Carbon Cleaning before tuning???

[swimming gti]

I have a Mk7 GTI with 70k miles, took it to a local VW/Audi guy to check everything as I'm about to tune it (EQT 93 Stg 1 through Cobb AP)

He scanned it and it said it found fault codes for cylinder 1 and there were 3 misfires. He was highly certain this was due to never getting carbon cleaned and from my opinion he knows a lot about these cars.

He says he thinks I should do it and that its better to tune a good car than a bad car but also told me it would cost between $600 - $1k!!

I know I "should do it" considering it's at 70k miles but this costs $600- $1k??? I know a lot of people on these forums have higher mileage than that and I never hear of them doing that.

Is there a cheaper option to fix this?

Would it cause any issues of I just didn't bother with it and tuned it anyway?

Appreciate the help!

 

[jay745]

That's pretty high. I used to charge 450, but yes you should do it just find a different shop.

 

[kevinkar]

Is the misfire counter cumulative or just since last start up? 3 in 70k is not a lot. 3 on the drive over to the shop could be a problem. Either way, it makes sense to start with a clean slate and not tune to the carbon. I'd do it.

 

[The Fed]

Three misfires is nothing. Buy your own VCDS for $199 and log misfires using Advanced Measuring Values while you're driving. Sound like he's trying to make money.

 

[swimming gti]

Is the misfire counter cumulative or just since last start up? 3 in 70k is not a lot. 3 on the drive over to the shop could be a problem. Either way, it makes sense to start with a clean slate and not tune to the carbon. I'd do it.

Will ask him.

I know I should do it but have spent just under $2k on getting brakes installed, DSG serviced and buying an AP within the past few weeks so don't want to spend another $800 or so on maintenance unless this is REALLY important.

If I tune it to the carbon, is that going to affect the tune long term? Like will there be any difference if I tune it and then clean the carbon as opposed to cleaning the carbon and then tuning it?

 

[swimming gti]

That's pretty high. I used to charge 450, but yes you should do it just find a different shop.

Yeah just dont want to go for cheapest as it looks like a pretty complex process...have had bad experiences with mechanics who dont know how to work on VWs

 

[swimming gti]

Three misfires is nothing. Buy your own VCDS for $199 and log misfires using Advanced Measuring Values while you're driving. Sound like he's trying to make money.

Cant my cobb ap track misfires the same way?

 

[Ezekiel81923]

Will ask him.

I know I should do it but have spent just under $2k on getting brakes installed, DSG serviced and buying an AP within the past few weeks so don't want to spend another $800 or so on maintenance unless this is REALLY important.

If I tune it to the carbon, is that going to affect the tune long term? Like will there be any difference if I tune it and then clean the carbon as opposed to cleaning the carbon and then tuning it?

You're using an OTS tune so you're not really tuning to a crusty motor in the same sense as you would be if it was a custom tune. The stage 2 tune is the same whether you have crusty intake valves or not. The car will run better with clean intake valves but the tune is the tune whether you flash it before or after you get them cleaned.

I am getting my valves cleaned tomorrow and I was quoted $865 for that portion of the work to be done. I'm also having MPI installed while it's off the so the bill overall is higher but if your final cost is closer to $600 for the walnut blasting that would seem to be the going rate these days.

 

[swcrow]

tune it and send it......deal with carbon cleaning once you've confirmed it needs it

 

[jay745]

Yeah just dont want to go for cheapest as it looks like a pretty complex process...have had bad experiences with mechanics who dont know how to work on VWs

I've done probably a hundred carbon cleanings if not more, it's actually pretty straightforward. The manifold comes off easy and the valves are right there. There really isn't a ton that can go wrong.

To answer your question on the order, it doesn't matter really. You just may be slightly down on power if there's a lot of carbon buildup but if you aren't having symptoms it's probably fine. Typically between 70-100k miles is when the buildup gets bad.

 

[swimming gti]

You're using an OTS tune so you're not really tuning to a crusty motor in the same sense as you would be if it was a custom tune. The stage 2 tune is the same whether you have crusty intake valves or not. The car will run better with clean intake valves but the tune is the tune whether you flash it before or after you get them cleaned.

I am getting my valves cleaned tomorrow and I was quoted $865 for that portion of the work to be done. I'm also having MPI installed while it's off the so the bill overall is higher but if your final cost is closer to $600 for the walnut blasting that would seem to be the going rate these days.

Yeah that's what I thought. Its a regular EQT tune so nothing custom. I'm sure the tune adapts in some way to the engine state but if I get it cleaned later I would think it would then adapt back to the clean engine?

Yeah let me know how it goes...my guy said $600 - $1,000 which is a pretty wide range.

 

[swimming gti]

tune it and send it......deal with carbon cleaning once you've confirmed it needs it

That's what I really want to do lol. Just not sure how big of a deal these misfires are...apparently the three misfires are from the last 50 drive cycles and they are on cylinders 1 and 3. Need to do more research

Not sure which data a Cobb AP gives you on this...but would it tell me data regarding when I would need a carbon cleaning? Like once it gets to a certain level of knock or something? I guess a lot of people would just wait until CEL comes on but im not that risky lol.

 

[jay745]

3 misfires is nothing to worry about

 

[swimming gti]

I've done probably a hundred carbon cleanings if not more, it's actually pretty straightforward. The manifold comes off easy and the valves are right there. There really isn't a ton that can go wrong.

To answer your question on the order, it doesn't matter really. You just may be slightly down on power if there's a lot of carbon buildup but if you aren't having symptoms it's probably fine. Typically between 70-100k miles is when the buildup gets bad.

So the reason it costs so much is probably just the labor?

Haven't noticed any systems apart from a light rough idle and the misfired detected...am just getting to 70k miles now. What would be the worst that could happen if I just tuned it and waited another 5k miles?

 

[swcrow]

That's what I really want to do lol. Just not sure how big of a deal these misfires are...apparently the three misfires are from the last 50 drive cycles and they are on cylinders 1 and 3. Need to do more research

Not sure which data a Cobb AP gives you on this...but would it tell me data regarding when I would need a carbon cleaning? Like once it gets to a certain level of knock or something? I guess a lot of people would just wait until CEL comes on but im not that risky lol.

nope....AP can't do that. You can run logs to go back and read to see when they occur, if you've been noticing if they are happening at certain times/conditions though.

move plugs and coilpacks to cylinders 2&4 and see if the misfires follow...if it does, replace plugs and coilpacks