Starting

[becketts]

Hi Guys,i'm a member from over the pond with a problem ! can you help?.I've owned my K5 for over fifteen years with hardly any problems,having said that i now have one!,i had a blown head gasket so while i was changing that i thought i may as well " because no work had been done to the fuel system" change the old fuel injector pump and injectors,having obtained reconditioned parts i fitted everything back together and alligned all timing marks,i cannot get the darn thing to fire up,glow plugs are ok and when i turn the engine over with a glow plug removed i get a good puff of vapourised fuel.
I've read that because of timing chain stretch i might have to move pump to get proper timing ,is that correct?,I'm at a loss as to what to do next!!!not many people over here know anything about these engines.Regards Paul

[john8662]

My guess is everything is still air-locked. If you lined up the timing marks, you should be close enough to start and run pretty good. To bleed the fuel system, loosen all 8 injector line nuts going to the injector. Charge the batteries up to full, then crank in 6-8 second intervals, letting the starter cool for about 2 minutes between cranks. You will crank the engine until you see fuel weeping from the loose injection line connections. When you get that happening, tighten everything back up, make sure you're getting good glow plug heat, and it should crank up after a crank or two more.

[NH2112]

My own extensive experience with airlocks :( shows that you can reliably start an airlocked 6.2L with only 2 injector nuts loosened up. This makes things much easier if you happen to have AC :D Just give it a bit of fuel till it smooths out.

[waorth]

Hi Paul

engine starting after changing pump/injectors:

- make sure your starter and batteries are in excellent condition

- connect everything like it should be (injectors, return lines etc.) Keep an extra eye on the pink power supply cable on top of the pump.

- remove ALL of the glow plugs

- do several start attempts, no longer than 20sec each and breaks of 2 minutes between to cool down the starter.

- after about 5 attempts you should get a good deal of mist of diesel out of ALL of the glow plug holes.

- install the plugs and start engine. Should start in no time. Put the throttle more to the floor than usual, to keep her running and pumping the rest of the air out.

This procedure helped for me in the past 7 years. You'll be amazed how fast your starter will turn without any compression. This keeps the stress down on starter and batteries.
IMHO open and close of the injector lines (with adequate torque) is more difficult than removing the plugs.

However last week I installed an electric fuel pump, so for future bleeding I should be able to do it without even cranking the engine. :D

Hope I could help a little. ;)

Regards from the continent. Walter

[becketts]

Hi Guys;
I will try what you suggest and see what happens!!,I will though mention a few details both to help me understand this engine and to give you more details.When i decided to change the pump i made sure that once the engine had stopped it wasn't turned over again until the job was finished,therefore the crankshaft gear,camshaft dear and the timing chain never moved,we haven't any special equipment over here that i can get my hand on to reset the timing,I marked up the pump gear in relation to the camshaft pulley before removing the pump gear so everything went back on as it came off.My question is this!! can you put the pump gear back on the pump with the pump 360 degrees (one full rotation ) :confused: out.
I was told by a diesel fitter over here that the engine should fire up with the Front cover/Pump alignment marks as much as 3/8" apart,rough but running.I've turned the engine over with 4 glow plugs removed and i get good diesel vapour,i will now try it with all 8 and also make sure there's no air in the lines.
All glow plugs are working in properly,and although one of the batteries is 7 years old the other is brand new,should i get another new one to replace the old one ?.

[TanM998]

I have had this problem with my truck, and I infact sent my pump back to the repair guy 3 times before I figured out it was a fuel delivery problem. The best way to diagnose this is to get a clear tube and connect it from the fuel filter to the injector pump. This clear tube shouldn't have ANY, and I mean ANY bubles in it in order for your engine to run.

Check that first, I am almost positive that the issue here is fuel delivery not anything else. I tried to bleed the air out at the injectors and it didn't work I had to crank the engine and then while cranking had to install the hose to the injector pump for it to be properly blead.

Your correct on everything with the timing. There is a big gear attached to the crankshaft which meshes directly with the gear that is bolted onto the injection pump. Even if the engine was cranked over with it out it still would be timed correct due to the pin on the pump which has to be seated in the gear. The timing marks that are on your truck right now are really worthless for your new rebuilt pump. But they can be a starting point, you DEFINATLY need to get the engine timed correctly now once u get it running.

But try the clear tube and then go from there. If you consistantly get air bubbles while cranking then you have an air leak in the suction side of the fuel system (from the tank to the lift pump).

Scott
'85 Tan M998 W/CTIS

[becketts]

Thanks TanM998 I'll try that! ,although today i tried a few other things,1st i rechecked the glow plugs OK,2nd while the plugs were out i turned the engine over and a good spurt of diesel vapour came out of all 8 cylinders although some were better than others,fuel solenoid was ok.Looking from the front i rotated the pump clockwise almost 1/4" away from the timing marks and it did make a feeble attempt to fire up! but before i could try again the batteries were flat
One point i should mention is that the pump i have on now although correct according to Oregon Diesel is not the same number as the one that came off,somebody in the past had installed a DB2 4091 pump off a 1981-2 engine instead of a DB2 4502 that should be on my 1985 one,what difference that would make perhaps somebody knows.

[TanM998]

If your glow plugs worked before, they should still work now, afterall there wasn't anything in that system that changed.

The timing marks on the injection pump and on the housing are stamped on there for the original pump / housing. If you install a new pump or have the old pump rebuilt these marks are null and void. The best thing to do is ignore them. They can be a starting point for your initial timing, but you REALLY need to have it timed professionally where they will take fuel pulses out of the no 1 cylinder similar to a gas engine where they use spark. This tool just costs a lot of money so no back yard mechanic that I knows has one.

Even if you get fuel out of the cylinder when the glow plug is out, there STILL might be issues with air in the system. You really need to just put a clear tube on the inlet to the inhjector pump. If the fuel is clear (no bubbles) then the only issue left is the pump either isn't working properly or it isn't timed in a way that the engine will run... If thats the case best thing to do is call the place that you would get the engine timed at once it is started and ask them for suggestions (or the place you got your injection pump from)

Hope this helps...

Scott
'85 Tan M998 W/CTIS