Hey guys

My broyhers 2001 24 valve 6 speed started running funny today! on his way to work the truck was loosing power and the cruise control came on out of no where! everytime he would hit the fuel it would want to die! it just had a new lift and injection pump put on it about a year ago! any thoughts on where to start?
Thanks
Eric

 

Checking for codes that have been set would be the first step. You can do the key on, key off trick to get them to display on the odometer, but better than that would be to get a code reader, or find someone nearby who has a Smarty.

Also check the fuel pressure at the inlet to the injection pump.

I have no idea on the cruise control issue--that's a strange one.

 

codes, fuel filter as mentioned.

The codes will narrow it down for you.

The CC thing is odd, could point to an ECM issue.

 

Ok!
I took the truck for a ride and as you are riding down the road you will be at 2100 rpm then it will just drop to a idle and you cant rev it up! the temp. guage goes all the way up to hot but the truck is not running hot at all. and it has no power! I pulled some codes doing the key trick!

P1488, P0606, P0342, P0112, P0217, P0117, P1295, P0122
After looking at the codes I thought it might be a TPS sensor! but the code that gets me is the P0217 code that is Decreased Performace due to engine overheat condition. So i Was thinking it might be the Temop Sensor going bad?
What do you guys think? I really Dont just want to start throughing Parts at it!
Thanks for the help!
Eric

 

I think you may be looking at an ECM issue. The majority of those codes have to do with sensor voltages being too low and you have an ECM code there as well:

P0112 - Intake Air Temp Sensor voltage too low
P0117 - Engine Coolant Temp Sensor voltage too low
P0122 - Accelerator Pedal Position Sensor voltage too low
P0217 - Engine overheat
P0342 - Camshaft Position Sensor voltage too low
P0606 - ECM failure
P1295 - Accelerator Pedal Position Sensor supply voltage too low
P1488 - 5V supply voltage too low

If the 5V supply voltage is off, it will throw off all of the sensor that use that supply for readings. The fact that you have the engine overheat code is probably due to the bad reading from the ECT sensor that made the truck think it was overheated.

May want to start with checking to see what voltage you are getting on the 5V supply circuit from the ECM.

 

I would start by making darn sure you battery connections are real clean ,and I mean remove battery posts and clean them .these trucks will do all kinds of weird stuff. then see if you get the codes and problem. if it comes back look over all the wiring for corroded connections ,after that try and locate a loner ECM to confirm ECM fault

 

Just another thought, did he do any work under the hood before this started? I've seen an instance where a sensor was plugged in wrong which caused some issues with the all of the other circuits on that same supply, although this usually caused an immediate issue since the supply was wrong as soon as you turned the key.

Is the problem intermittent? Or is there a specific action you can take that causes it to happen?

 

The Problem is all the time! He drove it home last night and it stoped messing up for 15 mins then it started again! Come on guys dont wish bad luck on me with the ecm!!!! Where can i find the 5 volt supply from the ecm? What color wire? what plug?

 

On the ECM, there are two different 5V supplies.

Pin #3 - Violet/White - this is the 5V supply that goes to the Camshaft Position Sensor

Pin #10 - Orange - the 5V supply used for the MAP and Oil Pressure Sensors

The APPS supply is separate on Pin 31 - Dark Blue/White, but I'm not sure what the normal voltage is.

The power for the ECM comes through Fuse #3 in the PDC and enters the ECM on Pins #48 (Red/White) and #50 (Red/White)

 

well tested the sensors and all the 5 volt feeds to them when i tested the ect feed and it had 5 volts! then tested the tps it had 5 volts! but i keep getting ecm codes! took all battery terminals off cleaned them real good and reinstalled them still the same thing! couple questions! 1. can i swap a ecm from another truck to see if it fixes the problem? 2. Do the trucks have to be the same year and same trans? does the key have to be programed to the ecm? does anyone know where to get a good ecm?

 

you can use a different ecm I have used a SO 5spd 01 ecm in a HO 6spd 01 ecm and it worked fine have not tried an auto ecm but it should work being the pcm controls the trans

 

I might suggest you check the wires going to the engine sensors especially down by the AC compressor lines. If you do a search on here they have been known to rub through causing an intermittent short. Failing that I would throw a Timbo APPS ($160-$170) at it, if it's not the APPS it soon would be anyway.

 

ok! I am a little confused! the ecm is located on the fire wall behind the air filter housing right? or is that the pcm? whatever it is, what is the one on the side of the motor called? the code reader says its a ecm fault. what one is the ecm that the code reader is talking about?

 

ECM- On the drivers side of the engine.
PCM - Passenger side firewall.

I'd also check the wiring harness towards the ECM and the plug.

HTH

AlpineRAM