Fuel injectors

before you get into that be aware that it can be any of the things listed causing the problem. this includes air leaks, like engine grommets or holes in duct work leading to engine, or vacuum leaks. See pictures for testing it still can be a bad PCM as well. disregard first two pictures.

Ok I'll check those out too, thanks!

Hello,

I have found some wiring diagrams and a couple of guises to help you get the problem fixed.

https://www.2carpros.com/articles/how-to-test-a-fuel-injector

and

https://www.2carpros.com/articles/how-to-check-wiring

Please run some tests and get back to us so we can continue helping you.

Cheers, Ken

I have an update on the injector circuit problem, I ran a few test and I replaced the injector harness, so far nothing has changed, it accelerates a little better but for the most part it's still running rough at times and it's all pointing to the injector itself. I wasn't able to check for air leaks yet, I'm still trying to find a cheap and effective way, I was thinking of running smoke through the brake booster air line to check that, I also pulled the codes again and this is what came up:
P0301 cylinder 1 misfire
P0171 fuel system too lean (cylinder 1)
P0201 cylinder 1 injector curcuit malfunction
P1131 lack of HO2S-11 switching
That's all I have for now, I'm going to test the compression in cylinder 1 tomorrow to make sure that's ok, let me know what you guys think, thank you!

Hello,

P0201 cylinder 1 injector circuit malfunction

Will cause the other codes. Did you test the injector?

Here is a guide

https://www.2carpros.com/articles/how-to-test-a-fuel-injector

Please let us know what happens.

Cheers, Ken

I ran some test on the injector today (what I could), the first test was with a long screw driver and I did hear the clicking noise plain as day, I did the same with a different injector and I noticed a different sound of clicking, I didn't know if that mattered or not.
I also used a multimeter with the ohms setting with the ignition off, the harness gave a reading of 172.2, injector gave no reading.
So what should I do next? Thanks for your help!

sunds like the harness is bad should only be 5 ohms from injector to pcm. tan wire and violet wire to ground should be same. also check for wire to be rubbing engine on block that may be problem. also check resistance of injector should be 11-17 ohms or around there.

The harness I checked was a brand new one I put on last week that made no difference in performance. I tried to check the injector itself but it didn't give a reading, I'm an amateur at using multimeters, I've never had to use them before, the wire isn't up against anything but the throttle body cover. I heard if there is no reading on the injector then it has an open in the circuit but I'm not sure. If the reading on the harness is high could it be the wiring? Thanks for replying!

yes the reading shold be what I gave in previous reply or its'grounding out.use your old harness and hook to injector take an ohm reading that way it should be close if no reading then the injector may be bad.

I ran another test this time with a probe light, while the engine was running I connected the red wire of the light to the positive battery post and the light to the left side of the harness and the light lit up, I then put the black wire of the light to the negative battery post and connected the light to the other side of the harness and no light at all. So now it seems like a bad ground somewhere, what should I do next? Could it be a bad pcm or the wiring? Thanks!

it cold be either if you check the wire back to pcm and it reads 5 ohms or less then it's the pcm probably but that you shold have verified first as a mechanic has to program the new one to your vehicle.check the tan wire to pin #2 on pcm if no reading or h igh on ohms then it s wire

So would I have to disconnect the harness from the pcm? I'm not sure which one it is because I tried to follow the wires from the injector and they go down behind the motor and as far as I can tell it goes into the top harnessvon the pcm. I thought there would be another connection harness between the pcm and the injectors but I think the wires go straight into it, not sure. I don't suppose that cleaning some ground wires would help. Thanks!

yes you disconnect the harness on the pcm and be careful not to bend any pins.removing and reinstalling harness. the plastic connector will be marked by numbers where wires are just make sure it's the correct color and number to check which I have given you previously. use dielectric compound when re installing for better contact. usually sold as bulb grease on counter at auto parts for around $2

Ok I'm going to give it a try this weekend, I'll let you know what I find out, this is kind of new territory for me, I'm worried about bending the pins now that you mention it, I can't tell you how much I appreciate all your help, I feel like I'm really close to finally finding the problem, I'll get back with you this weekend with the results and see where to go from there, Thank you!

By the way I have a couple more questions, since I'll have the harness off the pcm to test it, would it be a good idea to try some crc contact cleaner on the pins? And would I apply the dielectric grease on the pins or around the pins? Thanks!

don't bother with crc just put the grease when you can on pins

Im trying to get a reading on the pcm harness and Im having any luck, I don't think my multimeter pin won't fit down far enough to get a reading, I also couldn't get a readind on the pcm itself, am I doing something wrong? I took a picture of the pins and the harness to show you where Im at, is the battery suppost to be disconnected? Let me know, thanks!

if your multimeter won't fit you'll need something that will like either a pin or maybe a paper clip to take the reading.

Ok, I got a thin piece of copper and put it in the pin hole of the harness and it didn't give me a reading at all, I also had the battery disconnected, does this mean it's the wire? Thanks

I guess Im gonna assume it's the wiring since I didn't get a reading on the harness, I put it all back together after I put a dab of dielectric grease on the pins, it still runs the same. So should I be looking for a separate harness for the injectors or do they go straight into the pcm? Thanks!

first make sure it s the correct wire going to correct pin then do a reading again if no reading like ohm wise then start tracing the wire and connections then fix the wire if wire is pinched or broken

I dug through the wires on the harness to find the tan one you told me about and it went to the no. 2 pin hole and it didn't give me a reading on ohms, it was bundled with the other wires in really thick insulation, it runs all the way down to back behind the intake so following it is pretty hard. At least I know what I'm looking for now, thanks for all your help!

Check the wiring diagrams on the third post you can see the wiring and where it goes.

Please let us know what happens, we are interested to see what it is.

Cheers, Ken

you should get 0 -5 ohms on wire if that is what you are getting it's ok if infinity then it's broke someplace

Yeah I set my multimeter to the lowest setting on ohms and it it didn't budge, I even tested the multimeter to make sure it was working right and it was. I traced the wires from the injector as far back as I could and didn't notice any frayed wiring.

I looked at the diagram ken provided and it looks like the tan wire goes straight into the pcm and the purple wire goes to the idle air sensor ontop of the throttle body, the tan wire was the one that didn't light up the test light. If the wire is good then does that mean it's the pcm or should I run some tests else where? Thanks!

I think I may have a solution to finding the problem, what if I took the tan wire from the pcm harness and connect a new wire to it and run it around and connect it to the injector harness, that way if it still runs bad that would mean the pcm is bad, what do you think? Thanks!

don't do anything like that wire wise. have a mechanic verify what the problem is then if it needs a pcm he will have to program it for your car anyhow. they can be rebuilt

Ok I will, I'll let you know what they find out, thanks for all your help!

By the way, there is another clue if it helps, if it's warm outside like 80 or above, I'll notice that if I drive it down the road and turn it off for a minute and start it up the problem goes away, then about 5 or 10 minutes later it slowly comes back, then goes away and comes back, and sometimes when I accelerate it goes away then comes back. If that helps narrow it down let me know, thanks,

kind of sounds like a pcm but it could be a connection as well. that tan wire goes to pcm but it has a connection at injector harness and maybe along the way as well. if it's a wire a mechanic can find it.

I did one final test another mechanic told me about, he told me to do a continuity test with the multimeter from one end of that wire to the other so I did, I tested it like I did before from the pcm harness to the injector harness and it gave no continuity, no beep, no reading. But I will still get a mechanic to look at it to make sure, thanks for all your help!

Please let us know what happens, we are interested to see what it is.

Cheers, Ken

Hey everyone, I thought I'd give you an update on the situation I had, I had a mechanic look at the issue and he concluded that it was pretty much the pcm causing my problem, so now I bought a pcm from napa and had a dealership instal and flash it, and the results? Only half fixed. It made the rough idle slightly better and eliminated 2/4 trouble codes, the circuit malfunction injector 1 and lean condition bank 1 is still there. I did another test with a noid light for that injector and the light flashed when running. A tech at the dealership said something that he noticed the wire harness looked kind of twisted and could be causing the slight miss but thats not a actual diagnoses.
Sorry for such a late update. Thanks!

No worries thanks for getting back to us. Can I ask which codes are left? Number please :)

The only two codes left are p0201 and p0171, thanks Ken.

Hello,

It looks like you have an injector that is shorting out overloading the injector driver in the ECM. I would remove all injectors and test them here is a guide.

https://www.2carpros.com/articles/how-to-test-a-fuel-injector

Please let us know what you find. We are interested to see what it is.

Cheers, Ken

Thanks ken, is detrimental to the pcm to drive it this way? I sure wouldn't want to have to replace the pcm again.

Yep not good for sure. I would check the injectors ASAP.

Thanks Ken, I'll let you know what happens.