IP pump going TU.?.

Clb

Another old truck
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my 93 has less than ?50 k on it...
the ip will go from a grand total mpg of 14 to 7... averages 9 towing.
try to get it hot and sweaty towing for 3+ hours minimum.
atf trick next and before.
 

Enginerd

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Truck starts fine hot or cold. Lots O white smoke on start up, idles fine most of the time. Every once in a while sounds like it has a miss. While driving ( it gets interesting) at times truck will act like it's going to fall on it's face then pick back up, or out of no were find hp it doesn't normally have.

I just ran into these same symptoms on mine getting my truck up on its feet after a while of sitting. I replaced the return lines and filter and all that and still was having this issue. Then I saw a little wetness at the heater plug on the filter head. I pulled the filter head apart, ripped the heater element out (I read it doesn't even start working until 5 minutes of the truck running, and besides it at the top of the fuel filter. I don't know how effective that is), put an oversized o-ring on the plug and jambed it back in there. Fired right up and hasn't sneezed yet the last 400 miles.
 

Enginerd

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Well except I should mention that I had to prime it too because it would just die all of a sudden so I clearly had air intrusion. So if you don't have that then my comment may not apply. And I don't know bad IP symptoms from experience. Yet.
 

1983idi

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Your a 85 so i don't believe you'll have the fancy fuel filter head with the heater in it as the post above is talking about but on the old style filter heads there is some sort of stupid return line or something that I've had issues with on mine (1983). I would get a kit to replace your return lines and your issue may be fixed. I had the exact same thing happening where I would get a "burst" of power out of nowhere and the truck would kind of take off and then it would kinda settle back down as i kept driving. Replaced the injector return lines including that line and haven't had that issue since.

I was thinking it was my IP as well since I'm running the original IP and Injectors with 137,000 miles but fortunately that fixed it so before you try the IP try replacing the lines or eliminating that line. It isn't actually necessary and theres a write up somewhere about deleting it. Also I'll note that I didn't ever have any visible leaks on my hose the system was just drawing air in on mine.

Before someone jumps on my a$$ I am not saying it isnt the IP as it certainly could be but air intrusion is really common on these trucks and this was my experience.
 

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