99siky

Question: Is there any other place I can look into that will cause injectors to fail other than resistor box?

I have replaced my 450cc dsm injector on cylinder #4 twice now. This last one was a brand new injector from KOI auto parts. I am going to test the resistor box and see if it is bad but other than that, what else could I look into as a possible cause for this to keep happening? ECU? I have a P28 with Neptune. I checked the CEL code and it is a 16; Injector malfunction check. Also this only happens after the car is warm. Once the car is cold it runs just fine. Only happens when warm and when I shut it off for a couple minutes and then restart it (figured it out this time when I filled it up with gas). I checked resistance on the injector after warm during this problem period and it has no resistance or the meter cannot read it, when the other injectors stay at 3 ohms. Cylinder is getting spark and fuel is getting to the rail. Car ran fine before turbo install with no problems at all.

Right now it is on a basemap. I am trying to get this problem solved before I get it tuned so I don't have any problems on the dyno. I have not driven it that much on the basemap. Just to get parts here and there and to diagnose/solve the problems it has been having. Have not hit boost except for like 1 lb getting up to speed with traffic a couple times.

kyden

it is possible you have a bad injector driver on the ecu.

wantboost

iTrader: (2)

That or a wiring issue

99siky

I am going to test the resistor box either tonight or tomorrow and see if it is bad. I appreciate the responses. Honestly I was not the one to hook up the resistor box so I would have to double check the wiring completely to see if that is the issue. I am confident that the person who did knows what they are doing but anything is possible. Does anyone know what resistance I am looking for when I check it? I know if one of the four wires is off then it would be bad but is there an ohm I should be looking for? The injectors are at 3 ohms when the car is off.

wantboost

iTrader: (2)

No resistor box would cause a driver on the ecu to fail... might want to swap injectors around on the rail and see if the problem stays in the same cylinder.

99siky

I meant to see if the resistor box is bad not the ecu. The ecu was used before me so I will have to keep that as a possibility as well but I want to rule out other problems that are a cheaper substitute first. I will try to swap the injectors to different positions. A mechanic just suggested that to me today while I am at work to make sure its not another injector that is making the whole system bad. Thanks for the advice. I'm about to start checking everything right now and I will post up what I find out.

99siky

checked the resistor box and the same resistance was going to all injectors. the wiring going to each injector is right and shows continuity. at a loss. the only thing I can think of is to change the injectors around in the fuel rail or replace them all. Maybe one of the three others is causing the problem.

any thoughts?

Turbo-LS

iTrader: (4)

Sounds like a bad injector driver. If the resistor box is good and injectors are good then only one thing left. ECU. The resistor isnt what drive the injectors its supplies power and increases resistance the ecu will see. The ecu actually ground the injector to activate it and if one is bad then need new ecu

wantboost

iTrader: (2)

Yea with no resistor box, the drivers in the ecu get too much current, resistance and it will cook them.

If you're looking for another chipped ecu I have an auto p08 that was professionally converted to manual p28 then chipped.. I'll sell it stupid cheap (shameless plug Lol) and I give discounts to em1(99-00 Si) owners since I'm an OG em1crew member

99siky

I will try to work on it here in the next couple days before christmas. My plan is to switch the bad injector with another one and see if it is still a problem on the same cylinder. I just hope it doesn't fry another injector. If it does then at least I will know what it is. I've asked my tuner and he gave me the same advice. Switch around the injectors in the fuel rail and see if it does the same thing. He also said he could switch the injector driver in my ecu that I have now. I'll ask him how much it is. I might need to just get another one if it costs too much money. If it does I will definitely get that one off of you wantboost. Thank you, and I love my em1. It's the best!

turbohatch96y7

iTrader: (15)

[Q

If you ran the car with no resistor box, that's the reason you burnt out the driver and your injector coil.

Open up the ecu and inspect the drivers (tranisitors).
They're should be a noticable burn mark on the transistor itself or the board. You should be a ble to smell it too.

Don't be afraid to open up the ecu there's nothing in there that's going to fall apart.

Swapping injectors and Burning out another injector just plain retarded.

99siky

I didn't said anything about running this setup without a resistor box. I said I wanted to check to make sure the one I had was good. Which it is. the point of this is to determine if it is just another bad injector or not. The ecu was fine upon primary inspection before the install but I will open it and check again. which area am I supposed to be looking at? The tuner installed the neptune and checked all the components on the ecu before I installed it.

turbohatch96y7

iTrader: (15)

Sorry I read that part and thought you didn't wire it up at all, not that someone else did the install..
Okay if number 4 injector keeps failing check the wire from the injector to the ecu (with ecu connectors disconnected)
It should be a2 on your ecu (yellow wire). With a multi meter check for continuity from the ecu pin to the injector connector. (Doesn't matter if the resistor box is wired or not).
You should read zero or at least less than 1 ohm. Depending on which multi meter you use.

.
Then check from ( with the ecu disconnected from the wire harness) from a2 to ground. ( there should be no continuity there. The meter should no have a reading or say infinite.

For the injector drivers I would need to post a pic later to show you or do a goodle search for a pic

99siky

I finally found a good pic of the injector drivers. They are diagonally across from the chipped section of the ecu and are 3 tall black rectangles?

Also that was the first thing the mechanic, that was helping me, did was to check the wiring from the harness to the injector. That is how we found out it was at the injector in the first place. Sorry I guess I didn't mention that.

turbohatch96y7

iTrader: (15)

Yes those are transistors.
You can check them with a multimeter as if they were a diode. Probing across the emitter to collector.

Also recheck the wiring as I mentioned above, if you don't want to then there's no point in me helping any further based off of pure assumptions.

If you want to troubleshoot this your self buy a multimeter. If not tow the car to your tuner.

99siky

I have a multimeter and I have been checking everything myself. Also this is not an assumption as I actually was there, watched him, and helped him do it. I will check it again because I want to be sure. I was just letting you know that it was already done. I will also look into the ecu and check it once I start working on the car again. Thank you for your help. I will post up what I find as soon as I get into it.

99siky

So today I grabbed my computer before work so I could at least get that checked. I still need to check the wiring and other things once I get the time to really work on it. But as for now, I checked the injector drivers with the multimeter and the lower injector driver (furthest away from the outer box) is letting resistance through it while the others are not. So my assumption is that this one is bad and needs replaced? There are no visible burn marks or smell though.

wantboost

iTrader: (2)

They go bad internally, like a fuse popping so there won't be any external signs.