Got my 4BT conversion running on Thanksgiving Day! Gave Thanks

Had replaced fuel tank, fuel lines to/from, new FS1221 fuel filter, engine was disconnected for about 6 weeks between pull and install. No problems with engine whatsoever before pulling. Royal pain bleeding down lift pump & injection, then found I had overtightened the fuel filter cannister. I think I have it right now. Got it started, runs very strong, smooth idle, excellent power to governed speed, no stumbles.

1] Problem is it won't start instantly. Tried various bleeding procedures. Finally hooked up a remote start switch and bled Bosch VE pump inlet line at front of pump [where line it enters pump coming from AC Delco lift pump] while cranking engine. As soon as that line is cracked while engine's cranking truck starts instantly. Without cracking that line it takes 3 to 6 or more attempts and LOTS of cranking over. No air visible when that fitting is cracked.

2] During process of elimination I bled injectors many times. Seemed to get more air bubbles out of #2 than any other.

3] When bleedig injectors, whether fitting is only slightly cracked or opened 1/2 to 3/4 turn, the fuel only spurts up about 6" to 8", not like a high pressure spray that I expected. It did squirt fuel from injector to fender and hood a few times but mostly it doesn't seem to be a real high pressure squirt of fuel like I thought it should be.

Other than starting problems: WOW! This Cummnis is STRONG and runs great! Best and smartest thing I ever did for a vehicle! YIPES! Can't wait to install my HTT Turbo & 3,200 spring and twist a few screws.... Thanks for all the help I've gotten here, guys!

 

Lift pump: with engine cranked so pump lever works I find that it pumps strong for maybe 4-5 strokes, then pumping resistance quickly diminishes and lever travel [with the feel of pump pressure] becomes less and less to zero. With a diphragm pump and closed system it seems pump lever resistance should become greater, not less?

 

Check list:
Fuel tank vented? Remove filler cap.
Return fuel line to tank kinked?
Fuel line from tank to lift pump sucking in air somewhere? Clamps tight?
Intermittent electrical connection problem to injection pump? Run a test jumper lead to it from the battery.
Any fuel in the oil pan?
Correct fuel filter being used?

Good luck. Hope this helps!

 

Thanks very much, Trebor! I think all of that is good as I did my best to double check, but I'll triple check to be sure.

Fuel cap is vented, tank has its own independent vent. Hard lines are good and fuel flex lines are new, straight shot from tank to lift pump. Afraid to tighten clamps any tighter ha haha! No kinks on return line. Mechanical diaphragm-type Delco lift pump, like early 1st Gen. No fuel in oil pan. This FS1221 filter is the Cummins spec. for my engine, but I did overtighten it at first install. Going to crack it loose again today and triple check on gasket sealing. However the problem seems to be after fuel filter, between lift pump and injection pump. I'll price out a lift pump this a.m. I'm afraid that may be the problem, not sure.... Thanks again!

JimmieD

 

It would be nice to know what the low side pressure is doing. I'll bet the lift pump's dead. Cracking the inlet allows the VE enough of a gulp to start, then it runs on it's own with little or no feed pressue. Not sure how long it would last running like that, but it can't be too good for it.

 

Thanks Ace! I'm afraid you're quite right....didn't expect to hear what I wanted to hear, "Aw, that's just the fiddling valve, turn it 1/2 half turn and fiddle with it and you're good to go...."

I'm going to call around now. Wish I had an AC Delco diphragm lift pump P/N! I'll try a '89 1st Gen application and see what they come up with? Thanks, even though it wasn't good news.....

 

Well, well, well, good news for a change

Called Shucks [Checker/Shucks/Kragen empire] and an '89 CTD mechanical pump, Carter M73060, is only 52 bucks! I heard they were a hundred or better. Be here Tuesday...

Thanks, guys! Sure a nice thing to have some helpful guys to lend a hand!

 

New lift pump installed. No change at all. Won't start unless the line into injection pump is cracked while engine is cranking. As soon as that fitting is cracked open it starts instantly. Other than starting the engine runs great. Real puzzling......

 

CHeck the fitting and it's seal/seat. Maybe the seeal/seat is dammaged and restricting the fuel flow until you crack it then the fuel can go arround the obstruction.

Just a pure guess.

 

Thanks for the suggestion! I cheerfully accept W-A-G's at this point Didn't get a chance to work on it last couple of days, it's at the top of the heap for today.

Just can't figure why it is that cracking the last fitting going to injection pump makes it start instantly!??? Doesn't seem to bleed out any air when I do that or anything, just a pressure REDUCTION. Here I find everybody wanting MORE fuel pressure to their injection pump and mine wants LESS? Really very confusing for a diesel dummy

 

JimmyD,
Did the van you removed the engine from run without any problems?
I would try the old double two liter bottle fuel test next. Fill a two liter bottle with about one liter of fuel and run a temporary hose into the bottle attaching the other end to the fuel pump. Disconnect the return line and run a temporary hose to the empty bottle. Start the engine and see how it acts. Don't let it run out of fuel. If it acts normal then the problem is in the tank or lines. If it acts the same I would suspect the fuel shut off solenoid. Instead of bleeding the line try bumping the line fitting lightly with a small wrench or plastic faced hammer to see if it starts. Make sure your engine has a good heavy ground lead.

 

Yes, Trebor, it ran fine in the van. Drove 150 miles home and then drove it 75 miles and then a short trip and always flawless, instant starts. Used the fuel supply line out of that van and its fuel tanks, a solid steel line with new short rubber at ends for hookups. Used my old gasser fuel line as the return, new shrot rubber for connections. All new hoses and clamps.

I will do the bottle thing to eliminate possible causes. Being new to this it's probably easy to do something that an old pro would NEVER DO and still not even know I did something wrong! Thanks!

JimmieD

 

I've heard of VP44 (24 valve) equipped trucks having starting problems with high fuel pressure. What's the fuel pressure in your electric setup? More than 15-18 psi is too high.

 

Oh, I took your advice: I didn't install electric like I was intending to, just a common 1st Gen diaphragm lift pump. Hard to believe that this could overpressure a VE, huh? Also installed a new pump but pretty likely the old one was okay anyway.

 

Had you run it with the new pump? Sometimes you get bad stuff out of the box.
DP