[Ace#1]

Hey guys
This is my first time posting. I bought a 2009 cadillac cts 3.6 and it will not run. Whwn it does crank it runs really rough. So i read codes and looked at live data when it did crank and it showed injector 6,3, and 4 is not being commanded on the codes are p2152, p2155, p216d. I been working on this for about a month. Thanks a lot

 

[Joseph Upson]

You'll need to source the diagnostic procedure for those codes, because there are a number of things that can cause them. You will need to confirm your harness from the PCM to the injectors is intact end to end. Unplugging the injector harness and the PCM and checking continuity and presence of a short for each associated (injector) wire at both plugs is one approach.

I would identify the terminal pairs for each injector at the plug near the fuel rail and measure the resistance of each injector. I believe the injectors are the problem considering you have a mix of odd and even injectors involved and the PCM is not commanding them on. The PCM could be the cause, but unlikely considering you're getting relevant codes.

You haven't provided sufficient details on the motor although I suspect it is Direct injected, and a detailed, but brief description of the associated history would also be helpful. You probably have poor performance from the other injectors also, because a V6 will run on half of its cylinders from personal experience on a non active fuel management motor.

There may be other problems as well. Check for the possible presence of pending codes that the motor has not run long enough to set.

Welcome to the forum, although it may seem more like an initiation considering a problem appears to have lead you here.

 

[Ace#1]

Thanks a lot for your reply. Its a 3.6 direct injection. I have checked continuity from the injector back to the connector and it was good but i have not checked from the connector to the pcm i will do that on the morning and also check the resistance on those injectors. Thanks again for your help

 

[Joseph Upson]

My injectors some how ended up getting clogged. The car ran fine, but set lean idle codes for both banks. The long term fuel trims were nearly maxed out in the 30s as the PCM had adjusted them to deliver more fuel in order to maintain normal operation. Each time the codes were cleared until I discovered the injectors were the problem, the motor would run terrible on the first start following, popping/reversioning back into the intake and misfiring for several seconds until the PCM reapplied the fueling offset to deliver the additional fuel needed to overcome the deficit caused by the blockage.

You can source a local shop, possibly a machine shop to clean and test the fuel injectors, after the wiring is confirmed to be in good condition. Read up on it as they have to be rebuilt due to the special one time use seals they have and there are two high pressure fuel pipes along with the high pressure fuel sensor on the rail that are also documented one time use parts. It also takes patience, good tools and attention to detail to get the injectors out of the tight space. If the motor has over 100k miles on it they will take some effort to remove.

I am not sure if the injectors have an individual, or shared ground, but suspect it will be individual since the PCM usually withdraws a ground to disable electronics.

 

[Ace#1]

Ok i will check the wiring today if it checka out i will pull all the injectors and have them checked out and i will report back with you. Thanks again for your help

 

[Ace#1]

I checked the continuity on the injector harness back to the pcm connector and the wires seems to be good and the resistance on the injectors are all the same amd im still getting those imjector codes p2152 p2155 and p216d when i went to live data when the car did idle it was rough still and imjector 3,4,6 is not being commanded on when i let it ran for about 3 mins monitoring the live data those injectors was commanded on for about a second and disabled again i was wondering could it be the pcm

 

[Joseph Upson]

That doesn't rule out the possibility of those injectors being clogged and the PCM disabling them after determining the misfire is fuel related as opposed to ignition. The injectors are driven by as much as 65 volts and at that level the PCM maybe able to determine irregularities associated with the injector that help identify it as having a problem. If the valve in the injector is stuck closed, the circuit continuity will appear normal, but the driver load should be higher if it does not lift off the seat when commanded and that might be what the PCM is sensing as a possibility.

It could be the PCM, but again, you will need the diagnostic procedure to help pin point, or you can weigh the cost of replacing the PCM against the cost of refurbishing the injectors and use the process of elimination approach. A scan tool that can command the injectors individually might help, but there's no guarantee, considering I was not able to command my window to close when all it needed was the 10 sec relearn procedure to start operating again. For whatever reason, the scantool was not allowed to override the switch in that circumstance, although I could hear a click in the door with each command I sent.

Before I determined my injectors were clogged, I purchased a used PCM with the same part number as the one in the car and had it programmed as a backup in the event of a problem with the PCM, or to help troubleshoot.

 

[Ace#1]

Thanks alot your really helping me out ok what i will do is buy a injector for it and install it and see will the pcm command it to turn on on that cylinder and i ordered a used pcm with the same part number as the old one just in case. Im ordering a new injector now to check it. Once i get that done i will report back and let you know what i find. Thanks again

 

[Joseph Upson]

Thanks alot your really helping me out ok what i will do is buy a injector for it and install it and see will the pcm command it to turn on on that cylinder and i ordered a used pcm with the same part number as the old one just in case. Im ordering a new injector now to check it. Once i get that done i will report back and let you know what i find. Thanks again

You're going a bit fast. Please and I can't stress this enough, research the diagnostic procedure for those codes first. The used PCM will still need to be programmed even with a matching part number. The number match is because some times different part number PCMs in some of the BOSCH models will not work correctly despite having the same E69 identification from what I have read. Then it has to be identified by the BCM after install, which is a timely process in itself that will also require an instruction review.

I suggested refurbishing all of the injectors because of the injector removal expense when done properly by replacing the associated one time use parts. They may work fine when reused, but I certainly do not recommend it. You want to fix it, not go broke trying.

 

[Ace#1]

Ok your right im gonna reasearch those codes and see what i can finde on them and i will report back with you and i got another code p0087 fuel rail pressure low

 

[redheadedrod]

Having just gone through the injectors for my car I would suggest finding a price for the injectors new and comparing to the price of having them refurbished. For me I found AC Delco injectors for about the same price as sending them out to be refurbished. Had I known they would be the same price I would have just bought 6 new injectors and not worried about it.

My engine is newer but should be similar. Think I paid $25 per injector to have them cleaned but had to pay for shipping both ways. I bought 1 new injector for $35. I think if I had bought all 6 injectors I was out like $25 more than having the old ones refurbished.

 

[Ace#1]

Thanks im still checking wires but i probably will have to end up buying some injectors

 

[Joseph Upson]

Having just gone through the injectors for my car I would suggest finding a price for the injectors new and comparing to the price of having them refurbished. For me I found AC Delco injectors for about the same price as sending them out to be refurbished. Had I known they would be the same price I would have just bought 6 new injectors and not worried about it.

My engine is newer but should be similar. Think I paid $25 per injector to have them cleaned but had to pay for shipping both ways. I bought 1 new injector for $35. I think if I had bought all 6 injectors I was out like $25 more than having the old ones refurbished.

A brand new $35 DI injector for the 3.6L is suspect of possibly being a made in China counterfeit, where they could be purchased in GM packaging for next to nothing (I've seen single digit prices), an especially high risk IF purchased from ebay, so beware. Rockauto carries some of the best prices that can be had on OE parts and their best new OE price is double that for the LLT and nearly double for the LFX.

Some engine machine shops offer injector cleaning services locally to avoid the excess of expedited shipping expenses.

 

[redheadedrod]

Like I said, do your price checking... Mine looked exactly the same as the ones I pulled out and I paid $35 apiece with free shipping. Did not appear to be "chinese clones" but the real deal.

Just as my buying wheel sensors, 4 for $80.

Rockauto sells "refurbished" sensors for $39 for the LFX in which they do the same thing as I had done for the $25 apiece not including shipping.

 

[QueFixIt8]

Did getting the new injectors help?

 

[Petepull]

Did getting the new injectors help?

I love how you ask people if things worked out after they asked you a million questions and they don't have the decency to reply back.

 

[Padgett]

Help desk syndrome: you know it is fixed when the user quits calling.