disco td5 overboost

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ultra150

ultra150

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hi im suffering overboost checked all the norm problems waste gate arm free. new pipes all intercooler pipes new samco. changed the boost control modual still same cuts power at 3000 rpm then limpmode ...... restart then ok till 3000 rpm nanocom reports overboost ive unplugged the airflow meter still the same tried a new one still the same boost actuator changed still does it im at my witts end and ready to set it on fire joke lol:D
 
You say the arm is free - it needs to be REALLY SLOPPY,or can jam.Between you finger and thumb the disconnected arm needs to be able to slop back and forth with no effort at all.Also check the wastegate actuator pulls in a straight line,I have seen the compressor side of the turbo assembled slightly out of line making the arm jam as it moved.This can be fixed by slackening the ring of bolts and twisting the compressor housing into line.
You could also try ignoring the boost modulator solenoid and running it like a Defender TD5 - just have a pipe from the intercooler hose straight onto the boost capsule.I have one customer who has been running his like this for the last two years with no overboost and no ill effects.
 
hello every one its acually really sloppy to move the actuator arm is straight as a die lol ive done everything possible ive even ran it at 16 threads on the nut on the actuator arm still does it im at a loss now but will try the defender set up and see how it is ive tried new ecus every thing in the book no joy im ready to call it aday and jst give up nano com shows o boost and then shows boost as if it looses signal and then finds it again the actuator arm fluctuates fast on and off fast ????????
 
well hello every one im now running defender td5 set up pipe straight from intercooler pipe straight to boost capsual and runs better but still getting overboost and the dreaded limp home mode some one must know what this is??????????????
 
ultra150 said:
well hello every one im now running defender td5 set up pipe straight from intercooler pipe straight to boost capsual and runs better but still getting overboost and the dreaded limp home mode some one must know what this is??????????????
Click to expand...



OK .... is the EGR thing still in operation?

It can go wrong and that can cause the overboost situation.

Do you have a boost gauge?

Is the intercooler clogged with oily gunge?

Connect the inlet MANIFOLD to the capsule can help.

CharlesY
 
hi charlesy egr removed with propper kit nanocom readings manifold pressure 218 kpa just before it goes into limp mode i fitted a boost gauge and was getting 16 psi ambient was around 126 but its hard to look and drive the same time its shuts down to limp mode at 3500 rpms its doing me head in as it does it in 3rd gear 4th gear and fifth gear
 
ultra150 said:
hi charlesy egr removed with propper kit nanocom readings manifold pressure 218 kpa just before it goes into limp mode i fitted a boost gauge and was getting 16 psi ambient was around 126 but its hard to look and drive the same time its shuts down to limp mode at 3500 rpms its doing me head in as it does it in 3rd gear 4th gear and fifth gear
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What a pain in the butt!

I suggest you TRY a dodge .

Find the waste gate actuating capsule and the rod from it that pushes the waste-gate lever. These are really easy to get at on a TD5.

Use a 10mm open ended spanner and slacken the locknut, and turn it away from the winged section of the lever just a little. One 'flat' will be enough.

Now turn the winged part of the rod (the end that is nearest the Turbo) exactly three full turns AWAY FROM the locknut. Now bring the locknut all the way back and gently lock it. THREE full turns should be enough to make a difference.

The effect of this will be to make it a little easier for the system to shuttle the wastegate, and stop overboosting.

If it works - great. Then you can adjust as required.

If it doesn't work, three full turns the other way puts it back.

Five minute job dead easy, nothing to lose.

CharlesY
 
right done the actuator arm today i got all the way to the end like 26 threads showing and still getting overboost im ready to set the thing on fire lol the only thing i can think of now is that the turbo must be faulty ????? and not dumping the pressure off ive fitted a new actuator today to thinking may have a leaky diahphram still the same..... also refitted the boost gauge and its going off the clock as the one ive got goes to 30 psi and its hitting that.....
 
Last edited:
ultra150 said:
soz mate brand new one fitted no differance but thanks
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You said you had a boost gauge fitted, right?

Can you rearrange where that gauge takes its feed from?

I suggest you take a Tee-off from the last pipe close to the waste-gate operating capsule itself.

That way you will see if the capsule is getting full boost pressure.

If it is, the problem is in or after the capsule.

If is isn't, the problem is somewhere before the capsule.
 
ive got it on that pipe now so its only one feed from the intercooler hose still same also noticed today when it happens i get no reading at all from the airflow metre its in normall ranges before the overboost limp mode cutt off its got to be the turbo itself .... ive tee pieaced it from the boost actuator it flutters and still goes over 30 psi so now its set up like defender one pipe direct from intercooler pipe with tee peace for boost gauge ...... cant get me head around it
 
ultra150 said:
ive got it on that pipe now so its only one feed from the intercooler hose still same also noticed today when it happens i get no reading at all from the airflow metre its in normall ranges before the overboost limp mode cutt off its got to be the turbo itself .... ive tee pieaced it from the boost actuator it flutters and still goes over 30 psi so now its set up like defender one pipe direct from intercooler pipe with tee peace for boost gauge ...... cant get me head around it
Click to expand...


Any chance you have bad connection at the air flow meter?

The turbo itself will NOT do this unless the waste-gate valve is jammed tight shut.

CharlesY
 
I know you say the wastegate arm is free,but I cant overestimate the importance of it being sloppy as ####. It MUST not jam - even slightly as you flop it back and forth between your finger and thumb.Also try slackening off the link arm so it blows off earlier.
Remember the turbo can make full boost at as little as 2100rpm under full load,from then on it needs instant control of the wastegate to avoid overboost.
 
eightinavee said:
I know you say the wastegate arm is free,but I cant overestimate the importance of it being sloppy as ####. It MUST not jam - even slightly as you flop it back and forth between your finger and thumb.Also try slackening off the link arm so it blows off earlier.
Remember the turbo can make full boost at as little as 2100rpm under full load,from then on it needs instant control of the wastegate to avoid overboost.
Click to expand...


That's what I was trying to tell him, but I don't think he has the pressure sensor pipe connected where I suggested, between the capsule and the controller.

The ONLY cause of overboost MUST be the wastegate valve not opening when it should. There are only three reasons (1) it is jammed or (2) it isn't getting pressure to the capsule to open the valve or (3) the capsule is burst inside.
 
its a brand new capsual ... its set like defender now bypassing waste gate control valve ive set the waste gate arm at 20 threads no differance still get overboost waste gate arm is sloppy really sloppy it does not jam.... and it does get pressure to boost capsual thats where the boost gauge is tee pieaced in . when i return it to normal operation with the boost actuator control valve it still does the same .. so normall set up factory and defender set up factory both give same results.... the waste gate arm moves fully when driving . it has had new boost capsual new boost control valve new airflow metre new pipes what else can it be new maf sensor to...
 
It is time to take off the turbo EXHAUST OUTLET pipe, and physically examine the waste-gate valve.

I would not be surprised if it is deranged somehow. Easy to check this.

CharlesY
 
ultra150 said:
hhhmmm intresting i thought about it but not sure on how to do it any info mate would be great on how to do this
Click to expand...

Turbos are incredibly simple things.

Usually there are two ways to take them off
1. complete - take it off the manifold

2. split it where it is - take the thing off the cast iron exhaust turbine casing. You could remove the turbo centre body complete with the Inlet casing (the light alloy end)

Operation 2 might be a lot easier than you think, and the waste-gate would be looking at you.

I would have to look at mine to give further advice, but if you are saying that all else seems to be sorted, checking this would be sensible.

CharlesY
 
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