how long can the knock sensor last?

[sonicnofadz]

Recently while trying to tune my car I've noticed that I have been getting lots of unexplained knock at low throttle (even somtimes during vacuum). I have read up on all the phantom knock issues, and I have the revised lifters. I have a SAFC2 installed (using stock 450 injectors) and I tried adding more fuel around where the knock appears (2800-3500 rpms) but nothing makes it go away. I'm only running 10 psi off my new Evo 16G. This seems kind of strange to me, because Im really not running huge amounts of boost, but Im getting up to 60 counts of knock. My timing is getting pulled like crazy, and its getting pretty annoying. The car is a 91 GST, and the car only has 100K on it. My question is, could the knock sensor be toast? How long can one expect the knock sensor to last? If the person who owned the car before me never replaced the knock sensor, this would mean it would be 13 years old. Could the sensor possibly last this long? I am going to install my new 650 cc injectors soon but I don't want to tune my engine with high boost with a defective knock sensor. I have ordered a new knock sensor from SBR, but I thought that I would ask if this is a clear case of a bad knock sensor. Any input or suggestions would definitely be appreciated. THANKS!

 

[TalonJohn94]

I'm sorry I can't give you an answer, but I have the same problem and I was just about to post. I have a 1G TSi and I recently installed a EVO III 16g and a full 3" exhaust. And the way things go, I only have a SAFC installed for fuel. No pump or injectors. I am getting at least 43 counts of knock (Pocketlogger only goes to 43) at 45k or up. This is only when I don't get fuel cut at that same rpm range. And I'm only running like 11 or 12 PSI (MBC backed out).

What is your INJECTOR DUTY CYCLE at that knock count/timing pull?
If our injectors/fuel pump etc,.. are maxed out so fast, then why isn't the IDC like 100% at fuel cut?

I need to look into fuel control, but if the knock sensors are prone to failure, its all worthless.

Which knock sensors are more sensitive 1g or 2g?

 

[sonicnofadz]

Sorry for the double post (eek).

I'll have to check my logs tommorow. I think that the knock did come about when the injectors were pretty much at 100% duty, but I am not SURE...I remember seeing the knock happen when I was actually under vacuum so I KNOW for sure that it wasnt always the case. Tommorow I'll post some logs. I will soon be installing 650cc injectors, possibly a new fuel pump/afpr and a new knock sensor. We'll see if this helps at all. I didn't think that the Evo 16G could flow enough at 10-12psi to completely
lean out the stock fuel system! But maybe thats not what is happening. Hopefully someone with a little more tuning knowledge will enlighten us =) Oh btw I am using MMCD + PALM III for logging my runs.

 

[yo2001]

13 years old knock sensor should be replaced.

 

[sonicnofadz]

Yeah this is definitely what I am thinking...perhaps this whole thing is just because my knock sensor has become a little "crazy" over the years and is interpreting random engine noise as knock. I'm really hoping this is just a case of a bad sensor and not me melting my engine =) I find it hard to believe that 10 psi from a EVO 16G would be enough to completely outflow the stock 450cc fuel injectors. Oh and on a side note: I do have a EGT gauge installed, and even under full boost for long periods of time my EGT's never climb above 1400 F. I'm not sure if this is indicative of anything, but I'd imagine if I were running really lean shouldn't the exhaust temperature be a little hotter? I am not quite sure...

 

[TalonJohn94]

mmcd?

 

[sonicnofadz]

yeah MMCD is a freely distributed open source program that was written for the PALM OS by:
Dmitry Yurtaev. You can grab a free copy at: http://mmcdlogger.sourceforge.net/
Its a great program and I like it better than pocketlogger. Plus its free, I bought a PALM III on ebay for $50, and a cable for like $20, and downloaded this program. Data logger for $70.00 (w00t).