Low Boost

[cerberusiam]

Get a rial pressure gauge and check it. It is starting to sound like the rail is draining.



Still running a stock CP3? An Arson III kit may be a good investment.



Oops! I see Stage I CP3 now, my bad. From who?

 

[SShafranko]

I don't think the rail is draining but if it is it has to be do to another issue other than the CP3 not being able to keep up.



The reason i say that is because i never drained the rail with the Smarty, and i don't think it would happen with just the MP8 on 50% and stock programming.



Maybe you are right i am draining my rail and it is do to the CP3 not functioning properly? i switched the FCA a while back with another truck and no change.



It just seems like the way this truck is behaving is like the injection timing is being completely retarded for some reason. I don't even know if that's possible but thats what im thinking is happening somehow.

 

[SShafranko]

By the way that Stage 1 is really just a self mod. I modded the FCA and i also did my buddies. He has 90hp sticks with Smarty, MP8 amongst other things and his rail pressure stays around 22,000 WOT with same FCA mod.



I don't thing its that but its possible i guess. I should get a gauge though.

 

[TomJohnston]

I think it has more to do with the injection duration/pulse width being decreased or defueling as we like to call it. I do have a rail pressure gauge and the pressure actually goes up above 2300rpm when it should be going down if more fuel was being used. Have you tried to see if you can make more boost around 60-65mph in overdrive. I find at light throttle with some sort of load, towing or going up hill, I can make up to 50psi before I get to 2300 rpm then it drops (38-40psi)from defueling. I never noticed this until recently, even though I have been trying to resolve this low boost problem for more than 2 years.

 

[SShafranko]

I have noticed more boost at certain times but never even close to 40 never mind 50. Before I had this issue I boosted 42 according to edge attitude all day long with the stock turbo. Then my oil seal went on the compressor and I decided to go with an aftermarket turbo. I think I made a mistake with my choise but that's a hole other topic.



Anyway I give you credit dealing with it for that long. If I cannot find it in the next two months or so I willl return the truck to stock and get rid of it. I don't like to give up but I can't see spending all that money on aftermarket parts and then running the truck at 60% power for the next 5 years. Thanks for the help.



Sasha

 

[cerberusiam]

By the way that Stage 1 is really just a self mod. I modded the FCA and i also did my buddies. He has 90hp sticks with Smarty, MP8 amongst other things and his rail pressure stays around 22,000 WOT with same FCA mod.



I don't thing its that but its possible i guess. I should get a gauge though.

Is his an 06 or newer or ???



There are more than a few thread son the 06's defueling with Smarty about where you are talking about. I am not sure if anyone ever actually solved that issue.



Be interesting to see what your rail pressure is doing though to be sure.

 

[TCDiesel]

They are identical trucks,Same year and Mods. What's interesting is it ran good until xxx time,So My guess This has to be related to PCI somehow. I have been contacted by others that have replaced just about everything form Injectors to ECM. Some component or module is incepting this signal and contaminating it. It could be anything form coolant sensor to the IC. Hugh

 

[SShafranko]

Todd's right truck is same year 06, and almost same mods. There is something else going on and i would say Todd is right on. Something is messing with the signal to the ECM, just have to find it.



It's not the Smarty as i replaced it with a new one, and it was cutting out yesterday with just the MP8 on 50%.



If i had to guess i would say that it is something i caused indirectly probably with one of the mods i installed. I have to trace my steps back and follow all wires.

 

[cerberusiam]

Yeah, there is something in the 06+ ECU's that is NOT reacting well to some of these down loaders.



Without some pretty in-depth info and data logging its bordering on impossible to figure out exactly what is happening and how it is effecting the system as a whole.

 

[SShafranko]

I completely agree with you but on the other hand i have a specific problem which i think if i can trace it and resolve it i believe it will get me back to normal. That is my tachometer. I mentioned this before but right now it seems to be my only light at the end of a very dark and long tunnel.



At idle my truck stays at a costant 750 according to a scanner. The actual needle if you watch it long enough will sit at 600, then inatantly bounce to 500, then in thirty seconds or so bounce to 650 and so on. I also noticed that when i am at WOT at 3000 rpm the needle just violently jumps to 3300 or so.



This has been happening i believe since my problem started from what i can remember. When i installed the new ECM, as soon as i started the truck i had a feeling it was not the end of my story because the needle showed the idle to be at 550 when clearly the engine was at around 750.



Thank you for clearing up the pulsating fuel pump issue. Another one down.



I can't give up my heart won't let me but my mind is trying to.

 

[cerberusiam]

Maybe crank position sensor is throwing some weird signals and causing it to think its over revving? Possibly a scuffed wire on that or an injector circuit is introducing noise that is causing issues?



The AC compressor sense wire rubbing threw all kind sof weird behaviour into the trucks that it happened on. Grounding a TST to the battery instead of chassis ground totally fouled things up.



Serioudly wondering about your inverter and how it is wired in.



I am think out loud here of possibilities.

 

[SShafranko]

Thanks for all your good ideas.



The inverter sits under the passenger seat and i ran four 2 gauge wires to the passenger side battery with a fuse. Two ground wires and two hot. I did exactly what the instructions called for. I also have a remote to turn it on and off. I believe that i also hooked up a small maybe 16 gauge wire as a ground from the unit to the floor.



I checked the A/C wire and it is fine. I have not done anything with the CPS although i did move the wires around and check them for damage finding nothing.



Maybe its time to change the CPS anyway. Does it have any effect on the Tachometer? Same circuit?

 

[cerberusiam]

Thats the thing about the tach, its like the rest of the gauges. A fake. The ECU reads the CPS signal and makes decision based on its value, fire injectors, set timing, etc. The ECU then takes this signal and changes it to whatever, sends it to the cluster controller that then tells the tach what to do with the needle.



Since a diagnostic tool is reading a solid 750 rpm's and the tach is off one would assume the cluster controller is probably at fault as they are know for this exact issue. However, the ECU is outputting that signal the daig tools are reading and it contains all kinds of smoothing and failsafe algorithms to make sure the operator NEVER knows there are little fluctuations or problems until the truck just dies.



It is entirely possible the ECU is seeing issues that are never being propogated to the instruments or data port, further, the fluctuations could be so subtle that the smoothing algorthms are preventing the ECU from setting a CEL that indicates a problem but is affecting its operation because it is really a DUMB computer.



Add to that the 06's were first to switch to the CANBUS communication protocols for intra-computer communications and have been just a little on the hinky side at times.



I am beginning to think its a bad flux capacitor on the EPS manifold. :-laf:-laf

 

[SShafranko]

I am beginning to think its a bad flux capacitor on the EPS manifold. :-laf:-laf

Thats the only thing i haven't checked yet. Let me do that now.

 

[cerberusiam]

Thats the only thing i haven't checked yet. Let me do that now.

Had another guy on a different forum that was facing a lot of the same issues as you, replaced the ECU and still no joy.



Found out he had a bad battery even though they had both been replaced. Did you replace both batteries with the same type\size at the same time?



Just a thought.

 

[SShafranko]

I replaced both at the same time. Put in Optima reds. I'll check them bothh tomorrow. I have a list of things to check tomorrow morning. Thanks C.

 

[Kday]

Sorry, I don't have any answers for you just more questions. If I roll onto the throttle it'll boost up to 40 and accelerate great and when I give that last bit of throttle to WOT it falls off to low thirties with slightly increasing EGT. So I don't have the same symptoms as you, mine might just be wastegate related which I don't think as mine is disabled or defueling somehow. Just checking back in and will let you know if I find a fix that may help out you or someone else.

 

[TCDiesel]

Kday, Wastegate or Maybe Map sensor. Also remove the Quad see what happens.

 

[Kday]

Thanks TCwest, the Quad is only the rail psi gauge no module/programmer through it only Smarty and Striker. So the MAP sensor might do this? Also did it with the Edge Juice at the end of it's use. Drove it today and it acts like it's still fueling (EGT increase but boost loss). Thanks for the input.

 

[SShafranko]

Anyone know what symptoms would be associated with a bad valve cover gasket? I am refering to the injector wiring. I guess it would be different depending on the extent of the damage but any general signs?