acceleration problems after start up?

[stevesnider]

I have a 97 and after starting truck it doesn't want to take off. I had problems all winter . I replaced glow plugs w/ Kennedys QH plugs put a new glow plug harness on truck ,it wasn't the original one but plugs did come on . I had a new IP put on last summer 97k on truck. The truck starts fine ,better if I unhook coolant sensor but after starting the truck idles fine but doesn't want to move. It bucks and stutters for about 5-10 minutes down the road. It has been 60 degrees out at night . After truck is run the first 15 minutes evrey day it runs good the rest of the day until morning. I took it to the dealer last week he replaced wires going to GP controler. I talked to the tech this week but he doesn't know why it runs rough every morning. Can anyone help me out?
Steve

[rameye]

Without a lot of information on whats been checked so far I would start simple and cheap...

Disconnect, clean re-connect ALL grounds and battery connections. I cant help but wonder if in the AM some moisture has formed giving you a bad connection.

How good is your battery voltage? Poor battery voltage will give you bad operating conditions as well as a bad ground.

Whats the timing set too?? How did they set it?

Are you getting adequate fuel?

Start looking at the basics...The more obvious the problem is, can sometimes make it easier to find the source.

Note: Attack one problem per session...ie..do the battery connections one day see if that makes a difference.
This way you'll know what the problem was when it's better. Not knowing what the cure was is worse (for me) than not knowing what the problem was.

good luck

[charliepeterson]

You said the truck starts better when you unplug the coolant temp. switch? The truck runs better after it warms up for the rest of the day until the morning?

Both of these problems could be related with the temperature switch. The ECM will defuel if it thinks the truck is cold so everything warms up correctly. The transmission will shift differently too.

When the truck is warmed up everything is good so the issue here is when it's cold. The SES never came on? The ECM thinks everything is good when maybe the readings its getting aren't?

[stevesnider]

Charlie,
I checked the fuel pump and it's working the tech said it sounded like it took awhile to get the IP primed in the morning. Like it might have lost presure overnight. I allways have faith in what you suggest. The temp switch ,is that the same as the coolant temp sensor on top of the thermastat housing? This morning truck started ok after sputtering up the drive it took about 15 min to smooth out. It won't go over 2K rpm without sputtering but if i floor it and get over 2K it will run good and eccelerat fine. When it shifts I lose power until above 2k again. Do you still think temp switch?
Thanks , Steve

[charliepeterson]

It sounds more like your sucking air into the system now. Try following the fuel lines as far as you can looking for wet spots. Another thing to look at is the level in the fuel filter bowl after it sits over night. Before you remove the filter though run your hand under the housing, your looking for wetness. You will probably have to remove the two bolts that hold the housing onto the intake manifold first to get a better look. If you pull the filter up first you will probably spill some fuel and you will miss a leak at the fuel heater if you have one.

How is your sense of smell? After sitting over night you might smell a fuel leak in the valley between the heads. The easiest lines to follow are the ones going along the frame rail. Sometimes the "P" clips holding the lines secure can rub through.

If the first start is a long crank it can mean the leak could be in the suction side of the truck. This could be on the suction side of the lift pump too because the other side is kind of the pressure side to the Injection Pump. Suction leaks are the hardest to find because they don't always leak large amounts. A rotted piece of pipe with real tiny pin holes can give you trouble. Then after the truck is running these tiny holes don't really come into play because of the large amounts of fuel the injection pump is using.

Another way to test but a little more advanced is to run the truck off of a bucket or can of fuel. You isolate different parts of the system starting at the Injection Pump and work back to the tank. Some people use clear tubing on the return side to look for bubbles, this is the presence of air. You'll see bubbles in the bucket too.

I'm not trying to scare you here. Look for the easiest and most obvious places first.

[stevesnider]

Thanks Charlie ,
I'll look and smell for leaks in the morning.
Steve

[stevesnider]

I looked in filter bowl and it looked full Thursday morning. Sat. morn tooked bolts off filter housing to feel under it and found some moisture. It didn't smell like diesel though. The two wires comming off the bottom of housing are bare for an inch .I don't know if they have anything to do with the rough running. The truck starts fine but when I push accelerater it runs rough and dosn't want to go beyond around 17-19 K rpm Than all of a sudden surges to 3K . Let off pedal and does it all over again . It didn't seem real wet undr housing like it was leaking heavy. Where is the bowl heater located ? Is that where it leakes the most?
Steve

[rameye]

I'm pretty sure that bottom assembly of the filter is the heater.

I know that having the bare wires is not a good thing to have, that needs to get fixed now.

These wires could shorting together and making it run crummy...after the fix see if things improve.

ram

[stevesnider]

SES light came on today and my glow plug controler
wasn't clicking this morning . So I knew the controller was probably bad . After work went to Auto Zone , Codes P236,turbo super boost sender,P1656Manufacture Aux. input ,output. P1810,Transmision manufacture controle and p380 GP controller. I don't know if all this is why my truck has run like crap the past month but the SES light just came on today. The truck really runs rough now.

Steve

[charliepeterson]

This might be a long shot. All of these circuits come close together at the fire wall next to the fuel filter. With two circuits bare it sounds like something might have shorted out. The element at the bottom of the fuel filter housing is the fuel heater. This can draw lots of amperage. The other circuits could be melted together from this shorting out.

You're going to have to get comfortable on top of the engine and lay down to open the harness up. I would follow it back to the plugs at least and look at the pins real close.

[stevesnider]

Charlie , I talked to a good diesel mechanic today . The wires on the are just for the water in bowl light he said it shouldn't effect anything. I told him what was going on and he said it sounded like the timing was off from my new (8 month) old fuel injection pump. He told me a dealer that has a good 6.5 mechanic and said he is good at adjusting the FI pumps. I have to cut lawns all week but dropped truck off tonight. I hope it will be coverded under warrenty. Wish me luck I'll let you know what he finds out.
Thanks guys, Steve

[stevesnider]

The dealer called today the truck has a bad fuel injection pump . I just replaced it 3K ago. I had to drive to a GMC dealer because the chevy guy wouldn't cover it under warrenty. I'll let ya'll know how it goes. Steve

[charliepeterson]

Yes the dealer is correct about the GMC/Chevy thing and warranty work. Your well under on time, hopefully the mileage is under 120K?

[stevesnider]

I got my truck back from the dealer today. Runs great with new injecter pump. Coverd under warrenty!

Thanks for everyones help,
Steve