Boost cut

[Jonnybravo]

I've finally just done my first 1000 miles in the S2 and I'm still loving it however tonight whilst out with a mate in his 3 door Cosworth I got a bad case of boost cut when I hit 1 bar I stopped at a mates for a few hours then when I drove home it had sorted itself

What would cause it to boost cut so early ? monitoring wise everything appeared normal, it is running on the rich side but I can't see that being the issue.

Once thats sorted it needs MORE power, the 3 door is far quicker which is annoying

[UrS4boy]

1 Bar absolute (where atmospheric pressure = 1.01 Bar) or 1 bar relative (where atmospheric pressure = 0 bar)?

Either way, you may have a boost leak somewhere.

[Jonnybravo]

1 Bar relative, 14psi on the dot it held back.

I've just read some old threads and seen that coolant temp can bring hold the boost off, the car does currently run cold which is I'm assuming is down to the thermostat.

I'm reluctant to upgrade the hoses yet as I will fit a FMIC amongst other things and change them then, the car was totally normal on the way home though so I'm doubtinig its a boost leak

[UrS4boy]

1 Bar relative, 14psi on the dot it held back.

I've just read some old threads and seen that coolant temp can bring hold the boost off, the car does currently run cold which is I'm assuming is down to the thermostat.

If you have the automatic climate control, you can use Channel 51 to compare to the engine temp and diagnose whether the thermostat has gone to meet its maker.

[Jonnybravo]

No climate control sadly, as I have one here I'll change it to see if it cures the problem, I've ordered Vagcom for it anyway which wil help me keep an eye on what the car is doing

[HPmuirt]

If you have an ABY you should see around 1.15 bar in the higher gears and if you have a 3B you should only see exactly 1bar or 14psi on an ABY in 1st - 3rd.

Also the MFTS can indeed cause the ECU to restrict boost, but I thought it only did that when the car is over either 113C or 119C, not when cold.

An expert will be along shortly to tell you where the problem really lies

Cheers n

Si

[Jonnybravo]

Its a ABY with a Homefry, I've not been out in it today but it was totally normal on the way home last night, still no where near enough to shake the Ford off though !

Thanks for the replies so far :top:

[Rusty]

Hmmmmm, this sounds like a bit of a strange one. These are usually air leaks TBH, the car can make them all by itself as I found out all too many times. Usual dirty MAF, temperature sensors, fuel etc. are the other probs as you know already. Sounds like something still isn't right, when they're sorted they don't do this, mine's been clean for 2 years now I've said it before but Doug @ MRC is your boy.

[Jonnybravo]

Thanks Andy, I'll take advice off here but I'd rather struggle and sort things myself than pay anyone else, I've only had a few issues with cars in the past that I couldn't sort out but I know my limits.

First thing I must do is change that stat as its a known problem, last time vagcom was plugged in the only faults were with the airbag but there may be more now I have done a few more miles.

Out of interest what plugs do you advise for this car as I'm just about to put a order in for my weekly supplies for work so I'll add them onto the list.

Cleaning the maf is covered on here somewhere isn't it ?