Loss of RP

dodgeram082500

dodgeram082500

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May 4, 2009
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208
Had a question for some of the 4th gen guys. I have a 2010 manual bone stock other than an airdog. a few weeks ago I noticed that the rp was acting odd. by odd I mean after you first start it if you immediately take it on the road and beat on it the rail pressure is fine, but if you continue to beat on it cold or warm then the rp will drop (not only at wot but cruising too). Also another thing is if you just idle the truck for a while and then get it on the highway and beat on it it will keep up for a minute ,but then start doing the same thing. I've seen my RP hit as low as 6ksi cruising.

A couple of important facts 1. the P0089 Low RP code has come on a couple of times and also a #6 injector misfire. 2. this happen when the mini maxx is on any setting. All defuels are off on the minimax. Its to repeatable to be electrical.... This thing acts Like the ECM "thinks its supposed to do this". We have even tried to force it to make pressure with custom tuning (bumping the RP maps) ,but it doesnt matter if its on stock, H&S, or MCC tuning it does the same thing.

Here are what I've tried so far:
1. check FRV by plugging it.
2. change the fuel rail with the one on my drag truck
3. change cp3 with the one on my drag truck
4. taking the airdog out of the link and used the working stock system (Airdog put out 12 PSI and stock pump put our 7-8)
5. changed all fuel filters
6. Have check/retorqed all fittings from the rail to the head
Still does the same thing???

Any help?

Thanks in advance
 
I know you said you put the mini-maxx at stock but have you tried removing the programmer completely? You have already tried the three things I would have started with (Rail Pressure Sensor as I was assuming this was changed when you switched rails?, CP3, and stock tune).

Other cause might be a bad ECM but I would start with putting the truck back to stock tune and physically removing the Mini-Maxx.

Also if you didn't change the fuel rail pressure sensor when you switched rails that is the very first thing I would do.
 
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Yes sir, the mm was completely removed. And forgot to add the fact the rp sensor has been changed. Does anyone know what is involved in switching from the cm2200 ecm to the cm2100?
 
How often does it trip the misfire code? Swap #6 and #1 and see if the code follows.

Throw a scan tool on it when its acting up and do a commanded high rail pressure test, that would let you know all is good and no internal leaks.

At that point you will at least know what your looking for, sensor intermediately going bad are faulty ecm.

Hope this helps!
 
dodgeram082500 said:
Yes sir, the mm was completely removed. And forgot to add the fact the rp sensor has been changed. Does anyone know what is involved in switching from the cm2200 ecm to the cm2100?
Click to expand...

cm2100 has no TCM in it, but I see you are manual so it might work. I think the PCM would freak out seeing a different ECM though.

Tobin
 
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Ive only seen the misfire code twice. It only happens when rp is extremely low

I know that swapping the ecm is possible, but Id like to know what sensors are interchangeable if not all. I assume it would require a bench flash for the vin
 
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Swap 6 to 1 and 1 to 6 injectors and cross tubes.
 
Has it only thrown the injector misfire code and the low rail code? Or are there other codes as well. It almost sounds like the ecm is seeing something from a sensor telling it to pull fuel to the point of almost dying. I know that seems quite generic, but it's hard to say what sensor may be causing this. Were there any other codes?
 
6kspi doesn't seem that low if you're just cruising with no trailer etc. I was watching mine yesterday and I was around 6.5-7.5kpsi doing 75 on the freeway.
 
pac_master_7 said:
Has it only thrown the injector misfire code and the low rail code? Or are there other codes as well. It almost sounds like the ecm is seeing something from a sensor telling it to pull fuel to the point of almost dying. I know that seems quite generic, but it's hard to say what sensor may be causing this. Were there any other codes?
Click to expand...

Yes, those are the only codes I have seen. I thought maybe a pinched fuel line was somewhere at first then changed all hard parts and here we are. I agree its like the ECM "thinks" it's supposed to do this.

Also after speaking with several dealerships I've been told the same story by all of them. The story is "we can't see anything your gauges dont tell you already on the CM2200 due to cummins taking they're flow measuring abilties away from the scan tool they use ability. I asked how they diagnos a problem such as this ,and I was told "we take a read of the codes, then we send a list of those codes to chrysler, after that they send us a part to put on, if that fixes it then we send it out, if not we start over again."
What that means (at least to me) is chrysler "throws" parts at it until it's fixed. If anyone know this to be false, please let me know I'm friends with the service manager and would like to educate them otherwise. Also, does any have a suggestion of a good scan tool to get me buy at least until EFI Live supports the 4th gens.

Thanks again guys,
Lucus
 
takedown95 said:
6kspi doesn't seem that low if you're just cruising with no trailer etc. I was watching mine yesterday and I was around 6.5-7.5kpsi doing 75 on the freeway.
Click to expand...

I need to update that, thats at cruising speeds (55-70) with the go pedal matted.
 
I just did a 2012 and max RP on it is 15k. Its only got 3k miles on it. Throwing some codes similar to yours. We did injectors, s400 and minimaxx. I hope these new trucks arent having cp3 problems for some reason. Modded pump going on friday. We will see
 
Edited reread your post. We tried the cp3 as well no joy. Hope yours works out. Thanks again
Also this one has 53k on the odo
 
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If you unplug the fca, rp should max out. If pressure is still low you have high fuel return from either the injector or leaky connector tubes. The ecm only controls pressure through the fca.
 
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