cranks but won't start - Diesel Forum

gohdsl · 06-15-2008, 05:49 PM

once again I can't get my truck to start. about a month ago I had a starting problem(due to losing prime on my injection pump, I solved that problem by replacing the injector bleed off lines and all ran fine, til today). i went out to my truck this morning and it started, it ran for a second and started running rough then just quit, i cant get it to start back up.so I took my fuel filter off and replaced it with a new one(i primed it and pulled all the air out of the fuel lines) still no start. I then proceeded check the lift pump for proper operation and it was supplying fuel. Next I cracked an injector line off the injection pump, cranked the engine and no fuel was coming out. I hate to say the injection pump is bad. if so what would be some other signs that it might be bad?

bensonactec · 06-15-2008, 07:16 PM

I think there is a selinoid (electric coil operated by the key) on the injection pump, it is what basicly shuts them off when the key is turned off may want to check for voltage, and continuity there before condeming the ip

buford856 · 06-15-2008, 08:24 PM

If it is the solenoid you can check it with a magnet. turn the key on, place a relatively powerful magnet on the back of it and crank the engine over. if it starts pull the magnet off, if it dies its the solenoid. (assuming you checked for proper voltage first) Its probably not the way the dealer would check it but we have alot of equipment with electric solenoids, sometimes you want to check it without removing it, this works great.

gohdsl · 06-15-2008, 11:56 PM

what should voltage and resistance be across the solenoids cause I believe there are two of them?

cdnsarguy · 06-16-2008, 06:00 AM

Starter speed is a major requirement.... if you can count the engine RPMs it's too slow. The (FSS) fuel shutoff solenoid operation only removes closing tension on the metering valve which is spring loaded to open. If the MV is rusty, stuck, etc then it will not open and allow fuel to the internals of the IP.

Try the lift pump test below........

Take the filter header Schrader valve core out and hook a hose and pressure guage to the outlet.........crank engine see what you get for pressure, should have 4-6 psi from a good lift pump.
Volume test same place hook a hose to it crank over the engine 10 seconds you should get 1/3 pint of fuel minimum.
****Important the fuel shutoff solenoid (FSS) wire on the IP should be disconnected if you do not want a start just cranking. Re connect FSS after test complete.

gohdsl · 06-16-2008, 10:12 AM

when I installed my veggie oil kit I had to totally re-route my fuel system. in the stock configuration the lift pump pushed fuel through my fuel filter, however because of the kit it now has to pull fuel through the diesel fuel filter and the veggie fuel filter, so instead of creating pressure in the fuel filter it now creates vaccuum. so would that mean I would need to look for a specific amount of vacuum in in/hg?

gohdsl · 06-16-2008, 04:05 PM

I checked the three solenoids on the IP the lowest voltage reading I got was 11.85 V. the cranking rpms are fast enough to where I can't count them, and the lift pump puts out plenty of fuel. however there is still no fuel coming from them injection pump while cranking.

gohdsl · 06-18-2008, 02:50 PM

does anybody think possibly that the pump could still be losing its prime just like it did before I replaced the injector bleed off lines?

cdnsarguy · 06-18-2008, 04:39 PM

Could be there are numerous leak points.......... check out the info below...

http://www.intellidog.com/dieselmann/filter.jpg

gohdsl · 06-19-2008, 10:34 AM

what are signs of a bad IP? does it just go out? or do you just start losing power? I think its the IP because when it was losing its prime previously it wouldn't start at all(after it would sit for an extended period of time), but before it died it did start I just could get it to start back up. I've already pulled the IP off I might try to rebuild it or just go ahead and get a remanufactured one, cause I do a lot of driving and I need something dependable. It has already been replaced once I don't know when though. The truck has 150K on it. DB2 pumps are known for going out and not to be the most reliable IPs.

icanfixall · 06-19-2008, 01:20 PM

When you were cracking open the hard lines and bleeding out the trapped air did you hold the throttle wide open? If not then try it again but at wide open throttle. These injection pumps put out very little fuel with each stroke at idle settings. Even at full throttle its very hard to "see" ant fuel squirting out.

gohdsl · 06-19-2008, 05:54 PM

thats the thing there should of been fuel coming out even during cranking. I put a rag where i took the injector line off of the IP and it wasn't even moist after cranking it for a couple seconds.

gohdsl · 06-19-2008, 11:45 PM

before I pulled the IP I noticed that there was a little bit of fuel sitting on top of it, could this be from a bad seal/gasket somewhere within the IP?

razerface · 06-22-2008, 08:51 PM

I am working on the same problem. Good crank rpm's. Mine will start,,,run 1-2 seconds,,,,die,,,,,crank for 3-4 minutes and it runs.

gohdsl · 06-26-2008, 09:40 PM

Quote:

Originally Posted by razerface

I am working on the same problem. Good crank rpm's. Mine will start,,,run 1-2 seconds,,,,die,,,,,crank for 3-4 minutes and it runs.

you might want to replace the injector bleed off lines between each injector, cause mine did that earlier this year and I was having the same problem..it fixed it.