knock issues

[gordonbradford]

I have been a member for a bit and just havent had anything really to add or say on here till now. I have a 94 eagle talon awd 5 speed. Engine has about 8k since rebuild. Balance shafts eliminated; bcs restrictor removed; fuel pump rewired; hacked air box and maf; 3 inch turbo back exhaust. Essentially still stock. Fixed the coolant temp sensor and car ran awesome. And hooked up my datalogger and saw that the tps sensor was only showing 75% when the pedal was fully down. And then deteled the cruise control setup and fixed the linkage to hit 100% open. And now while under boost and WOT im getting alot of knock and lose of power. My datalogger says the following..... at 6500 rpm im getting 43 counts of knock. Timing gets retarded to 14 degrees ATDC. And the next full throttle run i got 5750 rpm 43 counts of knock and timing got retarded to 8 degrees ATDC. Also under WOT you can see the boost gauge hit 13psi and then drop quickly and then instantly come back in 1st gear. Then 2nd is fine. 3rd goes back to jumping around on the gauge. The gauge is 100% accurate and i can feel the car cut in and out. I do not believe i have a boost leak. Basically i just dunno what to do. And any help would be appreciated. thank you!

 

[90laserRSfwd]

sounds like your knock sensor isn't tightened to the block. Test for boost leaks then get back to use. What grade fuel do you use and what spark plugs are in your car? Did you check base timing with the plug grounded?

 

[gordonbradford]

sounds like your knock sensor isn't tightened to the block. Test for boost leaks then get back to use. What grade fuel do you use and what spark plugs are in your car? Did you check base timing with the plug grounded?

Possibly might be loose but i havent checked, i will check tomorrow. No boost leaks. I use 91 octane and NGK-R plugs gapped at .035. And no i have not checked timing. I will also do that tomorrow.

 

[Simpleman1]

I gapped my NGK plugs .028" when I had my boost set at 16 PSI. I don't know if that .035" gap contributes to your knock issues.

 

[knochgoon24]

If you still use the BCS, the jumping of the boost could be due to knock. If so, it's the ECU trying to decrease the boost to help keep the engine in one piece. It uses the BCS to hold open the wastegate until the knock drops.

 

[gordonbradford]

Ya i thought about spark plug gap to but i mean its basically stock i dont think the gap would affect it that much. As for the bcs opening to save the engine i completely agree. Especially since i did a boost leak test and i dont have any leaks. Also my datalogger is saying at 43 counts of knock its hitting 95 psi of fuel. Is that right? To me it sounds to high. And knock sensor isnt loose. I understand the definition of knock im just not sure how to combat it and why my car is doing it since it hasnt really been touched. I know if i get an fmic it will help. Do i need more fuel? And will safcII help me get the knock under control? Cause i have one sitting around just havent installed it yet.

 

[GSX93DSM]

I had the same problem except i have bigger injectors but, I adjusted my timing, new knock sensor, regaped my plugs and a little more added fuel with the afc and now im at 7 counts instead of 43. Just depends my gap is at .25 I running 18psi. What is all of your bolts ons

 

[1gTurboTuner]

Ya i thought about spark plug gap to but i mean its basically stock i dont think the gap would affect it that much. As for the bcs opening to save the engine i completely agree. Especially since i did a boost leak test and i dont have any leaks. Also my datalogger is saying at 43 counts of knock its hitting 95 psi of fuel. Is that right? To me it sounds to high. And knock sensor isnt loose. I understand the definition of knock im just not sure how to combat it and why my car is doing it since it hasnt really been touched. I know if i get an fmic it will help. Do i need more fuel? And will safcII help me get the knock under control? Cause i have one sitting around just havent installed it yet.

95 psi at idle?! 95 is way high for fuel pressure. drop to around 38 psi with vacuum line off.

 

[gordonbradford]

95 psi at idle?! 95 is way high for fuel pressure. drop to around 38 psi with vacuum line off.

no no no not at idle. At 6400 rpm.




bolt on's ummmmmmm exhaust? does that count? car is stock besides the exhaust, modded bcs, rewired fuel pump, hacked maf and box.

 

[Carmenpzito]

isn't the fpr supposed to go 1:1, so at 13 psi boost shouldn't it be like 52psi fuel?

 

[gordonbradford]

well i just installed my new fuel pump ive had for awhile and installed safcII which helped it a little but not good enough. In the next couple days my new maft gen 2 will be here along with the gm maf. And im going to install my aeromotive fpr as soon as i find the gauge i had. Then a front mount and piping next week. So im hoping that will help my issues. Anyhow if anyone has anymore input i would appreciate it.

 

[gordonbradford]

its my understanding the 94's never came with eprom ecu's? is that correct? If so well i have an eprom ecu in there come to find out. Is it possible that would cause my knock issue? Also i added 5 gallons of 110 to 8 gallons of 91 and it greatly reduced my knock issues to 19 counts at 7k at wot. So im happy for the moment with the reduced knock. If anyone has info on the ecu's id appreciate it! thanks!

 

[maddog_187]

You can always check motoguy's garage online. They use to keep a list of computer years!!

 

[gordonbradford]

Its been awhile since i posted in this thread. At this point im happy to say i no longer have any knock. Car has come a long way since i last posted. I have some pics this time around. In july i needed to do a clutch well as i was removing the transfer case one of the bolts stripped and it fell which to make a long story short turned into 3 months of physical therapy and what not after they reattached tendons in my right index finger. So it has only been up and running for last couple weeks. Which as soon as it did get running the mbc failed making the wastegate not open and when i went and launched the car i watched the autometer boost gauge straight max out. Well i ended up snapping the turbo shaft in 2 and the exhaust wheel decided to take my o2 sensor out and exit the back of the exhaust and bounce down the street . So i went with a big 16g and im quite happy with it now. Anyhow heres the parts/mods list and ill post pics in a second.



Seibon Hood
KYB GR2 shocks
Greddy turbo timer
Rims
Megan Turbo Back Exhaust
Datalogger
Rebuilt 14bTurbo
TRE 255Fuel Pump
Stage 2 Clutch and lightened flywheel
Powerbass AMP
Sub
Box
SS Oil Line
MAFT
3" GM MAF
Maf Wiring
Megan Front and rear strut bars
Intercooler
OBX FPR
EVO 560cc Injectors
LC-1 Wideband
Intercooler piping
blow off valve
Couplers
fuel fittings
LC-1 guage
water temp guage
Keydiver stage 3 chip
ball joints
trans seals
Buschur Racing Intercooler
Shifter, Linkage bushings, and wastegate flapper
Transfer case seals; driveshaft repair yoke
Fans
Knock Sensor
Tie rod boots
Cable bushings
flapper
Transfer Case
HID's
Couplers
HKS 272 cams

The original intercooler which was cauing the knock fyi. Was a CX racing 1 sided intercooler. Basically the cold pipe wasnt so cold . Let me put it this way I couldnt grab the pipe it was so hot. So that was junk. 14b also turned into junk. The obx fpr blew the seal on fire up. So had to go the aeromotive route. All the stereo stuff in the car has been removed. I bought a new knock sensor but never installed it thinking that we'd see how knock was after the new intercooler. And the wastegate flapper i havent installed either I was in a hurry to get the car together. Basically the above is a list of everything ive bought parts wise for the car since i bought the car in i believe it was in late feb. this year.

 

[gordonbradford]

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Also if your curious who did my intercooler piping and all the welding. My neighbor actually did all that. He's great at fabricating and did a great job on my car in my opinion. Most of the welds are tig there are a few that are mig. Since i used the original intercooler piping he made for the cx intercooler and just cut it in pieces to reuse the angle he had made. Hence the mix of the 2 welding types.

Let me know what you guys think! thanks!