Does Bosch pump need a lift pump?

[meerkatmag]

My Lucas cav was upgraded to Bosch, never had a lift pump on the engine before and one was not fitted. Now there's a loud whine coming from pump at half throttle above 2000rpm. I'm thinking it's being starved of diesel and needs a lift pump?

Does this sound right or is there another possible cause?

Thanks!

[V184]

I thought all cav models had a lift pump either on the filter housing or later ones on the block unlike the early Bosch one that had no external lift pump, perhaps the noise is the cambelt

[meerkatmag]

I may be wrong but I thought the early di didn't have a lift pump and later did? I've got a fuel filter housing with a manual pump on which I think was fitted instead of a lift pump.

The whine comes and goes with throttle movement. I can make it stop by moving accelerator back by a few milimieters and start again by moving it forward so I'm thinking it's injection pump as revs are barely changing surely belt would be unaffected by small movement of accelerator?

It starts suddenly at about approx 2200rpm and sounds the same as revs increase. The sound stops if i release the accelerator completely or if I put accelerator to near the floor.

Weird isn't it?

[V184]

I may be wrong but I thought the early di didn't have a lift pump and later did? I've got a fuel filter housing with a manual pump on which I think was fitted instead of a lift pump.

The whine comes and goes with throttle movement. I can make it stop by moving accelerator back by a few milimieters and start again by moving it forward so I'm thinking it's injection pump as revs are barely changing surely belt would be unaffected by small movement of accelerator?

It starts suddenly at about approx 2200rpm and sounds the same as revs increase. The sound stops if i release the accelerator completely or if I put accelerator to near the floor.

Weird isn't it?

As i said, I thought all cav models had a lift pump either on the filter housing or later ones on the block

[bambi mk 1]

Phillips screws in the rocker cover no lift pump ,10mm headed bolts in cover lift pump Lift pump was fitted to stop them cracking pistons but didnt till they fitted Bosch pumps

[V184]

Phillips screws in the rocker cover no lift pump ,10mm headed bolts in cover lift pump Lift pump was fitted to stop them cracking pistons but didnt till they fitted Bosch pumps

to answer the original question i would not think not running a lift pump would cause the noise

[bambi mk 1]

Phillips screws in the rocker cover no lift pump ,10mm headed bolts in cover lift pump Lift pump was fitted to stop them cracking pistons but didnt till they fitted Bosch pumps

to answer the original question i would not think not running a lift pump would cause the noise

The belt is probarly too tight

[meerkatmag]

Rocker cover has torx screws, don't know if they're original though. I'll have a root round and see if I can spot a lift pump that I've missed.

Thanks for help so far, so you think it's probably the cam belt? Does that fit with what's happening with throttle? Cam belt changed about 2 years ago but was refitted with the pump about a year ago. Noise been there since then, very quiet at first, but slowly gettinf louder. I might try to record it and post a video.

Cheers

[cherniy_chack]

Several years ago, I was repairing Transit, where the crankshaft burst and broke the cylinder block.
An old cylinder block was purchased without a lift fuel pump.
The motor was assembled and started normally if the tank had at least 25% of the fuel.
It worked normally and without noise at any fuel level in the tank.
Noise after replacing a high-pressure fuel pump can be caused by excessive tension of the timing belt or malfunction / wear of the Bosch pump.
First, change the belt tension.

[wojciech]

Maybe the reason for the noise is yet another?
The question is what timing belt you have now.
2.5D engines in 1984-1991 had a timing belt with 2.5mm high teeth and 25.4mm wide (nr 6138677). Since 1991, the timing belt has a tooth height of 3.5 mm (nr 1135355), and in 1997 its width was increased to 28 mm (nr 1135354).
If you still have crankshaft and camshaft gears with 2.5mm teeth, you should use a timing belt with the same height teeth. Even if the pump has a gear with 3.5 mm high teeth (Bosch from the period after 1991). The belt with high teeth will make a noise on the wheel with low teeth. In contrast, the belt with low teeth will work correctly on the wheel with high teeth.

[Jim Archer]

In theory, no the Bosch VE doesn't need a lift pump when fitted to Transits and their higher than normal fuel lift requirements, in practice, yes they do - otherwise Ford wouldn't have spent out on fitting them.

When did it last have a decent quality fuel filter?

The whine is the pumps internal lift vane pump cavitating due to fuel starvation.

Jim

[meerkatmag]

Fascinating stuff thanks so much.

I believe the belt was not changed with the new pump pulley, so I think it's the same size teeth as the van originally designed for. However I'll ask the garage that did it to be sure they didn't change. The pulley was definitely changed.

I thought the noise sounded like fuel pump starvation, reminds me of a pump that is running dry. I changed the fuel filter recently myself and it's not affected the sound really other than being a little louder the last time I took it out. The van is running much better now otherwise. Couldn't be an air lock could it?

I think possibly the fuel level in the tank does affect how loud sound is so that was what pushed me towards the lift pump however I haven't done extensive tests to be sure about the fuel level.

I'm a bit worried if the cam belt is over tight so was planning on trying to reproduce it with my head in the engine bay and pin point for sure where it's coming from.

Thanks

[meerkatmag]

So I fitted a lift pump near the tank and bled the high pressure fuel lines. Although the whistle is very quiet now, barely audible it's still there. So I guess it wasn't fuel starvation after all? I'll keep on diagnosing, I can't get it to make the noise when the van is parked, only seems to happen when it's being driven. So I can't be sure if it's the pump or the cam belt from the drivers seat.

I'm going to pop it to the garage next week to see if they have any ideas.
Cheers for the help.

[bambi mk 1]

Are you sure its not this viewtopic.php?f=4&t=188919&hilit=whistle&c=1

[meerkatmag]

Are you sure its not this viewtopic.php?f=4&t=188919&hilit=whistle&c=1

Haha yeah maybe it is! pretty fast now with all the work that's been done. They way he describes it is very similar to my van. If the whistle is quiet (like it is today) it's no bother at all. But last week it was so loud it sounded like the pump was going to explode.

I'll do some more research on whistle from exhaust. Thanks!