7.3 IDI with some issues

[Meads98]

Hello,
I know it's a long read but I'm real confused about what is wrong with my truck. I do want to say upfront that I'm definitely no mechanic but I know a good bit.

I just bought my first truck a 1990 f350 with a 7.3 IDI with a banks sidewinder turbo installed and it's been a nightmare from day one. Starting off with driving it home I noticed on the highway that it never wanted to get above 57ish mph at around 2k rpm even with my foot on the floor. It just felt like it made no power. After driving like this for about an hour I popped a radiator hose off on the highway. Luckily I had half a jug of antifreeze and a bottle of water but couldn't get the hose clamp back on very tight but I was able to get it to a U-Haul and decided to tow it back home (hose did pop again so it ran without coolant for a few miles). I got home late after that whole ordeal and put some water in it again and limped it off the trailer into the driveway ( hose did stay this time). So this morning I drained the water ,tightening the hose clamp, and put some antifreeze in it. I went to start it to cycle the coolant through and it wouldn't start. Cranked and cranked but nothing so I started digging for a few hours. The short of it is replaced the fuel filter and took off the line going to the ignition pump which spews diesel when cranked then I checked most of the injectors and they are not getting anything from the injection pump which makes me think that it failed somehow. Check the shutoff solenoid already and that's working fine. So this is where the questions start.

How does an injection pump fail overnight?

Why did it feel like it was making no power? The guy I bought it from said the injector pump was just replaced with an NA pump so it might need to be turned up but it was painfully slow. Like slowing down uphill in 3rd with no load slow.

Is there anything else I can check before replacing the pump?

Why did it overheat/pop a hose?

Is 55mph at 2k on the highway normal? I wanted to build this as a long distance camping truck.

Should I look into regearing it? It's running the stock zf5 with 3.55 on the rear diff which I thought would be perfect for the highway.

What else would you all recommend I look into.

I've been looking into this all last night and all day today and am still lost.

Thank you in advance to anyone who responds.

 

[DaveBen]

Welcome to Oil Burners! No fuel coming out of the injector lines when cranking means the injection pump is bad. Anything can fail, even new pumps. Who's pump is it? Others here will chime in about this issue. There are specific pumps and injectors that are good and a lot of junk out there. Air intrusion is another possibility. Good luck with your "new" truck.

 

[Nero]

There are several things that could have failed. Not knowing your level of familiarity with these engines, let's start with the basics. First off, is yours an auto or manual?

I would check to make sure the lift pump is functioning correctly, without it, the injection pump won't get fuel, period. You can check for fuel at the Schrader valve on the filter head while cranking. Should be between 4-7psi. Don't have a gauge? Fuel in general is good.

As for your speeds, it sounds like it's starving for fuel, you should be able to get up to 80 no issue, depending on axle gears.

 

[Meads98]

So I'm not sure what kind of fuel pump is but the guy I bought it from said it was a stock NA fuel pump so it would make sense why it felt like it was starving for fuel.
For neros questions it is a manual with the zf5 in it. I checked the pressure on the lifter pump and it was about 6psi so It seems fine.

 

[Nero]

Lift pump seems fine.
Using a stock n/a pump on a turboed engine isn't a bad thing, many of us run that way, we just turn the fuel adjustment screw up a little.

Next few things I'd check is the turbo, make sure it spins freely. A seized turbo can cause enough exhaust restriction to cause low power/no start.
Also check that your fuel shutoff solenoid has 12v and that it clicks when attached.

 

[Meads98]

I checked the shutoff solenoid and that is working fine. When I was driving I could hear the turbo spooling just fine so I don't think it's the issue here. It really seems like the injection pump was on its last leg and pushing it on the highway just sent it over the edge.

 

[Nero]

I hate condemning such an expensive part. It could be bad. Does it look new, or 'cleaned up'

 

[Kdo58]

It's old, and needs some love, lots of YouTube video, probably been neglected. And will needs lots of parts like a whole new fuel system. Shower heads, fuel filter, all new fuel lines, fuel tanks could be full of junk....

 

[Meads98]

Yeah I was really hoping it wasn't the pump but that's really what it's seems to be. It doesn't terrible but definitely wasn't new when installed.
As for the rest of the fuel system it seems to be working fine and fairly clean. I replaced the fuel filter already and that was pretty clean and free of gunk so I might be good on the rest of the system but we'll see.

 

[Nero]

Get a good pump and see if she runs. Nows a good time to put a turbo pump on it.

 

[Meads98]

Already looking into new pumps which is a pretty rough first weekend with the truck. Thank you all for your help.

 

[IDIBRONCO]

Why did it overheat/pop a hose?

This makes me think that maybe the timing was very slow.

Should I look into regearing it? It's running the stock zf5 with 3.55 on the rear diff which I thought would be perfect for the highway.

I would get the truck running good before making any decisions here. 4.10 gears do better for towing, but it also depends on the size and weight of your camper. Also, no 55 at 2KTPM on the highway isn't normal while running empty. Especially with a turbo.

It doesn't terrible but definitely wasn't new when installed.

Going by your words, it was replaced, but I didn't see you mention that it was replaced with a new pump. It may have very well ben an old, used up pump that was on it's last leg.

 

[Rondo]

with 3.55 gears in 5th gear at 2000 rpm would be around 70 mph