Truck won't start after turning up pump

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guys, I need help!

I decided to turn up the pump today and I followed the instructions I found on http://www.ecpe.vt.edu/~dfritz/technical/DIESEL/more_power/POWER_ve.htm
I had to take the power adjustment screw completely out to remove the lock collar. I made sure to make witness marks before doing this. I turned the screw in one turn more than stock. When everything was buttoned back up, I went to start it it wouldn't fire. I had a friend with me so we bled the lines, still nothing. We also tried bleeding the low pressure side and manually priming the pump.

I know it shouldn't be this complicated, am I missing something simple?
Thanks,
Rob

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93 W250 LE, CC, 4x4, 5spd

[This message has been edited by RobM (edited 02-08-2000). ]

 

[Archive]

Your link doesn't work, so I don't know what you followed.

You made a relatively serious error when you pulled the screw out all the way. You should not have done that. That screw is a stop for the governor lever that controls max fuel. I can't swear to it, but it's my guess that the lever slipped forward and pivoted below the screw, and now is permaently stuck in the "no fuel" position. If you are supremely brave, you could take off the top cover and verify this. However, since you are not a pump technician, I don't think you should.

Take the pump off, take it to an authorized Bosch service dealer, tell them what happened and how (yes, even if you get that rosy glow on your cheeks - I would get it, at least), and they should be able to fix it for you without all that big of a bill. Ask them to crank it to the max of the spec (and maybe fudge a bit) and give you an extra 50 rpm's or so beyond. Your bill will probably be in the $200 - $250 range if you did not damage anything, and they run it on the test stand. Less if the just right the governor and put the screw back in.

If you are seriously bent on fixing this yourself, email me, and I'll do a bit of hands on researh to verify my theory, as well as provide you with some detailed hints and instructions BEFORE you touch anything.

Lastly, make sure that you didn't accidentally knock off the wire to the solenoid, or even somehow break it. that would prevent it from starting... #ad
BTW, there should be 2 wires to it (it's just below the screw you took out, sticks up off the rectangular part of the pump just behind where the lines connect). Best of luck.



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Let's see, a tagline goes here. Something witty, perhaps? Maybe just profound? Naw. Can't think of a single thing to put here.
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Been a fuel injection tech for 13+ years. Someday, I'll actually LEARN this stuff...

 

[Archive]

Hi Rob, don't panic yet. Look below the fuel screw & you'll see the start/stop soliniod. Check that the wires {2} are both connected. It's real easy to knock the wire off when you are adjusting the fuel screw.

 

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Sorry about the link, its correct now. As far as removing the screw, I was following this tip from that site:
"From Dave Ellingson <d. ellingson@worldnet. att.net>
The easiest way to remove the collar is to back the whole unit out of the pump, put it in a vise and remove it (the collar). Be careful not to turn the screw in the lock nut as you are doing this or you will lose the "known" setting of the pump. After removing the collar simply reinstall the unit and adjust accordingly. "
It seems that it would be almost impossible to remove the collar while the screw assembly is in the pump as it is tack welded to the threads.

I am still getting fuel to the injectors, I believe, because it squirted out when we bled the lines at the injectors as I cranked the starter. Is this logical thinking???

Rob

 

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Well, I thought this problem was solved this morning but I guess not. #ad


I went out and checked the solonoid wires and they both seemed ok but I reseated them to be sure. I got in the truck and it started as if nothing had ever happened. The idle was about 150rpm higher than normal at 1000. I let her warm up for just a couple minutes and went for a test drive. It ran great with a noticeable power increase (and smoke). I drove about 5 miles or so with only one 'hiccup' where at a steady 45mph or so it just seemed to miss once for a split second like it had an air bubble. Other than that it ran better than usual. I got home and let it cool for a few minutes and shut down. I tried to start again about 15-20 minutes later and nothing #ad


any ideas?
Thanks,
Rob

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93 W250 LE, CC, 4x4, 5spd

 

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I think my problem is finally solved!
after sitting for a while the truck started again but died after driving about 2 miles. It did start right up after dying but quit again a moment later. Then I drove it on the highway about 20 miles and it hasnt happened since. There must have been some air in there somewhere I guess. ???


Rob

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93 W250 LE, CC, 4x4, 5spd

 

[Archive]

Rob, I emailed you about this, but it looks like you got things going. I would strongly encourage you to make sure your supply pump works well.

The difficulties in getting the air out are a hint that you might have no supply pressure, and that air is getting trapped in the filter.