Detonation

[1967 GeeTO]

Recently, I installed a Limit Engineering TA 49, 009 injectors, adjustable fuel pressure regulator and Red Armstrong chip for the 009's and 93 gas. I am experiencing knock per my Casper's knock guage (yellow lights) and Scanmaster (as high as 4.2). The knock occurs even at half or part throttle when the boost gauge gets to around 12-14 pounds of boost. I have increased the fuel pressure in incriments up to 50 pounds and down to 40 with no luck. I dropped it to about 37 and did not have detonation, but the motor would cut in and out. IAC and TPS #'s are in the proper range (20-25 and .40-.42).

For what its worth, I also have Red's fuel pump, ATR Houston style downpipe (no, the puck does not stick), ATR catback exhaust, new turbo "Y" hose and the turbo wastegate hole is port matched to the downpipe. Also, thinking it was bad gas or low tank (about 1/4 full) I filled up with Amoco 93 with no better luck. I have not installed a hot wire kit yet, but will in the near future. Boost should be set around 17 pounds.

I cannot tell you how it was running before because I recently bought the car and the first mod was the ATR downpipe to the stock turbo. As the wastegate hole was not ported, I was experiencing boost creep and could never test the car beforehand.

Any ideas to what the root of my problem is? I'm scared to merge onto the interstate with this situation. Please advise. Thanks, Sam

 

[quikv6]

hmm

Did you monitor your o2's during your tests? Also.....i recently had an xp pump go bad on me. it had about 8,000 miles on it. Im not saying thats your problem but its something to consider. I believe a healthy Xp pump should pump out around 1.3-1.5 gallons in sixty seconds. Mine pumped between .5 and .75 gallons. This is what i was told. Please...someone correct me if im wrong. On the "positive"...maybe its false knock...like the DP hitting or something. You should be able to eliminate that option by using good gas or xylene...and if the knock doesnt go away at 12lbs....then it may be false. Good Luck.

 

[TT/Ameasap]

Agree... Get good gas n there first and see if the KR goes away.

 

[1967 GeeTO]

No, I did not monitor my O2 numbers as I was concentrating on the knock. I installed the fuel pump and turbo in the same weekend. Because I was not sure where the boost was set, I put 5 gallons of 100 octane unleaded and filled the rest of the tank with Exxon 93. After some driving, I put in the 009 injectors. I did not have detonation at that point. When I got down to 1/4 tank, I put about 5-10 gallons more of Exxon 93. This is when the detonation began. I then filled up with the Amoco 93 and the detonation continued and worsened. So, to sum it up I don't think it is something rattling that is causing the lights to go off.

What O2 numbers should I be looking for? How do I read them? I don't want to blow up anything trying to get these numbers. How do I tell if the fuel pump is bad? Any other suggestions? Thanks again. Sam

 

[Dan Thompson]

When changing the turbo you where careful that the DP does not hit the frame or the crossover pipe.

 

[quikv6]

hmm

O2's should be like 780-820 ish WOT. They should remain relatively steady and consistant. You said you had a scanmaster...so the o2's are the three digit #s on the left of the main screen. Knock retard is on the right. Based on your reply.....it doesnt sound like false knock...because you said that when the 100 octane was in the tank...there wasnt knock...then the knock appeared when you filled up with 93. So it can be fuel related. I would turn the boost down to around 10lbs....and work your way up...until the knock begins. Monitor o2's also. One other thing to check: Make sure that no "unmetered" air is entering from anywhere, like through a hole in a MAF flex hose or MAF pipe. (after the MAF sensor) good luck...hope this helps

 

[Razor]

Post your scanmaster numbers at idle. I'm curious on BLM and TPS.

 

[1967 GeeTO]

Problem solved!

Thanks for your help. I'm feeling rather dumb. I turned the boost down as suggested by quikv6 and that seems to have eliminated the problem. I did not realize that shortening the wastegate rod not only increases top end boost, but will cause detonation at a lower boost level if the fuel octane is not there to support it. I thought adjusting the wastegate rod only affected maximum boost. Am I correct in this statement?

Anyway, after a ride around the block, I have no knock or knock retard registering at full throttle. It is currently registering around 14 pounds of boost. I will adjust accordingly.

For your review, these are the Scanmaster #'s. Does everything seem ok?

WOT O2: 750
Idle AF: 05
Idle L8 38-43
Idle Int: 123-135
Idle BL 103
Idle ATS: 143
Idle TPS: .40-.42
Idle IAC: 22

Is BL low? How do I adjust if so? Thanks again. Like I said, I'm still new to this. Sam

 

[Sydwyndr]

are you running a stock maf?? I had the same problem at 13-15 psi with race gas and a 93 chip. I just put on 3.5maf with T+ and all my knock went away. I figure with even minor mods the stock MAF easily surpasses 255 so to speak and the computer can no longer control the fuel. Just my .02

 

[1967 GeeTO]

Yes, I am running a stock MAF. You lost me with your references to "T+" and "255". I bought the car back in late January and am now about to hit 27,000 miles. I have replaced the Y-hose and also the duct from the MAF to turbo with a new GM replacement.

 

[Sydwyndr]

sorry bout that, i was referring to the translator plus which converts the signal from a chevy type mass air flow signal to one in which a buick can read being that replacement stock maf's are increasingly hard to find. the 255 reference was the stock maf limit of 255 grams of air.

 

[Razor]

Re: Problem solved!

Originally posted by 1967 GeeTO
Idle BL 103

Is BL low? How do I adjust if so? Thanks again. Like I said, I'm still new to this. Sam

Sam.. man i'm good

bl103 means the computer is pulling a lot of fuel out. It means its sensing the motor is rich.

typical cuases are MAF, high fuel pressure, bad injectors, wrong chip for injectors, etc. There is a lot of this on the board. Search for BLM or low BLM it will get you aquainted.. no easy simple cut dry procedure.

I would look at chip first, then fuel pressure, then MAF.. then injectors.

HTH

 

[1967 GeeTO]

Problem not fully solved.

When I took the car out last night, I was running about 14 pounds of boost and no detonation. Tonight, I shortened the rod one full turn and got knock. So, it appears something is still going on.

Thanks Razor for your suggestions. I have a local friend that, hopefully, wil let me swap maf's with to test. If that does not work I will try another chip. Any favorites for my combo? I have read favorable comments about Eric at Turbotweak and Jim Testa for the 009's. Since the injectors are new, I will assume that they are ok unless all else fails.

Fuel pressure is at 42 or 43 pounds. Should I adjust up or down?

I have and will search more regarding blm's. From what I have read, an air leak will cause high blm's but not low. Correct?

Did the other Scanmaster #'s appear normal?

One more question. How do I tell if the adj fuel pressure regulator is malfunctioning?

Thanks again. Sam

 

[Razor]

Re: Problem not fully solved.

Originally posted by 1967 GeeTO
Fuel pressure is at 42 or 43 pounds. Should I adjust up or down?

I have and will search more regarding blm's. From what I have read, an air leak will cause high blm's but not low. Correct?

Did the other Scanmaster #'s appear normal?

One more question. How do I tell if the adj fuel pressure regulator is malfunctioning?

Thanks again. Sam

Correct, air leak=high BLM, meaning air leak=lean condition. Your other scanmaster numbers look correct. Typical fuel pressure is 42-43 line off, but dependant on chip. Case in point.. the factory Buick chip was setup for 37 PSI. You can check your regulator with a fuel pressure guage, get a suitable braided hose and extend it to your windshield, then watch as boost rises, it should be 1 lb fuel increase per 1 lb boost increase.

Try the MAF, and for 009 chips.. Eric is the man. Tho i'm biased a little on his chips since I sell them Jim has a great reputation as well.

 

[justin7t]

Have you tried a different MAF yet ???

 

[1967 GeeTO]

Yes, with no luck. I borrowed a buddy's stock maf and still get the same numbers. I have turned the boost down to about 14 pounds now and still get detonation. I got under the car and shook the entire exhaust, including downpipe, and nothing is hitting anything. I suppose I'm going to try another chip. Sam

 

[TurboShane]

I would check your fuel pressure at WOT to make sure you fuel pressure is rissing with boost. 44 # line off with 14 #'s of boost should be 58#'s line on at full boost.

 

[1967 GeeTO]

Will do! Same buddy has a fuel pressure gauge with an extension line. I am really ready to get this car running right.