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Cm870 throttle issue - Printable Version

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Cm870 throttle issue - Hambone - 03-05-2019

Had the truck tuned and removed goverment BS, Been having boost issues so i have replaced cac,turbo accuator,exhaust manifold gasket ,turbo air supply control and boost sensor... Truck is running ok but if you idle truck up to 1500rpm it'll sit there a minute then idle down. No codes but if you put your foot down and hold it to 2000rpm truck will flucuate between 2000 and 1800,let off the pedal a little say 1900/1950 doesn't seem to fluctuate.... no codes but do y'all think it may be accelerator pedal ?


RE: Cm870 throttle issue - Rawze - 03-05-2019

Lots of bad programming running around for those enignes ...

who did the de-mandate?

does it have a boost/pyro gauge? -- How much boost is it making under hard pulls?

If you don't have those gauges, I would suggest installing them ASAP so you can monitor what has been done + help you save fuel/monitor things properly if you care about your engine and its longevity.





RE: Cm870 throttle issue - Hambone - 03-05-2019

Been working with Mommaburt last couple weeks. Get one thing resolved and another pops up,truck was only boosting to 28 on cruise and pedal,however it would boost to 38 on other occasions then back down to 28. Would run a constant 700+ on pyro with empty skateboard on flat ground and hit 900 on small pulls. Just replaced turbo air control valve and boosted to 32 now and 300 on pyro. Was idling the truck up to check for leaks and such when it started to kick idle off


RE: Cm870 throttle issue - Hambone - 03-05-2019

Well just had 128:F03 Sid 027p pop up


RE: Cm870 throttle issue - Chamberpains - 03-05-2019

What kind of truck and year? I don't know the exact code you have but im pretty sure it has to do with the VGT actuator control module. It has a "P" at the end so it is a Past code or Inactive. If it had an "A" it would be active or ongoing.

You said you replaced the turbo air control valve. Is it the red box under the air compressor on the drivers side or did you replace the air actuator on the turbo? The code could be from the failing control module or if you left the key on when you unplugged the control module. More info is needed. But it sounds like your getting things moving in the right direction.

There are a couple really simple and common problems why high idle will kick off. Speed sensor problems, clutch sensor problems cruise control switch problems, sometimes brake switch problems, neutral switch problems, sometimes reverse switch. It usually, but not always, has something to do with the truck thinking your moving or going to put it in gear.

Again more info on truck and everything you got going on is needed.


RE: Cm870 throttle issue - Rawze - 03-05-2019

(03-05-2019 )Hambone Wrote:  Been working with Mommaburt last couple weeks. Get one thing resolved and another pops up,truck was only boosting to 28 on cruise and pedal,however it would boost to 38 on other occasions then back down to 28. Would run a constant 700+ on pyro with empty skateboard on flat ground and hit 900 on small pulls. Just replaced turbo air control valve and boosted to 32 now and 300 on pyro. Was idling the truck up to check for leaks and such when it started to kick idle off

Mommaburt does good programming.

sounds like arm movement on turbo may be sticking?.


RE: Cm870 throttle issue - Hambone - 03-05-2019

Its an 07 international 9900i. Ive already replaced clutch pedal switch and had a new 13 speed transmission,clutch,throw our bearing,tailshaft etc installed 15000 miles ago. Yes it is the red box on drivers side but also replaced the actuator on the turbo, the actuator moves and the turbo freely travels.Idled the truck up again and when it kicks out registers 15mph real quick. The speed sensor is new but that doesn't mean much.I don't idle the truck having an apu but still want to figure it out.. I don't like not knowing. Appreciate the knowledge and help.also the code would come up active for a short time then go passive,but it has come up before any work was done.


RE: Cm870 throttle issue - Unilevers - 03-05-2019

you say it blips 15mph when stationary? That means your getting a pulse on the speedo wiring - Check for rubbing and verify the twisted pair is still intact for the speedo wiring. That is why your cruise is cutting out.


RE: Cm870 throttle issue - Chamberpains - 03-06-2019

Or if you have the old speedo sensor that can be adjusted, it'll look like a very large threaded stud, it needs to be installed and adjusted correctly. Take it out and clean the tip of it. Make sure its perfectly clean this goes for all speedo sensors. Then check your speedo pick up ring for chips and garbage in the teeth. Yes, this will require you to jam your head in a very awkward place with a flashlight and turn the tail shaft while you look in. If all is good, reinstall the speedo sensor all the way in till it bottles out lightly. Then back it off half a turn and lock the jam nut down. Check all your wiring like Uni said. Its very common for OEM to twist the wires or zip tie them to tight to something and have them ground out and touch each other.

Also, its very common for this problem to only happen when the oil is cold. My 9400i stops fluttering the speedo on high idle once the truck warm up. So I've never dug real deep in to resolving that issue on mine because its not a problem. I don't need high idle for anything.