Sudden onset rough off-idle and acceleration.

[teletech]

I've had my 6.9 E-350 for several years and other than return line kits haven't had to do much at all, I'm sure the fuel system is due for some love but after 25years and 350K the rest of the van is about done. Even though it doesn't owe me anything, another year of service would help me out and so...

I recently had a 25mile freeway run under a little more power than usual of late and when I came to the offramp the van was suddenly running very rough. When I accelerated it got worse, not too loud but really jerky.
Starts OK, low idle is poorer than before but not too rough, freeway is mostly fine, off idle is awful and slowly improves as speed builds.
Where do you guys think I should start looking? Injectors, pump, head gasket...?
As a van with a turbo it's a royal PITA to work on so I'd like to conserve what effort I can.

Is it worth sending injectors out for inspection/tuning or should I just buy a set? Similarly, if I suspect my pump is good but want to make sure is it worth sending out for inspection/test?

Further details: ATS turbo to a straight-pipe exhaust, boost and EGT has been on a steady decline for a while.
I ran 50-50 biodiesel for several years until I just got too hard to get around here.
Recently did O-rings and hoses on the return system.

thanks guys,
Pavl_

 

[mjs2011]

Some things to try before looking into major repairs....

You ran bio, which is really ******* seals. Check the olives in all your hard line connections. There is one into and out of the filter head, another going into the IP, and I believe more on the mechanical pump. They are little rubber rings around the hard line inside the flare nut. The bio could have destroyed these.

Also, you could try the atf fix. Take off your fuel filter, fill it from the small outside holes, not the center hole, with clean atf. This allows the filter to filter dirt out of the atf that may be present. Put the filter back on and run the van until you can hear the idle change. Shut off for a day and he next day drive it like you stole it.

Those are just some simple things, and they may not produce any results, but they cost significantly less than a pump or injectors and less time too.

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[icanfixall]

Welcome to the forum. Have the injectors or injection pump ever been replaced. If not they are 3 times past replacing. The eay least expensive thing is to run the auto trans fluid and see if that cleans up the miss. Then checking the filter to pump feed line seals called olives. Listening to your one more year and its a scrapper hurts. But thats fine. We are not see what this rig looks like..

 

[teletech]

I should have been more clear, the pump was new/rebuilt about 8years/60k ago when I bought the van.Well, I tried the ATF in a new filter. Let it run and then sit. No results other than it was pretty hard starting a couple days later, it was still rough and down on power. I checked all the hard lines for any apparent leaks and the system looks tight.

 

[typ4]

Likely a stuck injector, I had one on the dually and it ran like crap off idle, changed the bad one ,worked good now another one is dead. Since I just got an order of injectors im going to do awhole set.

 

[Zxmazza]

Ok about ip, what about injectors? Is there smoke, and where are ur fluid levels; and what r they like?


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[teletech]

Fluid levels are OK. Doing the injector line crack-open test indicates that two adjacent cylinders are not contributing, pulling the injectors shows fuel and it sounds like there is no real compression. I was planning to sell the van so now I have to decide to scrap it for whatever I can get and putting a head gasket on it and hoping I can get enough to make it worth my time.
It looks like you can do a head without disturbing the IP, correct? Can somebody with some experience suggest how long one head gasket usually takes in a van?

 

[Agnem]

Probably twice as long as it takes to do one in a pickup. You need to pull the IP, because you need to pull the intake and valley pan. Doing one side would be just dumb. Your better off selling it as is and letting someone else do it. You will have 18 to 24 hours into it I'd guess.