I've traced out a problem on my car. I have had an intermittent p0200 code. Which is a injector malfunction circuit fault. Drivers side bank is good. Noid tested and confirmed that it's the side that's running. Passenger side is cold to the touch. It has power going to the injectors on the passenger side. Noid test failed on all injectors. I was wondering if anyone has a picture of the fuel injector harness to see if there's a ground that is on each bank or if I'm missing a ground on the ecm itself. Is there a common ground that the computer uses for both banks? Where does it get it's ground to command the injectors? Is it possible for a ecm to have one bank go bad and not the other? I hope not because I'm sure that hp will stick it in and break it off for the credits I just bought for the computer not to mention the fact that the low life I bought the hp tuners from said it still had 6 credits left and actually had none when I bought it. So basically I'll have a grand into this ordeal if the computer took a crap. Please help out fellas. I need to get 250 more miles on her so I can get it dyno-tuned before the snow flies.....more. I'll have to leave her put up not running and no dyno figures for next spring. Thanks in advance. Btw many have posted on this particular code and it is particularly a pain in the butt to trouble shoot. Noone has really ever posted their findings or any input on the matter. There has been some but not enough to cover this issue. I intend to cover this to the end and give my input on a procedure to trouble shoot this the "kiss" way. Thanks again Chris

 

Each inj has a dedicated ground, that the PCM uses to trigger the injs.
What harness are you using?

 

Injectors are grounded by the PCM.
With key open engine off, check the injectors with a voltmeter, you should see 12V on the pink wires. If all injectors have 12V with key open then it's a ground issue. If not, check INJ fuses

Assuming a Gen 4 Fbody, the PCM has 4 grounds:
Pins 1 and 40 on both red and blue connectors, all of them are black wires.

Unplug the PCM and check if those grounds are ok at the PCM connectors using a multimeter and a paperclip. All of them should have 1 ohm or less from the pin to engine ground or battery negative.

If everything checks good, then the PCM is bad

 

Ok, I had rechecked all of what I said I did. I did a continuity test on all grounds from the computer from the harness itself. I checked continuity from the injector plug in to each of the pins on the harness. Verified that all of the injector plugs had power to them. Checked all fuses in the fuse blocks. And finally, I ohmed out the injectors last. 1-7 ohmed out at 11.7-11.8 On the number 8 cylinder which ironically is the most pita to get to work on has everything stuffed around it ohmed out at 13 originally. I took the fuel rail off and fished the little pita out and checked it again on the bench. It ohmed out at 12 then ohmed out at 11.8 I fiddled around with it and tilted it and tapped it. I continued to get 12.1 for a reading. I swapped number one and number eight injectors out. Did a noid test on the passenger side bank (which is the side that wasn't firing at all before) Now I have a noid light on the passenger bank. Disconnected the # 2 cylinder and did a noid test there which had a good noid test as well. I think that maybe I had reset the computer when I disconnected the harnesses etc. Unfortunately it is 10:30 and I cannot fire the engine since my little ones are asleep and preparing for their school day as well as the better half. So I'll have to wait for tomorrow morning at 5:00 am and test fire once everyone is awake.....well my house hold anyways. 5 am is fair game right ? lol Anyways I'll check it tomorrow afternoon/evening when I get off to confirm if the injector is the culprit. I will keep the injector company under wraps since this is a new injector and I don't really want to do any mudslinging. They had helped me out previously and I don't intend to forget that. Besides the point, crap happens. I'm just glad that I had a noid light test show up on the passenger bank. A wire problem or injector problem is better than a new computer and replacing the 3bar and licensing credits I just bought from hp! Thanks for the help and input guys. I'll update when I get some answers. Thanks Chris

 

How much allowable variance is there between injectors .1 ohm .2 or 1 ohm? How much? The injector is working at the present time. I have one being overnighted but I would like to know if I've pin pointed the problem or not. It would seem that I have, but I would like to be sure. This particular injector measured out at 13 ohms which differs form the 11.8 that all the rest tested out at. Once I got it outside of the car it ohmed out at 11.8-12.1 while I was handling it. I installed it on the #1 hole just so I can get to it easier once I replace it. The only problem I have with the scenario is that I have no way of really knowing if this is the particular problem because a. I have taken power away from the computer so it cleared the code and once I swapped the injectors from 8 to 1 it made the passenger side bank start to work as well as the drivers side worked as well with the bad injector installed on that bank and b. I haven't been able to run it long enough to make it have the problem again. I let it idle to basically running temp and it didn't throw the code again. Can injectors go bad intermittently? I'm leaning to this heavily just because I had good tests on grounds and power to the injectors when this code was thrown. This is what lead me to testing the injectors. Thanks for the input in advance guys. Injector guys please step in.

 

11.8 to 12/12.1 is not the issue.
I have a flow bench, test a lot of injs, and see most that I do, have some variation in ohm readings.

 

Injectors can be from 11 to 14 ohms, that is normal.
The only difference between a 11 and a 13 ohm is the current it will draw from the PCM driver.

Take the injectors to a cleaning shop, they can clean and flow test them. They may let you watch them working.
If the spray pattern and flow is consistent in all injectors, they are good regardless of their ohms.

 

Well I finally found the culprit to my p0200 code. Unfortunately, this won't be listed as a "common" problem that others will encounter. When I initially started testing the problem I had no symptoms to go by. It threw the code and I had good continuity to all injectors on the ground side, good continuity from ecm to common ground on the head and I had power to all the injectors. Passenger side bank was not working which I verified with a noid light. Drivers side bank was working like normal. I was leaning towards an ecm problem because I had exhausted all possibilities besides two remaining possibilities: check the injectors (which were new) and voltage issue to the injectors. I ohmed all the injectors which I had 11.8 on all except the #8 hole. It ohmed out at 14 in the car. I removed the pita and checked it on the bench. It ranged from 11.8 to 13 on the bench. I had an injector overnighted to see if that was the issue. Took the car out and made sure that that was the problem. I drove the car ALL day with no issues. The car coughed and died on the busiest street in town. Got the car back to house and started testing immediately since the problem still existed. I could never trouble shoot before because the problem would fix itself on its own before I could do any kind of analysis. I pulled the injector harness on the passenger bank and checked with the noid light. No injectors firing on the passenger side. Got the test light out and found NO power to the injectors. FINALLY, I have something to go by now. I began thinking about my situation. Before, I could never understand why the computer would kill the whole bank if there was an injector circuit malfunction. After I seen that I had no power to all of the injectors I knew immediately what the problem was. I had checked the fuses before as the first action in trouble shooting when the problem first started. I had good continuity through the fuse and I had power from one side to the other which was verified by the test light. So I narrowed it down to the common power feed from the injector 2 fuse/harness to the injectors on the passenger bank. When I did the fuse block relocate I removed all of the pins out of the block so I could reroute the harness through the fender without cutting any of the wires. I didn't get the pin pushed far enough into the block so it would lock into the slot. I could barely touch the fuse and interrupt power to the injectors (I had a test light hooked up in line from the #2 injector harness so I could visually see if power was being lost). I then took the pin out of the block. I checked continuity through the wire from the pin to the injectors. I twisted and moved the wire to insure that there wasn't any broken spots in the wire. Pushed the pin back in and re-tested. Power is good and solid now. Problem solved. Thanks for the input and help guys. I'll post up tomorrow with my .10 on a trouble shooting list to go through to help speed up the trouble shooting process for those who come across this problem. As for the injector, I called my injector guys up and discussed the possibility of having a bad injector. They didn't ask any questions or balk on anything. They had one flow tested and out the door the very next day under warranty. I wanted to verify the cause of the problem before I mentioned who I had got the injectors from just to make sure I wasn't throwing mud on anyone. Crap happens. Jon I would like to extend my gratitude on your excellent customer service and outstanding warranty. Kudos to Fuel Injector Connection! Anyways, I've written a small novel and it's time to head it to bed. If anyone has any questions please let me know. I'm not an expert by any means, but I'm well informed now lol. Thanks Chris