Big flat spot in low revs and slight increase in tappet noise - after new head gasket and new chains

[matth76 1]

Hi

I've just had a new stainless steel exhaust manifold fitted by Storm Developments today and had new head gasket and tensioners kit fitted (this includes all timing chains). Storm were really helpful. The stainless steel 6 branch looks amazing.

I have a couple of questions though which have resulted from my journey home:

I have noticed the 'usual' vr6 tappet noise is just a bit noisier than normal (although only if I have the window open and I'm not travelling) but it is absolutely fine travelling along - smooth and quiet as usual, although the VR6 noise does drown out everything else. I've been told this kind of tappet noise is pretty normal by Stealth, and a few other companies. Should it be slightly more noticable after just having had the timing chains and head gasket done?

One other thing I noticed today was a big flat spot / no decent power between 1k and 2k revs. After that the needle dives for the red line and I get a surge of power - it's almost as though I have a turbo and I have a bit of lag! The 6 branch manifold certainly increases top end torque. I have been told that the flat spot is likely due to the ECU relearning the fuel air mixtures but I have been driving for two hours on the way home from Storm and the flat spot is still there (will it normally take longer than two hours for the ECU to sort things out?). I was told my car was originally overfuelling and this has been rectified by Storm. Could it be perhaps that now the overfuelling has been rectified my car will not feel as quick as it used to in the low down revs? Could it be my MAF sensor that is faulty? Storm did say my original "lamda" sensor was on it's way out so they fitted a second hand one. Could the lamda sensor they fitted be faulty? Either way I am taking it back in 500 miles time for an oil change and to resolve any problems. Any input or comments from here though will be really useful so I can ask the right questions when I go back after xmas.

Could the flat spot be a normal after effect after having a new head gasket fitted? It is a standard head gasket that was fitted. The garage did re-align my throttle body by the way as well as it wasn't correct before. They did a fault check with my car while it was in and there were no faults - although a faulty MAF won't necessarily show up which is why I think it could be possibly this.

The ECU was reset while it was with them but should I do it again myself by disconnecting the battery - would this possibly resolve my flat spot problem? If so, what is the procedure to reset the ECU?

Thanks for any help guys.

Cheers

Matt

[matth76 1]

By the way a complete oil change was done (as would be necessary with the head gasket change) and the oil they used was semi-synthetic 10w 40. They said it is better than the VW syntha silver because it has an anti-gunge additive.

Any ideas?

[silverline 0]

some cars do have a learning process in the ecu, i dont know if the vr is the same? you'll prob find the manifold has taken away the initial low end torque, cant be serious if the car is fine through the rest of the rev range. i ve recently done chains and tappets on mine and there is no tappet noise now altho it did take a while for the oil pressure to get to 1 or 2 of the tappets causing them to rattle yours maybe taking its time to pressurise as well? are you sure its not the injectors you can hear? mine "tick" which could be mistaken for tappets but thats just injector noise.

[Eat this 2]

iv just had 268 cams and a 6/2/1/ manifold and dont seem to have lost any low end torque

and yes the vr6 ecu does learn

[matth76 1]

The ODB2 ecu learns. Do you think it may be damaging to rev the engine too high (even when the oil temp is fully warmed up)? I was under the impression I didn't need to run it in or treat it any different after having the chains and head gasket done.

I am going to try and reset the ECU tomorrow to see if this eliminates the flat spot. What are the steps I need to follow? I believe it is one of the wires on the battery that I need to disconnect.

Thanks for your replies. Does anyone else have any info on this?

As far as I know the 6 branch exhaust manifold was supposed to increase "mid-range" torque. Although it only seems to be top end power that has increased, from about 3.5k onwards and it does rev much quicker to red line once it passes 3k.

By the way my car has done 76k miles.

[andy 0]

Could the flat spot be a normal after effect after having a new head gasket fitted?

Absolutely not. It should feel brilliant. I fitted new chains/clutch/valves/gaskets a little while ago and the car felt like new. Maximum compression restored an all cylinders, nice quiet chain and tensioners. It was tappety for a few minutes the first time it was run, which is normal as hydraulic pressure has to be achieved, then it was the quietest VR6 engine I've ever heard. Smooth and Powerful :-) Just like yours should be. If it doesn't feel right, take it back, you are the customer...

Resetting the ecu is irrelevant now, yours will have been reset by nature of the work that has been carried out on it as the battery will have been disconnected anyway. They should have run through basic settings which will let the ecu calibrate itself to the sensors in your engine as they stand, yours will be different if they have adjusted your throttle position sensor.

[matth76 1]

Thanks for your reply. Are you able to drive it normally (i.e take it up to any revs as long as it is all fully warmed up) after having a new head gasket and all chains done?

Could the change in oil cause the tappets to be slightly more noisy? I'm wondering whether the new exhaust manifold is causing the flat spot between 1-2k revs. What do you guys reckon?

[mightyvr6 0]

Yes to your first question. The tappets should be quieter after an oil change. Not sure about the flat spot.

[matth76 1]

I'm thinking the flat spot maybe due to the 6 branch exhaust manifold ...it seems to create a fair bit more power above 3k revs but below 2k it's a bit flat. It does drive and pull very strong and smooth from 3k-5k revs.

Glad the answer was yes to my first question as I did take my car to 5k revs a few occasions on the way home to test how the car felt (once the oil was fully warmed up of course before going over 3k) I was a bit worried that perhaps it was not a good idea to do this after having a new head gasket fitted.

Is VW syntha silva 15W40 semi synthetic? The oil they used was 10W40 (which I assume is slightly thinner?) could this perhaps be why the tappets are slightly noisier?

Would fitting a 4bar fuel pressure regulator from a corrado 2.9vr6 help to improve throttle response low down in the revs? The standard fuel pressure regulator is 3bar on the golf vr6. Storm recommended this and also The Phirm. I was wondering what difference it would make to low down response (which is lacking at the moment with the manifold).

Thanks for your help mate.

[Eat this 2]

iv got synta silver in mine now and its deffo 10-40 and verrry quiet (but i do have new tappets)

i also have 268 cams + a 6/2/1 manifold and theres deffo no flat spot even before the remap it was strong all through tbh the remap has sorted the underfueling out and made it pull hard all the way to the limiter instead off tailing off slightly

[28v6r 0]

This may sound funny but check your oil level , remember that if the level is low then the VR6 senses this and has an inhibitor to protect it from over revving during this, also check the oil filler cap is on correct if its slack then this will create the same sluggish feel to the engine as its not building up pressure. Nothing to do with the oil pump so don't panic there, for those who are interested.. slacken the cap slightly and see what happens, again the engine will feel slightly retarded due to the loss of pressure.. retighten and all will return to normal...

[RIX 0]

crap olie you use over there in gb,i only either mobil 1 5w50,ore castrol 10w60 they will take the top of the sound from the tappets,if the ecu is not reset buy storm(ore dis.con the bat.)there can go up to a week before it

[Eat this 2]

i have more mods than mat and didnt get any flatspots anywhere it just underfueled

[matth76 1]

They haven't wrapped the manifold no. Just used a heat shield. I was told the heat wrap wasn't really necessary (even though I would pay them to do this and did ask them) they said because it was very high quality it wouldn't make much difference wrapping it and could actually be worse as heat would build up.

How easy is it for a garage to check if the cam timing is out? Could this cause the flat spot then? Am I right in assuming a remap won't sort out the cam timing... the head has to be taken off to sort this out?

I have a high flow cat and free flowing exhaust - could it be because the system is actually 'too' free flowing and has reduced back pressure a bit too much? Would a remap help correct this? Other people on here have had a decat and 6 branch but not suffered this problem which is why I'm thinking it could be something else.

The tappet noise bothers me though.

The oil filler cap was on tightly by the way. Bit of a mystery. I hope The Phirm are open this week as I may take it down to them to have a second opinion.

[matth76 1]

I've just had a listen to it now and it actually doesn't sound that tappety anymore (and its a cold morning) - no more than it used to. Yesterday it sounded more tappety though which is a mystery. I think the noise may be made more distinct from the new manifold as that seems to 'tick' slightly as it gets hotter. Also I have noticed a 'rectangular patch' on one of the branches coming off the manfold (it's stainless steel and no weld marks or anything) but just curious as to what it might be - is this usual what is this?

Also, what is the small yellow container of liquid in the top left (drivers side) back of the engine bay (right before the windscreen - it has a pink dipstick thing that refuses to stay down - it seems as though it could be the brake fluid container but the dipstick keeps popping up half way - what is this and can I simply tape it down??

The oil level seems fine by the way. I'm going to take it for another drive later to see how the flat spot is. Will a remap sort this out?

I was told the rev needle would dive to the red line so it could be the characteristics of the manifold I now have. Certainly gives a nice howl at high revs and pulls you back in your seat! !lol

[Slim 0]

That is the brake fluid container, the dip stick is there to let you know the level, don't bloody tape it down.

[silverline 0]

Also' date=' what is the small yellow container of liquid in the top left (drivers side) back of the engine bay (right before the windscreen - it has a pink dipstick thing that refuses to stay down - it seems as though it could be the brake fluid container but the dipstick keeps popping up half way - what is this and can I simply tape it down??

[/quote']

yeah thats the reservoir for the brake fluid. i guess it floats as a level indicator?

[Eat this 2]

Also' date=' what is the small yellow container of liquid in the top left (drivers side) back of the engine bay (right before the windscreen - it has a pink dipstick thing that refuses to stay down - it seems as though it could be the brake fluid container but the dipstick keeps popping up half way - what is this and can I simply tape it down??

[/quote']

yeah thats the reservoir for the brake fluid. i guess it floats as a level indicator?

yes it is if u tape it down the brake warnin light comes on lol

[matth76 1]

lol good thing I didn't cheers. Is it supposed to protrude from the top by a couple of inches? Brake fluid can't leak out while the dipstick is half way out can it (just that I have never noticed it protrude like it is before)?

I took my car for a drive today - the tappet noise is fine - slightly tappety as it used to be maybe even slightly quieter - not sure why it was noisier yesterday. But the car does seem to have lost power in total I suspect... and there is a clear flat spot early on in the rev range, mainly between 1-3k revs. What could cause all of this? The top end power doesn't feel quite as strong as it used to, although it does remain smooth which is good. I'm concerned about the flat spot though.

I was told by a couple of companies and some members on here that a 6 branch should increase mid range torque. I seem to have lost some to be honest. I don't think it is the 6 branch causing my problem as others with a similar 6 branch haven't lost any power - I assume the MAF sensor maybe something to do with this... what does anyone think? I was told the garage reset the ecu (normal practice) when they did all the chains and head gasket etc, so I shouldn't have to reset the ecu again.

What about cam timing: how can I or a garage tell if the cam timing is out of sync? Is this easy to diagnose and fix? Would incorrect cam timing cause a slight loss in power?

To recap, I had the following done to my car:

Fitted new chains/ tensioners.

Fitted new standard head gasket.

Fitted 6 branch exhaust manifold.

Also realigned throttle body.

Also fitted second hand lamda sensor.

Reduced the fuelling level (as car was over-fuelling).

They did a VAG COM fault check and found the throttle body alignment to be incorrect so fixed this (fault disappeared). VAG COM also showed up the original lamda sensor as being faulty so Storm fitted a second hand lamda sensor (fault disappeared). They also corrected my fuelling as my car was overfuelling. This was corrected and fault disappeared. No other faults remained on VAG COM after this.

A faulty maf sensor may not appear on VAG COM... could this therefore be the culprit? Not sure why it would suddenly fail after the work was carried out. My car did drive really well before. Could any of the work carried out above cause slight loss in power?

Thanks again for any help.

Matt

[Slim 0]

Phone the garage and tell them, they worked on the car so they'll know more than anyone on a forum who hasn't seen or driven the car.

[silverline 0]

if the timing is out then really it needs to be completely checked and readjusted, theres no easy way round that. did you have upper and lower chains and tensioners done?

[matth76 1]

It was a complete "head gasket and tensioner set" that they did which included all tensioners and all timing chains - everything. I will be speaking to the garage tomorrow and also the Phirm as they know my car pretty well.

I was wondering if anyone had experienced a similar flat spot and knew what caused it or how it was resolved.

Thanks for any help.

[RIX 0]

you don

[VR6Pete 1,455]

I'd go with the timing tbh.... do you have any problems starting the car up?

[Eat this 2]

normally if the timings out a tooth ud get really bad low revs and fine high up or the other way around not a fairly small flatspot