new head on....loud hum at 1000 rpm, wont go over 50 mph

[draper3000]

Good evening, (I have a 4WD 2.5 TD Bongo)
So after 4 months of slow painful home labour (machanics not pregnancy), with many many hours of help from my Dad,we have a new Cylinder head, new gaskets, some new pipes, all on my Bongo. We broke a few bits here and there that we had to fix on the way.

But....

Just been for the 2nd test drive today...and found that:

There is a loud and deep hum at 1000 rpm,

Wont go over 50 mph, no extra power in the higher gears.


Any ideas welcome:

Could it be:

Turbo not working properly?

Injectors? not working properly (went back in fine?)

One of the Valve/Solenoids got broken and possibly not perfectly fixed. Not sure what they do but maybe they control fuel flow at higher speeds?.... (its part 18-741C on the below linked diagram)

http://www.lushprojects.com/bongopartsm ... 03.html#13

Any help would be great, otherwise its off to a garage for £60 diagnosis....

Cheers
Jon
P.S. This has been a long slow drawn out cylinder head change, most definitely an education in the workings of a bongo.

[dandywarhol]

If its got a winter pack the exhaust flap could be closed. Or something trapped in the air intake.

[draper3000]

how would I know if it has a winter pack on....where abouts would it be closed?

Would that cause the loss in power as well as the hum at 1000 rpm or do you not think they're connected?

The air intake should be completely clear.

[bigdaddycain]

Have you got a switch near your drivers knee with a picture of an engine on it? (should be next to the "rear" switch if you have manual aircon...)

[missfixit70]

Winter pack has a switch by your right knee - when you're sat in the drivers seat, operates a valve in the exhaust under the passy seat, fitted to bongos from the north of Japan with twin battery set up.
The solenoids you're asking about aren't anything to do with high speed, assuming you mean the 4 under the drivers seat? the 2 rear ones are to do with the egr & the other two are to increase the cold start idle speed & idle speed when a/c is on.
Not sure about the humming, but it does sound like it could be a turbo issue.

[bigdaddycain]

Have any pipes around the turbo been disturbed?

[draper3000]

thanks for replies..

yes pipes around turbo have been disturbed, some were disconnected, when removing the old head.

Not sure if I have switch by drivers knee, never noticed it. Obviously have the bonnet pull pull lever and the fuel cap lever.

[You've Been Bongod]

check your vacume pipes

my mazda 6 had the vacuum pump changed and was exactually the same and i noticed i had put 2 vacuum pipes the wrong way and as soon as swapped them back it was fine

[missfixit70]

thanks for replies..

yes pipes around turno have been disturbed, some were disconnected, when removing the old head.

Not sure if I have switch by drivers knee, never noticed it. Obviously have the bonnet pull pull lever and the fuel cap lever.

Higher up than that, above the fuse box, lower bank of switches will be one of two switches/blanks if you have it.

[draper3000]

Just been out and looked for switch by drivers right knee. no luck there I dont think.

Above the fuse box there is 1 switch with a picture of a fan with 'REAR' written on. I'm assuming that turns on and off the rear air con, though I'd never noticed it before.

...

Question to 'You've Been Bongoed'...

Did swapping the vacuum pipes over solve both the speed and noise issues?

Also can you please explain where the vacuum pipes are. Are the vacuum pipes connected to the valve/solenoid thing I mentioned at the top???

Cheers

[bigdaddycain]

It sounds like you don't have the winter spec bongo then, if you saw the "rear" switch, you'd have seen the switch that closes the flap in the exhaust. (the switch with the pic of the engine on it) Are you absolutely certain that all the pipes/tubes connections to the turbo have been returned eactly how they should have been? Could something have been damaged when they were disturbed? We are talking high pressures associated with a diesel turbo engine here, anything amiss on that front would most definitely affect the power!

[draper3000]

I'm pretty definite that all the turbo pipes were returned and secured properly. One was replaced as it was quite worn.

I guess I will investigate the vacuum pipes, maybe try and find a replacement for the one that we fixed. If its still not right after that, I will finally bite the bullet and pay a garage to take a look, and investigate the turbo side for me.

Baby on the way (due in January) so the less I spend on the Bongo the better really. Now thinking we may have to get the bongo fixed, get it perfectly running then sell the old girl and buy a family car...Citroen Xsara Picasso is current front runner.

[dobby]

Wouldn't buy a Citroen unless you've got deep pockets, our Xantia nearly bankrupted us.

[bigdaddycain]

Citroen Xsara Picasso is current front runner.

Oh please no, they are even worse than the Vauxhall Zafira!

Have you ever noticed that the only "cars" that seem to be on the back of an RAC lowloader is either the picasso, or the zafira?

Let's get that bongo of yours fixed!

[draper3000]

funny you mention the the Zafira....thats no.2....

Basically after looked at What car for family....on their MPV chart the Zafira is no.1. and the Citroen is no.3 I think.

Maybe I should go back to a VW Bay Window (Perhaps a new one), at least when they brake you can generally get your hands in and fix it quite quick.

Do you think its ok to drive the Bongo whilst I wait for a new Vacuum Pump Valve thingy..

??
Please say yes, as I'm now running late for work (If cycling) as I couldn't resist the chance to finally drive to work again.

Cheers

Jon