hey make sure the return line that comes from the injector pump and injectors back to the tank is clear... on my 89 chevy suburban the return line that goes to the tank was restricted.. it originaly had the charcoal canister set up... my return line was restricted at the tank and it smoked bad around town and acted like a gas engine loading up with a bad carb... also make sure the tank is vented.. diesel and gas are vented different..

 

drove it down the freeway today. Engine starts stumbling just over 60mph, fuel pressure maintaining 4-5 psi, boost around 10 psi, egt's around 700
Should I still drop the tank and take a peak or do you guys think this is something else?

 

Well I think I can rule out the fuel tank or fuel lines(return and main feed). I spent the last few hours blowing them out with an electric air pump, no restrictions, could never build any pressure, verified the fuel cap is vented. Still having the same problems when locked up and in over drive trying to go faster than 60mph, I feel like the engine starts vibrating a bit around 55mph, then when I try to exceed 60mph it shakes a bunch and losses power till I easy off the pedal. I did try a test, I mashed it with the TC locked up and kept out of overdrive, could get it going faster than 60mph with 22 lbs of boost, 900 degrees on the egt gauge , fuel pressure never went below 7psi(better now that I cleaned the lines). No tachometer yet but was obviously much higher rpm's than when attempting to go faster than 60mph in OD. I'm stumped, any ideas?

 

Back to head scratching.
Where is the fuel gauge tied in?
Still sounds like not enough fuel.
Cheers Steve

 

what kind of fuel pressure are you seeing when driving around blackduck?
I bought a tapped banjo bolt and Teed into the line right after the fuel filter before the IP.
anymore ideas? I bought the fuel heater delete nipple, I'll be removing that in the next few days(no visible leaks but still..)


Just a thought... I never had these problems before i swapped out my alternator a month ago, i did have a voltage spike of 18v for a minute or two before I was able to adjust the voltage regulator properly. idk if it could've damaged the fuel cut off solenoid but just throwing that idea out there.. I get a solid 14v at all times, can see the voltmeter needle move up and down a little(+/- 1 volt) with the blinkers on.

 

Ok I made a video to help us diagnose the problem, wth is going on here?
Pay close attention to 10:20-10:35 tried exceeding 60mph, this is when I'm losing power and it feels like the gas pedal is trying to fight me, no noticeable black smoke when it happens, lose all boost during it, fuel pressure never went below 5-6psi while driving, 7psi at idle
start-8:20 driving through town 35-40 mph
8:22 exceeded 60mph with TC locked and OD disabled,
8:50 downshifted going 60mph
9:45 entered Hwy
10:20-10:35 tried exceeding 60mph(problem time)
10:35-11:45 cruising 50-55mph
11:45-11:55 OD on, TC disabled, tried to see if I could go faster than 60mph with different results, same problem observed
13:15 exit freeway
13:15-end 30mph driving through town

 

Cannot help with my pressures but you do have your gauge on the right side of the fuel filter and 7 PSI is fine.
Have you had a good look at the FSS cable? Good tight connection and no frayed wire.
Maybe just the engine movement but that cable seems to move a bit.
Could try gutting the FSS and giving it a run to eliminate that side of it.
If the pedal is kicking back at you the governor maybe trying to shut it down,
That would mean internal problems in the pump.
Cheers Steve

 

"Right" side meaning the left side of the filter housing where the hardline goes into the IP?
Gutting the fuel supply solenoid? Like take it apart and clean it? I swear all this started happening after I swapped alternators a month ago idk if it has anything to do with it. I dont have a pcm, ecu, or tcu all manual with switches on the dash so I wouldn't think the alternator could do that.

 

Blackduck, are you thinking I should rerun the FSS wire with a little more slack? like the engine movement is wiggling the wire and intermittently shutting off the fuel supply? I think I misread you comment wrong for my last reply

 

Right as in the correct side.
Just saying to check the FSS feed wire for a good connection and no frayed wires to thin it down. Also do you have a good earth/ground wire to the block/body/battery
You can remove the plunger and spring from the FSS and re-install the body. You will need to use the manual shut off lever to get it to stop.
Check the plunger for the rubber tip, they have been known to come off and restrict the fuel flow.