Hi all, so I am new to the forum and I hope I am in the right place, maybe you can help.
I have a 2008 Ram 1500 w/ 5.7 Hemi and 145000 miles.
I have popped two codes:
P308- cylinder 8 misfire
P208- cylinder 8 injector circut open
(P308 hystorical) ??

Symptoms include rough idle, white smoke coming from exhaust with heavy fuel odor and something leaking from area of 8 cylinder when injector is plugged in and engine running. I do not have coolant in my oil and it doesn't seem like I have a blown head gasket (tho I could certainly be wrong)
While driving seems to be rough and tough to accelerate, wants to stall out when coming to a stop, and fuel consumption is really heavy.

What I have done so far is replaced cylinder 8 coil pack and injector, plus pulled head cover to check for broken valve spring.
I have also checked continuity from ecm to injector and to the coil pack with what seems to be no break in the wire.
I did a quick compression test on cylinder 8 with 130 psi and radiator compression test which holds at 15-16 psi and I also pulled spark plug from #8 and seemed to be dry

For some reason it seems like I am dumping massive amounts of fuel or not burning it off????????????
I am at a loss!!!!
I still have same problem and any help would be much appreciated!
Thank you

 

Is the control side of the injector circuit grounded out somewhere?

 

Just cut the ground wire for the injector and coil and wire straight to the ecm and also check the 12+ to ground to make sure your getting power

 

Hey thanks you, I will try those today!!
Thanks again!

 

Ok, so what I have so far is:
On my injector connector, (not the injector itself), I have 12.3 v on BN/lb wire and 11.9 v on BN/wt wire with power on and no engine run.
Am I correct in that I am getting power to the injector all the time?
I haven't traced the wire loom yet which is what is next I guess.

I appreciate your time and patience as I am not much a a mechanic when it comes to vehicle electrical problems!!
Thanks again,

 

Injectors should always have power, yes. PCM controls ground side of the circuit to fire them. With the injector unhooked, key on, there should be NO continuity to ground on the control side of the connector.

 

Hello Justin0943,

When you say wire direct to ecm, can you elaborate more??
When it comes to vehicle electrical I am not very good.

BTW, Ok, so what I have so far is:
On my injector connector, (not the injector itself), I have 12.3 v on BN/lb wire and 11.9 v on BN/wt wire with power on and no engine run.
Am I correct in that I am getting power to the injector all the time?
I haven't traced the wire loom yet which is what is next I guess.

I appreciate your time and patience as I am not much a a mechanic when it comes to vehicle electrical problems!!
Thanks again

 

Hello HeyYou,

I appreciate the response, so what I have is with injector #8 unhooked, key in on, engine not running I have 12.3 v on BN/lb wire (is this the control side) and 11.9 v on BN/wt wire (is this the constant 12v power)? I checked all injectors and only get 11.9v on BN/wt wire ( which I am taking as the constant power).

Does this mean I have a bad PCM?
Thanks for your help!!!!

 

Hey all,

So for everyone helping me with my Ram here is an update! I sure do appreciate all the help.

What I have found is with the key in off position I have constant 12.1 volts to all my injectors. On #8 I have constant power plus 12.2 volts on what I believe is the control side from PCM.
I have traced control wire through loom back to PCM #1 connector at PCM with no visible breaks or grounding. So I am getting 12.2 volts on control side and constant 12.1 volts on feed side whether the key is in on or off position on #8 injector connector. Does this mean I have a bad PCM computer or is there something else I can check.

Again I so appreciate the help and time!!
Thanks again

 

Is that with the injector connected? If not, and there isn't a short somewhere in the wire between the injector, and pcm, that's a bad pcm.