cdti power issue

[johnandchris]

Hi folks. I am puzzled by this one.
Had the 160 map done last year but didnt really detect any difference in power.
I have a new maf, new top hose (club version, 2 piece with sensor), egr bypass kit, viton o rings etc.
Car revs fine to 5k. Pulls smoothly just lacklustre, no real turbo kick. Had it on the torque obd and it shows max 85bhp. 0 to 60 13.5 secs. Turbo boost about 19 but no vacuum (ie when revved the boost kicks in up to 19 but the drops to zero and i would expect it to go negative into vacuum). No black smoke or white smoke. No fault codes.
Any ideas?
Regards
Joh

[Union Wheels]

Hi johnandchris,

what does the torque app. say about the MAF readings.

There have been several posts showing the readings as the revs rise and you can compare them to your readings.

Pete.

[pm77]

Try unplugging your maf and see if that makes a difference.

[johnandchris]

Tried unplugging the maf. No difference whatsoever.
When i used the obd on my petrol, the turbo guage showed boost when the pedal was pressed and, when foot was off, vacuum. This boosts up to 17psi but doesnt go into vacuum. Possible boost leak?

[wullie480]

Hi folks. I am puzzled by this one.
Had the 160 map done last year but didnt really detect any difference in power.
I have a new maf, new top hose (club version, 2 piece with sensor), egr bypass kit, viton o rings etc.
Car revs fine to 5k. Pulls smoothly just lacklustre, no real turbo kick. Had it on the torque obd and it shows max 85bhp. 0 to 60 13.5 secs. Turbo boost about 19 but no vacuum (ie when revved the boost kicks in up to 19 but the drops to zero and i would expect it to go negative into vacuum). No black smoke or white smoke. No fault codes.
Any ideas?
Regards
Joh

Tried unplugging the maf. No difference whatsoever.
When i used the obd on my petrol, the turbo guage showed boost when the pedal was pressed and, when foot was off, vacuum. This boosts up to 17psi but doesnt go into vacuum. Possible boost leak?


Does the car engine brake more than you'd expect my wife's zt used to slow as it went down hill if in gear.
Similar issues to yours tried loads of different parts swapping from one zt to another but noticed oil residue on the actuator so I swapped out the turbo for a spare I had and it transformed the car now drives as well as mine has always done.

[johnandchris]

Hi.not noticeably engine braking more than normal. Will have a look at the actuator and see if oil is leaking though.

[johnandchris]

As the turbo is kicking in (although not much of a kick) could it be a boost leak. Can't hear anything but I suppose the noise of the engine could drown a leak out. Would this explain the 16-17psi boost and the lack of vacuum?

[Mike Noc]

You won't get a vacuum with a diesel engine, as they aren't air throttled.





.

[johnandchris]

Ok. Well that sorts that theory. Any other ideas? Plenums are dry and clear.

[RPWC]

Boost sensor?

[johnandchris]

Is there a boost sensor on the cdti. If so do you know where it is

[spyder]

Is there a boost sensor on the cdti. If so do you know where it is

That would be the MAP sensor, located on the drivers side of the inlet manifold. Can easily be removed with a 10mm ring set spanner.

Try cleaning it with some electrical cleaner and no sharp objects, changed mine and did feel a difference.

Craig.

[johnandchris]

I have replaced the maf sensor. Is this the same as the map sensor?.

[spyder]

No John, MAP measures the inlet manifold pressure. MAF measures air flow.

[johnandchris]

Removed and cleaned the inlet manifold and while i was at it i cleaned the map sensor.
Now seems to run even smoother (was smooth anyway) but no increase in power.
Really puzzled as i have had the 160 upgrade from philt4 who gave it a clean bill of health when done but we couldnt test it as the front suspension was knackered.
Any other ideas?

[maxxpump]

When we had the 160 remap done to our motor the difference was stark!

Since you have sorted you MAF, EGR that means it could be as suggested a MAP problem or it could be a blockage further down the line i.e: cat blockage or exhaust (but as you said there is no smoke and your engines misbehaving it could indeed be a cat issue). Have you replaced your air filter? they can cause some issues, but might not be causing your issue. another one to check is that the fuel system is letting enough fuel into your engine. I did have a similar issue after I got my remap and my UBP was causing the loss of power, funny as it was so gradual I didn't think it was. But then I replaced it and then my problem went away, even though the pump wasn't completely dead! if non of these I would be stumped.

[johnandchris]

I can hear both pumps running. I already have a new itp insert. Might just bite the bullet and buy an ubp.

[Mike Noc]

Disconnect the UBP outlet pipe where it enters the fuel filter and place in a large jar. With key to position II you should get a strong flow of fuel into the jar with no air in it.

As long as you get that the LP fuel pressure delivery is fine up to the filter.

Usually if the ECM detects a lack of fuel pressure from the LP sensor it puts the engine into limp mode limiting the revs, so if it revs freely in neutral again the LP delivery should be fine.

[wullie480]

I can hear both pumps running. I already have a new itp insert. Might just bite the bullet and buy an ubp.

It won't be the under body pump.
I feel your frustration I tried all sorts back and forth trying to get to the bottom of why the wife's just wasn't the same as mine.

[Snagger]

I don't know if this Bosch fuel rail on this motor has an over pressure relief valve or not, opposite end to sensor, so this may not apply, it will have its own leakback pipe if it's got one, and should not leak any diesel at all, but I know on my Accord if it leaks back, it does cause pressure rail pressure loss, but in most cases not enough to trigger EMG fault.

Tried swapping the pressure rail sensor for another ?, contact clean the rail sensor plug with switch cleaner, or simply un plug / replug a few times to clean off any surface corrosion, the loom up to the sensor has been known to chafe in this area as well, giving timing probs.

Snagger.