throttle issues

[Paul Amestoy]

Keep in fixn stuff on this suburban...thought all was well till this morning..while driving around 70 with OD... seems that I did not have throttle till about 1/2" of ped movement then full throttle... seems worse at high speed but I need to know if I can clean the throttle controller, or need to purchase new.... Can I check it first?

98 6.5 auto K2500 145K

[turbovair]

Each time my throttle sender failed it was replaced under warranty.Is your "service throttle" light on? If so, it should have stored a code. On mine, the pedal would just go dead and the truck would only idle.The last one has been in for 60,000 now with no problems.

[Turbine Doc]

Paul,

I suspect APP has gone bad, I have to hit the book for diagnostic recommendations, but in mean time try this, get above 35mph and go on cruise control if you have it, if you can add speed and reduce speed using that then I'd say with high certainty it's the APP cruise control adjusts speed thru the PCM not APP.

[Turbine Doc]

Okay Paul,

APP accelerator position codes are P0220, P0221, P0222, P0223, P0225, P0226, P0227, P0228 looks like you will need a scan tool to read the values during testing, a Snap on MT2500 will work for this, There are 3 sensors in the APP module maybe some other readers as well for sure Tech 2 if you have access to one. It is also possible to have intermittent setting of these without lighting the MIL/SES light

According to the manual most likely cause ia a loose connections on terminals in APP, several tests I can send you once you get a tool, or maybe you can borrow a APP module, if it is not APP then book says PCM is suspect.

[ 12-03-2003, 01:24 PM: Message edited by: tbogemirep ]

[Paul Amestoy]

Thanks,

I have a scan tool ( do you know anyone with a 6.5 td that doesn't smile.gif ) NO CODES... I tried the cruise and it also acts like the pedal... So I need a few things? First of all where do you purchase a manual?.... second where would you go from here

P

[rjschoolcraft]

The manuals can be purchased at the Helm, Inc. (http://www.helminc.com/helm/homepage.asp?r=seo11502) web site. These are the factory manuals and are better than Haynes or Chiltons. Hope you get it fixed.

[Scooby]

[QUOTE]Originally posted by Paul Amestoy:
[QB] Thanks,

I have a scan tool ( do you know anyone with a 6.5 td that doesn't smile.gif )

I dont have a scan tool for the OBD2 vehicles!! WHere is the best (cheapest)place to get one ??

[Turbine Doc]

Paul I'll be hitting the books again later to see if it has any recommendations, I thought for sure one of the APP codes would be present, what kind of scanner do you have, on My MT2500 I can view 2 history files, 1 in the engine data view and the other is in the transmission view which also has some engine data in it not always present in the engine data log.

I've found that some hard codes not present in the active code list are stored in the history view in either of these, have you checked in the history file for stored intermittent codes; that might give us more to go on.

Not all codes set the MIL light, when my injectors were acting up I was getting intermittent appearance in the history log of cylinder imbalance, never thought anything of it until after changeing the injectors and a performance fluke was cleared up, maybe same is happening here on yours.

[Turbine Doc]

Paul,
Any luck on this one yet I looked in the manual and found nothing in it that jumps out at you that says look here, 3 most suspect, loose/bad connections, APP module, Bad PCM, did you get a chance to pop on a scanner and look in the history to see if a code was in the history section but not illuminating the MIL light or an active code.

[Paul Amestoy]

Finally limped the beast into a decent GM dealer for diag....guess what a pump!.... Now they are stating that it is 6 months old but 14K miles so it is out of warranty.... what is the warranty on that pump anyway......I would think the pump would push some codes out...btw My code reader is a simple $ 150.00 probably can't do as much as yours


P

[Turbine Doc]

Bad Inj pump, did they expand that????

I wonder what codes they read to determine that, before condemning the pump several things to try, 6 mos old I think they are pulling a shuffle on you, does it stall or just have the lack throttle issues you reported, could be bad lift pump, PMD, optical sensor, crank sensor all external components significanlty less than a IP you can replace for a lot less than $2000, did you check fuel filters including one in tank.

I had a similar problem a while back while towing on engine filter was partially clogged and no power while towing, need to verify IP is getting proper fuel delivery.

I'd give Kennedy Diesel a call for more info on what to look at, also do you know somebody with a better scanner than you have, any shop with a Snap-On MT-2500 should be able to pull them for you of course tech 2 would be best, also ask for the specific code they pulled for verification, I'm not trying to second guess your dealer, but don't want you to pay for more than you have to.

A bad PMD does not give codes but the manual says replace pump, when all that is required is to replace the PMD $250 is avg if I remember correctly.

[Turbine Doc]

Paul found this in another post this AM you might want to give them a call if IP is truly the culprit
http://www.accuratediesel.com/