• Welcome to The Truck Stop! We see you haven't REGISTERED yet.

    Your truck knowledge is missing!
    • Registration is FREE , all we need is your birthday and email. (We don't share ANY data with ANYONE)
    • We have tons of knowledge here for your diesel truck!
    • Post your own topics and reply to existing threads to help others out!
    • NO ADS! The site is fully functional and ad free!
    CLICK HERE TO REGISTER!

    Problems registering? Click here to contact us!

    Already registered, but need a PASSWORD RESET? CLICK HERE TO RESET YOUR PASSWORD!

Help needed with my 96 suburban

1twisted1

1twisted1

Member
Messages
86
Reaction score
2
Location
Garden City,Michigan
Hello gentleman

I have searched for the answer to my question and have not found it so its time to post the question here.

Just picked up a 1996 2500 6.5 suburban 2wd with 286K on it. the truck was a one owner truck with tons of dealer maintenance, truck runs like a dream with one little issue. I have zero throttle input when its cold and for some reason yesterday it had a ton of blow by when cold, but once it warm up the throttle works and the blow by is gone. I have included some videos to show you whats going on. Before you say anything I know it probably need glow plugs and so i know its an injection pump not a fuel pump as i say in the video.

please watch the videos before posting as the issue just goes away once its warm.

Time from first video to last is 1:03pm - 1:30pm just so you know the time line and its 38 degrees at the time of the videos

https://www.dropbox.com/sh/o60cjcz3mozpvki/AAA5INTa1ntO6QwLoZRDhWEVa?dl=0

Thank you in advance
 
Last edited:
The vids were just pics for me. When you say cold how cold are we talking? My 96 with close to 300k would have a dead pedal so to speak but only after it hits around -20 and worse the colder it got.
 
By cold mean it does it every time I start it if it hasn't run that day or if the engines cold enough not to register on the temp gauge. it did it today and its almost 40 degrees out
 
I had a similar problem on my 96 turned out to be the IP. Unplug the temp sender that's by the thermostat and see if it makes a difference.
 
so was it the IP or the coolant sensor? And here's the crappy part I'll have to wait till morning for the symptoms to come back. Its been three hours since I took the videos and I just when out and the truck runs fine, throttle works perfectly. This issue is just messing with me.
 
Videos worked for me.
Exhaust smoke wasnt blowby, that was a unburned fuel. Any codes from when the check engine is on?

Follow AK's thread, but I would start with removing and cleaning the grounds, most important is the ones at the transmission dipstick location, and battery cables. Big power can arc and blast through, but tiny voltages and tiny amps just dont have the umf (did i spell that right?) to get through.

Also, here is a fun one for ya, try pouring a pan of hot water (not boiling but close) slowly over the ip and see if that clears it up quicker. Obviously be amazingly careful to not splash yourself.

Guessing you already tried the spare pmd.
 
Thanks Will L I understand the white smoke out the tail pipe was not blow by, i state in the video while showing the oil fill tube "of course know it going to make a lair out of me" because there was no blow by.

I read AK's thread fully. The symptoms his truck was exhibiting are different that mine, hard starting & miss while driving. My truck does neither of these, starts right up and runs smooth as silk once the throttle starts working (warmed up). I have not checked the codes as i don't have a reader and the trucks not plated at the moment.

What does the hot water over the IP do?

So a bad IP will stop the throttle from working till it warms up?
 
What have you been running for diesel additive?

Do you run additive all summer and winter?

Where do you get your diesel? Is it Bio?

I run a FFM bowl full of Sea Foam through every filter change.
 
Just bought the truck, unsure about what fuel or additive the original own ran. I will be running 30w with every fueling now that i own it, along with power service (gray in summer. white for winter). No bio that I know of in my area but some stations will add it to make more $$ and not advertised it as we all know.
 
1twisted1 said:
Just bought the truck, unsure about what fuel or additive the original own ran. I will be running 30w with every fueling now that i own it, along with power service (gray in summer. white for winter). No bio that I know of in my area but some stations will add it to make more $$ and not advertised it as we all know.
Click to expand...
In my opinion, if you run bio, you do not need to run anything else for lubricity.

I have also heard bio varies in quality throughout the nation. It's possible the previous owner ran some WVO or not so good bio - that will gum things up - especially when cold.

I would try running something that will clean things out. Injector cleaner?

I haven't had to do much of that, so I'm not big on good products for that.

I would run about 1/2 gallon of fuel out the T drain and see what it looks like.

I would also fill the bowl with Sea Foam, hotwire the lift pump, turn the key to run, run the return line to a container and let it run for quite a while. I would also add something to your tank.

Not saying it will fix anything, but I think it is possible that something is gumming up a little when cold. It might be something you can clean out.
 
The idea of the hot water is to see if the komputer timing system is fighting you or something mechanical. If the hot water helps then I'm thinking stepper motor in ip is loaded from fuel* and not allowing timing to correct for temperature.

The fuel* is a wacky rare ordeal, but ran into it twice years ago. The fuel heater not heating as it should, The fuel is not gelling in open air, but when it is under pressure in a small fuel line, then goes through the ip screen and expands into a larger chamber it works like refrigerant in an a/c system going through an expansion valve. So the fuel dumps a few degrees and begins to cloud once in the ip. Optic sensor is blinded and the signal to advance timing to help cold temp wont work. Then some morons idea that the pedal input should be ignored takes over and programming wont let it work.

So getting the body of the ip hotter than the fuel wont let the fuel shed it's heat to the body of the ip. Now the fuel wont cloud, and thats it.

Hotter fuel fixes it also, but doing something quick and easy to make the fuel hot is harder.

If the 30 second attempt to try this doesn't work, then you need to throw a scanner on there to read what IP is doing. If it does, your fuel heater isnt working proper, and /or fuel supplier needs more kerosene and alcohol in the fuel.
 
You have 286K on a timing chain that can't take the load of the IP. Even if you have a small 30K on a new timing chain it's stretched out pretty good. They go on tight and come off loose. I suspect that's your noise. Won't hurt to check the IP gear bolt torque through the oil fill if you are really worried.

In warmer climates I find with a lack of timing at idle wonky DB2 that 30 weight makes it harder to start and smokes more. I have started running Power Service DieselKleen and find it's easier to start with less fogging the street smoke. Not saying this is your issue, but, the lube studies never noted any starting difference like I notice.

I would verify all the glow plugs are good and getting power. My DS4 for all it's misery always started better than the worn DB2's I run.
 
So, if this is a new truck, that may be why the PO sells it.

I like JR's suggestion to use fuel additive and see if that can help.
Personally, I like the 2 cycle oil plus a proper diesel additive.
I know people are putting oil in the diesel but if that oil is too thick, it will not help in the cold weather.
The 2 cycle oil and diesel additive are designed to burn with the fuel.
The good diesel additive will also reduce the gelling temperature so the fuel stays fluid.
There is also a chance that the truck may be sitting for a long time and in that case, the fuel may be bad also.
By driving it around, it may get everything flowing again.

Have you changed the oil? If not, get a synthetic 5W-40 oil that will help starting in the winter.
A good oil filter will help the oil also.
 
When I switched to Amsoil, they recommended the 5w30 heavy duty diesel engine oil. That's about all I've ever used.

Except when I got the deal on the Mobile 1 5w40 synthetic. I didn't care for that oil because of the 10,000 mile oil changes. I only change oil every 20,000 miles with the Amsoil and the bypass filters. I've never had an oil sample come back bad

If you swap the timing chain, I would go with a set of gears from Leroy

i USE A FEW DIFFERENT PRODUCTS. Schaefer's winter or summer additive, Power service products, Ashless 2 stroke oil,
Opti-Lube XPD Diesel Fuel Improver
and Sea Foam for cleaning the bowl and running through the IP when I change the fuel filter.

I change the fuel filter and air filter every oil change - 20,000 miles

 
Last edited:
truck was all most empty when i bought it, put 20gallons in it and drove it 2hrs home, figured that trip woul d have cleaned out bad fuel or stuck injectors.
 
You must log in or register to reply here.
Back
Top