87 Limited T High Speed Miss, Detonation

[kensgs01]

Hi,

Fairly new to these cars but mine has a miss under load at full boost. I also hear some slight detonation. Otherwise, if you stay out of the turbo, no fun, and drive normally the car runs great. I recently replaced the cam sensor, was making a ticking noise, and put it in exactly as it came out. It dropped back in perfectly, same spot. The car started right up and ran just like before.
However, I don't know if it pinged before I changed the cam sensor. Never really got on it then. Is there a common thing that would cause the miss/detonation? Running 94 Sunoco. The engine is stock except for the turbo that was upgrade to the T60? And the chip was changed to what I don't know yet. Also has a 3 inch downpipe. Car runs very strong until it starts to break up a little with your foot in it. All these mods were done before I got the car and I am just learning about them. Has 96K on the clock and motor never been apart. Thanks for any help or suggestions.

 

[rodman99999]

Do you know if the fuel pump has been replaced and what size the injectors are? Is there an adjustable fuel pressure regulator on it? You've got to find out what chip's in there. The fuel system has to be able to keep up with the turbo upgrade, and the stocker was barely adequate for the factory tune. If the chip has too much advance for the octane you're running(like a, "race" tuned chip), it will cause detonation. Do you have a Scanmaster, or any other way to keep track of the engine parameters while at WOT? Any idea how much boost the turbo's making? Lot's of variables. If the car starts and runs OK; the Cam Position Sensor is fine. Could be the coil pack, sparkplugs or wires too.

 

[kensgs01]

Thank you so much, Rodmann99999. I guess I have a lot to check out. The injectors look stock because of the part numbers on them. Don't know about the fuel pump or chip yet. I do know they took the car to the track a few times and it supposedly ran a 12.90 something. (I may be able to reach the previous owner again and ask a few more questions, I think the chip is a Bulldog? If that makes any sense). So I'm guessing it might be a race chip and they ran with some high octane; higher than 94 Sunoco. I am glad the cam sensor is good as it sits, thanks. Car idles great and has good street manners. Just gotta get this miss and ping out....thanks again...

 

[rodman99999]

Finding the owner, and getting as much info as you can, would be the best thing to do. A boost gauge and Scanmaster(or some other data logger) are minimal for tuning these cars and keeping track of/out of knock. You may just have an old fuel filter, that's restricting flow at WOT. Test fuel pressure, and be certain it's around 48PSI(vacuum hose off). Don't do anything at WOT until you know the fuel system's up to it, and for what octane the chip's burned. It's also imperative to know what injectors you have(for sure), if you're going to replace the chip. Do a "Spring Cleaning" on your car( The Grand National / T-Type / Turbo Regal Buick Spring Cleaning Guide ), to be certain all the basics are covered. Lots of good info/tips on that page, especially if you click on the "resources". One more thing: Check your Throttle Position Sensor for correct voltage at WOT and throttle closed also. That being out can cause the same symptoms.

 

[IrvJr]

Please tell me you have a boost gauge?

 

[rodman99999]

Applied Technologies made a Bulldog chip, but I don't remember if it was a street or race chip. Regardless- It would be obsolete compared to the Turbo Tweak chips and their tunabilities.

 

[Just a Six??]

Applied Technologies made a Bulldog chip, but I don't remember if it was a street or race chip. Regardless- It would be obsolete compared to the Turbo Tweak chips and their tunabilities.

X2 Get rid of it & get a chip burned from Eric at Turbo Tweak
Also do some reading here www.gnttype.org & www.vortexbuicks-etc.com

 

[rodman99999]

BTW- You'll have to know exactly what size injectors you have, to order a custom chip. If they ARE stock; go bigger and get a chip to with them. Eric sells packages(I believe).

 

[kensgs01]

Got a combination vacuum/boost gauge, pillar mounted. Thanks. What would be a safe/good reading?
Thanks...

 

[kensgs01]

Thank you "Just a Six"....great sites for info.

 

[Dabigguy]

With that turbo you will need bigger injectors. Hopefully you didn't hurt the car when you got on it.

 

[rodman99999]

Got a combination vacuum/boost gauge, pillar mounted. Thanks. What would be a safe/good reading?
Thanks...

Assuming you have an adjustable wastegate actuator, and are running the stock wastegate solenoid: Back off to 12-13PSI and see if the problem goes away. Find out everything you can about your fuel system from the previous owner. Does the car have a hotwired fuel pump? If it does there should be a heavy gauge wire from the alternator back to the fuel tank connections, usually with a 20 to 40A relay, either by the tank or engine compartment. If not- get one. This will give you an idea of what to look for: (http://www.gbodyparts.com/product_i...d=105&osCsid=0275ec5732bdb09ff7ffc00559ce85f5) Click on the picture of the harness.