What are possile causes for pinging and hesitation at higher RPM?

[CarNutNat]

At WOT in my '86 T-Type, right around 5000 RPM I'm getting a slight ping and a hesitation. Under 3/4 throttle it doesn't do it. I just bought the car so I'm trying to learn as much as possible as quickly as I can. The guy I bought the car from said the coil pack is new. Yesterday I replaced the plugs, fuel filter, filled it with 93 octane, added a can of octane boost and changed the oil. I have new plug wires coming on Monday or Tuesday. So far, the car has a Flowmaster exhaust, no catalytic converter, K&N stock design filter, 160 stat, and a Thrasher chip. I also ordered a new O2 sensor, adjustable fuel pressure regulator, green tip injectors and a cold air kit with a 9" K&N cone filter. In all of your experiences, what would cause a ping and a hesitation like this? I'm clueless. Thanks!

BTW, where is the 02 sensor located?

 

[Nick Micale]

Rev limit?

At 5000 RPM you are probably hitting the rev limit with the chip?

WOT ping with pump gas is common, and if you continue to do this, it will be time to replace heads gaskets, if not pistons.

 

[Ormand]

You need a scan tool of some kind. Save the money you spent on the octane boost (it doesn't boost much, maybe from 93, to 93.5) and get a scantool. Then you won't have to guess what's happening. I didn't see any mention of the fuel pump. If you are running the original fuel pump, with no hot wire, you are asking for expensive repairs.

 

[GN-231]

You need a boost gauge and scan tool to make sure your car is running properly. Maybe over boosting? Maybe wrong spark plugs, just run the ones recommended on gnt-type.org. Go through the tune ups recommended on that website for a start.
Octane boost is worthless as stated. If you want to run more boost on pump gas, then you need an alcohol injection foggler for your intake. Aren't green tip injectors not much more than stock? I would send them back and definitely buy some blue tops or 50 lbs. You will only need to get larger injectors in the near future if you go with greens.
You may not have enough fuel at higher boosts which is critical for these cars. You need a hotwired fuel pump set up and a high volume pump. Don't run high boost without the fuel or you are going to need a wheel barrel to pick up your trail of parts that you leave behind the car!

 

[CarNutNat]

Thanks for the replies guys. I did forget to mention that the fuel pump is hotwired. What is the rev limit of these cars? Is it exactly 5000? If so, that may be my problem. Mine is going above 5000 according to the stock tach. Not sure how acurate that is though.

 

[wiked87gn]

how much boost are you running, u need a boost gauge and some type of tunning device, such as a Scanmater 2.1. feel free to ask lots of good people here to help you out.

 

[smokin'6]

Im running up to 5200-5300 rpm, so you can run above 5K
The o2 is in the exhaust pipe below/behind the turbo
My 'green tops' are 42.5, more than handling my set up below, in fact according to Scanmaster and fuel/air meter, Im running too rich!

 

[CarNutNat]

I really do need a boost gauge. I don't know how much I'm currentyl running. The stock boost gauge goes all the way to 15 real quick when I get on it. The wastegate is adjustable but I have no way of knowing how much boost. I'm taking the car to Scott Shiner on Tuesday (Buick tuner here in PA) so I'm hoping he can help me out.

By the way, here is a picture of my T-Type.

 

[XLR8]

High boost and KR or pinging are BAD. The causes of the pinging could be either not enough fuel or not enough octane for the amount of boost being run. I would turn down the boost - lengthen the WG rod untill the pining goes away. And GET A SCAN TOOL!

 

[CarNutNat]

That's a good idea. It never really dawned on me that the boost may be too high. Does anyone know what the length of the WG rod should be to be running at the stock boost setting? Or should I just keep lengthening the rod until it hits a maximum of 15lbs of boost? Is 15lbs stock? I'm not even sure.

 

[Racetronix]

Originally posted by CarNutNat
Thanks for the replies guys. I did forget to mention that the fuel pump is hotwired. What is the rev limit of these cars? Is it exactly 5000? If so, that may be my problem. Mine is going above 5000 according to the stock tach. Not sure how acurate that is though.

But do you have an upgraded pump?

 

[Momar]

Would he really need an upgraded pump if he doesnt have the boost turned up yet?

I just wondered because I just got an 86 GN. It is all stock. I already made the wastegate adjustabe, but it is set back to the stock length. I should be getting the boost gauge within a week. I plan on getting the hotwire kit next, but I was reading on www.gnttype.org a budget 10 sec buildup. Well, I know that the guy on there had turned up his boost to around 18-19 w/ the only fuel mod being a fuel enhancer by red(what does this do?). He was runing 104 octane booster or something to do that, but even on 93, he was running 16 psi. Can the stock fp's usually take this? I know that the fuel pump in my car was replaced recently, but I am betting it is a factory replacement. I will be doing a full fuel system upgrade before I would do much else, but wondered if I would be safe to turn up the boost to around 16 psi or wherever I can turn it up to without showing knock w/ the stock pump?

Ben

 

[wiked87gn]

unscrew the rod until the hole lines up with the pin to where you dont have to pull on the rod to get it in, that should be stock setting..

 

[Racetronix]

Originally posted by Momar
Would he really need an upgraded pump if he doesnt have the boost turned up yet?

I just wondered because I just got an 86 GN. It is all stock. I already made the wastegate adjustabe, but it is set back to the stock length. I should be getting the boost gauge within a week. I plan on getting the hotwire kit next, but I was reading on www.gnttype.org a budget 10 sec buildup. Well, I know that the guy on there had turned up his boost to around 18-19 w/ the only fuel mod being a fuel enhancer by red(what does this do?). He was runing 104 octane booster or something to do that, but even on 93, he was running 16 psi. Can the stock fp's usually take this? I know that the fuel pump in my car was replaced recently, but I am betting it is a factory replacement. I will be doing a full fuel system upgrade before I would do much else, but wondered if I would be safe to turn up the boost to around 16 psi or wherever I can turn it up to without showing knock w/ the stock pump?

Ben

Most people would agree that before you do any HP mods to your car a fuel pump upgrade should be done.

 

[CarNutNat]

I don't know if the fuel pump has been upgraded. I wish I would've known to ask that when I bought it. Would I want an upgraded internal pump or would an external auxillary pump be what I would want?

 

[Racetronix]

Originally posted by CarNutNat
I don't know if the fuel pump has been upgraded. I wish I would've known to ask that when I bought it. Would I want an upgraded internal pump or would an external auxillary pump be what I would want?

Internal.

This is the most popular setup:
http://www.racetronix.com/RX-G7-FPKG.html

 

[Momar]

So for the 159.99 that includes the hotwire kit? Thats not a bad deal. The best price I had found on the pump by its self so far was 119, and this kit rewires the pump and appears to come w/ the hotwire kit.

 

[Racetronix]

Originally posted by Momar
So for the 159.99 that includes the hotwire kit? Thats not a bad deal. The best price I had found on the pump by its self so far was 119, and this kit rewires the pump and appears to come w/ the hotwire kit.

.... and also a body ground upgrade and new in-tank wiring.

 

[mcponch]

pinging

hi,just one thing here. you keep asking about ,boost boost setings. all good questions......BUT. NICK MICALE IS VERY GOOD WITH THESE CARS. ALL YOUR QUESTIONS WILL BE FOR NOT, IF YOU DON'T GET A SCAN TOOL.......... SCAN TOOL. PLEASE GET ONE OR YOU WILL BE DOING HEAD GASKETS AT THE LEAST. good luck. FRANK.