Turbo short circuit to positive..??...FIXED.....

[GingerMagic]

Update...

I was thinking to myself 'why does the swirl-flap move back really slowly when powered by the turbo EV vacuum?' when I had a look at the vac pipes from the pump to the turbo EV and there was a kink in the pipe.

I was a very relieve individual, swapped the pipe with my 4mm spare pipe and when for a jubilant drive up the road, and did it fix it..??

Did it arse

I temporarily plumbed the swirl EV to the turbo to see if I could see/hear the turbo diaphragm opening/closing when revved past the magic number, but I couldn't, which fills me with dread because I think it should have moved at 2100RPM

However, the 4mm vac pipe that feeds the turbo EV was getting 'swollen' when I rev the engine, which I never noticed on the thinner pipe.

Confused, maybe the turbo diaphragm, maybe the wiring, maybe I should think about removing the turbo from the donor car which I will positively* enjoy*

[Doggy]

I'm confused too.

The slow movement of the swirl flap diaphragm may be due to the turbo EV not being designed to work an actuator this big and/or the non-continuous operation of this EV.

I'm trying to remember how the swirl should operate - I think it's connected to the vacuum pump below 2100 RPM, then shuts off.
If that's right, then in your test using the swirl EV, the turbo should get max vacuum at tickover, (i.e. minimum boost), then the vacuum should shut off giving max boost above 2100.

I can't understand the pipe swelling, you would think this can only happen if it's pressurised. If so, where's the pressure coming from?
I presume your servo's working, (which confirms your vacuum pump's OK)?

Is it possible the 4mm pipe was being sucked in to a smaller diameter until the EV operated, then 'relaxing' to its normal shape, which looked like it was swelling?

[GingerMagic]

Another update.....

Earlier today I checked the wires to the turbo EV and there are no signs of splits or crimping, so I squirted some cleaner in the connector anyway. I then redid the vacuum pipes with the old leftover pipes to eliminate these too.

Took the car for a spin after clearing the fault, and it came back as soon as I put my foot down...

I looked on PP2000 and yes, the turbo OCR goes from 53% at rest to around 40% when revved ( I was cheekily driving while looking at the laptop, but the results were too risky to look at... ) so I guess there is power going to the EV.

The car will be jacked up one day so I can inspect the intercooler pipes from underneath.

Is there anything I may have overlooked that will affect the turbo overboost? There is a video on pootube about a guy with a 607 2.2Hdi with the same problem, but no audio and I think it may be pointing out the 3rd piston deactivation as being an issue?

Google / other Peugeot Forums suggest a VAF, which is a way of determining the position of the vanes in relation to the MAF, which seems to be part of the MAF circuit on later Peugeots....

' VANE AIRFLOW SENSOR (VAF). The VAF has a mechanical flap-style sensor that is used on Bosch and other import multiport fuel injected engines. The function is the same as a mass airflow sensor, but air pushing against a spring-loaded flap moves a rheostat to generate an electronic signal. '

Anyone able to lend me a MAF to try out.... I have a 110 MAF here but I think they are different from the 2.2 Hdi.

[Doggy]

I don't think the 3rd piston deactivation solenoid is in any way related. As the name suggests, it's used to stop one of the 3 pistons in the HP pump developing fuel pressure at lower engine speeds (and is not vacuum operated).

I'm no expert on VAF's but I think they were what was used before MAF's became common. The only two I've ever seen were on my bro's '85 Manta GTE with analogue Bosch LE fuel injection and my '91 Carlton GSI 24V with its early Bosch Motronic system.

A 110 406 MAF is 80mm diameter and a 2.2 is 90mm, (oddly 110 C5's are 90mm).

I could send you my bro's old MAF if it's any help - it causes a flat spot below 1800 RPM, but might help you with elimination.

[GingerMagic]

I could send you my bro's old MAF if it's any help - it causes a flat spot below 1800 RPM, but might help you with elimination.

Yes please Doggy, the MAF is one of the more expensive things to buy for elimination purposes.....

[Doggy]

I'll organise it as soon as I can, hopefully send it off tomorrow.

Gimme your address there....



Just to be on the safe side, PM me your address again, please.

[GingerMagic]

I have just come in from penetrating my turbo.....

The inlet was liberally sprayed, as was the EGR entrance while applying vacuum to the turbo.

I used a vac pump to watch the axle move when vacuum applied, which it did, but only after 300 on the gauge, so the first two pumps didn't move the axle.

It starts to move at 300 and is fully retracted at 400 - I'm not sure if this is normal.

Sorry about the vague measurements, I'm not sure what the vacuum is measured in....

I won't use the car for a couple of days and I'll be popping out from time to time to extend/retract the axle in the turbo with the hand held vac pump.

Oh, I swapped the MAF with a know good one ( thanks Doggy ) and still getting the boost issue. I also cleared out the tiny pipe from intercooler to MAP sensor (easier on non-coupes) and that was all good.

[dirtydirtydiesel]

Sounds like it's the turbo a fault then bud

[GingerMagic]

Aye, it probably is - I was just exhausting all other possibilities before attempting to remove my donors turbo for reconditioning and replacement.

When I last drove my car, I kept it in 3rd gear for miles - even up to 70mph / 3500 rpm, to try to blow out the injectors etc. The performance at 60-70mph when I put my foot down was still impressive, which kinda makes me cling on to the hope it may not be the turbo..

[GingerMagic]

Hooray - its fixed.......

I have been racking my brains as to what I have overlooked in my elimination of possible reasons for the fault, and I was just contemplating on how to go about swapping the engine bay fuse box to eliminate that when I sort of had an idea.

I checked the vacuum system at the servo end, thinking that this would prove the pipework was okay, but when I checked the turbo EV for vacuum before the turbo, the reading was very low - but I didn't think to check the level of vacuum before the turbo EV. This proved to be equally crap, so the problem was no vacuum to the turbo EV. I swapped the turbo EV vacuum feed from the 3-way restrictor on the vac pump to the blank I have by the servo and voila..!!

All it was, was a partially blocked restrictor....

The car is now back to its usual self, and is of course upsetting the local Aldi's and Beemers ( beat a posh looking Alfa earlier... )

Thank you everyone for your support, and I'm so glad I don't need a new turbo....

[dirtydirtydiesel]

Well done buddy, one for the K.B ?
Glad you got it sorted

[steve_earwig]

Splendid Nicely fathomed there.


It's good news all round today!

[jonsowman]

Well done Kelv, great detective work

[Doggy]

Great news Kelvin, well done!

[gumby6371]

Glad you sorted it Kelv, is your vac system still standard?
If you lose the dozer and EGR EV's you can also lose the reservoir and the restrictors. Should stop any re-occurrences with a bit of luck.