Scanmaster tuning question (long)

Black Box

Out cruisin'.
May 29, 2001
squeeze87 had tuning issues similar to this, but I didn't want to interrupt his post, and this is a little different. I've been trying to tune the GN today since I've just installed my Scanmaster 2. I have that "archaic" Pit Bull chip (like BLACKBADGER) that was originally installed in the car by the original owner in 1988. In other words, I have no idea about it's programming.

The first blast I made today, Boost was at 12psi, FP was 43psi, O2's at 765-780, with 0* KR. The coolant temp has stayed at a consistent 175* all day long. I thought it could go higher than 12psi, so I upped the boost in 1psi increments until I got to 15psi, where it developed 8*KR. I adjusted the FP in 1psi increments until I got to 48psi and the KR went away but the O2's shot up to 835. That seemed kind of high so I lowered it to 46psi. I'm running Sunoco 94 (with MTBE) in it and I am still getting 4*-5* of KR with the O2's running about 805-815. It seems to knock around 4200rpm in 2nd gear. It's not a "rattling" knock, It's more like it knocks once (audibly), like 2 pieces of flat metal being slapped together and that's it. OUCH.:eek: It did this exact same thing a while back with the stock WG before I installed the Walbro 340, Accufab FPR and Hotwire kit. As soon as I installed those, the knock went away. It just wasn't getting enough fuel. But I am hesitant to go too high on the FP because I don't know too much about the flow charachteristics of these injectors (Red Tops) at higher pressures (the point where they develop an erratic spray pattern). I was wondering if you guys thought 48psi FP and 835 O2's were too high?

BLACKBADGER mentioned in another post that the Pitbull chip has rather high timing. Is it so much that it can't handle 15 psi boost with 94 octane fuel? It does have rather crisp throttle response. :)

On top of that, it has stored a Code 13 (O2 Sensor). Since the O2's had gone up to 835 at one point, is that more than the O2 could hande and it's fouled now? The O2's are still fluctuating as they should during normal driving, around 425-460, which leads me to believe it's still funcioning properly. I haven't added any additives or race gas to the tank, it's straight 94. It's the original O2 Sensor so I was planning on replacing it anyway....and now I'm thinking about a new chip for these injectors. Either that or I may start blending race gas with the 94 like BLACKBADGER does, but only if absolutely necessary.

Sorry that was so long, but this tuning game is new to me. I'm used to wrenching on V8 Camaros; I never knew these TR's were so finicky.:( I'd like to get up to 18psi boost but I'm certainly not going any higher yet.

Thanks in advance
Take that Pit Bull out as fast as you can. Get yourself a new Joe Lubrent, John Craig, Jim Tesla, etc. chip. The ATR chip is to aggresive w/ the timing. The new school chip burners run less timing and that alows you to run more boost w/o KR getting out of control. The ATR chip is a thing of the past. Take that out and make some real power.

Thanks for the info. I hadn't decided if I should get a new chip for the Red Tops, or just wait and get one when I step up the 009's. But hell, $50 isn't a lot of money to spend compared to having to put in new head gaskets. :D

I might try mixing some 110 octane race gas with the pump 94 stuff and make some runs at Lebanon and see where that takes me. But that could be an expensive proposition every time I fill the tank. It's $25 for a 5 gallon barrel of the stuff at the local Citgo station:eek:

Can anybody comment on the O2 data?

I forgot to mention your O2 sensor is probably OK. Look at the O2 cross counts. Should read 5+ at idle when warm then go 15+ when crusing. This is one way to tell the condition of the O2 sensor. The more cross counts the better, in general. You will "foul" the O2 sensor using the leaded race gas. I sugest going to Sherwin Williams and pick your self up a 5 gal. drum of xylene. You can mix that w/ the 94 pump gas and get close to 100 octane. Mix 30% xylene. i.e 6 gal 94 pump gas to 3 gal xylene. This is much cheaper and will not hurt the O2 sensor. Also will not harm anything else as long as you keep the mixture below 40%. I use xylene and pour 1 oz of Marvel Mystery oil in per 1 gal of xylene. Its is a pain but well worth it. Do a search on xylene or zylene get more info.

If that is the origional O2, maybe not a bad idea to swap in a new AC Delco.

Don't forget to pull that Pit Bull:D That should allow you to get close to 18 psi on pump gas. Other than the O2s being a little high and the KR every thing else looks good.

Lower the Boost to 14 and retune for .800 mv O2s and 1-2 deg. KR until you get a new chip.

Thanks for your help Greg. The O2's while at steady-throttle cruising are running between low 500's to mid 700's. They dip into the 150-175 range once in a while for 1 frame, then go back to 500's-700's. At idle warmed up they are in the 500 range. I noticed the BLM is low at 105, which means it's running rich from what I understand.

I'm gonna look into a Lubrant or Jay Carter chip on Tuesday. I'm gonna try the xylene too.

I am gonna replace the O2 sensor and the knock sensor too, along with a fresh set of plugs, Just to be safe.

Thanks again,
O2 numbers

835 is not too bad high. On the street you'd like it to be a little closer to 805-815, but with that chip it's better to be safe than sorry. When you had it at 760, that's way too low for 93 octane. Timing in those chips are borderline insane for street driving. If you're going to bigger injectors just wait and get a chip made for them if you're going to be making the swap within a month or less. If not, then get another chip right away, there's no reason to tear something up with that pit bull chip.

On your knock situation, it sounds like you may need to check your downpipe. It may be hitting the frame giving you that metal on metal clank you described.

HTH, Donnie
Thanks Donnie, I am gonna try the xylene in the meantime while I get a new chip burned, and clean out the IC too.

I probably wasn't gonna order the 009's until December or so when I order a bunch of other stuff.

I'll check the DP this afternoon and see if there's any marks in it from hitting the frame.

Thanks again to all.
Steve :)
Latest Update

Ok, I took the car out this evening and put about 6 Gallons of Sunoco 100 unleaded in it. The KR is all but gone except for .9* on the shift. The loud knocking I had before is gone. I did check the DP before that and it is not hitting the frame or the A-arm anywhere.

Then I had the bright idea to uncork the dump tube....that was dumb. The O2's went down to 645:eek: at WOT and there was 3.9* KR and it was breaking up at higher RPM's, when I backed off to 3/4 throttle the misfiring went away. I'm guessing that without the exhaust restriction (old Super Turbo mufflers) it just needs more fuel (duh), should have thought of that before. It did pick up 1psi of boost when uncorked. The cap is going back on the dump tube and the Pitbull is definitely out of there.
Now you can be 100% sure that all or the KR is REAL :mad: I would run the 100 octane until you get the new chip in and retune or pull the boost back till you get 0 KR.

Is there a specific reason why you are going with the 009? If I were going to buy new inj. I would go with the 50s. Supposed to be very street frendly and linear. I have red stripe 40s now and will go for 50s soon.

Looks like your moveing in the right direction.

Yeah, it is good to know what I'm really chasing.:D I must admit, that was the strangest sounding knock that I've ever heard. Never heard any other car knock like that, usually it's a slight rattling sound.

I was going with the 009's because I looked up on one of the vendor's sites (can't remember which one) that they were good enough to get into the low 11's, and around 545 horsepower. That's further than I want to take the car on the strip, I'd really like to concentrate more on the handling. But if the 50's (MSD?) are better on the street, then I'll go with those. Thanks for the suggestion. I have no intention of going any biger than a TA-49 on the car.
Do you think that xylene might work as well in the meantime as opposed to the 100 octane race gas? The chip is being ordered today.

Yes. Go with the xylene. Same thing as the unleaded race gas you are buying, but half the cost. Don't forget the Marvel Mystery Oil. Stay with the 33% mix w/ 93 pump gas. Hopefully that will take care of your KR untill the chip comes in.

Not realy saying to 009 aren't good just have heard on the 50s are very easy to program for. Making it easyier for your chip programer. Besides we all know once we meet your ET goals then we ALWAYS want to go faster. Might as well go for the 50s then you won't have to spend more $ later.
Thanks for all your help, it has made this much easier.
I keep telling myself that I don't wanna go any faster than 11.50's, but I know I'm lying to myself :D
Well, I am off to the store to get the xylene, gonna see if Home Depot has it.

Tuning problems

Blackbox. you said your KR virtually went away using 100 unleaded. I don't understand why your O2's went down so far by just uncorking your dump, doesn't make sense. The only thing I've ever notice is a pound or to gain running out my fender well dump, with a little quicker spool up. The xylene around here was 10 bucks a gallon, so it didn't make sense to run it when I could get 2.5 gallons of trick 101 for the same price and treat more pump gas. What kind of settings are you gettin on your new chip. The pitbull is a tad aggressive on timing, but things sure happen quicker(i.e throttle response,spool-up) Had a lubrant chip that was a street chip 92 octane 20* timing 17-18lbs of boost and it was just sluggish in comparison to the old archaic Pitbull. So I put the old dog back in and I make sure I'm running at least 96 oct. so that I can run 20Lbs of boost on the street. Now what I'm thinking of doing is having Lubrant redo this chip with around 30*-32* degrees on bottom and the step it down at WOT to maybe 22*. That way I can have the best of both worlds, faster spool up and throttle response and then be able to run the higher boost levels at WOT with the lower timing(prophylatic protection). Used to run 16-17lbs boost on the street, it don't compare to 20 lbs boost my friend, if I had to go back to the dismal anemic lower boost settings (16-17) I might as well get a mustang or or a turbo VW. As I mentioned earlier I've been using 116 mixed with 91(1:4 ratio) 116 is 6 bucks a ga(cheaper then xylene)l, but it allows me to run 20lbs with about 1-2.5KR which is liveable. 02 sensor(they don't die immeadiately once lead touches them) is still working and if I have to buy a couple more, before I can afford a Alky system, so be it, there's such a noticeable difference running at 20 lbs, no going back! I'm hoping to run 21-23 safely on Alky, the system will pay for it's self, the price of race gas and xylene is ridiculous! :D
I don't know why, when uncorked, the O2's went down that far and why the KR went up to 3.9. The car ran great with the 100 octane and the O2's were still around 835 (I know, that's rich)when it was corked up. But the sh*t hit the fan when I uncorked it. I am thinking that with the dump tube uncapped, with no the restriction in the exhaust, things flowed that much quicker and the fuel pressure wasn't enough to feed it. This is all theory of course, as I am no master of TR's by any means. But that could explain why it was breaking up at the upper RPM's when uncorked, although I immediately thought of ignition problems when it happened. :mad:

I have a new O2 and Knock sensor, a set of CR43TS plugs, and a set of MSD Super Conductor wires that I'm gonna install this weeekend. I ordered a Jay Carter Chip and just told him my combo and what I was running for boost, and that I currently had the Pitbull from 1988. He said he didn't need any other information. This will be my first chip (Pitbull was in the car when I bought it) so if it needs more/less timing then I'll have it changed.

I will admit that I do enjoy the crisp throttle response of the Pitbull, I'll just have to see how the JC chip works out. I do drive it more than race it, and would rather sacrifice some speed for the ability to run plain 'ole pump gas and get rid of the KR once and for all. If I find it's too sluggish then I'll go with more timing and the xylene/pump gas. Not many places around here sell race gas, I can only think of 2 right now.
Thanks for your input.
PITBULL and OCTANE requirements

Yea there ain't to many places around here either, just 2 that I know of. Mr Carter will probably get you a variable timing chip, with plenty of timing on the bottom and pull it out at different rpms to WOT. I talked to him once and if I had the money I'd have him make me a chip like I described. With 30-32* degrees on the bottom the pull it out to around 22* at WOT. My next investment hopefully will be an SMC Alky kit. Blackbox I'm a newbie as well and just jumped in when I saw you had a Pitbull chip, I like the old Dog, and it thirsts for higher octane and had to do alot of tweaking/expermenting with gas mixes to find a happy medium without blowing a h-gasket, that's how much I like the higher timing . Again the difference is altitude as we are a mile high and need the timing advance, and at higher altitude you can get by a little less octane. I think about 1 full point less for every 1000' elevation gain, you have to run about 2-3 lbs more boost to get what some one baselines at sea level to get the same power level because of lack of air(less partial pressure). Think you'll like the JC chip. This ol boy runs a Conley Mag4(around 36-38 * timing advance all the way thru) with 116 of coarse, no O2 sensor, 28lb injectors set at 42.5 static and to my knowledge has never blown a H-gasket in over 7 yrs, probably one of the most consistant cars around, he may not be the fastest, but is probably the mosy consistant, plus he's kind of the Patriarch of the GN around here, I've learned alot from this gentleman and stand by his thinking on high timing. It's fun tweaking these cars each one is different and the same combos may not work on different cars. The high timing here goes against the majority thinking here and most abhor even the thought of high timing. But a few of us like it . Have fun tweaking my friend.
I will definitely be keeping the Pitbull chip for when I go to the track so I can see the difference between the two, they have 116 leaded there.:cool: I hadn't given much thought to Alky, but that sounds like a viable alternative, as I'd like to turn up the boost to the 20-22psi level eventually.

Being new to TR's is quite an experience. I'm used to "bolt-it-on-and-go" cars like the 5.7L IROC I used to have, but I am actually starting to have fun with the tuning, I love the Scanmaster.

BTW, what are your thoughts on the low O2's and high RPM miss after opening the dump tube? I was surprised that it knocked at all with straight 100 unleaded in it, I keep thinking it leaned out with all the extra airflow, but I'm not sure.

If I could afford to run the race/pump gas mixture, trust me, I definitely would! Hopefully JC will burn the chip like you said, with a decent amout of low end timing, and pull some out in the upper R's, since that's where I was experiencing the KR. But I have to agree, that Pitbull certainly makes the car responsive off the line!:cool:

I just drive the car too much to be able to afford mixing fuel right now(even though I am spending a lot on parts:)), I'm still grinning from ear-to-ear every time I drive the GN, I went 5 years without a fast car (last one was the aforementioned IROC)! It was quite a drought! The IROC was mildly modded, and as much as I miss it, it was a slug compared to the GN.:)
Good luck with your ride,