tuning box gremlins?

[julianm]

Just joined today maybe i can get some pointers on a problem ?
Have a mk iv tdi 115 recently fitted with a "tuning box" no obvious problems prior to fitting.After fitting i now find that when reaching a certain speed in fifth or sixth gear what i assume is limp mode is activated.
(marked loss of power)
Switching the ignition off/on clears the fault and full power is returned.
This is the second unit i have tried so assume it is a fault on my car?
Tech. people at manufacturer suspect turbo over boost.
Is limp mode being activated because of the power increase? no loss of power is evident in standard trim at any speed.
From searching through the threads a split/punctured hose could be responsible any other possibilities?

[tsunami]

Is the tuning box a well branded one or is it one off ebay or like?

[Eshrules]

ok, i might be being a bit blunt here, but had i fitted something to my car and then my car became faulty... guess what id do first, thats right, take the part off.

get the tuning box off, first of all. (i can only assume it is a cheapy of eBay? )

next thing to do , is check all hoses for boost leaks, listen for any excess air at idle, you could have something as simple as a leaky boost pipe, the braided ones.

there is the slim chance that your turbo could be clogged up, the vanes are sticking or the vane actuator could be sticking, but id go with the first few suggestions first....

[tsunami]

ok, i might be being a bit blunt here, but had i fitted something to my car and then my car became faulty... guess what id do first, thats right, take the part off.

AMEN TO THAT!

[julianm]

Blunts ok.....Assumptions not.
The unit is branded (£380) not off e-bay!!
It has been returned for testing and found to be ok.
Its not going back on the car until i find out what triggered "limp mode" your advice will hopefully be useful in pinpointing the problem.
Thanks

[Gee]

Is this similair to the type of tuning box i bought from ebay?

Paid around £30 for it and was slightly jubious about fitting it but judjing by the positive feedback and the knowledge of the seller i thought id give it a go!

Anyway wacked it on and the car was a bag of *****, despite having eratic revs in idle, a flat spot a thousand miles long the car would'nt even go! took the <removed> off immediately and tossed it in the bin.

How can these people sell these pieces of <removed> and blatently lie?

[julianm]

Think not
Been totally happy with the "box" no flat spots ,increased torque,smooth power band, then it hits 104 (allegedly) and the limp modde kicks in ....bummer! Having a diagnostic check/service tues hope to get it sorted.
cheers

[oaktreegarage]

inside your potentiometer/variable resistor casing,sorry tuning box casing there is generaly a screw,turn it anti clockwise a little then test drive,repeat this till your car stops kicking limp mode in,even fancy van aaken boxes can be adjusted the same,ive done this to a few customers cars with same problems.Cheers simon

Think not
Been totally happy with the "box" no flat spots ,increased torque,smooth power band, then it hits 104 (allegedly) and the limp modde kicks in ....bummer! Having a diagnostic check/service tues hope to get it sorted.
cheers

[The Muts Nuts]

Is this similair to the type of tuning box i bought from ebay?

Paid around &#163;30 for it and was slightly jubious about fitting it but judjing by the positive feedback and the knowledge of the seller i thought id give it a go!

Anyway wacked it on and the car was a bag of *****, despite having eratic revs in idle, a flat spot a thousand miles long the car would'nt even go! took the <removed> off immediately and tossed it in the bin.

How can these people sell these pieces of <removed> and blatently lie?

Because people still buy them............

[Eshrules]

Blunts ok.....Assumptions not.
The unit is branded (£380) not off e-bay!!
It has been returned for testing and found to be ok.
Its not going back on the car until i find out what triggered "limp mode" your advice will hopefully be useful in pinpointing the problem.
Thanks

we are so used to seeing this stupid resistor 'tuning boxes' popping up here that we make assumptions now. fair play to you if it is a 'proper' tuning box, although i still have reservations about putting a tuning box on my car that has not been tested on my car.

one thing you have to bear in mind is that these will contain standard maps for the golf mk4 1.9 tdi and whichever engine it has been applied to. it will not have been tested nor adapted to any of your own cars 'quirks' as such, it can cause issues.

i think the comment above about adjusting it will be reducing the level of boost being generated, this could be the cause of the limp mode. you have to remember, you will not always see an immediate effect when a problematic part is fitted.

eg K&N oil panel filters, these are well known to foul your MAF, but you would not see this for perhaps a few 1000 miles.

you dont say if you have tried running the car without the tuning box, to see if it still enters limpmode, perhaps this could be tried?

i think the diagnostic is likely to simply show an overboost situation, which we have already established but i am doubtful as to any other part being faulty, id seriously consider whether the tuning box you have is having a positive effect on your car.