6K rpm knock??

[IPT]

OK. Some time for ideas.

I am tuning my 1G. Using the PMS datalogging and I can not get the car to award timing above 6000 rpms I data logged my car a couple of months ago with a Pocketlogger and I had the same problem. I thought I had a problem some where else and did not think of it. It as the same thing. On the posket logger I could get it to 0 counts of knock and then at 6000 rpms the knock count would spike and the ECU would pull timing.

The same thing is happening now. I get a good timing curve (up to 25 degrees) before 6000 rpms. As soon as I get to that point the timing starts getting yanked!!! I have tried to richen the mixture up to help, but I keep richening it up til the car will sputter. I started off on the lean side and worked my way up to the sputtering. My O2 voltage is around .92 up until the 6000 rpm mark and then I drops to .88V

This is starting to piss me off the car pulls GREAT until 6000 rpms and then it just falls on its face. I will be replacing the O2 sensor here and try that. I will also be checking to see if the knock sensor is "looks" bad. (the epoxy is starting to some out) Other than that I am lost.

HELP!!!!

Any ideas?????

 

[NJGSX96]

Check your plugs and wires. Maybe even ignition coil or alternator. Could be the spark is breaking up at the higher rpms. Happened to me and a couple friends.

Doesn't sound like the knock sensor only because it is isolated above 6K. It is good to check that anyways.

What turbo? Exhaust? Fuel delivery? IC? How much boost?

 

[IPT]

Mini-mutt turbo, 18psi, 3" o2 elimnator exhaust, 650cc injectors, PMS w/MAF DSM Performance FMIC.

I have new spark plugs to put in. The wires are MSD. they have been replace recently.

Would the spark cause the knock though???

 

[IPT]

The funny part is that it happens AT 6000 rpms. Not before or after. It is very consitant

 

[NJGSX96]

It is more the lack of spark. If your coil is going or the plug wires are going, it usually breaks up the higher the rpm. Even an alternator going south could do it. I don't know the reasoning for it since I forgot the whole shpeel my friend told me explaining it.

if it isn't that, I don't really know. Sounds like ignition though. That or fuel. Could also be phantom knock. My friend has that in his 90 GSX in 3rd and 4th gear. We replaced everything on that, tuned it real good and it still knocks.

i will ask around and see what I can come up with for ya.

 

[swordfish]

What fuel pump are you running? Whats your base fuel pressure with the vacuum line off?

jeff

 

[IPT]

I have a walbro 255lph fuel pump. I do my tuning in 2nd and 3rd gear. It pulls timing in both so that would not be phantom knock right?? Right now I have no way of checking my rail pressure.

 

[swordfish]

With that pump you should have no problem with fuel pressure. Hmmm. I'm stumped.

jeff

 

[jw]

Too much timing advance will have less power. Try tune to max out timing at 7krpm to 22degree with your PMS. Turn up the boost to compensate for the lower timing advance. The car will feel fast. Another thing is the stock cams will not help you after 6krpm, it's a no win situation. Get some HKS cams and you will feel the difference.

Stock fuel and coil has ran 10s. So, unless you have a problem already with that, you problem lies with too much timing.

 

[swordfish]

I hope when you say "stock fuel" you mean stock fuel lines and rail.

jeff

 

[jw]

I must not have my coffee when I wrote that.

 

[IPT]

I can get the timing to advance nicely to 25 degrees at 6K than they start to go down hill form there. Are the cams to blame?? I have been thinking of doing the cams soon, but I was going to wait until I rebuilt the motor.

I am just trying to get a good timing curve so I can go to the track and get a good baseline before I replace almost everything. It is starting to piss me off. The car pulls great til 6K then It feels REALLY flat. no more pull. IT IS ALWAYS AT 6K RPMS!!!!

HELP!!!!

 

[jw]

In case you didnt read my previous post, I have told you what went wrong. TOO MUCH TIMING is the problem.

 

[IPT]

It did not matter what I tuned the timing curve too. If it was at 25 degrees at 6K it would be at 15 by 7K. It was pulling 5-10 degrees between 6k and 7k.

I checked my knock sensor today and it did not look healthy. The epoxy had melted out or somehthing to that extent. I ordered a new on today and will install it when it comes in and see if that will take care of the problem.

 

[jw]

You do have PMS right?

 

[IPT]

I have a PMS unit with the blow thru MAF sensor.

 

[IPT]

I got my new knock sensor in. After pissing around trying to get the old one out.. After inspection of the old one I saw that the epoxy on the end that sits up against the block was no where to be seen. My thought is that at 6K RPM the motor was jsut getting noisy not really knocking just noisy and it was thinking it was knocking..

Any ways I installed the new one. I will try tuning after I get my turbo back this week.

PS I have a pic I will post tomorrow of the new and the old knock sensor side by side.

 

[IPT]

Here's the pic of the old knock sensor next to the old one. Which one is which??

 

[NJGSX96]

Did you notice a difference?

 

[IPT]

I will have the car back together on Friday. I will see then.

 

[IPT]

HELLO I changed out the knock sensor and the car feels like a totally different car. Just pulls real smooth no break up and does not feel like it falls on it's face above 6000 rpms.

This just went up there on best mods I have done to my car right after getting the tranny rebuilt. The car is soo much fun to drive now. I have a water leak in one of the coolant lines going to the turbo (I installed a 50 trim original mutt this weekend also). I have not got it tuned in perfectly and it still pulls a couple degrees of timing up top that I need to take care of, but the car Just feels sooo different. I LIKE IT!!!