Engine/Transmission (1994 - 1998) hard start/no start.

[KCanepari]

I have a '96 12 valve with 267500 miles. never had a problem with the motor except replace lift pump two 1/2 years ago. the other morning (2:30 am) I went out and started it. it started fine then after 2 minutes it shut off and wouldn't start. took filter off and filled it with diesel and some power service, got it to run, ran fine all day. changed the lift pump and fuel filter next day, it ran for one day and then the next it's very hard to start and then if you were to shut it off after a couple minutes it won't start at all again. There's no codes, checked fuel shutoff. what could this be?? it seemes when I prime it there's good fuel flow. all the hoses are new except for the short stainless braided one.

 

[Joe G.]

It could be a fuel heater problem. Email me at -- email address removed -- for my 12 valve fuel supply system write up, how it works and how to fix it.

 

[KCanepari]

How do I bypass the fuel heater? Can I plug the rubber hose directly into the lift pump with an adapter? I put some fuel treatment in and filled the tank and it seems to be running a lot better. we will see if it starts in the morning. I'm going to drill out the banjo and test the fuel pressure.

 

[KCanepari]

P. S. the fuel heater has been burned up and not plugged in (electrical plug) since I got the truck 40,000 miles ago

 

[DonFitzwater]

plumb in a clear line before, then after the lift pump. This will allow you to find out if you are sucking air and where it is coming from in relation to where you have it installed. We used that trick on a Scotty motorhome and it turned out to be a fuel line running to a generator that also used diesel.

 

[EKlem]

Where are you located and what are the temps like?

 

[KCanepari]

it was +20 when it wouldn't start, 40 when it wouldn't start, and then 20 again when it was running today. this thing has started and ran fine at -10. Id like to know the best plumbing method around the preheater

 

[Calebh9806]

How Can i turn up my idle it runs a little below 800 rpm's right now and i'd like to turn it up, cause in the morning without being plugged in it wont start real well without the throttle being pressed ??? and What Fluid does the Rear end take ..... No book for the truck when i bought it ?

 

[Joe G.]

How do I bypass the fuel heater?

My fuel system write up has how to do that with pictures. You don't bypass it, you remove it and throw it away.

 

[Joe G.]

How Can i turn up my idle it runs a little below 800 rpm's right now and i'd like to turn it up, cause in the morning without being plugged in it wont start real well without the throttle being pressed ??? and What Fluid does the Rear end take ..... No book for the truck when i bought it ?

There is no harm from pressing the throttle a little bit to start it. I do that all the time.



Setting the idle up takes a 10mm box end wrench. Find the throttle linkage rod. Follow that with your hand until you find the lever on the injection pump. Then feel around until you find a lock nut on the adjustment screw. Loosen the lock nut with the wrench. Use your left hand to pull on the throttle linkage a little to take the pressure off the adjustment screw. Then you can turn the screw with your right hand. When you have the idle like you want it, tighten up the lock nut.

 

[KCanepari]

My fuel system write up has how to do that with pictures. You don't bypass it, you remove it and throw it away.

I don't want to do that, I want to completely bypass that whole set-up. there's already a filter in the tank and a screen on the lift pump, that pre-filter is also pointless. I want to run the line straight to the lift pump.

 

[Joe G.]

There is no screen on the lift pump. The screen is at the bottom of the fuel heater/pre-filter assembly. If you just remove the fuel heater from the assembly (5 minute job at most) then you don't have to use any more hose than you already have. The fuel comes into the input fitting as it does now, then goes through the screen, from there it goes to the sort curved hose to the lift pump. All you need to do the job is a 17 mm socket plus u-joint, extension, and ratchet and an 8mm allen wrench. I don't think you know how it's put together. That's why I suggested that you email me for the write up.

 

[KCanepari]

I've had the pre-heater apart and know exactly how it's put together. I've also changed my lift pump twice and know THERE IS a screen in it. If you unscrew the fitting on the pump that that short piece of hose goes into there is a screen right there. The less hoses and fittings/clamps the better. I'm just going to run the line directly into the pump.

 

[Joe G.]

The screen in the input fitting is a check valve. If that fails because of grit you have to replace the lift pump. If you have the pre-heater apart you didn't need to put the heater thing back in. The whole thing goes into place without the heater element just fine. No need to mess with changing anything. You can take the heater element out with the assembly on the engine without disturbing any of the clamps and hoses.

 

[Wedge]

I took Joe's advice and pulled the pre-heater, I found that if I put a vacuum on the plug it would leak... very easily!!

 

[KCanepari]

I'm going to try that, but I put a gauge on and seems to be plenty of pressure. The truck will start now on second try with pedal 1/4 way down cranking for 20 seconds each time. will stumble bad at idle up to 1500 rpm then fine. will start fine when warmed up but will still stumble sometimes. could this be injectors? timing?? could someone tell me how to check the timing?

 

[WDimig]

still sounds like a air leak issue.

 

[KCanepari]

I completely by-passed the fuel heater and am still having the same problem. There's a small coolant leak at the very back of the engine on the turbo side right around the head gasket. Could the head gasket be shot? would that explain why it runs better when it warms up, does it seal itself?

 

[WDimig]

even if for some reason you are losing enough compression on the #6 cylinder, there are still 5 more cylinders that are ok, and the truck shoud run on them. i may have mised this, but have you checked your lift pump pressure?, if not enough pressure, could cause a hard start issue also.



wes

 

[KCanepari]

brand new lift pump, I will recheck pressure tomorrow. The truck has plenty of power, it just stumbles under 1500 rpm mostly when cold and starts hard.