Bosch VE pump; won't idle after rebuild

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Flynn
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Posts: 30
Joined: Sun May 27, 2012 1:23 pm
Location: England

Re: Bosch VE pump; won't idle after rebuild

Post by Flynn »

Okay guys; I might have something to offer her in way of an explanation. Let's just have a recap on how it all started. The original pump was leaking, I pulled it to renew the distributor head seal. It initially fired up then died again, I thought it just had air in it. But it kept on doing it so I knew something wasn't quite right. Five rebuilds later I had the same problem. Another pump had the same problem, I had done nothing but light modifications to it (stupid I know). Every obscure problem under the sun was investigated-nothing worked.

I had tried the clear fuel lines and although they showed up a few tiny bubbles every now and then, I replaced the lid seal which seemed to stop them, but not stop the problem.

Dare I speak too soon but if would appear some calibrations were thrown out on the original pump. I had no throttle rest screw to begin with on that pump and it worked fine, so obviously no reason to suspect it. It would idle fine if I used the grommet thing on the throttle cable (that you can use to slacken or tighten the cable) but since the rebuild it must have thrown out the calibrations somewhat (I used levers out of another pump) so then I couldn't fine tune the idle enough with the grommet on the throttle cable bracket. All this is what I am assuming was the problem with the old pump, I haven't actually tested it but the new pump had the same symptoms and they seem to have been solved by replacing the throttle rest screw and adjusting it. It offers a degree of very fine adjustment that you can't get even with the splines on the throttle shaft.
Flynn
Cetane Booster
Posts: 30
Joined: Sun May 27, 2012 1:23 pm
Location: England

Re: Bosch VE pump; won't idle after rebuild

Post by Flynn »

Just thought I would post an update on this, since I did get a lot of advice. It turned out to be that the fuel filter was blocked to the extent that it was affecting the injection timing slightly. With a new filter in the engine was as good as new. As it turns out the pump that I had rebuilt was fine in the end. For some reason the new pump that I had put on seemed to work for a few minutes but then revert back to the behaviour of the previous pump.

Edit: I just realised I said the rebuilt pump was fine before I rebuilt it, this was a mistake. It was leaking from the head seal but I believe afterwards the blocked fuel filter lead me to continue to believe that the pump was still faulty. So it was a combination of the two.
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