Reply With QuoteBoost modulator? Sticking wastegate? You need more than 12psi
Master
Just about ready to put the old girl down, the car that is.
It's performance has not been all that brilliant but now I have a pyrometer and a boost gauge fitted so I have some indication of what is (might) be going on.
Towing a 2 tonne caravan, pulling up hills EGT getting up to 700 deg if the gauge is reading right, is this too much?
Acceleration **** poor especially when trying to accelerate hard at all speeds.
NO faults logged in the ECU other than occasionally 'Driver input error' so looks like a TPS to be done but I know the symptoms of that and it is different.
Boost fluctuating, 20 PSI - 10 - 20 - 10, I backed the boost off till it sits at 12 PSI and the vehicle is gutless, as really I expected but now boost remains constant at that.
All of a sudden I'm cruising at 100 KPH and doing it easily, slow down for a town and I'm back to the gutless saga.
Tonight I have cleaned, IAT, MAF and MAP sensors, I will take it for a run tomorrow without the van and see what happens.
I will test the MAF and MAP if I don't get a good result, the MAP was very 'greasy' for want of a better term. Possibly just a build up of oil fumes.
The vehicle had been seriously modified before I bought it but I don't know about ECU remapping though.
Ah the joys of cars!!!!!!!!!!
Cheers
Mike
Last edited by nismine01; 14th September 2017 at 09:09 PM. Reason: typo
Moderator
Boost modulator? Sticking wastegate? You need more than 12psi
The Phantom - Oslo Blue 2001 Td5 SE.
Half dead but will live again!
Nina - Chawton White 2003 Td5 S
Slowly being improved
Originally Posted by Judo
Wizard
SubscriberYou bought a vehicle that has been "seriously modified" by someone else, don't know if the ecu has been remapped to suit? I think you're in for a lot of sleepless nights, old mate!
Take it back to basics. Air, fuel, boost. One of these is not in synch with the others. Pick one, set it at what you think is right, then make the others work with it. Simples! (He says with tongue firmly in cheek)!
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1999 Disco TD5 ("Bluey")
1996 Disco 300 TDi ("Slo-Mo")
1995 P38A 4.6 HSE ("The Limo")
1966 No 5 Trailer (ARN 173 075) soon to be camper
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AT RESTfaulty waste gate valve or loose or split hoses?
Wizard
I'm with Muppet. Disconnect your boost modulator and bypass it. To clarify, unplug the modulator and connect the boost hose from the pipe between the turbo and intercooler directly to the turbo.
See how that goes.
There is also a chance these hoses to the modulator are an oil soaked vacuum hose that now blows up like a balloon under pressure. I've changed all mine for SAE30 rated fuel line to get around that issue.
Hope that helps.
http://www.discovery2.co.uk/faults/w...egate_mod1.jpg
Swaggie
12 psi is for idling around miss daisy
Give it some oomph
ChatterBox
SubscriberTake off for boost gauge in the wrong spot , no damper fitted?, if thats all good then yep , boost modulator, youll need to shorten the rod a few turns if bypassing till you get a new one, you certainly won't be flattening your eyeballs with acceleration with 12 psi boost pulling 2 tonnes, 700 degrees is OK but will be better with more boost,
YarnMaster
SubscriberMy Dad called it "The joys of motoring"
D2a Td5 Manual, Chawton White. aka "Daisy"
Build date 11th Oct 2003
Freelander 2 2011, manual, the daughter calls it Perri
Before I had a Land Rover I did not have any torque wrenches. Now I have three.
LROCV #1410
Fossicker
There is a certain piece of advice going round that I just dont get.... and thats disconnecting the boost modulator control valve to improve power
As I understand this valve I all it can really do is increase boost, and there is little a faulty valve can do to reduce boost
Let me put it another way
With the control valve bypassed the Wastegate control valve is permanently connected to the boost pressure, its a nice simple relationship as pressure rises the wastegate opens.
With a functioning control valve present the ECU has the option to block the connection between the boost pressure and the wastegate valve, blocking this connection will increase the boost pressure, and using a PWM signal the ECU can actually modulate the boost pressure UPWARDS
With a faulty control valve you will have one of threescenarios,
a) the wastegate is permanently isolated from the boost pressure (quick test, try blowing through a disconnected valve if its blocked this is possible), and you will hit overboost pressures
b) the wastegate is never isolated from the boost pressure, so its functioning exactly as if the valve is bypassed
c) the valve or pipework leaks causing loss of pressure to wastegate... this scenario could cause overboost, or you could lose boost pressure due to leakage, easy to diagnose either way
So, if your engine is constantly going into overboost, then yeah there may be a benefit of bypassing the valve, but, if your not achieving boost pressure why are we bypassing the valve, and if the valve is faulty why are we not diagnosing the fault and replacing this rather cheap part.
Of course I could be completely misunderstanding the function of this valve, in which case I'm probably not the only one.
Wizard
SubscriberHi Mike
I purchased a lj50 susuki many years ago that had been shot. Count 53 entry holes, worst one put a crack in the block. Restored the old girl but left most of the holes. the cracked block was restored using chemiweld (still sealing 7 years later). The reason for the holes, broke down on the way home on top of a hill that was visable from the back porch of the house, so the owner and his mate got on the turps and had there revenge. It sat in the same spot until I payed $50 for it about 2 years later. So what I am saying is sometimes a few holes wont hurt.
cheers
blaze
ps
was my first 4x4
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