LB7: #1 injector shorted

[2004LB7]

I would put it all back together less the upper valve covers and test the connections at the fcim. If all looks good test run it. If it still has issues take the ohm readings that the fcim connector for each injector and report what each one is here.

If everything still checks out but doesn't run then maybe it is the fcim

 

[TheBac]

I honestly leaned toward the FICM from his first post.

 

[2004LB7]

I bet you are right Tom

I was just thinking of a few last steps to do that dont cost anything before braking down for an FCIM. The codes listed could be a number of things, one of which is a short to ground. Brakes in the wires, bad connections, too high or too low resistance, etc. All can cause the codes listed

By putting it all back together and testing it at the FCIM connector he can rule out the injectors and harness. This would give him a good idea if he needs another FCIM

 

[TheBac]

Oh no, don't take that wrong....I completely agree with your diagnostic tree.

 

[2004LB7]

Here's a thought for Tylerrc34

Is your codes for injector 1, 3, 5 & 7? Or 2, 4, 6 & 8?

The original poster had codes for the injectors on the passenger side but I see that you have the drivers side open along with the bale connector. Are you sure you have the right bank of injectors?

 

[Tylerrc34]

My codes are for injector Group A which are numbers 1, 4, 6 and 7.

P0201, P0204, P0206, P0207, P2146

P0201 - Cylinder 1 Injector Circuit Malfunction
P0204 - Cylinder 4 Injector Circuit Malfunction
P0206 - Cylinder 6 Injector Circuit Malfunction
P0207 - Cylinder 7 Injector Circuit Malfunction
P2146 - Fuel Injector Group “A” Supply Voltage Circuit/Open

Here's a link to my original post on DF...

http://www.duramaxforum.com/forum/0...-limp-mode-throwing-6-codes.html#post12017145

 

[Tylerrc34]

Am I right that on LB7s the FICM converts 12v to 96v?

Also, with key on but without the engine running, should I be seeing 96v at the injector pigtail harness from the FICM or does the engine have to be running?

 

[Tylerrc34]

I'm going to hook it all back up tomorrow and check these things.

BTW I had a total of 6 stripped allen bolts on my upper valve covers, what a pain in the ass! I had to buy a welder to get them off!!! There ain't exactly a whole lot of square footage in that engine bay for a welder. I got them off though!

 

[2004LB7]

The FCIM does step up the voltage to 96 volts but only for a split second to open the injectors. You would need to put a scope on it to read the voltage at it will be a pullsed signal. I think the 96 volts is to open it and then it drops down to a lower voltage for holding it open. Remember this is only on the pilot and injection cycle so it is very fast

Also, go down to your local hardware store and get yourself some regular hex bolts to replace the allen head ones

 

[2004LB7]

My codes are for injector Group A which are numbers 1, 4, 6 and 7.

P0201, P0204, P0206, P0207, P2146

P0201 - Cylinder 1 Injector Circuit Malfunction
P0204 - Cylinder 4 Injector Circuit Malfunction
P0206 - Cylinder 6 Injector Circuit Malfunction
P0207 - Cylinder 7 Injector Circuit Malfunction
P2146 - Fuel Injector Group “A” Supply Voltage Circuit/Open

Here's a link to my original post on DF...

http://www.duramaxforum.com/forum/0...-limp-mode-throwing-6-codes.html#post12017145

So passenger side, it sounded like you were working on the drivers side on an earlier post

 

[Tylerrc34]

So passenger side, it sounded like you were working on the drivers side on an earlier post

Injectors 1 and 7 are on the passenger side and 4 and 6 are on the driver side so in order to check group A one must remove both valve covers!

 

[Tylerrc34]

By putting it all back together and testing it at the FCIM connector he can rule out the injectors and harness. This would give him a good idea if he needs another FCIM

When you mentioned testing at the FICM, how would you do that? Should I read voltage at the harness going to the injectors for 12v with key on?

 

[2004LB7]

Unplug the connector on the fcim. Prob the pins there going to the injectors

 

[Tylerrc34]

Oh I got it. Yes I'll do that. I just wish there was a way to bench test this damn FICM. I will update...

 

[Tylerrc34]

So I found my mistake, I was using a setting too high on my multimeter. I switched to the most sensitive setting (200) and retested and my number 1 injector is reading 50 ohms while all the others are reading .5 ohms.

So it seems as though that's my problem.

 

[2004LB7]

Is that right at the injector? Or on the harness somewhere?

Its good you found something as now you can get it fixed

 

[Tylerrc34]

That's measured right at the injector studs.

My biggest hurdle will be removing the allen bolts without stripping them. I bought a reman injector from Pensacola Fuel Injection so it should be here mid week.

 

[2004LB7]

If I where you I would cancel that order. Do a search here and read all about Pensacola's "great" injectors. Save yourself the pain and get em from LDS. They are also a vendor here

At a minimum, keep your injector and swap the solenoid out

 

[Tylerrc34]

I've read a thread about swapping the solenoid and one person suggested not to do so because the solenoids are specific to the injector.

Have you swapped a solenoid?

 

[zakkb787]

If you read a thread about that, you need to read up on Pensacola reviews.