Car hesitates while boosting

[Deadly BlaZe]

Yes, I know, do a boost leak test. I did, and there's no leaks anywhere. And yes I have new plugs and wires. I was wondering, is it possible the hesitation is because I have an open element K&N filter with no heat shield and the engine bay just gets too damn hot so it sucks in all that hot air? Just wondering if it's a possibility as it seems the hesitation starts after an hour of driving the car.

 

[xveganxcowboyx]

It's possible heat soak is causing some problems. Almost all my hesitation problems have been from knock and having timing pulled. I would look at possible causes of knock or false knock.

Do you have a logger?

 

[Deadly BlaZe]

It's possible heat soak is causing some problems. Almost all my hesitation problems have been from knock and having timing pulled. I would look at possible causes of knock or false knock.

Do you have a logger?

Nope, no logger. I don't hear knock either. I use 93 octane fuel always too. What reasons would there be knock?

 

[DankDSM]

Knock is caused by preignition. This basically means that you are not getting enough fuel. I saw that you had a mbc. If you have the boost turned up too much this could be the problem. It seems you mostly have a stock motor so this is the only reason i could see you having knock. Try turning the boost down and see if this helps.

-Josh K.

 

[2gAWDTalon]

Are you running higher than stock boost? I had a problem with my car breaking up real bad, I changed the plugs, wires, boost leak test ect. It came down to a theory of it being the coil pack was getting weak and the spark was getting blown out by the boost. To test this theory I turned down the boost from 20 to 15, hmm the car runs better but still breaks up. Next I turned it down to 10psi and the car ran almost perfectly smooth to redline. This confirmed my theory and I replaced the coil pack and the problem was solved.

 

[Deadly BlaZe]

Well actually I took the mbc off because my stock boost is already at 13-14 psi STOCK (except for mbc restrictor removed). And besides that, I don't get the hesitation when I hit full boost, it starts when i start building boost even with the throttle down only 50%. So I'm sure it has nothing to do with the boost. And as previously stated, I start getting the hesitation after about an hour of driving (basically when its hot).

 

[MrBoxx]

What kind of plugs? What kind of wires?

 

[Deadly BlaZe]

What kind of plugs? What kind of wires?

NGK BPR6ES plugs and MSD wires

 

[MrBoxx]

It could very possibly be knock. I just read where you say the hesitation occurs below 50% throttle. In this case, it could be phantom knock. This summer, I had a phantom knock issue at anywhere between 17% and 30% throttle position, and knock would skyrocket.

Do you have any way of logging your timing or knock?

 

[Deadly BlaZe]

It could very possibly be knock. I just read where you say the hesitation occurs below 50% throttle. In this case, it could be phantom knock. This summer, I had a phantom knock issue at anywhere between 17% and 30% throttle position, and knock would skyrocket.

Do you have any way of logging your timing or knock?

No I have no way of logging. What's the reason the motor would be knocking? Compression on the motor is great, I always give it 93 octane, and correct plugs and wires. Could the air filter with no heat shield be the problem? I've read about heat soak and how it could possibly cause preignition.

 

[MrBoxx]

It could be hot engine bay air, or it could be phantom knock. The only way to know for sure is to either get a logger or change the knock sensor.

On the other hand, it also could be a bad coil as previously mentioned, or something totally unrelated, like a bad batch of gas.

 

[95gs200k]

I actually just experienced the same problem in my 93 tsi. Turns out it was "phontom knock" from a bad lifter. the lifter was periodicly bleeding down so when i would pull the valve cover it was gone no tick, and all lifters were pumping up . I got lucky and caught it doing it at idle and could visually see the lifter squirting improperly. Hence I will be getting the newer designed quiet lifters tomorrow and should be in by mid afternoon. Neways, if you have a lot of tick it is time to get lifters and get rid of that knock. Do you experience a lot of lifter noise when it is cold? That was my first symptom. good luck.

 

[Deadly BlaZe]

It could be hot engine bay air, or it could be phantom knock. The only way to know for sure is to either get a logger or change the knock sensor.

On the other hand, it also could be a bad coil as previously mentioned, or something totally unrelated, like a bad batch of gas.

Well I drove the car after it cooled down a bit and I didn't feel a hint of hesitation. Strange. Also, is phantom knock bad? And how is it related to just normal knock? I know I could/should search for this, but since were on the topic

 

[Deadly BlaZe]

I actually just experienced the same problem in my 93 tsi. Turns out it was "phontom knock" from a bad lifter. the lifter was periodicly bleeding down so when i would pull the valve cover it was gone no tick, and all lifters were pumping up . I got lucky and caught it doing it at idle and could visually see the lifter squirting improperly. Hence I will be getting the newer designed quiet lifters tomorrow and should be in by mid afternoon. Neways, if you have a lot of tick it is time to get lifters and get rid of that knock. Do you experience a lot of lifter noise when it is cold? That was my first symptom. good luck.

How loud are the lifters supposed to be? The only time I can hear anything in the motor at all is if I open the hood and listen carefully and I can hear some movement of parts. Other wise, I can't hear any noise from the motor that sounds irregular without listening closely.

 

[xveganxcowboyx]

Phantom knock is any sound that makes your knock sensor think you are knocking when you aren't it is not bad for the mototr (because you aren't actually knocking) but it will cause timing to be pulled and loss of power.

PK can be strange. I've been trying to track down some I've been getting in neutral and first gear at partial throttle. No luck so far. I've also had phantom knock from (I believe) a dying turbo scraping/rubbing.

You might start by checking on the condition of your knock sensor (see if it's leaking). That was the advice given to me. Sounds like your lifters are allright, but an oil change with some thin stuff might help to be sure. (sea foam it first)

 

[MrBoxx]

Also, is phantom knock bad? And how is it related to just normal knock? I know I could/should search for this, but since were on the topic

Yes, it's bad. It's basically the knock sensor "hearing" knock that isn't really there. So now the knock sensor "hears" knock and says to the ECU "Hey man, the engine's knocking! You need to retard the timing and get rid of it!" And so the ECU retards timing until the knock goes away. Retarding the timing kills performance. On a logger that can't log knock itself, you'll see a significant dip in the timing numbers after a certain rpm/at a certain TPS %/ or at some other pretty noticeable point. Raw knock values are also nice to see. A 43 count is what's said to be the maximum, so a 43 count of knock at say, 3500 rpm and 10% throttle is indicative of some serious phantom knock. However, a knock count of maybe 12 at 6500 rpms and 95% throttle would be more indicative of "normal" knock, from preignition, high intake temps, hot spots in the cylinder, low octane, lean condition, too much ignition timing advance etc. Neither situation of knock is good, though.

I'm still learning about all this stuff, so if I got any of it wrong or left anything out, someone can correct me.

 

[Deadly BlaZe]

Yes, it's bad. It's basically the knock sensor "hearing" knock that isn't really there. So now the knock sensor "hears" knock and says to the ECU "Hey man, the engine's knocking! You need to retard the timing and get rid of it!" And so the ECU retards timing until the knock goes away. Retarding the timing kills performance. On a logger that can't log knock itself, you'll see a significant dip in the timing numbers after a certain rpm/at a certain TPS %/ or at some other pretty noticeable point. Raw knock values are also nice to see. A 43 count is what's said to be the maximum, so a 43 count of knock at say, 3500 rpm and 10% throttle is indicative of some serious phantom knock. However, a knock count of maybe 12 at 6500 rpms and 95% throttle would be more indicative of "normal" knock, from preignition, high intake temps, hot spots in the cylinder, low octane, lean condition, too much ignition timing advance etc. Neither situation of knock is good, though.

I'm still learning about all this stuff, so if I got any of it wrong or left anything out, someone can correct me.

Performance aside, does it actually hurt the motor itself?

 

[xveganxcowboyx]

Read the post above his. No. At least, not like real knock. Just a performance killer.

 

[Deadly BlaZe]

Read the post above his. No. At least, not like real knock. Just a performance killer.

Oh my bad, I accidentally skipped right over your post. Well, first things first, i'll put the original airbox over the filter and see if that improves things. Thanks for the advice guys. Very helpful.