HELP!!! TRUCK ONLY RUNS ON ALL 8 WITH VALVE COVER OFF

[03LB7 09LMM]

okay so i just recently bought this truck and ive narrowed my issue down to one of the injectors or more than one not sure is shorting to ground but only with the upper valve cover on if i take the valve cover off(on the driver side) it runs flawless as soon as you put the cover back on itll run for just a moment and then short and kill bank 2 of injectors i know someone somewhere has had this problem before theyve had to no possible way im the only one ive done some reading on it and no explanation was found also all the injectors on the driver side ohm out to 1.8-1.7 and there is no harness rub behind the alternator i just replaced the engine harness to be sure it was good and replaced the 6-8 injector harness ive got the other one for the 2-4 injectors if i need to put it on i just didnt wanna replace it if i didnt need to

 

[2004LB7]

What's the resistance reading to ground with the cover off and with it on?

 

[03LB7 09LMM]

What's the resistance reading to ground with the cover off and with it on?

how do you check that?

 

[03LB7 09LMM]

What's the resistance reading to ground with the cover off and with it on?

are you saying hot lead to injector stud and ground lead to engine block?

 

[2004LB7]

Yes. Good to check both side of the injector to a known good ground like a clean spot on the engine or battery terminal. You will have to pull the connector off the FICM to probe the wires from that side as obviously you won't have access to the injector studs with the cover on.

 

[03LB7 09LMM]

Yes. Good to check both side of the injector to a known good ground like a clean spot on the engine or battery terminal. You will have to pull the connector off the FICM to probe the wires from that side as obviously you won't have access to the injector studs with the cover on.

ok ill do that here shortly and couldnt i just slap the cover on and use the injector harnesses plugs to check it?

 

[2004LB7]

You could try that but it is always a good idea to check the whole line all the way back to the module

 

[03LB7 09LMM]

You could try that but it is always a good idea to check the whole line all the way back to the module

im getting OL on the ohm meter

 

[2004LB7]

What range are you using? Normally you start with the lowest range and increase it to see if you get anything. Resistance im the M ohms is not unusual but if you have any in the low K ohms then you'll probably have issues. OL means open line or basically beyond the measuring range of that setting

 

[03LB7 09LMM]

What range are you using? Normally you start with the lowest range and increase it to see if you get anything. Resistance im the M ohms is not unusual but if you have any in the low K ohms then you'll probably have issues. OL means open line or basically beyond the measuring range of that setting

i used a different meter this time and the injectors all come out to 0.6 and the ground check it zeros out

 

[03LB7 09LMM]

What range are you using? Normally you start with the lowest range and increase it to see if you get anything. Resistance im the M ohms is not unusual but if you have any in the low K ohms then you'll probably have issues. OL means open line or basically beyond the measuring range of that setting

when i put the cover back on and have it running if i push the cover down to put the bolts in it it will shock the piss out of me and at the startup of the truck it sounds like a gas motor with a plug wire off just arching to the valve cover itll do that a few times then throw itself into limp mode im wondering if it is possible for an injector to be too tall or not have the same clearances as a oem or whats the chances of an injector not being seated all the way in the cup?

 

[2004LB7]

I've never measured the clearance above the injectors to the valve cover but I'd think that something would have to be very wrong for them to make contact. Maybe the lower cover gasket has been replaced with silicone and double crush washers are installed in the bottom of the injector bore?

Can you put something thin like tape or paper over the injector or on the underside of the cover and see if the injector makes contact and leaves a mark?

 

[darkness]

This is on the lmm yes?

 

[2004LB7]

The OP put it under LB7 hard parts so...

 

[DAVe3283]

Can you post a photo of the injectors, especially the solenoids at the top?

I agree, it sounds like something is very wrong for them to be that close to the valve covers. Does the lower valve cover have the rubber+metal bushings that prevents it from getting compressed too much by the bolts?

I suppose double copper crush washers under the injectors could move them up, but I didn't think they were that close to touching that it would cause this problem. Other problems, sure.

Sent from my FlashScan V2 using Tapatalk

 

[03LB7 09LMM]

Can you post a photo of the injectors, especially the solenoids at the top?

I agree, it sounds like something is very wrong for them to be that close to the valve covers. Does the lower valve cover have the rubber+metal bushings that prevents it from getting compressed too much by the bolts?

I suppose double copper crush washers under the injectors could move them up, but I didn't think they were that close to touching that it would cause this problem. Other problems, sure.

Sent from my FlashScan V2 using Tapata

i can tomorrow I know for a fact that 3 of the 4 on the driver side aren’t stock’s because they do not have the little plastic divider on top of the solenoid it’s just smooth with the 2 copper studs

 

[03LB7 09LMM]

See how the top of the others aren’t divided like the other one

 

[2004LB7]

Are they taller?

 

[03LB7 09LMM]

Are they taller?

I took a piece of straight bar and laid across the tops of all 4 and they are all the same height

 

[darkness]

The OP put it under LB7 hard parts so...

I didn’t see that . All this upper valve cover removing had me phased lol.

when i put the cover back on and have it running if i push the cover down to put the bolts in it it will shock the piss out of me and at the startup of the truck it sounds like a gas motor with a plug wire off just arching to the valve cover itll do that a few times then throw itself into limp mode im wondering if it is possible for an injector to be too tall or not have the same clearances as a oem or whats the chances of an injector not being seated all the way in the cup?

If you’re getting shocked when you push on the valve cover to bolt it down, seems the problem is at the valve cover. Bolt it down and check both harnesses to the cover. You should never get any resistance between the pin and the cover. And if you can hear it arcing there should be a burn spot somewhere.