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Discussion Starter #1
Im having what seems like a misfire around 2000 rpm, the truck idles fine, but seems to have lost a little power on the top end. I just had the hrvp replaced for the 2nd time in 10k, injectors are new, fass LP, fuel pressure is [email protected] idle and never drops below 12.5. the symptom is worst with adrenaline turned up, but does happen when it is off, just less severe. The reason i suspect the MAP is becuase i had 0237 come up once, but it hasnt come back since i cleared it so maybe not? And i do have a banks brake and i have heard they can cause the IAT to gum up and go bad. Maybe? No? :confused013:
 

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Problem with the pickup in the tank?
 

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Discussion Starter #3
i thought that myself but kind of ruled it out because if i peg it to the floor it will go all the way to the red line smooth as silk. it is only when it is under a mild load, like going up a hill empty at about 1800-2100RPM that it will start to hesitate and if i dont get out of the throttle it will surge and jerk, almost violently sometimes.
 

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I have the exact same problem ! Also my tachometer is jumping a little when it missfires.
I changed the crank sensor with no improvement.
 

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How many miles are on the truck? I was going to suggest having the crank sensor tested, also I could be wrong, but I think there might be a cam sensor on the 01 and 02's. Might wanna look into that. Have you pulled the codes? Maybe an internal failure with the VP timing?
 

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Discussion Starter #6
the truck has 75,000 mi. on it, the only code i get consistantly is 0500(no vehicle speed sensor) I had the hrvp and injectors done about 6k ago and it just threw a p1691 at me last week so i took it to shop and they put in a new hrvp, and said the hesitation/misfire/surge issue actually got worse. So they put in a third hrvp, and still no improvement. So it isnt anything to do with that, and they tested the rest of the fuel delivery system and all is good. I just cant help but think it is a sensor going bad, but i dont know much about that kind of stuff, and i dont want to have to spend the money replacing things that are not broken. this seems to be a needle in the haystack kind of thing. im definetly going to look into more about the different sensors and stuff, and just hope it is not anything internal.
 

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I know in gas applications and some diesel, that VSS can reak all kinds of havoc. When mine went, it turned on a few lights in the dash made the cruise inop, and caused some dead pedal issues as well.
 

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Im having what seems like a misfire around 2000 rpm, the truck idles fine, but seems to have lost a little power on the top end. I just had the hrvp replaced for the 2nd time in 10k, injectors are new, fass LP, fuel pressure is [email protected] idle and never drops below 12.5. the symptom is worst with adrenaline turned up, but does happen when it is off, just less severe. The reason i suspect the MAP is becuase i had 0237 come up once, but it hasnt come back since i cleared it so maybe not? And i do have a banks brake and i have heard they can cause the IAT to gum up and go bad. Maybe? No? :confused013:
As for checking the status of the MAP and IAT I would find a Scanner that reads live data and check the operation fo the 2 sensors... I know ScanGauge II will check the IAT but the MAP sensor is way off in the ScanGauge...

But most all mis-fires are either air leak related, lift pump related, VP44 related, or injector related...

so I would do a lift pump diagnostic and pay attention to step 13b...
Lift Pump Diagnostics

Other than that I would look at having the injectors pop tested...
 

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Discussion Starter #9
thanks for all the help, as soon as the shop opens monday i am going to see what they have and havent tested so far, and suggest some of these ideas to them if they havent already tried them. hopefully we can make this problem go away without digging too much deeper. thanks again
 

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Today i took off the contact to the MAP sensor and sprayed it with wd40. I also sprayed some contacts that is between the TST powermax and the MAP sensor.

It seems like my problem is gone ! Truck runs fine now.:party018:
 

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mine does the exact same thing. replaced the IAT still does it. I get p0500 all the time as well.gonna replace the injectors soon.:confused013:
 

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Discussion Starter #12
well i talked to the shop this afternoon and they tested the lift pump and everything is good. there is no air in the fuel and pressure is good. the hrvp is brand new, but they are going to order one from different manufacturer since the last two from the current company apperently didnt work. they replaced the overflow valve, and they are also going to replace the VSS, which is causing the 0500 to come up. I told them about the cleaning of the MAP/IAT sensors, it sounds like they already tested them and they were functioning properly, but they are going to clean them tomorrow just to be sure, hopefully that works. They have done many test drives and no new codes, and no new symptoms, they had it on the dyno-408HP/855TQ, w/o the smarty, and all is well except it hesitates/misfires/surges at around 2000RPM. my truck has a cancer that no one can find!!! PLEASE-:help1:
 

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bump.. having some of the same problems,
 

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:ditto: only mine is boggy at 3/4 - full throttle from 2500 - 2700rpm. very sluggish on the top end. fuel filter?:confused013:
 

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:ditto: only mine is boggy at 3/4 - full throttle from 2500 - 2700rpm. very sluggish on the top end. fuel filter?:confused013:
Fuel pressure is what??? :confused013:

If you got at least 10 PSI or more your fine...
http://mopar.cumminsforum.com/tips/cummins/2ndgen24v/lift-pump-diag/fuel-pressure-specs.jpg
 

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Referring to the original post. Get the shop to monitor the RPM signals in the scanner. There will be PID's for four different RPM readings. They need to compare these reads when the issue is occurring. Also monitor the APPS while driving and see if there are any voltage spikes. One last though, never rule out air without checking for it first. Air can do some funny things that never make much sense.
 

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Discussion Starter #17
Referring to the original post. Get the shop to monitor the RPM signals in the scanner. There will be PID's for four different RPM readings. They need to compare these reads when the issue is occurring. Also monitor the APPS while driving and see if there are any voltage spikes. One last though, never rule out air without checking for it first. Air can do some funny things that never make much sense.
I will inquire about the rpm signals tomorrow. But to monitor the APPS can i just use the TPS% guage on my adrenaline pulse moniter? If so, then the APPS is fine because the pulse monitor never spikes. And i have never had any codes related to APPS or TPS.
 

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Discussion Starter #18
Also i wanted to thank everyone again for all the good info. Ive learned more here in the last 2 weeks than i have in the last 2 years ive had the truck. So far there are still no leads on my trucks illness, so keep the ideas coming i really appreciate it.
 

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When my truck had the exact same problem as you describe, the electric plug wouldn´t really sit tight on my Map sensor it was a little loose so i took it off, sprayed it with wd40 and put a little glue on the outside of the plug to hold it i place.
I also messed with a cable that goes to the injection pump and has something to do with the TST powermax box.
I don´t know which fixed the problem but its gone now.
 

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i bought a fuel pressure gauge but i didn't get a reading. i wonder if it is a gas engine gauge or will a gas gauge work? the pamphlet said no. the vendor who sold it to me said no worries.... any thoughts?
 
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