Rough Start

mtb.rxstar · #1 03-23-2011, 07:13 PM

So I've got a '82 244 D24. At the time of purchase (a month ago) it fired up like a champ. I drove it around with the previous owner and everything seemed to be pretty good although the acceleration was a bit slow but that might have just been a perspective thing since I just drove there in a VW GTI mk5. I drove the car home that day (90 miles) and the next day I went out and the car wouldn't start

After a while I figured out that I'm getting air in the fuel pump (Bosch VE) and that if I just kept cranking the engine over for 15-30 seconds it would sputter and then fire up. Once running I can drive it around and it will be just fine, although if it's been idling for a long time and I push the accelerator (to the floor or anywhere in between) it won't rev up. I can coax it to finally accelerate but after (15-30 sec) a while of very low pressure on the pedal. Also, when I rev the engine manually while looking at the engine and pump a few bubbles and some drops of diesel form around one of the distributor pressure valves and leaks down.

So is my 'air in the pump' diagnosis right? I already replaced all of the low pressure injector hoses and fuel 'to' and 'from' hoses so other than the pump I'm not sure what else it could be. Am I looking at a pump rebuild? or do I need to work on bleeding the pump better and if so how?

That's about all. Thanks for reading and any advice would be great.

ngoma · #2 03-24-2011, 12:23 PM

IP and injectors are self-bleeding. Shouldn't leak anything from the distributor head outlets. Are they tight in the dist. head, and are the nuts on the injector lines tight (not too tight!)? Clogged fuel filter can limit revability.
If it still has the clear hose from the fuel filter to the IP, try shining a light behind the tubing to see if air bubbles are entering the IP inlet.

nick · #3 03-24-2011, 01:17 PM

Have you had the chance to verify all the connections are tight with a wrench?

If you find the fuel system to be in good working order, I'd check the pump timing. Before you mentioned the fueling issues it sounded like you were describing a condition where the sprocket on the cam shaft slipped (the one for the IP) and retarded the timing.

mtb.rxstar · #4 05-07-2011, 05:18 PM

Well I found the culprit of the air leak...the main shaft seal. It was in there all cock-eyed. So now after having spent a weekend rebuilding it I'll need to see if it starts...

mtb.rxstar · #5 05-26-2011, 07:05 PM

So I installed the pump last weekend made sure my marks on the timing belt were all lined up, filled the pump with diesel, hooked the fuel lines and sucked diesel through 'Out' hose, installed all the accelerator/cold start stuff and turned the key...nothing.

Ok well I suppose back to the diagnosing drawing board.

Removed an injector line, cranked, no squirting fuel, not even a dribble. Ok...
Electronic shut off valve--electricity? Yep. Huh...
Timing belt skipped? Nope.
Accelerator flywheel properly installed? Think so.
Cold start properly installed? Think so.

Well I'm out of ideas besides, pride aside, incorrect assembly of the pump, but I'd like to exhaust all 'external' possibilities. So if anyone has any ideas I'm all ears!! Thanks.

v8volvo · #6 06-02-2011, 12:41 AM

I am working through something similar with another member here (ngoma) on a 1985 D24T engine with a pump that we re-sealed. It turned out that part of the internal throttle/governor linkage came apart in the top of the pump as we were assembling it, without our realizing it. The car wouldn't start after reassembly and the pump barely moved any fuel into the injector delivery lines. Finally discovered it was because there was no throttle control, and very little fuel volume being injected. In the process now of fixing it, and hoping this will get it to fire up.

Working inside a Bosch VE pump isn't simple stuff and there are a million paths to having a problem on reassembly that will keep the car from running, or at least running right. If it's not putting out any fuel, you need to figure out what the source of that problem is, even if it means taking it to an expert.... until then, without any fuel being injected, it ain't gonna run.

How far did you take the pump apart? Just a front shaft seal and the rest of the external seals, or more than that?

mtb.rxstar · #7 06-24-2012, 04:48 PM

Well admittedly I haven't touched my Volvo in almost a year! Yikes! I even considered selling it not running! No excuses but at least now I'm back at it.

To recap, I stripped the pump down to its shell, rebuilt with new seals, bled the air out with a vacuum pump from the return line, double checked the shut-off clicks when given 12v, cranked for a little bit and nothing comes out the injector lines. Once that didn't work I cracked the top to check the throttle linkage as per v8volvo's advice assembled. Still nothing.

I guess my question is shouldn't it start squirting diesel within the first 15-30 seconds of cranking or do I need to risk burning the starter motor out to get it to start working? Or is improper assemblage the only explanation? Damn that thing is a beast to get out of the engine bay!!

ngoma · #8 06-25-2012, 09:47 AM

Yes, it can take considerably longer than 15-30 seconds. Especially if the injector lines are dry. Give the starter motor sufficient time to cool off between attempts. Also important: Keep the accelerator lever wide open, to help speed more fuel thru the system.

If you are concerned that the IP is no longer operating correctly, you can loosen the injector lines at the IP side to see sooner if it is pumping fuel, without having to wait for the injector lines to fill.

michaelovitch · #9 06-29-2012, 03:05 AM

Buy a manual diesel fuel pump (the ones you squeeze by hand with one way valves) and use it to prime the pump.
it's cheap and avoid to crank like mad and burn your starter.

just reinstalling following the marks will not be enough.
you maybe will start it but you need to adjust the pump accurately then.

v8volvo · #10 06-30-2012, 03:38 PM

Agreed with the two above suggestions. First ensure that the pump is properly primed -- much faster and easier on your starter if you use some kind of external feed pressure (e.g. hand primer bulb or low-pressure electric lift pump inline before fuel filter) to help the process along, and even then it does take considerable cranking. Give your primer bulb some good squeezes until you feel some resistance build up, or energize your lift pump, then keep injector unions loose and hold fuel pedal to the floor and crank until a good amount of fuel is running out of all six of the unions.

Then you get to close them back up, and see if it will start. If it does, hooray. If not, you get to figure out whether it is a fuel delivery or injection timing issue, or even a glow plug problem. Look and smell for white smoke from the exhaust. If present, then you are getting fuel into the combustion chamber, but either at the wrong time or without preheating from the glow plugs. If it will start but only poorly, or won't stay running, or makes big smoke and noise after it starts, then you need to check timing again as well. If no run and no smoke at all, then you are still not getting fuel through the injectors, which, assuming the pump is adequately primed, indicates an internal pump problem such as a broken high pressure piston or a problem with the throttle linkage that you didn't catch before. Hopefully you won't have to go there!

My guess is that once you get it primed and timed, it will fire up just fine.