appreciate it, I'd prefer something with the wire colours, functions, and locations on the ECU plug.
I feel like I'm getting close... at least I'm learning a hell of a lot and hopefully this will all make for a good write up.
 
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