I need boost help kill gremlins

[wickedmotorhead]

Alright guys I have been replacing everything on a pretty clean 70k mile car to help track down a knock problem. I thought it was a fuel problem, but now I just dont know. Heres the symtoms:

Very large knock under any load. I get knock with any boost or under high rpm even in park. I get KR from 5 to 38.

Things I checked and replaced:

I put a new walboro pump and harness from racetronix, new accufab fuel regulator, new fuel guage. I set FP to 45psi line off drops to about 38psi line on. I put 100 octane fuel in it. Checked for loose exhaust, flexplate bolts and anything else that might be hitting. I am not sure how to get readings from the scanmaster for diagnosis at WOT. Would readings at idle help? I dont hear any physical knock. I have the knock checklist but wanted your inputs as well with these symtoms. Would a knock sensor go bad just under load and be fine the rest of the time? Please give any sugestions I havent been able to spool up for almost a year. I cant take it anymore.

Specs:
Engine was built by Cal Hartline with specs as follows:
.020" overbore, forged turbo pistons, speedpro rings, billet main caps, double roller, 210/210 cam, Champion GN1 aluminum heads, ported stock intake, ported stock intercooler, 40# injectors, dual fuel pumps, new TE-60 turbo , Terry Houston 3" downpipe, ATR 3" crossflow dual exhaust, dual thermostatically controlled fans, external oil/trans cooler, new alternator, water pump, battery. PMAC tranny with raised stall stock converter.

Shane

 

[JDSfastGN]

double check the downpipe and make sure its not tapping anywhere as this can cause all kinds of problems. Then check the motor mounts as with that kinda knock it could be the culprit. I really doubt its real being it knocks in park. Good luck with it

 

[buickpower]

you can get WOT readings by just depressing the pedal so that tps voltage exceeds 3 volts for 1 second. this puts it in record mode and it will automatically record the lowest o2 value and highest knock. afterward you can view these by pressing and holding the recall button. if you keep holding that button and then depress the other button as well, it will tell you the mph that the that those numbers ocurred at. they will be stored until your next WOT blast or until you shut off the car.

 

[Hot Air]

You might want to check torque on the knock sensor.
Conrad

 

[wickedmotorhead]

Thanks so far, I will check the downpipe and motor mounts again. I will also check the knock sensor, Im just weary of touching it since I don't want to induce any more problems. BTW how in the hell can you get a torque wrench in there to check or am I missing something? Keep your inputs coming. Thanks again, Shane.

 

[wickedmotorhead]

Ok take back the getting to the knock sensor to torque it...looks like just remove the coil pack and move the dog leg harness thingy. Looking at the connector how do you remove it? And should it be able to rotate around very easily on the sensor itself? Man this thing is driving me and moreso my wife crazy! Might have to rethink using it as a daily driver if I cant figure this out soon.

 

[wickedmotorhead]

Ok I brought it up to temp (180) tonight and took it out for a spin. I cleared the ECM before anything. I rolled into the throttle around 25mph and as soon as I got to about 5psi of boost the scanmaster showed about 9.8KR and from 55mph about 5.5KR and both times it popped and stuttered like it was about to die. I got a tiny bit of KR with any boost. I hit some pretty nasty bumps (enough to knock my boost gauge of the a pillar) and stuff with ZERO knock as well. I can't even get a WOT reading since it cuts out and pops and sputters.

Here are my scanmaster numbers when I got back with a temp of 70 degrees outside temp.

O2=jumped around but ussually displayed in the 600-700 range
AF=05
LB=34-36
BAT=13.4
INT=126-134
BL=101
CLT=175
ATS=113
r=750-775
TPS=.42
IAC=30
MPH=00 (duh!)
MAL=00


Hopefully this tells something. I did notice when I was inspecting for loose stuff (which nothing even remotely budged) that the spark plug wires were pretty corroded on the coil side. Not sure if this could couse these kind of problems. Keep the suggestions coming.

 

[neat]

I don't know if this will work on a Buick, but on a late model chevrolet you can just un-plug the knock sensor for diagnostic purposes.

Un-plug the knock sensor and take it for a short drive. Just be very carefuel about how much boost it see's, and listen for any auidible detonation.

If it builds boost and runs well, my vote is bad knock sensor.

Good luck!

 

[Kevin87TurboT]

Here's a couple more things to check with your Scanmaster. Make sure that the TPS is functioning properly at WOT. You should see around 4.5 volts. (This is something that you can do with the engine off/key on.) Also be sure that your MAF sensor (L8 in your Scanmaster) is functioning properly. It should read close to 255 with boost levels in the double digits (with your turbo size). What does it read at 5 lbs boost? Do you monitor your Fuel Pressure at WOT?
Good Luck,
Kevin

 

[wickedmotorhead]

I can't get to WOT without it cutting out, sputtering and popping. I will try to get the readings that I can. I also can not get into the double boost without the same.

 

[Kevin87TurboT]

Have you tried a different MAF sensor? Can you hear the knock? It doesn't sound like real knock if it does it without a load.
Good Luck.
Kevin

 

[Spl170s]

hard maf pipe or stock hose? i was getting unreasonable knock at low levels when i had a stock hose on there that had a hole in it tht coudln't be seen. put in a new hard pipe and it helped me alot.

i still have knock issues...but none due to that anymore! ha ha

Do you have the chip setup for your injectors and mods as well?

 

[wickedmotorhead]

I have a hard maf pipe and havent done a different maf yet. I cant hear any knock, but Ive never heard knock is it pretty obvious? I just got a new chip from red for my specs. I just did a compression check and all cylinders were consistantly in the 135-150psi range with no visible leak down. All my plugs looked carbon fouled black sooty with the tip brown. I'm putting in new plugs and plug wires since the current plug wires are really corroded. I checked the resistance on the coil pack and two were 11.45 and one was 11.32 ohms. I think I forgot to mention I also put in a new fuel filter. I have gone over the entire engine compartment and put it up on a lift to look for any loose parts. Everything is extremely rigid. Im banking on poor ignition via the wires. I'll keep ya posted on the money pit, but keep the suggestions coming I'm new at these cars and I've learned a ton already. Thanks.

 

[wickedmotorhead]

GOOD NEWS!! I changed plugs and made some new black MSD 8.5mm wires and she runs harder than I ever remember with ZERO KR!!! So I took out a friend thats never ridden in a turbo Buick before and found out that my brakes suck when trying to slow to a stop at 85mph in front of our shop. I slid over the center maridian going about 50mph and bent my front rim and thank GOD thants all I did. No wonder my car hates me. Next on the list is new AP Racing C5 6 piston brakes with 14" floating rotors. That should help along with some suspension mods. These things dont handle too well from the factory as I found out in what could have been the end of it all. Stupid damn kids!

But besides my stupidity thanks for all the help I learned a lot over this 8 month period trying to track down the gremlins and hopefully I can help others now from my experience just dont ask me how to drive.