Passat Turbo Control

Tea drinker

Find the throttle control a bit iffy on my passat. It goes too strong on small throttle openings, if you leave it 1/3rd down it will pull hard all the way to redline. Floor it and the pull is actually less. I'm guessing this is something on turbo control, or maybe a remote chance of MAF or MAP issues.

Any ideas?

Chimaera

Year, engine? Any other faults? Had diagnostics run? Any modifications?

Tea drinker

sorry that would be a 2003 1.8t . It's not chipped etc.

Tea drinker

I changed the oil at the weekend and disconnected the battery while I was at it, checked a few connectors and nothing seems frayed. Seems a bit better but still not right at all, defo more power on 1/3rd throttle than full, though full throttle improves the closer it gets to redline. I think it needs bigger main jets ;-)

Nissan doctor

Tea drinker wrote: »

I changed the oil at the weekend and disconnected the battery while I was at it, checked a few connectors and nothing seems frayed. Seems a bit better but still not right at all, defo more power on 1/3rd throttle than full, though full throttle improves the closer it gets to redline. I think it needs bigger main jets ;-)

Just fit a bigger carb:eek:


The boost control sensor often goes faulty on these but would usually throw a fault. Have you checked all the intercooler pipes?

Tea drinker

Nissan doctor wrote: »

Just fit a bigger carb:eek:


The boost control sensor often goes faulty on these but would usually throw a fault. Have you checked all the intercooler pipes?

Thanks, Yeah, those intercooler pipes sometimes sort of pop half way out.... but no they are good. I think they were new ones (2008) as was the boost sensor which sits on the intercooler.

Any point to disconnect the MAF.. which I think was also renewed in '08

I have a weird feeling something is just connected backasswards. Would a faulty egr do anything? I'm going to try a spare N75 valve tomorrow. I might try changing the direction of the re-circ valve if possible, I'll have a look online see if I can find a pic of it fitted.

The only code I found (with un activated vcds) was:
VCDS-Lite Version: Release 1.1
Tuesday, 13 December 2011, 21:49:46.
Control Module Part Number: 4B0 906 018 DH
Component and/or Version: 1.8L R4/5VT 0002
Software Coding: 11501
Work Shop Code: WSC 00028
VCID: 6AA741AB0571
Additional Info: WVWZZZ3BZ3P184126 VWZ7Z0B5826030
1 Fault Found:
18010 - Power Supply Terminal 30: Voltage too Low
P1602 - 35-10 - - - Intermittent

I've cleared that as I think it was either the weekend disconnect or the battery ran low while I was abroad and needed a charge to get it going again. I'll recheck when I get the vcds re activated.

Chimaera

Bear in mind there's a huge element of personal perception going on here

The response of the car to a sustained pull from low rpm is going to _FEEL_ very different to burying it after cruising at e.g. 2k rpm.

There might actually be nothing wrong here. Only way to verify this is on a dyno, or with a stopwatch.

Ded_Zebra

Has the car felt this way all the time you have owned it or has it got worse over time?

Tea drinker

Ded_Zebra wrote: »

Has the car felt this way all the time you have owned it or has it got worse over time?

yep, I have it 5 years though I was away for most of last 2 and a half years.... and more or less been like this from year dot.

Yes it's subjective chimaera, but seems very real and the butt dyno agrees!
Wheelspin is definately more evident with the harder push, so I think that seals it.

I picked up a spare N75 valve I'll try this tomorrow...

Ded_Zebra

The reason i ask is that recently the old man got an Opel insignia. It's a diesel (the first i have driven) I notice that when you press about a third down on the throttle it seams to pull really hard (when it comes on boost). However when you accelerate in a similar situation at full throttle it doesn't feel as fast. For a while i thought that there was something wrong with it. However after getting used to it i realized that it pulls the same (more or less) at 1/3 throttle and full throttle (until high revs 4000ish). I was just wondering if is was a similar feeling.

Tea drinker

Yeah I changed the N75, not much different. It did seem to partially fix itself the other day when it was very cold.

Now that I have my VCDS working any suggestions on what to log?
I logged group one, O2 was hopping around from -2.3 to +3%, see yellow line in attachment

Tea drinker

Any ideas lads? It goes very well but this boost problem is peeing me off.
It spins the wheel unnecessarily sometimes and gives unrequested hard acceleration away from the lights, "ok" for me that's used to it but when wifey starts driving next year will be a bit wtf.

If I can describe it more accurately, on part throttle e.g 1/3rd pedal, it seems to accelerate hard once the boost comes in and the engine seems to respond to the extra boost and keep accelerating. When floored it will pull ok but it actually pulls harder as I get OFF the throttle.

Chimaera

I'm not sure what group it's in on the petrol engines, but have a look at logging MAP requested vs MAP actual and see what that looks like?

Is the accelerator DBW or cable on your car?

Tea drinker

I done a log on an athlone trip I think it was retard I was checking, and it showed very little, 3 or something. That log is attached. The car was going well anyway.
Now I put in another load of petrol and it seems back to as bad as ever, so is it possibly timing pull in relation to knock?
I guess if I run another log and see what retard is being set that tells the story......
I don't think it could be a fulty knock sensor "inventing" knock. Could they be overly sensitive to knock? Seems like a remote chance of that though. Still it almost seems like there are two issues, more than requested power on small openings vs less than requested on large throttle openings. *

* you all proabably have that problem :-)
Chimaera, the 2003 cars are DBW



Oh I checked the wastegate actuator is moving and seems not to leak when pressure is applied via pump.

d o'c

doubt if it's timing I think if ecu backed off timing you'd see it through all throttle ranges.

I'd be looking at MAP as MP will vary with load.
check the small pipes for clogs as well as splits
I'd also look at TPS

Tea drinker

Well I went over the hoses and couldn't find a leak, made a boost pressure tester from an old bean can with a tyre valve in it, couldn't hear a leak (garage was noisy anyway).
I cleaned the vehicle earths as this is listed as a problem area by some people, plus the car had been standing for a while so I figured no harm.
Around the same time it started running a little rough on tickover, and then it started running a lot rougher, eventually started belching black smoke out, plugs covered in fluffly soot as expected so I replaced the front O2 sensor and that sorted the richness, and ran a lot better. Still running badly though, really pulling back on acceleration so replaced the MAF and.... it's not much better. Getting long term lean codes, and it sometimes pulls back (stops accelerating altogether) when giving it welly. This evening it went from Steady to flashing cell and I see it has misfire cyl1 and cyl2. I'll post the codes later.

I'm lost!

crosshair1

Have you cleared learned values each time you've replaced a component, otherwise your ltft will take a long time to right itself.

Tea drinker

OK, here's an update, some of is checks that George Dalton PM'd me to try (thanks George!) Well, I checked the plugs and they are PFR6Q with about 10K on them. And they are soot black again, so I cleaned them with a wipe of a cloth and wiped their insultors too.
I think it didn't adapt to the new MAF right so reset the ECU again. (thanks crosshair)
Swopped in a pair of spare coilpacks for the 2 with the miss (original VW).
Took it for a spin and it really went well even on full throttle. It gradually adapted I suppose and while it's back going well for now it is back again doing it's better pull on part than full throttle....
Got one fault code (slow adaption) for the other lambda (B1 S2) but as it's not part of the fueling I'm not too pushed..
I'll keep an eye on it and see how things develop - or not!

PS thanks for the help guys

Tea drinker

ok the miss came back strong today, it's occasional missing under normal driving and a lurch when changing gear. Push it hard and at 4K or so it hits a "rev limiter" , you can keep your boot in and it might pull strongly through and then start missing again.
Today I swopped in a secondhand assembly of all the small hoses under the manifold and the associated valves, and the suction pump assembly. No difference.
I swopped in a spare N75, no difference. Pulled the fuel pressure regulator, a little bit of dirt/metallic debris on it cleaned it off, tapped it out and blew carb cleaner through - no difference. Might try a new fuel filter though there's only 20K miles on this one. Might first pull the fuel rail (first pulling fuse 28 and running engine till it stops) and take each injector and clean it. Checked one plug and it was clean, if a little heat discoloured(?), sort of orangey looking. Threw in 2 bottles of injector cleaner and filled the tank.
That's it for now.

Tea drinker

Dropped in a set of FSI coilpacks and while it didn't fix the bad misfire and pulling back problem, the better spark does mask it to an extent.
I have 2 things to chase, a slight boom from the engine at higher engine speeds... might be a leak/crack somewhere in the exhaust causing the noise and affecting fueling with false lambda readings.
Second thing is the SAIP error below. I guess the hoses crack or are their internal errors with these pumps?

VCDS-Lite Version: Release 1.1
Saturday, 19 May 2012, 19:54:30:29918
Control Module Part Number: 4B0 906 018 DH
Component and/or Version: 1.8L R4/5VT 0002
Software Coding: 11501
Work Shop Code: WSC 00028
VCID: 6AA735750571
Additional Info: WVWZZZ3BZ3P184126 VWZ7Z0B5826030
3 Faults Found:
16523 - Oxygen (Lambda) Sensor B1 S2: Response too Slow
P0139 - 35-00 - -
17832 - Secondary Air Injection System; Bank 1: Leak Detected
P1424 - 35-10 - - - Intermittent
17536 - Fuel Trim; Bank 1 (Mult): System too Lean
P1128 - 35-00 - -

Tea drinker

fuel trim block 32 are 1.9% and 22% multiplicative.
The second one is out of whack right? MAF is new , Lambda is new... well it was 3 weeks ago.

George Dalton

It all points to a leak in the intake system somewhere.

Tea drinker

George Dalton wrote: »

It all points to a leak in the intake system somewhere.

Been over the intake again today, pulled the diverter valve looks fine, had a look for leaks underneath, can't find anything. inflated the air intake using an air line and it only releases pressure very slowly.... I suppose a little is normal.
It's definately going better with the new FSI coils but I can still light the mil and get a flashing mil when accelerating at motorway speeds in 3rd, it's just harder to do it.

I'm going to be working the weekend but I might have to invite myself down to you next week ;-)

crosshair1

Is it a genuine maf?
You also cant disregard the o2 b1s2 as it does have influence on fuelling although not usually enough to feel driving.
Can you pressurise the exhaust?

Tea drinker

crosshair1 wrote: »

Is it a genuine maf?
You also cant disregard the o2 b1s2 as it does have influence on fuelling although not usually enough to feel driving.
Can you pressurise the exhaust?

hmm I didn't know that about the S2 sensor.
About the exhaust, well, I soaked the manifiold, turbo and cat in water stuck 2 spuds up it and fired it up, no obvious leaks but there does seem additional hum in it. I think the flex pipe is going, but that seems very far away from the 02 sensors to have any effect?

Oh and the maf is a bosch stickered recon unit, packaging looked the real deal. I think I'd rule out the MAF unless a wiring issue to it.

crosshair1

I wouldnt rule out the maf until you test it or replace with a known good, there are a large amount of counterfeit sensors etc on the market.
.. it should give 4.5v out under maximum load