faut code help please

[Karlos the Avant]

hi all

i have been doing a bit of work on the car last few weeks A4 avant 18t fwd 1997

i have changed the n75 valve, dv, plugs, oil/filters, coolant temp sender and soon to have nice cream leather interior fitted in it.

The problem i now have is Vag-com is picking this fault up:

Address 01: Engine
Controller: 8D0 907 557 T
Component: 1.8L R4/5VT MOTR HS D06
Coding: 04001
Shop #: WSC 06325
1 Fault Found:
00575 - Intake Manifold Pressure
11-10 - Control Limit Not Reached - Intermittent
Readiness: N/A

after changing all the parts above the car run like id put rs4 block in it {i wish lol} compared to how it was before.
now im back to reduced power and it seems as if the car is holding back on me.
i get a lot of engine noise revs ect but no movement to match its like some one is pulling me back as im trying to go forward is the best way i can discribe it.
the car has only got 83k on it but no history from when i bought { i thought id take my chances because i loved the car from day one}

i still love the and car just wanted to know if anyone could point in rite direction to go next.

i am trying to get it all running correct before i get stainless custom made and fitted, then i want it remaped to give me that little bit more bhp.

i will be greatful for any help offered as ive search the google and this forum but they seem to say it is what ive already changed ?

many thanks in advance
Karl

 

[aragorn]

That suggests that there is no boost.

I'd be checking the boost control hardware, ie the actuator, wastegate arm and suchlike.

 

[Karlos the Avant]

That suggests that there is no boost.

I'd be checking the boost control hardware, ie the actuator, wastegate arm and suchlike.

thanks mate but if you could tell me how do i test these things?

im not that well up on a turbo unit

just want it running rite now getting a bit fed up lol

with thanks
Karl

 

[aragorn]

Well check over all the pipework from the N75 to the turbo to ensure none of its split or blocked.

It could possibly be a siezed actuator or wastegate so you'll need to get in there with your hand and see if they're free, its a tight squeeze though.

Assuming your sure the N75 is working correctly and the pipes are fine, then it might suggest a fault with the turbo itself. Our car had a similar fault before we owned it. The wastegate valve had come off and dropped down the exhaust somewhere meaning the turbo couldnt produce any boost.

The fault code suggests to me that the ECU is demanding lots of boost from the N75, but its not being provided.

 

[Karlos the Avant]

Well check over all the pipework from the N75 to the turbo to ensure none of its split or blocked.

It could possibly be a siezed actuator or wastegate so you'll need to get in there with your hand and see if they're free, its a tight squeeze though.

Assuming your sure the N75 is working correctly and the pipes are fine, then it might suggest a fault with the turbo itself. Our car had a similar fault before we owned it. The wastegate valve had come off and dropped down the exhaust somewhere meaning the turbo couldnt produce any boost.

The fault code suggests to me that the ECU is demanding lots of boost from the N75, but its not being provided.

hya mate

thanks again, i have had my hand in there and all seems to be conected, i can here the gate opening when i pull the rod and the rod can be seen to be moving when i start the car and rev it up.

i have just been for a ride and it seems to have a bad flat spot when i put my foot on the gas.
it is also missing when i am rolling along at low revs and seems to be holding back when foot goes down.

im a bit stuck now to be honest mmmmmmmmmmmmmm ?

 

[aragorn]

It could be a faulty MAF?

The engine doesnt have a boost pressure sensor and relys on the MAF for everything. If it was underreading you'd be running lean and it would think its not getting the boost pressure its asking for?

Try giving it a clean with some brake cleaner and see if that helps at all.

 

[Karlos the Avant]

It could be a faulty MAF?

The engine doesnt have a boost pressure sensor and relys on the MAF for everything. If it was underreading you'd be running lean and it would think its not getting the boost pressure its asking for?

Try giving it a clean with some brake cleaner and see if that helps at all.

cheers again arogorn

i will have a look at this today and my front abs sensor has just come as well so hopfully will have abs back on today and no fault codes all being well.

im going to clean the throtle body today as well see if that make any difference to the running.

i will let you know later mate and thank you for your suggestions because i was running out of ideas to be honest

regards
Karl

 

[Karlos the Avant]

i have cleaned the throtle body out today and i did find a small amount of oil in there?

any sugestions on the oil i found or is that normal?

i have cleaned the MAF and changed the abs front pas sensor, the abs fault has change and i can only asume that i have not pushed in far enough, i did have open circut warning and now just speed sensor abs fault showing.

i came to work tonight and the car is running very poor { had to gear down to get it to 60mph up hill}

the car seems to have a humming/vibration going louder the more i try to push the gas down but still no power there and sounds like a lot of intake noise as well?

it looks like i have been beat on this one and will have to pay some garage to look at it and repair if poss because i travel the motor way every day and need to use the car.

anymore help or sugestions i would be greatful

kindest regards
Karl

 

[aragorn]

It does sound like either a MAF fault, or from what you've said there, a blocked cat. Its got to be mechanical if vagcom cant see it.

Try unplugging the MAF and taking it for a drive. Try not to give it full bhoona, but see if it drives any better. If it does then it suggests the MAF is fubar.

 

[Karlos the Avant]

It does sound like either a MAF fault, or from what you've said there, a blocked cat. Its got to be mechanical if vagcom cant see it.

Try unplugging the MAF and taking it for a drive. Try not to give it full bhoona, but see if it drives any better. If it does then it suggests the MAF is fubar.

after reading some of your old wright ups on here, i was thinking may be the cat blocked it used to be ok at low very slow revs without pushing my foot down and just easing the pedla down it used to pull better.

i can only think that now everything else is repaired that was causing a lot of low boost and power loss that the gases that are being produced can no longer get out the knacked cat quick enough.

Would i have to drop the front pipe to knock the insides out the cat or does it have to be opened up on the top or botom of the cat to get the insides out ? or can it be done in place and would it just blown the crap out the back ?

thanks again mate i will look at your new suggestions and sure in time i will get there lol

 

[aragorn]

What you describe there is very similar to how my dads old turbo acted with a blocked cat. At light throttle it drove relatively normally. If you jammed the boot down it just bogged down and died. To get it up to 60mph you had to really feather the throttle just right.

A quick test would be to slacken the bolts between the cat and turbo off, so therse a big gap, and take it for a drive. Again it wont be perfect as the lambda isnt seeing all the flow and will be seeing extra gas, and it will be noisey, but it will give you an idea. If it suddenly performs a lot better then the cats being restrictive!

To gut the cat you'll need to remove it completely. the biggest issue is unbolting the cat to downpipe bolts as they're really hard to get to from any angle.

 

[Karlos the Avant]

What you describe there is very similar to how my dads old turbo acted with a blocked cat. At light throttle it drove relatively normally. If you jammed the boot down it just bogged down and died. To get it up to 60mph you had to really feather the throttle just right.

A quick test would be to slacken the bolts between the cat and turbo off, so therse a big gap, and take it for a drive. Again it wont be perfect as the lambda isnt seeing all the flow and will be seeing extra gas, and it will be noisey, but it will give you an idea. If it suddenly performs a lot better then the cats being restrictive!

To gut the cat you'll need to remove it completely. the biggest issue is unbolting the cat to downpipe bolts as they're really hard to get to from any angle.

i have not had chance to test the cat today but i did unplug the maf and it didnt run any different as i can tell.does that mean my maf is knacked as would of expected it to run worse when unpluged ?

i did manage to get the abs sorted, pushed the sensor in a bit more and for first time since i got the car i now have no warning light on my dash so that is cool as

best thing i did buy was the ebay vag-com lol

i will try the car again tonight on way work and scan again in morning when im home, i have cleared all the fault that i could see on vag-com.

there was a list of faults for the centrol locking, but none have come back so thats cool.

 

[aragorn]

If the AFM was stuffed i'd expect it would drive better without it, as the ECU will default to a limp home safety map which has mostly correct values in it. As there was no change, i'd expect its not that.

If its bogging down when you open up the throttle, but goes alright with light throttle, give the cat a try next!

Central locking module logs the alarm activations as well as the faults so you often find lots of faults in there.

 

[Broken Byzan]

you could just drop the 02 sensor out,that should give enough flow to see if there is a difference.
So with the MAF off there was no difference? As tbh the only way an early car can sense/see boost is via the MAF readings. Its possible it's borderline so not kicking a code yet.

Have you logged the MAF readings at all?

 

[Karlos the Avant]

you could just drop the 02 sensor out,that should give enough flow to see if there is a difference.
So with the MAF off there was no difference? As tbh the only way an early car can sense/see boost is via the MAF readings. Its possible it's borderline so not kicking a code yet.

Have you logged the MAF readings at all?

i will be honest and say i dont know how to log the maf reading ?

but i think it may be the cat to be honest i tried it coming to work tonight and as soon as i pulled up i looked under bonet and the turbo was glowing red.

after reading a old post on the forum i think the cat sugestion may be spot on and i was kind of going down that route myself after trying alot of other ideas on here.

if i get time in morning i will get one of lads in garage take it off and knock the **** out of it.

im planing on new stainless at end of month so will be ok till then with knacked empty cat and may leave it on there with new exhaust.

big thanks to both you guys and will let you know over the next day how it goes

kindest regards
Karl

 

[aragorn]

Yer glowy turbo does sound like its the cat!

 

[Karlos the Avant]

hi all

I have been looking at car today and i have managed to get the lambo sensor out to let a bit of gas out,

took it round block, the car is not bogging down with that out and confirms the idea that the cat/exhaust is blocked.

I will be booking it in for next Friday for the stainless system and im going to leave the cat off.

Im hoping i can get twin sided back boxes {1 either side} but not if i can get the other side past the fuel tank but will have look when its on ramps.

I will take some pics and post update when its all done and fingers crossed that the car will run like a dream for once.

Karl

 

[Markey]

The cat broke on my A4 half of it broke off and turned round inside the cat blocking the flow. Car was very slow and would struggle to get over 70. Hills were just out of the question.

 

[Karlos the Avant]

The cat broke on my A4 half of it broke off and turned round inside the cat blocking the flow. Car was very slow and would struggle to get over 70. Hills were just out of the question.

mine same mate, realy bad trying to get power up and up hills it just gives in lol

im hoping new system will sort it out because all the other work and parts i have changed the last few week are doing nothing till i get this problem sorted.