1999 Golf TDi Auto ALH no power untill 3500rpm

[Sleeper_Avant]

Dont have VAG-COM but i do have a Bosch KTS 670

replaced guides and lifters etc on 1999 golf ALH Auto after bought off a mate, that had slipped the belt by about 8 teeth and wouldnt start

Got it up and running after skimmed head, new valves, guides and all seals fully replaced inc belt kit.

Vac pipes all replaced, everything checked and Vanes not sticking etc

bit knocky but starts fine,

but totally no power below 3500rpm, then like flicking a switch at exactly 3500 it takes off like a missile, keep your foot down and it keeps pulling to redline.

back off below 3500 in any gear (manual and auto shifting it) and again, very very gutless, bordering on dangerous infact.

live readings seem fine, mass air flow, fuel temp, etc
Boost pressure is 14psi (atmospheric, that rises to 32psi peak and sits arround 24/26psi when booting it over 3500) so take 14psi off the values and that is "actual" pressure
boost comes in nice and early as it should also.

ive tried manualy adjusting the pump fractionally each time untill it wont start and got it to its best,

my KTS allows me to use the same graph as VAG COM with the start of injection and fuel temp etc and seems within specs. from what i can see

it has a fault code of "44F8 start of injection control, Control difference"

such a weird one, and its into me for a fortune now and hope it isnt the pump

when it is "flat" the IQ is 23, that drops to arround 20/21 if going up a gradient, but can spike 28/32 when its boosting fine

Please help as i am a bit clueless, got manflu and cant think straight

Thanks in advance, Sean.

[Monkeymagic]

Are you getting any other fault codes. This is vf diesel right? Eg seperate pump.
Im thinking you have a clogged pump. I have seen this before when the rubber vanes in pump were gummed up.from cheap diesel and sitting for long period.

[sam80quattro]

may sound stupid but a astra 1.7cdti i had recently did this, nothing at all untill 2.5k and i dont just mean off boost and lacking power but seriously about 10hp lol .. no heaters either so i checked thermostat and found it was missing. fitted a new 1 and as soon as the car was up to temp it worked faultlessly.

[Sleeper_Avant]

nah not temp, i put a new C.T.S in it when i did the head as it had previous codes

no code now and warms up fine, heaters toasty etc

it does get a bit better the longer you spank it, sometimes, but rarely, it is ok a lower revs

and it sat for a month broken.

100% no other codes

tried moving the pump again tonight from non running to shuddering like mad but again, nowt once the sweet spot was found

[Sleeper_Avant]

also NO smoke at night with cars behind before or after power.

will be driving 3 hours over the weekend so see what happens,

it also had this code before i bought it, with jumped belt, sorted timing out but still same injection code

unplugged the pump harness tonight,
battery voltage to the N108, and resistance is bang on for every sensor i tested

wishing i found something.

its green and cos im in the motortrade, ive always known green cars are bad luck!
bought a brand new MAF from TPS yesterday, fitted it outside and it has an open circuit that the old one doesnt have!!
so booked into VW on monday so i can get a replacement (no resistance between no.2/3 or 3/4 terminals, just open circuit!)

how infuriating after all the other greif ive had with it

[Tony Stark]

Did you check the needle lift sensor in injector #3?

[Anagonda]

Wifes car had bad MAP-sensor. It behaved like described. It had like 10 hp. You could go to the highway as there was not long enough highway in Finland to get it up to speed. I once tried, full throttle for 80km and we were doing 120km/h. The speed climbed one km/h at a time it was hilarious but slow!

But if you have all the power the engine should have after 3500rpm check for vacuum leaks(or N75). As the vnt is operated so that the vanes are closed with vacuum. If they are not closed the engine has terrible turbolag. My bigturbo tdi vanes are not fully closed and boost spikes in after 2500rpm and in 200rpm it gets from 0bar to 2.5bar...

[Sleeper_Avant]

Tony Stark,

the resistance was perfect when checked, although i know this doesnt always make the issue if resistance is fine and the sensor could be faulty.

would be obvious as its in limp mode, 1-2000 is ok power, 2-3000 is shockingly bad, 3-3500 ok, 3500-4500 is like flicking a switch

and this is one of the things it can do, go into base suggested mapping mode

going to get the `scope on it over the weekend and see what waveforms i get.

hope it is an injector, i will put a set of 5 pot 150bhp ones in there from a T4, Volvo engine or the A6 inline 5 2.5tdi 140 bhp models

Anyone got a set??

[Sleeper_Avant]

Anagonda,
this car gets regular MAP sensor swops as it got driven hard, usually every year or so and the sensor is perfect

[thecrim22]

i no u say maf is ok but had a very similar problem with a 2000 passat 110/115bhp and it was the maf also the inlet manifolds can get carboned up so mite be worth checking that but i assume u wud have noticed it when you did the head?

[Sleeper_Avant]

yes mate, head and inlet both imacculate now, will be putting PD150 stuff on when its running right.

and i bought a NEW MAF from TPS, put it on in the car park and its got an open circuit! no signal feed!!

booked into VW monday morning, hopefully they wont mug me off or i will kick right off, didnt do that with old MAF and it looks like a shyte chinese copy

[thecrim22]

quite lucky up here weve got a parts suplier that does exchange bosch units for between £20-£40

[Sleeper_Avant]

Right been driving the car all day today and took some live readings:

when its crap, IQ is 21-23max, when it opens up it jumps to 27, then climbs strongly to 36 give or take a bit.

removing no.34 fuse makes the idle much much better, i.e doesnt sound far too knocky!

and i could smell diesel smoke out the exhaust, cant with the fuse in!

but drive it with full boost 34psi (full vac to actuator from the pump, no N75) and it has no power whatsoever and just as knocky above 2000rpm,

very very bizarre.

Also fuel temp is always 32-38degreesC, even after a flat out thrash....... im guessing this could also be an issue lol

Also i used a generic code reader and got codes:

17656/P1248/004680

what are the other causes of low IQ? What governs this?
Is it just the needle lift sensor?

HELP!!!!!

[Sleeper_Avant]

oh and what governs the start of injection timing? needle lift?

[ManiacuV6]

If you have a LOw IQ you need to adjust it . Search for : "hammer modd " At idle with engine at normat operatin temperature you shuld have something close to 4.2 mg/stroke .