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94 Blazer 6.5 problem

A

Acesneights1

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Hey a buddy of mine has the above mentioned truck. I have not seen the truck in person yet but am going to look at it hopefully tommorow or wed. Here is what he says is wrong.

The symptoms were it would start up and run to redline(but I would shut it off before that happened). Prior to that it would buck on the highway: as if the throttle were an on/off switch. You either had a perfect idle or 100% full boost acceleration> nothing in between. It wouldn't be as bad some days especially if you were travelling under 35mph, but on the highway it was always there. And most days it was always there

He said two shops told him the IP. I know the IP can do that but can the PMD also do it ? I was gonna plug in the one I bought from Ferm and see what happens. No idea if he has codes yet.
He hates the truck so I may see if he wants to sell it(the final straw in my divorce...)
 
Yes, PMD can also cause that symptom; coupled with the bucking on the highway, it is quite likely, actually. Try a used PMD - any other PMD, just long enough to start it. That'll tell ya.

That being said, broken armature can also cause the runaway thing, but it's a heck of a lot more expensive if you're wrong. :D

Either way, if he sells it to ya cheap, you're a short repair away from a good running 6.5 Blazer!

(I wonder if you can sleep in the back of that thing?)):h):h
 
Of course you know these diesels are worse than booze or drugs. It really is an additction and a costly one....
Hi, my name is Kenny and I'm a diesel addict..
 
Aces,

How about the voltage check of the resisters in the APPS with the key in run, and the multimeter looking for smooth voltage transistion when slowly putting the throttle down?
 
Likely the PMD is going south.

It could be an IP issue but as easy as it is to plug in a good PMD I would give that a go right quick first.

A bad PMD will cause a full throttle condition.

This is why the fuel shutoff on the IP. The ECM will detect an overspeed and shut the thing down.

The shut off solenoid is not the normal means to shut the thing off. It does shut down when the key is off but is designed to be there so the ECM can shut the engine off in case there is an overspeed beyond what the governor circuits can normally handle.


MGW
 
Got the PMD and GMTDScan so I'll be over there today hopefully. The APPS is a good idea as well. I thought that with my 94 but it feels like it's sucking air. I just gotta feeling it's the pu tube. Would make sense since I'm superstiiuos and the Dodge needs one.
 
OK. I checked it out today. It revs as soon as you start it. No codes. I plugged in my PMD and it didn't rev but would really come off idle. It shakes badly. It was spewing alot of raw fuel smoke as well if I tried to give it fuel. The thing that bothers me is it didin't rev with my PMD but as soon as I pluged his back in it did. Wondering if there is more than one issue. At idle opened t valve and fuel came out, truck stayed running. Put my hand on LP could feel it working. His fuel tank and fuel lines are not that old. Year maybe. Will post a snapshot of the engine when I get home later. could the IP be toast with no codes ?
 
With all the symptoms and the check done with a different PMD the IP is likely the culprit.

Most things that goes south on the IP will set codes though.

A malfunctioning APP will turn on the STS light or will set a DTC.

Now as far as addictions go.

Intavenous diesel use Hmmmm now thats an idea. I'll take mine with the red die please, I hate the green look.
 
Kenny
The Fuel solenoid in the IP may be sticking due to some galling.

Try a heavy load of tranny oil in the tank. Maybe a gallon and see if the issue abates some.

If the problem gets better then its probably an issue in the IP with the Fuel solenoid hanging up.

The fuel solenoid moves in its bore one helluvalot.
This is a delicate ballancing act with the ECM checking and rechecking settings and adjusting the solenoid.

The solenoid is constantly moving and any galling or roughness will wreak havoc with the way it works.

Any crap or water over time will ruin the delicate parts.

A 2 micron filter IMHO is the best choice, along with a large collection bowl that can be seen easily.

Water will ruin these things in short order.

The lack of lube in the new ULSD also does not help either.

How much time on the IP ????


MGW
 
Generally an ECM issue will toss some sort of code or at least it can.

Te ECM' on these trucks have had a fairly good track record with minimal failures.

Now there is always the possibility of bad grounds at the rear of the intake manifold or the battery cables.

Poor voltage and or grounds will cause all sorts of Havoc, hate and discontent.

MGW
 
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