Loss of turbo boost?

[Captain Jack]

Hi,

Over the weekend, I paid a £6.20 entrance fee into South Wales for a real-life version of Dodgems. My... Wales has such poor driving standards, unbelievable. Cutting you up (I was cut up by a huge bus on a roundabout), slow driving in the fast lane and just plain wankers. No wonder there's a sniper, sorry, speed camera on every corner there..

Anyway... over the past week, I have experienced some odd loss of turbo boost when accelerating. Once the boost is on, it stays on, but occasionally when change up a gear, the turbo is lost and can take up to a good few seconds for it to suddenly kick in. This only seems to happen when trying to accelerate hard-ish, especially going from 4th to 5th gear but it does happen in others. It doesn't happen all the time - maybe only one time in ten. Almost feels like it goes into a limp-home mode but nothing comes on the MFD or the dash.

I swapped the vacuum tubes between the EGR the turbo but this only made things worse where the turbo wouldn't kick in until 2500 rpm. Did I need to swap the wiring as well?

It could of course be the fuelling (HP pump?!?) or some issue with air supply but I couldn't see any split hoses. I do have a leak on the intercooler but it has been there for years.

Could it be the new remap I had recently? That one has deleted air doser and the EGR from the ECU but the air doser is still physically in place.

Any other simple things I can check?

Cheers
CJ

[crackpotterpig]

If you have any intercooler leaks this will of coarse limit the boost pressure as it will be lost, could be showing up more now as you have had the remap done.
Or may be worth checking the dreaded egr to make sure its fully closing and isnt partially staying open,I always advise people to get rid of and bypass the egr system as they are great when new but when they get a few years old and have a build up of soot,etc they become troublesome.

[Captain Jack]

EGR does not exist on my car - it's blanked out.

[crackpotterpig]

ok, if you dont have the eml illuminated i would check intercooler pipes and clips or look at replacing the leaking intercooler.

[Busman]

Hi Alex. What's the score with your throttle position sensor? Just that when mine went it gave just these symptoms.

[Captain Jack]

That was on my mind as well, Richard. Next time this happens, I'll try accelerating with the cruise control stalk as that bypasses the throttle sensor.

[GingerMagic]

Hi Alex, try swapping the pipes and wiring with the electrovalve next to the end one, see if it makes a difference.

Also try using half-throttle when accelerating to see if it is the TPS - its only a 5 minute job to clean anyway. Mine would light up EML on dash when flooring it and stall a bit but fine if I'm gentle, better now cleaned.

[Welly]

I thought TPS as soon as I read this, I used to get trouble with mine when accelerating hard the 'values' would be all over the place and flag a fault.

They used to be cheap enough (£60.00) to replace from the dealers. It's a toss up between getting a proper code read (£60.00) or taking a gamble and replacing the TPS yourself.

[Captain Jack]

Hm, well it hasn't done it since that time and I've done a fair few miles going up and down the M5. French electrics strike back?

[Busman]

Hi Alex, try swapping the pipes and wiring with the electrovalve next to the end one, see if it makes a difference.

Also try using half-throttle when accelerating to see if it is the TPS - its only a 5 minute job to clean anyway. Mine would light up EML on dash when flooring it and stall a bit but fine if I'm gentle, better now cleaned.

I cleaned mine about 18 months ago and it's been fine ever since. Takes about 15 mins and costs no money.

[Captain Jack]

Will take a closer look at TPS if it does it again. No harm in cleaning it.

[406dailydriver]

Will take a closer look at TPS if it does it again. No harm in cleaning it.

your symptoms sound similar to what i had recently, try unplugging your MAF as this is what my problem was, once unplugged it was cured, now waiting for a MAF to come from ebay.

HTH

[Captain Jack]

It happened again yesterday. While holding the gas pedal down, I hit the accelerate button on the cruise control and it went off straight away with the turbo. I have since managed to learn to replicate it by flooring the pedal - it doesn't seem to do it if I floor it gradually as opposed to straight away.

Does that sound like a TPS?

[GingerMagic]

Hi CJ, yes it does to me. Sometimes my car goes better if I use half-throttle rather than flooring it.

Cleaning is easy enough and after reading most of your threads you are a very capable chap.. It won't fix it but be easier to live with until you can get a new one, or diagnose it as something else?

[Captain Jack]

Hi Kelv,

Since putting your TPS on and forgetting to plug the cable in, I have the dreaded Aunty Pollution fault. After plugging it in and driving for a little while hasn't cleared it. It's been a few weeks with it still being there. When flooring it, especially when overtaking, the boost doesn't kick in, making it annoying and bordering on dangerous.

I am thinking of getting a new one but unsure whether it will actually fix the problem....

Thoughts?