[Justnutsandbolts]

Update: injection pump was the problem.

Question: - Engine rpm surging under load >30mph...

It was the injection pump ! The replacement was very straightforward, the worst part were all the injector lines and the lower bolt by the passenger side. Thank you for all the help. I will update the YouTube video description with a link to this thread.

www.dieselplace.com

VIN 5B4KP42Y033368329
2003 Workhorse p42 NON-turbo 6.5 diesel

Hello all, long time lurker but just joined... the truck is a retired USPS stepvan bought from govdeals about 2 years ago..it was running ok until recently. I have read a few posts that had similar problem but the Original Posters have not shared what had repaired their issues.

The video makes it seem like I am letting off the pedal but I'm not. Also, when I try to accelerate, it sprays a lot of black smoke from the exhaust.

It had a P0251 code = injection pump fuel metering control "A" and I cleared it and it has not returned after over 100 miles.

I have already replaced the Dorman 904-104 PMD module that's mounted remotely and changed the oil.

I still need to replace the fuel filter.

Here is the video:

I am not sure what's next. I'm afraid it's an injector problem but I wanted to pick your brains before I go that route since the connections are very rusted.

 

[OkDually]

Welcome to DieselPlace

 

[Justnutsandbolts]

I will be replacing the fuel filter today and keep everyone updated

 

[OkDually]

I will be replacing the fuel filter today and keep everyone updated

Make sure to check/replace the air filter also

 

[Justnutsandbolts]

Replaced fuel filter, air filter.

Added diesel clean to the bowl, let it idle for 2 min and shut it off for 30 min

NO CHANGE.

I noticed it is worse once the engine is warm.
When I floor it WOT at 35mph, there's no power, it does accelerate but smokes terribly (black smoke).

It sounds like the same problem in this thread:

Stumped - 1993 6.5 surges at slight throttle

Well, I'm stumped! My 1993 6.5 diesel is surging only when the throttle is slightly pressed. I have no air intrusion and have 7-8 psi of fuel pressure at the engine. Recent work: New fuel line pre-lift pump (old had air intrusion) and installed a Reman IP a few months ago to try to resolve a...

www.dieselplace.com

Not sure what to do next, I use this truck for my plumbing business and just thinking about selling it at this point.

 

[OkDually]

Replaced fuel filter, air filter.

Added diesel clean to the bowl, let it idle for 2 min and shut it off for 30 min

NO CHANGE.

I noticed it is worse once the engine is warm.
When I floor it WOT at 35mph, there's no power, it does accelerate but smokes terribly (black smoke).

It sounds like the same problem in this thread:

Stumped - 1993 6.5 surges at slight throttle

Well, I'm stumped! My 1993 6.5 diesel is surging only when the throttle is slightly pressed. I have no air intrusion and have 7-8 psi of fuel pressure at the engine. Recent work: New fuel line pre-lift pump (old had air intrusion) and installed a Reman IP a few months ago to try to resolve a...

www.dieselplace.com

Not sure what to do next, I use this truck for my plumbing business and just thinking about selling it at this point.

Go through all of the grounds using the link provided in the 6.5L FAQ page. Grounds-Grounds-Grounds The importance of good grounds.....

Install a piece of clear line on the return side of the Injection pump Question: - 1999 GMC Bluebird 6.5L TD - PMD &amp...

 

[dieselolds]

Check to ensure the injection pump mounting nuts are tight.I have seen cases where the injection pump was fluttering back and forth because it wasn’t fastened firmly in place.

Is fuel pressure decent leading to the fuel filter housing?Is P0251 still the only code?

 

[paleyjim]

You said the P0251 cleared and did not come back, but what is causing the SES light in your video?

 

[Justnutsandbolts]

I will check the grounds and install the clear tube today.
The IP is hard to get to in the step van.
Is there anywhere I can install a fuel gauge on?

There are no issues at idle but it will smoke if I raise the RPMs.

The SES light is due to P0380 Glow/Plug Heater Circuit A because one of the connectors has corroded off. The truck still starts OK.

Seems like another one here with a similar issue. Asked him to update with his findings:

1998 6.5 surging / sensitive throttle - WITH VIDEOS

OK, I've searched the forum, and I'm a bit lost. I see lots of guys with parts bazookas just blasting parts at their trucks, and I've gotten alot of conflicting info. Ive got a 98 C3500 6.5. Bought it with 120k. At that time it had a goodwrench engine in it, unknown when replaced. Done...

www.dieselplace.com

 

[Glagulator]

If you have one of the glow plug connectors corroded off, that will not set a P0380 code.

Conditions for Setting DTC P0380
• PCM has commanded glow plugs ON and
voltage at the glow plugs is less than 4.0 volts.
or
• PCM has commanded glow plugs OFF and
voltage at the glow plugs is greater than
4.0 volts.
or
• PCM has commanded glow plugs ON and there
is more than a 2 volt difference between glow
plug voltage and ignition voltage.

 

[OkDually]

I will check the grounds and install the clear tube today.
The IP is hard to get to in the step van.
Is there anywhere I can install a fuel gauge on?

There are no issues at idle but it will smoke if I raise the RPMs.

The SES light is due to P0380 Glow/Plug Heater Circuit A because one of the connectors has corroded off. The truck still starts OK.

Seems like another one here with a similar issue. Asked him to update with his findings:

1998 6.5 surging / sensitive throttle - WITH VIDEOS

OK, I've searched the forum, and I'm a bit lost. I see lots of guys with parts bazookas just blasting parts at their trucks, and I've gotten alot of conflicting info. Ive got a 98 C3500 6.5. Bought it with 120k. At that time it had a goodwrench engine in it, unknown when replaced. Done...

www.dieselplace.com

You can T in a fuel gauge anywhere in between the lift pump and fuel filter housing

 

[Justnutsandbolts]

Unfortunately no change after cleaning the grounds.
There was no air bubbles in the clear tube.

I dont have a stalling issue.

In Park, I cannot gradually raise the RPMs, it just jump up to ~3k suddenly, then comes back down to normal idle. Today it idled rough after a couple high revs, I shut it off, restarted and it started idling fine.

I checked the solenoid and it plunges fine. Anything else I can check before I go after the IP and injectors?

Passenger side lines are corroded so I'll probably have to replace those as well.

 

[OkDually]

View attachment 646376
View attachment 646375

Unfortunately no change after cleaning the grounds.
There was no air bubbles in the clear tube.

I dont have a stalling issue.

In Park, I cannot gradually raise the RPMs, it just jump up to ~3k suddenly, then comes back down to normal idle. Today it idled rough after a couple high revs, I shut it off, restarted and it started idling fine.

I checked the solenoid and it plunges fine. Anything else I can check before I go after the IP and injectors?

Passenger side lines are corroded so I'll probably have to replace those as well.

Uncontrolled rpm's are two things...
1. PMD issue
2. armature in the IP is worn/bad = injection pump replacement

Since you have replaced the PMD that leaves only the IP..

 

[Justnutsandbolts]

OK. The van only has 60k miles. Surprised it would go bad at this low of a mileage.. i guess I'll have to order one.

 

[Wreckinball67]

VIN 5B4KP42Y033368329
2003 Workhorse p42 NON-turbo 6.5 diesel

Hello all, long time lurker but just joined... the truck is a retired USPS stepvan bought from govdeals about 2 years ago..it was running ok until recently. I have read a few posts that had similar problem but the Original Posters have not shared what had repaired their issues.

The video makes it seem like I am letting off the pedal but I'm not. Also, when I try to accelerate, it sprays a lot of black smoke from the exhaust.

It had a P0251 code = injection pump fuel metering control "A" and I cleared it and it has not returned after over 100 miles.

I have already replaced the Dorman 904-104 PMD module that's mounted remotely and changed the oil.

I still need to replace the fuel filter.

Here is the video:

I am not sure what's next. I'm afraid it's an injector problem but I wanted to pick your brains before I go that route since the connections are very rusted.

Do you have an EGR valve? I had a similar issue and wound up replacing the EGR solenoids as well as the MAP sensor.

 

[Justnutsandbolts]

I am not sure. I will check. I don't know what GM engine year these 6.5L non-turbo is compatible with.

Would unleaded fuel mixed with diesel cause the issues I am having? I remember it started happening after I filled it up.

 

[Wreckinball67]

Gasoline mixed with diesel...not sure what would happen but, it wouldn't be good. If you suspect this, I would drain all the fuel and start over. Additionally, if you have an EGR valve, it be in the center of the air cleaner once you remove the air cleaner lid. Should have a round vacuum diaphragm on a cast iron base.

 

[Justnutsandbolts]

Gasoline mixed with diesel...not sure what would happen but, it wouldn't be good. If you suspect this, I would drain all the fuel and start over. Additionally, if you have an EGR valve, it be in the center of the air cleaner once you remove the air cleaner lid. Should have a round vacuum diaphragm on a cast iron base.

I'll drain, put everything back together and start over...
I'm thinking I should at least replace the injectors while I have the top apart and replace the fuel lines as well.

I do not have an EGR valve as shown in this picture:

 

[Dadddyoh]

OK. The van only has 60k miles. Surprised it would go bad at this low of a mileage.. i guess I'll have to order one.

It is quite possible that the USPS did not use a lubricity additive in their fuel tanks with each fill up. This is needed with ULSD. There are several on the market use 1oz per every 2 gallons of diesel.

 

[Justnutsandbolts]

Quick update:

Replaced all injectors, lifter pump, fuel filter and fuel lines... Still doing the same thing.
I bought a Stanadyne Reman pump from D&W Diesel, which is going in today&tomorrow.