Thread: Boost pressure

Boost modulator, new one is cheap , you can bypass for now , have you got a nanocom?

Originally Posted by nismine01

I hear of and see people getting 20PSI boost, I'm running a boost gauge and having boost cut (or fuel cut) and surging around 18PSI.
I need to find a cheap effective way of curing this while retaining decent boost.
I was considering a resistor in the output wire from the MAP sensor, has anybody gone down this type of method with success?

I've just spent over $8,000 (trans recon and s/hand motor) and was offered $1,000 today as a trade in on a new ute!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

That just aint gonna happen.

Cheers

Mike

If your gauge is accurate it means that is not overboost cos that's at 1.42Bar so no MAP clamp would help, unless you live somewhere high and the ambient pressure is below 80KPa... it's most probably the turbo overspeed protection which cuts the fuelling when the MAF exceeds 680Kg/hr(or so), unplug the MAF and see if it cures it or not

I have tried two MAF sensors, no guarantee that they were both not a fault, I will try disconnect and see.

Meanwhile, as I have been backing off the boost the problem has been more apparent so today I wound the boost up.
No more variation but 'Fault' boost pressure exceeded on Nanocom.

I also have a TPS, (driver input error) fault, other makes must use the same TPS, does anyone know what?

We have a cheap auto wrecker here in SA, 'U Pullit' where you go get your own parts and they cost a lot less.

If I thought a BMW had the same it would be cheaper than $836.00.

I have bypassed the boost solenoid and taken the feed from the inlet plenum chamber itself to take any inter-cooler restriction out of the equation.

Cheers

Mike

Tps = Throttle Position Sensor , Your Throttle pedal

My brothers is giving the exact same issue as nismine's

Is there any way to repair the TPS?

And what a stupid setup compared to the V8, which uses a cheaper rheostat type ... why not just keep the dame design across the entire range!

Originally Posted by AK83

My brothers is giving the exact same issue as nismine's

Is there any way to repair the TPS?

And what a stupid setup compared to the V8, which uses a cheaper rheostat type ... why not just keep the dame design across the entire range!

One word, safety.
The V8 is NOT fly by wire, there is an actual cable connected to the butterfly, the pedal position sensor will be used for info.
Take a scenario, your rheostat faults full open pedal. One sensor says full open, so you go full open throttle. Now you are dead.
On the V8 the fact that it has the cable means you won't die.

Now the TD5, if a single track sensor said wide open throttle you die. Hence the reason for dual track opposing voltage sensor signals, they have to agree for the ECU to do what is said, now you don't die. At some point someone must have thought that wasn't good enough (triple nine calcs?) and put the 3 track sensor in, although there is some blurb that the third one is for resolution not safety.

Any input that can cause serious injury is always dual input to avoid a single faulting sensor causing catastrophic failure and potentially death. Aircraft usually have 3 sensors and ECUs use a voting scheme to decide what average of 2 to use at a time.

Originally Posted by steve_a

One word, safety.
....

Thanks Steve .. didn't know how they work.
Did have a SAAB once that I think had fly by wire(ie. no cabled throttle), but the ex drove that off into the sunset ... otherwise my understanding of these things is on in that they exist .. not how they work.
I remember the SAAB once went into a limp mode when I mashed the loud pedal hard to effect some wheel spin in the wet. Wheels spun for a split sec, and engine power got cut. (fair enough .. as you'd expect.
What I didn't expect was when the actual pedal itself when harder than a brick... like a brick was placed behind it and couldn't be pressed.

So I'm thinking maybe that's why the D2's TPS is so expensive too. SAAB's was horrific back then well over the $1K mark.

So back onto the boost issue.
If I disconnect the WGM, I do this from the WGM to the wastegate itself, I guess.
Does the loose tube now also need to be blocked(ie. pressure leakage) or is it better to leave it unblocked?

Of course this is just for testing to see which part/s needs replacing.

Originally Posted by AK83

Thanks Steve .. didn't know how they work.
Did have a SAAB once that I think had fly by wire(ie. no cabled throttle), but the ex drove that off into the sunset ... otherwise my understanding of these things is on in that they exist .. not how they work.
I remember the SAAB once went into a limp mode when I mashed the loud pedal hard to effect some wheel spin in the wet. Wheels spun for a split sec, and engine power got cut. (fair enough .. as you'd expect.
What I didn't expect was when the actual pedal itself when harder than a brick... like a brick was placed behind it and couldn't be pressed.

So I'm thinking maybe that's why the D2's TPS is so expensive too. SAAB's was horrific back then well over the $1K mark.

So back onto the boost issue.
If I disconnect the WGM, I do this from the WGM to the wastegate itself, I guess.
Does the loose tube now also need to be blocked(ie. pressure leakage) or is it better to leave it unblocked?

Of course this is just for testing to see which part/s needs replacing.

WGM bypass

Hose off intercooler inlet straight to waste gate on turbo, either use a new complete length of hose or a joiner?
Block the one going to the air intake

Cheers Lemo