Problem bleeding bosch fuel injector pump

[Winmac]

That fuel under the cover would never see those high pressures the article mentions.
What was there for a gasket, I'm thinking there are orings but it's been awhile since I had one apart.

A rebuild would be the last resort unless you have several hundred dollars to spare.

 

[jrchafin]

Agree on the rebuild. Going to replace the gasket and see how it goes. The gasket is definitely a specialized one. Looking online, many pumps have an O-ring sealing this, and it looks like they also fail frequently. The guy at the injection pump service told me that the newer models have this specialized gasket. It is a stamped piece of metal coated with a tough, flexible rubber type material. It looks like the rubber coating disintegrated on the old one which is what caused it to leak.
If it lasts another 6 years I'll be fine with that. If it fails quickly, I'll have the pump rebuilt. Just need a day off from work so I have time to reinstall everything.

 

[JimRB]

If you send me a note I can send you a few Bosch manuals that explain VE pumps.

 

[JimRB]

Or do some Google searches. Bosch VE diesel fuel-injection pump manual. - 4x4 Community Forum

 

[jrchafin]

Thanks for the manual link. It gives a decent overview of what's going on in the pump. Couldn't find PSI in that chamber though. That's OK. I have a new gasket and we shall see if it works.

 

[jrchafin]

So finally got time to put the new gasket in my fuel pump and re-install. It doesn't leak any more, but unfortunately doesn't run right either. I think there may be something wrong with the pump, but before I take it for a rebuild, I want to make sure I'm not missing something I can fix.

It's a VE type injection pump, which runs off a pump gear with a woodruff key. I did not crank the engine or move the location of the pump gear while the pump was off, and did not rotate the pump either. I was careful to align the key with the pump gear when I put the pump back on, and I've aligned the timing marks between the pump housing and the engine block. The engine runs, but very rough and has some strange behavior.

It starts and idles fairly well, but when I give it fuel, it doesn't do anything at first. Then, once I add enough throttle, the engine takes off and jumps up RPM, running fairly well, but still rough. It smokes gray intermittently, and even back fires some.

Controlling the throttle on the pump itself with my hand, the first inch or so of rotation doesn't have any effect in the engine, and then it suddenly takes off, jumping to 2000RPM or so. If I release the throttle it returns to a rough idle. So is something stuck inside the pump? I can't see any other explanation for why the throttle would be doing this.

Any advice on troubleshooting would be much appreciated.

 

[adietrich1214]

I just had same problem with my 6530 mahindra. 2000$ later after a pump rebuild found that these bosch pumps REALLY suck.
299 hrs and basically a common issue is for there timing piston to fail and go out of normal movement range. this lets it chew itself and the entire timing apparatus , hitting the outer plate and causing the gasket to finally fail. This is the piston that runs perpendicular to the engine just under that gasket plate on the inner side of the pump. Ernie at D&W diesel in Syracuse knew exactly what it would be and was able to describe to me exactly symptoms and what the plate would look like.
Not a mahindra part but really lousy for a 3500-4000$ part.
Apparently this timing piston and circuit are very hard to bleed so if pump goes dry even once, there can be air that doesn't leave and results in the timing piston rattling to auto destruction. You get smoke and failure to reach rpm above 1400-1500 as well as loss of power.
I'd suggest not fooling around with the inner gasket and get it in to a reputable pump shop ASAP.
On the 6530 and I suspect other mahindras, be careful removing pump. easy to crack the timing cover(we did and fortunately had a talented welder who could weld the mediocre cast material around there pump shaft access plate) to do it again Id go straight to removing the timing cover and gain proper access. hope this helps someone.
I will be contacting Bosch.....

 

[thepumpguysc]

NO NEED to contact Bosch.. They have already determined the cause & there is a service bulletin that states the reason..
Dirty filters & or air in the system.. NO WARRANTY..
I've seen pumps that were replaced w/ 20 hrs on them, destroyed internally.. because the customer didn't change the filters.
Another good preventive measure is> replace the lift pump, if so equipped..
I've rebuilt hundreds of those pumps for the same reason..
Air gets in the system, starts hammering away at the advance piston.. the small clip becomes dislodged & eats the internal aluminum housing to bits..
The first symptom is loss of power, hard start & then leaking pump at the advance plate..
I cant count how many calls I get for>> "do you carry the gasket that goes on the little plate at the bottom of a Bosch pump??"
a $3.00 gasket usually turns into a $2000.00 pump.. The main pump housing ALONE is $500.00 list price.

 

[adietrich1214]

Right but to make a pump that touchy and reportedly difficult to bleed the advance piston seems ridiculous. Getting rid of this machine. All maintenance was followed per manual.