Snowturtle
Registered User
Thanks, I'll pick up a gauge today!
New IP
- Thread starter Snowturtle
- Start date
While it should be 5-7psi the IP only needs a couple PSI at the inlet. I can't recall for sure but I seem to remember someone posting specs on an e-pump thread that even 1psi at the IP was adequate. I've run a lot of miles with a wimpy Facet that definitely does NOT give 5-7psi across all RPMs and if I keep it floored in 2nd gear or 3rd on a long climb t doesn't take long before the FuelFilter light illuminates but there is no chugging or hopping. You can still drive with a failed lift pump as the IP will, at great cost to itself, suck fuel from the tanks but it won't take much throttle before the filter light illuminates. The only time I noticed any behavior like you describe was when I still had air in the lines. Of course I have no idea how you might get air intrusion below 2000 RPM and then have it seal above 2000 RPM. Any chance this could be a case of the lift pump installed improperly, as in the arm is above the camshaft instead of below?
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Snowturtle
Registered User
That's a thought, maybe I'll take it out and try again. I haven't been to town to buy a pressure gauge yet - I assume if it's in wrong it won't be pumping? But I do get fuel out of the schrader valve when it's running...
Think I have it backwards--the pump arm rides BELOW the cam.
I suppose one of the next moves would be to run some fuel line from lift pump to a can of fresh diesel and see if the behavior changes. It sure sounds like air intrusion but it's odd that the truck starts right up normally. I've read some folks install a clear piece of fuel line before the IP so they can check for air bubbles in the fuel. I prefer rubber fuel line on the lift pump outlet to fuel filter inlet anyways because you get rid of that hard line and it's olive seal.
Snowturtle
Registered User
I like the thought, I can't see any reason other than fuel supply. I'm going to go pull that out and check it. That could also explain why it took me a while to get it started when I first finished the work. Maybe at higher rpms the IP sucks hard enough to supply itself but not at low rpms. Thanks for the input!
Snowturtle
Registered User
That's a great idea, I hate those olives!
There are lift pump to filter and filter to IP lines made by Russrepair known here as @typ4 to get rid of the olives, if you have a 6.9 or early 7.3 there is still one olive from the IP to the metal return line on the drivers side of the engine that runs back.
I prefer the later style return line, 89.5 and newer.
Holley e pumps do not seem to seal worth a damn, so when they ho out in my experience you get a large vent to atmosphere, causing your truck to run like crap and then die…
I prefer the later style return line, 89.5 and newer.
Holley e pumps do not seem to seal worth a damn, so when they ho out in my experience you get a large vent to atmosphere, causing your truck to run like crap and then die…
Snowturtle
Registered User
I got my injectors from Russ, I'll check his site for those lines. Thanks
raydav
Full Access Member
I got rid of the filter on the engine. On the frame, about about halfway between tank and IP, I have a Racor 2 micron filter, then a supply pump. I have the original vacuum switch after the supply pump.
Several times I have had the supply pump turned off, and driven three miles at fifty MPH, and finally noticed at the first major intersection. Seems to run fine with no inlet pressure. I never did that with the original filter on the engine. So I may have less restriction now. This chassis, with the original 460 or the IDI has never had a mechanical pump.
I recently replaced a several years old DB2 5069 with a CDD 90cc. I started the engine, with the supply pump turned off, before and after IP replacement. The new pump started quicker and smother than the old. I apparently got an increase in both output pressure and inlet suction.
No, I don't recommend running without a supply pump. But sometimes it happens.
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raydav
Full Access Member
What are "olives". On the van and my cars supply lines are 3/8, return are 5/16, and all the hard connections are brass compression.
The_Josh_Bear
Full Access Member
Square cut o-rings inside the brass fittings on both sides of the stock filter and the IP inlet. I think just those 3 total. They get hard over the years and brittle, leak. It's HARD to get them out once they get really hard. But as a PM no big deal if the previous owner actually did it. I had to burn mine out the first time I changed them. Eventually deleted them with better stuff.
Snowturtle
Registered User
I took of my lift pump and reinstalled just to make sure it was right - the new olive on inlet side of the filter was already buggered up. I didn't have a new one so I cut a chunk of fuel line to put in there. I'm going to concentrate on getting rid of those! I still don't have a pressure gauge but the lift pump was putting out plenty of fuel before the filter. Truck ran about the same after all of that but maybe a little less black smoke. Tomorrow I'll focus on making sure all of the fuel connections are better and will get a pressure gauge to test output after the filter.
Can someone remind me how the olive works? The first time I put it over the flange in the line, this time I held the flange at the back of the nut and put my homemade olive in the nut after it.
Can someone remind me how the olive works? The first time I put it over the flange in the line, this time I held the flange at the back of the nut and put my homemade olive in the nut after it.
Snowturtle
Registered User
I think the inlet to my IP was a solid connection, not an olive - is that what Kansasidi was talking about? We're talking about the line that runs from the filter to the center of the IP between all the injector lines, right?
If its a formed steel line, there's an olive under the connection nut. Was a factory installed part.
