Right just to set the scene:

I ve got an my00 uk turbo. Its got a full scoobysport exhaust system, an ITG panel filter, an a tek 2.5 ECU.

Had the car for about 4 months and have had no problems till about a month ago.

Basically i think its overboosting but im not sure. What tends to happen when it does it is; when i accelerate in 3rd 4th or 5th you can feel the car kind of stuttering as it gains speed then all of a sudden........bang. big thud! and away again. really is quite ferocious when it does it. If i keep my foot in it will keep doin it. Mostly happens in 5th gear 75mph@3000rpm. Does'nt always do it though.

Is it overbost?
if so, What causes it?
how do you cure it?
Is it doing any real/permanant damage to my car?

Apologies if this has been done to death but the search facility doesn't seem to be workin.

Thanks in advance, Matt.

 

It's extremely likely I'm wrong, but I'd think the explosion you hear is the wastegate opening violently. It looks to me like you're overboosting and the wastegate is blasting open suddenly, dropping oyur (excessive) boost into low levels again, and then you're building up too much all over again. I'd check to see there's nothing obstructing the wastegate.

 

Best way to confirm it ifs overboosting is sit in 4th or 5th and floor the car, at around 4-5k you may feel the car "pulsing", with on-off power, this will confirm its overboosting.
It could be down the the weather, the colder air increases boost due to the denseness of it, do you know if the car was mapped in summer or winter?
Should add that what the plusing is, is the car hitting the boost cut off, keeping the engine safe, so no damage will be caused (well supposedly).

Tony

 

Thanks for the quick reply.
How exactly do i check the wastegate? If im honest i barely know one bit of the engine to the other.

So you think it's overboost! What would cause it though!?

Matt.

 

hey Tony,

Right............ the car i bought from a friend and the TEK ECU was already on it. As far as im aware its "an off the shelf map" ?!?! from john banks?!?!

I had it on the the rollers at prosport about 6 weeks ago and the ecu had to be reset cos when they ran it, it only made 220bhp. After it had been "reset" it made 245bhp.

Found the whole thing very strange. Do know why it had altered itself to run low power in the first place??

I'm very suspicious of the ECU thats on it. Don't think its doing me any favours.

Matt.

Oh yeah! it is pulsing by the way. It's what i described as a stutter
5th gear @ 5k revs.....how fasts that tony

 

Matt,

There shouldnt be much, if anything wrong with the ecu if John has set it up, he normally sets these up so they have a fair bit of safety in there.
You could be having another problem though, running at 245bhp, the car should be under the boost cut out, i would have a look at the boost solenoid, see if its clogged (lhs of the engine when you look in, he says trying to remember where it is lol!)
Had a similar problem with my old MY00 PPP'd decat car, overboosting slightly, and down on power, turned out the solenoid was clogged, cleaned and worked fine afterwards.
If your still bothered about the map, have a word with John, he wont mind one bit

Tony

PS, should say that if your still not sure, Pete at Prosport will look at the car for you, always take my cars there

 

5k in 5th?
about 127mph

Tony

 

Quality

So you think its down on power too? I agree.

When it ran at prosport i said i thought it was a bit low but the lad that run it did'nt seem to think so. they did'nt know why the ecu had to be reset to get me back upto 245. They were really nice guys. v.helpfull but did'nt seem to know alot about my ecu. might give them a go tho and see what happens.

will try and get in touch with john banks also about my ecu i think.

your a gent tony, cheers for the help

 

Thats one of the troubles with remapped ecu's, you dont know exactly whats been done with them, unless you know who did it and what they normally set everything up to.
245-250 for a tek2, if its a tek 2.5 it should be slightly higher than that though, and trust me, those guys do know what they are doing they have sorted one or two problems out on my cars that a main dealer couldnt find (not a subaru!) so i wouldnt take my cars anywhere else

Tony

 

You need a boost gauge hooked up. They start at £30. You are in the dark otherwise. Every car is a bit different, the duty cycles for boost control are a little higher than the standard ECU to produce more boost. However, depending on the breathing mods on the car the peak boost, and hence the smoothness or held level will vary.

Other common reasons for being down on performance on a car of this type and age are MAF sensor and spark plugs.

Additionally, mappers have to tread quite a fine line with the boost control systems on the older ECUs to avoid peaks on the road when it rains or the car is driven hard in a high gear for example. Consequently the boost target may not be achieved on the dyno, particularly the first run, if the run is short, or there is insufficient load on the engine.

I can confidently say that if you refitted an OEM ECU and the MAF and spark systems are healthy, along with a healthy engine and turbo which neatly hits and holds the 13.7 PSI boost target that then fitting the ECU will give an obvious increase in torque and power.

 

Hi John,

Thanks for the reply.

I had it serviced 3 months ago and i had the spark plugs changed to HKS ones. A problem perhaps. I shall test the MAF sensor tomorrow also.

I think i will definately invest in a boost gauge of some description. I have been looking at an ECU data monitor from scoobyworld. I think TEK do a near identical one. Would this be a worth while investment?
Been lookin into knocklinks as well but not too sure whether i need one with the light mods that i have?

The car was run three times on the R/R. Twice when it made 220 and then once with the reset ECU when it did 245. Peak boost was 1.1 BAR/

Why would it have altered the boost to need reseting in the first place?

Thanks for your help so far. Regards, Matt

 

Should really be hitting 1.2 bar to be doing its best. Data monitor isn't really required, cheap boost gauge will do, mechanical will respond quickly and show you the boost behaviour better than a digital read out.

It shouldn't really behave much differently after an ECU reset except it will run about 2 or 3 degrees retarded for the first few runs until the ignition has advanced again.