Engine idling to high

[Weldrup33]

Hi this is my first post on this site so please bare with me 

 

I have a 2002 Dodge Ram Cummins 1 ton 6 speed manual 

it idles at 1000-1200 rpm with the engine hot or cold 

 

the only mods are a banks big hoss tuner and banks air intake 

 

I just replaced all six injectors, the lift pump, the cam sensor 

 

i've also checked the apps sensor with a multi meter and a scan tool the truck is not showing any codes other than a faulty air intake heater relay 

I'm not sure what to try next 

 

 

[Mopar1973Man]

5 minutes ago, Weldrup33 said:

I just replaced all six injectors, the lift pump, the cam sensor 

 

When you installed the injectors did you tight the hold down caps first of the crossover tubes first? You are suppose to snug the crossovers first to ensure a good seal of the crossover tubes before tightening and locking the injector in place. 

 

7 minutes ago, Weldrup33 said:

it idles at 1000-1200 rpm with the engine hot or cold

 

ECM idle software is controlled by coolant temperature so when you say hot or cold. What is the hot temperature? The colder the coolant temperature the higher the idle will be.

[Weldrup33]

I tighten the crossover tubes first then the injectors but this problem was happening before I changed them

operating temp driving is 89 degrees Celsius is what my scanner is saying

[Mopar1973Man]

Did you mess with the APPS sensor doing any kind of voltage adjustments? If you have, you are going to have to re-do it and make sure the voltage is below the tag voltage. 

 

 

 

Edited April 2, 2017 by Mopar1973Man

[Weldrup33]

Yep I set the apps sensor below tag limit I even unplugged it to see it would run off the soft wear in the computer and a reset of the apps but there's no change 

[Mopar1973Man]

Ok if you unplugged the APPS sensor and still idling high I have to say there is a ECM issue then. Do you have a friend or someone you can trade ECM's with by chance? Something about the ECM thinking the RPM is too low and it feeding excessive idle throttle. 

 

Another idle is do the Blue Chip hot wire test and see if the VP44 will idle normally without the ECM attached if so this proves the ECM is the problem. If it's still idling high then it would be VP44 issue.

[Weldrup33]

How do I do a blue chip hot wire test?

what trucks would have the same ecm as mine

[CumminsTech]

I know it says it's for a no start case but the procedure is still the same checking the wires on the VP plug.

 

HOT WIRE TEST - THE "FOR SURE TEST" TO DETERMINE IF THE VP44 IS WHY THE ENGINE WON'T START

It is very rare, but possible, for a problem with the wiring harness or the CAN Bus wires to prevent the engine from starting, so if you want to be 100% sure it IS the Injection Pump causing the no start, follow the following directions exactly, to be sure of not damaging a possibly good pump. This test POSITIVELY eliminates the possibility of overlooking an electrical problem caused by other components that could affect the start or run function of the VP44, as long as you have verified fuel delivery to the Injection Pump. Remove the electrical plug at the back of the Injection Pump and hot wire the pins on the pump as follows. Get two wires long enough to reach from the battery to the VP44. Install an INSULATED ¼ inch female spade connector onto one end of each wire.Use a set of dykes and cut the flat part and one of the "curls" away from each spade connector to leave one "curl" , which will be about the right size to go over the pin on the pump. Connect one INSULATED connector to pin 7 on the pump, which is the pin on the BOTTOM row of the socket on the Injection Pump, closest to the engine, to preferably fused (10 amp is fine) positive battery power in the PDC (Fuse box under the hood), or directly to the positive battery terminal if you like to take risks!.

Connect the other INSULATED connector to the pin directly above the previous connection, the top row of pins, the one closest to the engine, and attach the other end to battery ground. Now try to start the engine and if it doesn’t start, you absolutely positively 100% need an Injection Pump! If the engine starts this way but NOT with the big plug installed on the pump, you know there is something in the harness or CAN bus wiring to the ECM telling or causing the engine to not start. Call me for help if this is the case.

 

 

Here is a link to the blue chip diagnostics page

https://www.bluechipdiesel.com/vp44_diagnostics.html

Here is a pic of the VP plug and the wires coming from it in the engine harness with there  functions

I may have missed but how are you checking for dtc's? I'm wondering because if it is throwing a p1283 which is vp pump controller detects continuous voltage at idle select pin 34 on engine harness or pump controller detects open or short to ground on idle select pin 34 on engine harness the symptoms are that it will only idle or idle will be stuck at a slightly higher set speed. This happens when communication is lost between the vp44 pump controller and ecm.

Edited April 2, 2017 by CumminsTech

[Weldrup33]

my truck is not throwing any codes at all only if I unplug something like the apps then it will other than the high idle and a very slight sputter when I rev it up  alittle in neutral say 2000 rpm it runs great 

 

I will try a hot wire to the vp pump and see what results I get and let you guys know 

[Weldrup33]

Cummins tech 

your discripion says that pin 7 is on the bottom and your pic shows it on top can you clarify

please 

[CumminsTech]

It's all in how you hold the plug to look at it. Go by the picture if you are looking at the plug in your hand it should have the arch like a smiley face it's the lower right pin on the plug is #7. pin 7 on the pump, which is the pin on the BOTTOM row of the socket on the Injection Pump, closest to the engine,

[Weldrup33]

Ok now I see it 

my truck runs with the hot wire bypass to the vp44 pump but it runs rough and idles at 900 rpm 

[Mopar1973Man]

Something is wonky... It's still idling high so I'm going to wonder if possibly the VP44 key is sheared? I'm wondering if the timing of the shaft is bumped advanced and kicking the idle up from that. Being the ECM and all sensors is out of the picture with the hot wire setup.

 

I'm also wondering about the 6 new injectors it could be part of the issue. What kind of injectors did you get? Were they pop tested before shipping to you? 

[Weldrup33]

The injectors I put in are Bosch 275 hp 

i'm wondering if it's because the engine was cold when I tried it  maybe I should warm it up first 

[CumminsTech]

I agree there is something going on in the fuel system seeing as the pump is isolated from the ecm. I don't know how confident I am about the key being sheared but I guess you can take off the breather from the gear cover and see in with a light and mirror probably have to take the nut off the pump shaft to see for sure but you might be able to without. I think I'd lean more toward injectors if they are not from a reputable builder. Could be ones fueling more than another like mike asked do we know for sure if they were pop tested and flow matched as a set.

I see Bosch rvs soo never mind on the reputable builder part. 

Edited April 3, 2017 by CumminsTech

[Weldrup33]

I'll have to check the pump shaft 

should the engine run good when you run the hot wire mine runs rough when I do that

[Mopar1973Man]

Should idle smoothly. The VP44 electronics have enough there to make it idle normally or high idle without a ECM even hooked up. If its idling rough then its either injectors or something up with the VP44. 

 

I do know that bad injectors can produce high idle and random misfire issues. My previous +50HP injectors were rather high idling and randomly misfire with a rough idle when it did misfire.