Starting Problem

[icanfixall]

A DB2 pump is the Stanadyne injection pumps found on our idi motors. The name gets shortened around these parts because most know what is being talked about. You have not asked a dumb question at all. Now if you tried to do a pump replacement and removed the top gear cover, then found the injection pump gear attached to it... Then you made a dumb mistake... Working on these motors is mostly stupid simple but..... If you have never done this work its kinda tuff figureing out some of the right and wrong ways of working on these motors... Usually dumb is not used in this forum... But misinformed or somebody told you this or that id kinda looked at with a smile.... Nobody here will laugh at you but we will laugh with you about things.... I know something about these engines but not everything. Some time back about 3 years ago I needed to turn down my injection pump. Well after I did this the truck smoked worse. It took me about a week to figure out what went wrong... And I know which way to turn the fuel screw in the pump... But I turned it the wrong way... I actually turned it up instead of down... I went over everything I had done and finally remembered which way I turned that small screw... I posted that for a laugh... It was an inlightening moment for me.... Kinda the feeling when you head pops out of the backside about something....

 

[OHIDI83]

Ok, installed new pump and same thing. NO START AHHHHHHHHHHH. Ok, now what. I went back to basics. I know I am getting fuel to the IP with correct pressure and volume. I have fuel coming out of the return line to the IP and out of the fitting on top of the IP. I'm so lost why this thing is still not starting. PLEASE HELP

 

[MR.T]

You may have already done this... Try cracking the lines on top of all the injectors 1/4 turn, disable the glow system, hold full throttle, and crank it several times for ~10 seconds (wait a few minutes between cranking intervals to keep the starter happy, maybe keep a charger on the battery).

Each injector should have the same amount of fuel dribbling out the cracked fittings. Tighten them all, enable the glow, and see if it starts.

Best of luck-

 

[OHIDI83]

Ok, so after installing new pump and attempting to bleed and still no start, I decided to go back to basics. I pulled the fuel supply line to the IP and found that during cranking the fuel going to the IP was no constant. It would pulse. By this I mean I would have a nice steady stream for about 2 seconds than nothing for about a 1-2 seconds than a nice steady stream again for about 2-3 seconds then nothing for about 1-2 seconds than again and again. So this has to be my problem right? Should there not be a constant stream of fuel with no pulsing at the IP from the supply line?

 

[MR.T]

... It would pulse. By this I mean I would have a nice steady stream for about 2 seconds than nothing for about a 1-2 seconds than a nice steady stream again for about 2-3 seconds then nothing for about 1-2 seconds than again and again. So this has to be my problem right?

Yep, 3 seconds of no lift pump flow while cranking sounds like a bad lift pump, or something wrong with the suction (fuel valve, tank empty, etc).

 

[OHIDI83]

bump suggestions please

 

[Goofyexponent]

Hmmm. Pull your dipstick....is there the smell of fuel in the oil? Thinned out at all? You will know it if it is!

Ok...lets just make sure of a couple things. Are you getting 12 volt to the pump....yes.....but is it a good strong 12 volts? BigRigTech learned me a few things about current. Check it with a test light, and it's fine....check it with a fog light bulb and it might be a different story.

When we did the 460 gas to 6.9 diesel conversion, I think he had a solid 12 volts with the key on....but while cranking it lost power and wouldn't run. Do you have a good 12 volts while cranking?

Take a wire, hook it to the wire on the right hand side of the IP and plug it into the positive side of the battery....start the truck. To shut it off, you must remove the wire...it won't shut off with the key. Try this first.

If you back ONE injection line off at the injector, don't remove it, just back it off and try cranking you will notice a little spit of fuel...like a drop or so. Hold the pump throttle lever WIDE OPEN and try again....Lots more fuel?

There was no surging at all....it was like someone just reached over and turned the key off eh?

Did the truck smoke at all? Blue smoke, or excessive black smoke?

You should fill in your signature and let us know what you have for a truck. Changing the pump lets us knwo you have some mechanical ability....so we have something to work with anyways

 

[icanfixall]

That is how the mechanical lift pump works. You will see the fuel pumping but not all the time. It works off an arm in the lift pump following a cam lobe made just for this action. If you placed a finger over the line it would build up pressure and the flow would be constant... You now have drained the injection pump when you removed the line off of it. Connect everything and this time crack open some injector nuts at the injector and hold the throttle wide open so more fuel and air goes thru the lines....

 

[MR.T]

That is how the mechanical lift pump works. You will see the fuel pumping but not all the time. It works off an arm in the lift pump following a cam lobe made just for this action. If you placed a finger over the line it would build up pressure and the flow would be constant... You now have drained the injection pump when you removed the line off of it. Connect everything and this time crack open some injector nuts at the injector and hold the throttle wide open so more fuel and air goes thru the lines....

I was thinking that too, but he wrote 3 seconds without flow. Sounds like a long time between pump strokes???

 

[Compu Doc]

I was thinking that too, but he wrote 3 seconds without flow. Sounds like a long time between pump strokes???

I'd hook everything back up the way it was with one exception. I'd take a gallon of diesel and stick a hose in the container that is connected to an electrical fuel pump with the pressure end going to the injection pump. If it starts then you know what your problem is and how to fix it.

With an electric pump you wont need to crank the motor to bleed air from the schrader valve near the filter. I have ran out of fuel three times in my truck in the time I owned it and not once did I ever have to bleed the injectors to get it restarted. All I had to do was belled the air from the schrader valve

 

[MR.T]

Doc, the electric pump sounds very handy -- good idea.

OHIDI83, what Icanfixall mentioned about a restriction to the lift pump discharge, and then doing your flow test again might help too. Maybe some clear tubing so you can watch for bubbles.

You might want to switch fuel tanks just in case you are sucking some air with a bad pickup or fuel valve that's acting up.

 

[OHIDI83]

Ok, before I took off the fuel line to the IP I tried to bleed the IP by loosening the injector lines and cranking with wide open throttle and I was getting nothing at the injectors. This is why I decided to pull the supply line at the IP. I am so confused this makes no sense to me. When the truck died it was dark and was not able to see anything from the tailpipe if there was anything. No surging or nothing. I'm sure I have twelve volts at the FSS b/c I have ran a jumper wire straight from the battery to the FSS.

 

[OHIDI83]

I laugh that you say I have some mechanical ability b/c I am a BMW technician. It's funny how we assume that some people have no idea.

 

[OHIDI83]

Ok, so I charged my battery's last night and got some motivation to try to get this thing started. I noticed that while cranking I'm getting white smoke out the tail pipe. The thing does not even try to start. Pulled the dipstick to check oil and it's oil. No milk. Also removed the radiator cap to check coolant and its coolant. No mixture of oil and coolant. What does the white smoke indicate? Not sure with this motor? Any ideas? Did I get a bad new IP?

 

[alienturtle]

It's funny how we assume that some people have no idea.

because some people REALLY have no idea. Thats what the forums are here for..questions and answers. and as icanfixall has already stated there is no such thing as a stupid ? on this forum.

to my knowledge the white smoke means coolant. has the coolant gone down any since you started?