Alky Tuning Question.....having some issues


Keepin' The Shiny Side Up
Dec 30, 2001
I did a DIY alky kit on my T-type late last summer. My problem is sometimes I see a lot of knock and it goes away. Sometimes I see a little knock every 2 or 3 frames. Sometimes none at all.

147K mile stock motor, new bearings, timing chain, valve springs, all seals and gaskets at 119K. Good even compression numbers, good vacuum, etc. Stock turbo w/ ported inlet bell and compressor inlet and outlet, stock intercooler, blue tops, afpr, 307 pump, ported elbow, 2 3/4" DP, 3" single shot exhaust.

Before the alky kit I was running a Jim Testa chip on 92 octane and 14-15psi. I really dont remember exactly, but I would see knock every now and then, nothing over 4*KR.

When I did the alky setup, I started tuning it in with that chip, and a .035 NOS jet in the alky, coming on at 12-13psi. Initial test runs yielded serious bogging! I stepped up to a 20* JC chip, same deal. Boost level was 20-21psi. No knock w/ either chip. Eric Marshall did a chip for me, and it helped. Car felt pretty good. I went to the track and ran low 14s, EGTs were 1520s, rich, with some knock on initial spoolup. So I bought 3 new jets, .028, .026, .024. With the .024 jet in coming on around 12-13psi, sometimes I would see lots of knock on initial spoolup, and it would be gone for the rest of the run, but still rich at the top end. Im pretty sure it was not false knock cause I could hear it under the hood. I tried lowering the spray on point to 10psi or so, and it didnt help much. I havent messed with it much since then. The few times I have floored the car since fall I just watched the SM to see if the initial spoolup knock went away in the next frame. It usually did.

Today I filled up the alky bottle for the first time in over a month since it was nice out today, mid 50s. (Isopropal I think, 70% from walmart). The car is currently set on 20psi solid. And I have changed the jet to the .026. Im stuck between wanting to lean it out for higher EGTs and lower 02s, but afraid of the knock Im already getting with it being rich. I floored it after filling the bottle........10mph roll. The boost comes up pretty freakin quick in this car, and as soon as it jumped over 15psi I heard the most godawful sound under the hood. Rapid tapping noise, aka popcorn, but NO knock on the scanmaster. Oh yeah, a huge cloud of black smoke puffed out of the tail pipe too, and it has done this before. Obviously I let out of it. 02s said 898. Okay, checked temp, BLMs, INT, vacuum, etc to make sure I didnt blow the thing up and cruised down the road a little ways. 35mph roll I let off the gas and stomped on it again. Boost came up, heard the popcorn noise again, but it wasnt as loud or long this time, and yes, I stayed in it through 2nd gear and let out. It registered 12*KR at 40ish mph. Dont remember the 02, probably 830s or 840s. Hrmm, okay. Get on the highway, with my other GN buddy behind me I slowed to 10mph and brought up the boost on the brake and hammered it. It kicked to first and spooled hard, tired hazed a little, no knock. Hrmm, bangs 2nd gear, no knock, 02s in the 8-teens. Boost solid at 20psi, 2-3 shift comes (flares badly, like 1.5 second flare), and I heard the popcorn sound again briefly, glanced down and saw 5.4*KR. It went away in the next frame and continued to pull in 3rd gear. Recall on the SM showed the lowest 02 at 804 at like 74mph. EGT was 1535 max (I did not run the car up much in 3rd, probably close to 100mph. My buddy said no smoke this time? What gives. Seriously.

Info on my chip, Eric Marshall chip, 23* timing in 1 and 2, and 21* in 3rd. Maybe its too lean down low on spoolup? But what about the rich condition!?!?! Sometimes Ill see a lick of knock midway through a gear, but not often. Maybe there is something mechanically wrong with the car? I know the possibly slipping trans does not help things. What about a flat cam lobe? Ive got other things going on the GN, but I would really like to straighten this car out and get it to STOP knocking. I know if it keeps doing this Ill eventually hurt something, even if its just knocking on spoolup. I know this is long and winded, but Im hoping somebody has some input for me. Thanks fellas, any responses are appreciated!!!!!!!!!!!!!!!
With stock turbo, intercooler, and 70% isopropyl, I used a .030 jet and as now, I have it come on at 8-9 lbs. I was running low 13s on street tires. I think you need to use a 20* or lower chip until you get it not to knock. Get yourself some denatured or better yet, find some methanol and run it straight. Buy some zylene to up your octane numbers to see if it helps. Hard to say what your problem is but I'd look at the chip. I'm using a thrasher 92 right now. Try not to blow it up looking for your problem. ;)
Do you have the hot kit for the 07??, hows your grounds points do you have the ground kit?

I would try to find the problem fast 12* of KR can hurt .....

See there are some issues you havent mentioned.

One is if you lower the boost to 14 PSI and stomp on it, do you see KR? Next O2's in the mid-upper 800's is really fat, and can cuase KR. If your tranny isnt shifting as should, then you will see KR on the shifts.

See the problem is trying to get that initial point dialed in with sufficient alcohol to not have it knock at 20 PSI. Your car should run 20 PSI with zero KR, if it will run 14 without alky and zero KR. And if your getting KR becuase of insufficient octane.. your going to hurt the motor. Plain and simple..not amatter of if..but a matter of when.

Not having a way to record your runs doesnt help diagnose it either. I am of the assumption your motor is tuned properly with all the readings on the scanmaster within normal limits.

lastly..there are too many variables as to the installation of your alky kit to really say. But my feelings are either your spraying way too much, or there is a tuning issue with the car..if the kit is spraying as should.

I hate the changing jets deal trying to figure stuff out..and you should be running straight denatured or methanol until you have it figured out. Straight alky is way more forgiving than mixes for what your trying to do.

I've had cars here with boat loads of KR and the reason was injectors were bad.. no amount of alky will fix an improperly running motor.
Red Regal T, when I put a "street" chip in it bogs really bad and just feels like its being choked for lack of a better description. I USUALLY run denatured, but it was 6pm on a Sunday and the hardware stores were closed, plus I didnt really want to spend 10 bux on a gallon. Yes yes, I know.......dont even say it please. But the point is last time I messed with it, it had pure denatured and 92 octane in the tank. Very similar problems.

5ltretr, yes its hotwired, been hotwires since 2 hrs after I bought the car. Grounds are good and clean.

Razor. I have thursday and friday off, and I will be putting it back to street trim, JC 20* street chip and 15psi. Im also going to change the plugs back to the CR43TS's from the NGK UR5s. Yes, I know high 800s is PHAAAAAT, and I know the reason for knock on the 2-3 shift. 92 octane is all we have out here, and when I used to run pump gas and a street chip all the time, sometimes Id see some KR, sometimes I wouldnt, from tank to tank. Yes, KR hurts the motor.........thats pretty much common sense.

The scanmaster and EGT have worked just fine for my tuning style in the past, however I see your point on not having a way to record. Maybe Ill find someone with direct scan or turbo link to record some runs. Either way, yes, the car is pretty good tune, and always has been. I dont let things slide in that department. However the only thing I have noticed out of range is my BLMs at idle (open loop idle w/ Erics chip). Usually 140s, sometimes 150s. Cruising on the highway they are 140s also. The only time they go down is when I let off the gas.

What are the variables in my alky system? Its a pump, a nozzle, a reservior, and a hobbs switch? The spray on light is on the pump, and the light comes on, and I have verified pump operation. In fact, 2 weeks ago I pulled the IC and up-pipe while I was tinkering on the car. The only thing I noticed that was odd was when I opened the throttle blade and looked into the plenum, I could see that there was some alcohol pooling, or still on the powerplate. However I cleaned that out.

Thanks for the replies......I just need to track this things down. Heres a few what ifs for you guys.....

MAF? Reads 04 at idle sometimes, usually 05. It maxxes out at 255. 1 screen removed. Might take the MAF off of my GN and see what happens, Ive never had a problem with knock in that car.

What about a flat cam lobe? However I dont see abnormal vac readings, or pulsing vac readings.

You have a good point about the injectors. Its been a long time since I have had xylene through the fuel system. Couldnt hurt. AND, if I needed too, I could try the blue tops off of my GN in the car, see if that clears things up after I see what happens on street chip and pump gas.

Lets see, what else.......what about nozzle placement? I think its fine where it is???? Looks like its time to start at square one, and start moving up from there. Its winter so I guess it wouldnt hurt to run the street chip and 15psi and mess with it more in the spring. I just gotta get rid of this knock. Again, thanks for the replies, keep em coming. 10,000 brains are better than 1!!!!
Oh yeah, Im also doing a heated 02 sensor, not that it will help, but it cant hurt.
Bammm.. idle BLM's being high.

This is the tuning issue I speak off. That tells me your computer thinks the car is lean and is adding fuel. Which really screws up the way the car runs.. Ive seen plenty of cars with popped HG's due to running them when the idle BLM's were high. This means vacuum leak, air leak, injector, MAF, O2, etc... issue.

Do a search under high blm's.. ive covered the book with this issue. Until this is fixed..dont run the car anymore at WOT. also bet your fuel economy has hit the toilet. Lastly high blm's cause washdown of cylinders.. better keep an eye on the oil, since extra fuel will break it down..nothing worse than a little knock, using oil thats been diluted by fuel.

See tune is not always plugs, wires, and filters.. you have to understand what the computer is doing and why. get your BLM's at 124-132 at idle.. take it from will be a totally different car.

I'll leave ya with is ;)
Razor, heres where Im at.......

Im 99% sure there is not a vacuum leak. Im curious about an air leak past the MAF. Im curious about the MAF itself. Im curious about the injectors, since I have had them on the car for at least the time its been since the motor was out (119K to 147K). I changed the 02 a few months ago.

So, obviously I will look over all the vac lines, I will check all my connections from the MAF to the T-body, I will swap MAFs, and if it comes down to it, I will swap injectors.

Just to make you feel better and show you Im not a flaming idiot..... since summer time the car has only been WOT maybe 20 times. Still bad, but its not like I beat on the car on a daily basis. In fact, up until this past sunday, it has not seen over 10-12 psi for probably 2 months. So Im confident nothing is hurt. I will do a compression check again to see how things are HG and ring wise. Might also do a leakdown. Anyway, fuel economy isnt bad, I usually get 18-20, half highway, half city driving. I change the oil every 2200-2500 miles, mobile 10W40 with 1 quart of Lucas Oil Stabilizer, and a PF52 filter.

Im aware tune is not in a few select areas. I went to college for automotive tech for 4 yrs, and am ASE Certified in 6 of 8 areas. Im just asking for some other ideas, to get peoples brains going besides mine. Sometimes multiple minds work better than one.:) THANK YOU FOR YOUR REPLIES. Thursday and Friday I will be tearing into this thing, suppost to be in the mid to upper 40s here in KC. Hopefully I will get this car lined out so I can beat up on some Mustangs. Theres not much worse than sitting at a light next to a punk kid in a Stang knowing you can beat him, but that your car is not exactly running correctly.:D
Hey Neil,

Was that the car we tuned realtime? Or was it your GN? I remember the one we tuned had the blm's right on.

What can happen sometimes is if cell 15 is on the high side, say 145, the computer had to add some fuel to get back to an a/f of 14.8, which is fine. But when the blm lock hits at WOT, it goes to 128. So now you have a situation where the blm was 145 and then sometime during spoolup it drops to 128, which is a 13% drop in fuel. That can cause a momentary lean condition.

If you want, when you stick JC's chip back in, send me the chip and I can change the blm lock to wait a little longer. I can also make some adjustments for the blm's if you don't find any leaks or anything. If the blm's are high overall, you might want to double check the fuel pressure with a different gauge and see if its too low.

Talk to you later,
I dont think ill of you. Just that I have seen too many instances of hurt motors when issues like BLM's are out of whack. So if I dont pull out the flag, I would be doing you a dis-service.

Check all your vacuum lines with a vacuum pump. And make sure theyre not dropping vacuum on its guage. Visual doenst go very far on these cars, unless its dead obvious. PCV is another culprit as well as injectors, MAF, cracked header, bad O2 sensor, bad ecm, bad gaskets, hole in IC, etc.

Lots of areas to look at. Upping FP should drop them in a linear fashion. If upping FP doesnt.. it screams vacuum leak.

To trying to help..been there..
Eric, no we didnt ever hook up the labtop in the grey car. Just the GN........

What you explained about the momentary lean condition sounds dead nuts on. On spoolup is exactly where my worst knock occurs. I will mess with it the end of this week and see where Im at. If you want I can send the chip for a freshening. I really want to just go back to the way the car was and tune it properly then step back into your chip and alky. The car shouldnt be too far off in tune, however the BLMs are something I have noticed to be off lately. Ill check it out. Oh, and the FP is at 42 line off, on my autometer FP gauge..........

BTW, as you can see in my sig, I will obviously need to get with you on a street and alky chip for my GN, something about the same as Zaks first alky chip for his GN.

Razor, Im sure you dont think "ill" of me, sorry, just in a bad mood, working 12-13 hrs a day takes it out of you. I just wish I had more time to work on my cars. Anyways......................Ill get a vacuum pump tomorrow at work for cheeep, just one of the pump ones right? You bring up a good point on the computer. Wouldnt hurt to swap the MAF and the ECM from my GN for troubleshooting, since the car is currently down for mods. Hey listen, thanks for the replies, they are greatly appreciated. In a perfect world all of our turbo cars would run perfect......but hey, that wouldnt be any fun now would it? ;)
Alright, got a few things done on the grey car today. While I was changing the plugs I did a compression test.

1 - 137 2 - 138
3 - 134 4 - 135
5 - 133 6 - 133

Plugs were all whiteish, like they always are except #6. It appeared like it was wet with something. Not terrible though? I dont know.

I changed back to the CR43TS plugs from the NGK UR5s, .034 gap. I Ohmed the plug wires, changed chips to an old Jay Carter 20* street chip that Ive used in my GN for years. I reset the IAC and TPS. IAC counts are 20-24 hot in park, engine load is 19-22. INT was mid 120s, BLM was mid 120s. FP is 43 line off. Lets see, my 02 was reading slowly and the numbers where not moving much so I changed that too, didnt get around to doing the heated 02. I changed the donut gasket on the DP just because it needed to be done. I took it for a drive this evening, boost was at 15psi exactly. The only thing I dont like about this JC chip is the idle in gear is quite low at 650. Im gonna mess with it some more tomorrow. So I let the car warm up driving around town and watching all my parameters on the SM2. I went on a backroad and layed into it about 10mph. Car felt pretty good for pump gas and 15psi. I got 2.3KR at 30mph, lowest 02 was 773 at 37mph. I did a WOT run from 1st to halfway though 2nd, the MAF is going to low 240s at WOT. Lets see........during the first WOT run I went halfway though 3rd gear, but the road got a little bumpy so I had to shut down........I watched the SM2 throughout the whole run.....I noticed that besides the 2.3KR about halfway through 1st gear, I only saw 2 or 3 frames of knock the rest of the run. These included like 1.something, .02, and .09KR readings throughout the run. Tomorrow if its not raining, Im going to do some more tinkering on it. Mess with FP, and that IAC for idle quality. Umm.......I will probably change injectors too, or run a gallon of xylene through it to hopefully clean it out, along with a Fuel Filter. Is it possible that #6 plug is fuel fouled due to the injector? I guess I need to go a little further into this thing. Any comments, ideas would be great, thanks fellas.
See how fast your losing pressure on the rail after you shut it off. If within a couple minutes it drops have your answer.

Aside from that, numbers look good. Ive seen where stock injectors cuase KR.. fuel pressure test is a given. You can also pull them out and check the screen for trash.

Back under my rock :D
I have blue tops......and, I finally got motivated to pull the blue tops out of my GN, and put the MSD 50s in it. So I have that set of blue tops to try if needed. Might just change them out anyway, Ive NEVER had a problem with KR in the GN. Then I can send out these other blue tops and get them flowed and balanced. There was one thing I forgot to mention though. With this JC chip, my vac reads lower. Idle, hot in park its like 15-16 inches. In gear its 11-12. It used to be 13-14 in gear......however, Erics chip is an open loop chip. Any thoughts? Thanks!
One chip you said idle was lower..That one will have less vacuum :)

You have access to direct scan, do some runs, send em my way.. I'll look at them see if something sticks up.