2 psi boost from an AAZ

[regcheeseman]

Just stuck a boost controller on my AAZ and gave the boost pin an GTD esque grind.

removed the EGR and plated it over

First run out and I'm getting 1 psi - not too good

added 1/2 turn of fuel screw.

Now getting nearer 5 psi but smoke is silly and idle is up to 1100 rpm

Back off 1/4 and there's a bit of haze and about 2 psi.

Power is definitely up on standard but not to what I would expect

Not sure if my workshop 0-30psi pressure gauge is up to the job - though it calibrates fine with a static pressure.

So assuming the low boost figures I'm getting are correct, and I'm using the small eco turbo (03?), could it be turbo wear or wastegate leakage and is there any way of telling between the two?

[Rabbit TD]

I too have had low boost with my engine ever since I got my rebored and all new or rebuilt parts including turbo 1.6 TD in Feb.  I've  never seen over 5 psi out of it yet with the Autometer Sport Comp gauges line tapped into the elbow on the manifold.  It's just a rebored 1.6 T/D and a rebuilt turbo modified to what MJM turbos calls Stage 1.  I don't really know what to expect out of it because I don't know what the stock one is supposed to make.  I haven't touched any fuel settings yet but stock is supposed to be at least 10 isn't it?  I still have the original Garret that was on the 83 Jetta engine, I didn't try it because the wastegate actuator was all rusted away and I still have no clue as to how they ever assembled one of those things.  I cut the top off to look inside and the valve in it has a hole drilled down a ways to help cool it I assume but it looks like to me it could cause a big boost leak.  I think I will put it back together after first lapping the valve and worry about a wastegate later because from what I've seen so far It looks like one would never be needed at these pressures.  As far as I'm concerned all this turbo does is whine to let you know one is present but I really believe it's doing more harm than good and just causes an exhaust restriction.  This engine has no more power on a mountain than my N/A did which got 10 MPG better also and smoked terrible doing it.  I am using it's pump now too with the T/D engine as I haven't gotten it's pump back on yet.  I've tried a million timing settings and the boost doesn't change a bit and have rebuilt Giles injectors as well {155's} and this engine doesn't smoke any more than a fairly new TDI.  I thought this Stage 1 would help this motor but I'd be happy with 10 psi. if I could get it now.   

[burn_your_money]

regcheeseman do you have VWs silly "part time turbo" setup? You can tell by looking at the wastegate. If it has 2 hoses going to it then you have the part time turbo, and that could be your problem.

[regcheeseman]

Wastegate actuator does have two feeds - a boost and a vacuum. Is this what you mean?

The vac is disconnected with the rest of the EGR rubbish

I'm thinking the problem is down to the gauge not reading right and the pump shutting fuelling down really early.

It seems to pull fairly strong, then boost stops building about 4000rpm

more investigation due and a decent boost gauge.

[gldgti]

i'd say you are having wastegate issues.

the wastegate on the k14 with 2 way actuator is VERY effective. you need to ensure that you have it all connected up the correct way around. if you have vacuum going to the vacuum side, the wastegate will be open.

personally, i think its a good idea to keep the part time gear intact, since if you're running a 1.6td boost pin like i am, then you'll automatically take an economy hit while cruising if the turbo is full time - you'll be adding more fuel because of the LDA when you dont really need it. you can easily adjust the position of hte microswitch controller in order to customise the throttle position at which the turbo kicks in, and besides that, if the rest of the electronics are working, the turbo should kick in automatically above 3200rpm.

i would almost bet that the wastegate is your problem anyway.
hope to help.

[vanbcguy]

LDA only adds fuel at WOT - it's basically an adjustable WOT stop inside the pump.  If you're highway cruising it doesn't come in to play at all...

All that said, the proof is in the pudding.  If your economy is better with the wastegate open at cruising speed then...

[gldgti]

well, the lda adds fuel when the boost increases enough to push down the diaphragm against the spring.

if you have a k14 on a 1.9 in a car like a mk3, it'll happily make over 10psi while cruising on a flat-ish bit of road at 3000rpm (120km/h with my CHD tranny).

more to the point, why shouldnt the engine be more efficient with hte wastegate open and when you only need 10-20 hp, since therefore the engine will have a more "open" exhaust to flow through...

[vanbcguy]

AFAIK the LDA actually just moves the governor lever stop inside the pump - it doesn't have any ability to add or reduce fuel on its own.  The NA pumps just have a solid pin where the LDA governor stop sits.  The idea is to delay full fueling until boost has come up...  IE if you floor it it holds off full fuel until it sees boost - the LDA diaphragm gets pushed down, the pin rides to a narrower part of the cone, the full fuel stop moves allowing more fuel.  But if you don't have the pedal far enough down for the governor lever to hit the stop then it's irrelevant, the LDA doesn't come in to play.  At least that's how I understand it...

I'll totally with you on opening the wastegate to reduce exhaust restriction.  The only reason I can see to have the turbo engaged would be to add a bit more air to help ensure you really are burning ever last bit of the fuel you put in.  Really the only thing that makes me wonder is hagar over on the other forum with is "magic smileage" formula that includes about 3 PSI of boost at cruising speed.

[regcheeseman]

AFAIK the LDA actually just moves the governor lever stop inside the pump - it doesn't have any ability to add or reduce fuel on its own.  The NA pumps just have a solid pin where the LDA governor stop sits.  The idea is to delay full fueling until boost has come up...  IE if you floor it it holds off full fuel until it sees boost - the LDA diaphragm gets pushed down, the pin rides to a narrower part of the cone, the full fuel stop moves allowing more fuel.  But if you don't have the pedal far enough down for the governor lever to hit the stop then it's irrelevant, the LDA doesn't come in to play.  At least that's how I understand it...

Not on my pump, the LDA affect the linkage ratio between the throttle and the governor by means of a varying pivot allow an increase in fuelling across the rev range.

personally, i think its a good idea to keep the part time gear intact, since if you're running a 1.6td boost pin like i am, then you'll automatically take an economy hit while cruising if the turbo is full time - you'll be adding more fuel because of the LDA when you dont really need it.

Why? If I'm cruising then I'm off boost, if i'm using boost then I'm not cruising!
As an aside my part time setup doesn't seem to be configured the same way - I'm running a euro ECO ish motor with all the pump electronics - that seems to control the vacuum solenoid.


I gave the car a sound thrashing over the weekend and it's definitely better than it ever was, not a patch on my GTD - The gov will have to be modded next as it just isn't enough yet.

[vanbcguy]

AFAIK the LDA actually just moves the governor lever stop inside the pump - it doesn't have any ability to add or reduce fuel on its own.  The NA pumps just have a solid pin where the LDA governor stop sits.  The idea is to delay full fueling until boost has come up...  IE if you floor it it holds off full fuel until it sees boost - the LDA diaphragm gets pushed down, the pin rides to a narrower part of the cone, the full fuel stop moves allowing more fuel.  But if you don't have the pedal far enough down for the governor lever to hit the stop then it's irrelevant, the LDA doesn't come in to play.  At least that's how I understand it...

Not on my pump, the LDA affect the linkage ratio between the throttle and the governor by means of a varying pivot allow an increase in fuelling across the rev range.

Hmm... My impression was that the lever that contacts the LDA linkage internally only makes contact when the accelerator is nearly all the way to the floor.  Exactly how close to the floor depends on what the smoke screw on top of the LDA is set to...  I tend to think of the LDA as a "max fuel delay device" rather than a "fuel enrichment device".  It prevents maximum fueling until it sees boost, at which time it allows more fuel if the driver is requesting it.

I think we're saying more or less the same thing though - I might have confused things by mentioning anything about the governor.  I wasn't meaning that the LDA had any relationship to RPM... 

My point to the OP was that the LDA wouldn't be adding fuel on its own during highway cruising with 3PSI or so of boost...  It ALLOWS more fuel when boost is present, but it doesn't independently increase fueling without accelerator input.  IE it won't waste fuel during normal driving...  Really its entire purpose is to REDUCE smoke versus an NA type pump without an LDA.

[regcheeseman]

had a GTD pump in bit's the other night for a gov job. Knowing I'll be doing an AAZ joke LDA pump soon I took a bit of interest in it's setup.

It seem that for any given throttle position the input from the LDA actuation lever would result in a increased stroke on the pump head (that's how it looked to me anyway!)

Would be nice to have had the oportunity to get the two pumps apart together to make some accurate comparisons.

[Rabbit on Roids]

it takes about 10 psi of boost to even move the pin tho. unless it has a stronger/weaker spring. so basically, when the LDA sees 10 psi or above, no matter what throttle position, it cranks up the fuel. least thats how mine works. anyone ever give there LDA a blast of air from the air compressor? it revs up just like you touched the throttle lever.

[regcheeseman]

it takes about 10 psi of boost to even move the pin tho.

looking at the witness marks on my old GTD pump (running 7 psi max) would say that 7 psi was good for 10mm of pin travel

The AAZ pin has similar witness marks on the pin

[vanbcguy]

anyone ever give there LDA a blast of air from the air compressor? it revs up just like you touched the throttle lever.

OK, well that answers that pretty darn well!!  So the LDA does come in to effect at any time then, regardless of where the accelerator lever is at.  Noted!!

Only thing I'll say though is diesel engine speed is regulated by the amount of fuel added... so the amount of fuel energy needed to push the vehicle along at 120 kph on flat ground is always the same.  If the LDA is adding fuel with the 3PSI or so of boost encountered with level cruising, you either must let off the pedal a touch or the car would accelerate!  End result should be the same amount of fuel being burnt, unless the back pressure from the turbo is restricting things enough to cause more fuel to be consumed.

[Rabbit TD]

anyone ever give there LDA a blast of air from the air compressor? it revs up just like you touched the throttle lever.

OK, well that answers that pretty darn well!!  So the LDA does come in to effect at any time then, regardless of where the accelerator lever is at.  Noted!!

Only thing I'll say though is diesel engine speed is regulated by the amount of fuel added... so the amount of fuel energy needed to push the vehicle along at 120 kph on flat ground is always the same.  If the LDA is adding fuel with the 3PSI or so of boost encountered with level cruising, you either must let off the pedal a touch or the car would accelerate!  End result should be the same amount of fuel being burnt, unless the back pressure from the turbo is restricting things enough to cause more fuel to be consumed.

I'm new to the turbo thing but the LDA doesn't add fuel at just 3 lbs does it and I know it can be adjusted to add sooner or later and also the quantity.