Sputtering at 22-26 PSI HELP!

Luke

Member
Joined
Apr 2, 2006
This problem started yesterday after installing a Cardone remanufactured LS1 MAF. I've heard that these are often bad out of the box but I don't want to jump to conclusions until I hear from you guys.

I had high BLMs that were being caused by my ported descreened LS1 MAF. My BLMs were pegged at 160 and my Scanmaster was showing AF 02 - 03 at idle. While the BLMs were way too high the car ran great other than the occational off idle stumble. This week I installed Razor's alcohol injection kit and tuned it to run boost to 27 psi through my TE-60 With no knock. The car felt strong! Trying to get a handle on my BLM issue, I installed the remanufactured LS1 MAF. After running for about a year with BLMs constantly at 160, it felt like a miracle to watch it slowly drop to 128. However the My scanmaster still shows AF 03 at idle... Shouldn't it read 05 - 07? or is the LS1 MAF supposed run lower than the stock MAF? Anyway the car seems to be a lot better driving under normal conditions. No stumble off idle, slightly smoother acceleration, idles softer at a slightly lower RPM. After driving it around a little, gave it some boost just enough for it to activate the alcohol about 12psi then backed out of it. I tried again easing it to full trottle when it gets to around 24 psi at about 4800 - 5000 RPMs the needle on my boost guage flutters extremely fast from 22-26 PSI and the car feels like it stops making power. I since the only thing I changed was the MAF, I suspect that is the problem but can a MAF sensor really cause that much disruption at WOT when it behaves so well driving under normal conditions? Or is it a problem with the tune being out of whack since the BLMs have suddenly dropped 32. I'm going to try my old MAF this afternoon and see what happens. Any help is always appreciated.
 
my car usually flutters like that if i missed a boost leak somewhere... i would do a boost leak test. pretty quick and easy if you already have a tester made.
 
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26 lbs !!!! That's awesome. I want that too! I guess I gotta bite the bullit and buy an Alky kit!
Sorry....I'm not replying about your question.....still learning myself.
 
In my experience there's absolutely no problem on these cars that can't be caused by a bad coil pack. Increase the boost 1 PSI and it stutters - bad coil pack. Boost fluctuates - bad coil pack. Drips oil...
 
Boost leak

my car usually flutters like that if i missed a boost leak somewhere... i would do a boost leak test. pretty quick and easy if you already have a tester made.

To be honest, that was my first idea too. I checked all my charge pipes and I do not hear any vacuum leaks. I had a boost leak before and it felt totally different than this. It would sputter a lot slower and I could feel the car jerk back and forward much worse than it's doing now. I left a BIG part out of my explaination: I can actually build up 27 psi (Max boost) before WOT. It only seems to happens at or very close to WOT...
 
In all sincerity, I have a coil pack in the garage that runs flawlessly at 22psi and sounds like a stutter box at 24psi. I have another that has no miss but lets the boost rise to 24psi then falls to 17psi and then the boost just rises and falls. I spent 6 weeks looking for boost leaks on that one. Finally changed the coil pack and problem solved. Wanna drive someone nuts, put that coil pack on their car :D
 
boost leak tester is almost always a homemade peice...at least ive never seen one out for production. i made mine from a 3" rubber PVC coupler with a pipe clamp on each end, one end has a PVC end cap RTV'd and clamped in with a schreader valve in it. the other end gets clamped on to the turbo inlet where the maf pipe would go. then just use a tire inflater on your air compressor and pressurise the entire intake system, pause and listen for leaks. its MUCH more effective than just listening for vacuum leaks with the motor running as most of the vacuum is always in the intake and not really in the IC piping anyway.

I had an IC pipe that worked fine, but when i hit bumps it would move and be a HUGE boost leak...it was strange because everything looked tight...but i reseated and retightened it the boost gauge shot up to 20 PSI fast instead of just getting stuck at 12 PSI...then the boost leak tester blew off the turbo... :) Thats usually a sign you're good... heh
 
It may be a stupid question, but you never know sometimes. You have a translator, right?...and the dip switches are set correctly? Do you have an extender chip? Its normal to see the number cut in half with the extender. When I was running the LS1 MAF and the translator, I had a neverending low BLM problem I couldnt get rid of. I got the updated 6.22 chip for the extender, set the dip switches for 3" MAF (even though its a 3.5???)..and the BLM issues disappeared forever. Ive since gone back to the stock MAF and still run the extender chip. Runs better than it ever did, all around, than with the other stuff. As for the fluttering sound, I get the same thing when I have detonation...and its detonation that the scanmaster doesnt pick up at all. Try pulling 4 degrees of timing out and see if you issue goes away. The scanmaster may say no knock, but it only seems to pick up pre-ignition knock, not detonation knock.
Do you have a gap on both sides of the crank sensor? Is it tight?
What is the turn on point for the alky? My car runs MUCH harder if I have the turn on point set for full blown spray at 14psi...well set at 9 on an SMC kit..not progressive. It spools fast and pulls like a mofo...and its easier to tune around since you dont have that temporary rich bog to tune around. But having the turn on point set that high, makes it critical that I prime the line right before I get on it. If I dont, that 1 second delay will bring on knock....and not the knock that shows up on scanmaster. Its the "flutter" sound knock.
 
You probably fouled the plugs with the high BLM's. Also at high boost levels, gap the plugs to a tight .032 so the spark doesnt blow out from so much boost.

HTH's
Bo
 
i just glanced at the replies, so it may have already been said. Make sure the gap is tight and the plugs are in good shape. like TT/Ameasap said.
 
Ignition...

I've just added a new set of Denso Iridium ITF20s. The plugs are gapped at .035 I hear this gap is good for an MSD. The plugs are indexed with the open gap facing the exhaust valves. I'm using an MDS DIS-4 Plus. The plugs and MSD are about two weeks old. I have an ESP coil which was on the car when I bought it. I'm thinking That could be the problem. However I still haven't swapped to my old MAF yet.

Even with High BLMs I'd get 750mV to 780mV on the scanmaster.

Oh and yes. I have Maf Translator v6.22 Switches have been set correctly.
 
Your spark is blowing out at .035 gap. Pull them and regap them to a tight .032 and that should help if not fix your problem.
 
Blowing an iridium spark out is not easy. The problem lies elsewhere. Read my post again and tell me if any of what I said cures your issue.
 
Gap?

Your spark is blowing out at .035 gap. Pull them and regap them to a tight .032 and that should help if not fix your problem.

I don't think its blow out. I ran 23 psi on race gas with my ESP coil and cr42ts plugs at a wide .037 gap without blowout. Now I'm running iridium plugs gapped at .035 and have an MSD ignition to intensify the spark and I'm only running 4 more pounds of boost. Not only that, the car ran great at 27psi less than a week ago.

If it's a spark problem I think it's the coil like mark said.

It could be my msd acting up too. I hear these things can die quickly or can be hit or miss? Some hate 'em some love 'em. I'll try bypassing it and see if the problem goes away.
 
2-step from a roll! Yet another reason for hondas not to race from a stop.

In all sincerity, I have a coil pack in the garage that runs flawlessly at 22psi and sounds like a stutter box at 24psi. I have another that has no miss but lets the boost rise to 24psi then falls to 17psi and then the boost just rises and falls. I spent 6 weeks looking for boost leaks on that one. Finally changed the coil pack and problem solved. Wanna drive someone nuts, put that coil pack on their car :D

It does sound a little like a stutter box. It rapidly (AND I MEAN RAPIDLY)causes boost to fluctuate between 22 and 26 psi. The needle on my boost guage is an orange blur yet the car doesn't feel that rough when it happens, it only feels like it looses power and the RPMs hesitate to climb. It sounds like the first coil you describe. It runs fine while driving normally. If it runs fine during normal driving, can I verify that the coil is bad with a resistance test or will that only tell me if a coil doesn't work at all? For S&G here are my numbers.

Passenger side coil: 12.07 kOhms
Center Coil : 12.47 kOhms
Drivers side coil : 12.49 kOhms

What coil pack should I try? Another ESP, Fullthrottlespeed.com's High Output coil (good price), or just an OEM?

Thanks
 
So......do you have an equal gap on both sides of the crank sensor, and is it tight? Does it look damaged in any way? Have you tried pulling a few degrees of timing advance out?
Your coil is fine.
The ignition module may be suspect, but I have a $100 autozone crappy ignition module...the mounting holes werent even tapped and they use the smaller gauge wires than stock. The "blowout" I always thought I had was too much timing, mimicking blowout.
 
I don't get it.

So......do you have an equal gap on both sides of the crank sensor, and is it tight? Does it look damaged in any way? Have you tried pulling a few degrees of timing advance out?
Your coil is fine.
The ignition module may be suspect, but I have a $100 autozone crappy ignition module...the mounting holes werent even tapped and they use the smaller gauge wires than stock. The "blowout" I always thought I had was too much timing, mimicking blowout.

I'm so confused. I tried to show a friend of mine (who's better with engines than me) what the car was doing. And nothing happend... The car is running just like it was before the sputtering started. Last night I had it up to 28 psi with no problems. Crank sensor was checked and is fine. I was running 21 degrees of spark advance but then bumped it to 25 and turned the alcohol up a notch. No knock. No sputtering. I think I'm developing an exhaust leak at my header drivers side header gasket because I can hear a light ticking and the spoolup feels a little slower. Could that have been the cuase of the stuttering? I wouldn't think so but who knows.

I'm running pretty rich now as the scanmaster consistantly shows 800 - 820mV. I couldn't get the O2s down on the scanmaster below 800. I set my translator to run 4% lean at WOT with no change. Then I set my extender chip to run 4% lean for "Lo Gear WOT" and still the O2s at above 800.
 
I'm so confused. I tried to show a friend of mine (who's better with engines than me) what the car was doing. And nothing happend... The car is running just like it was before the sputtering started. Last night I had it up to 28 psi with no problems. Crank sensor was checked and is fine. I was running 21 degrees of spark advance but then bumped it to 25 and turned the alcohol up a notch. No knock. No sputtering. I think I'm developing an exhaust leak at my header drivers side header gasket because I can hear a light ticking and the spoolup feels a little slower. Could that have been the cuase of the stuttering? I wouldn't think so but who knows.

I'm running pretty rich now as the scanmaster consistantly shows 800 - 820mV. I couldn't get the O2s down on the scanmaster below 800. I set my translator to run 4% lean at WOT with no change. Then I set my extender chip to run 4% lean for "Lo Gear WOT" and still the O2s at above 800.
Using a specific magic number with the factory O2 sensor to tune A/F is about as useful as using a ouiji board to adjust timing. The o2 sensor's curve is so steep that its almost like an on-off switch. Start with timing in the middle. Turn alky at least halfway up. Have alky turn on at 12psi. Go WOT in 3rd gear. Ignore O2's. What is the KR saying? Is it making a popping sound even without any KR? If so, add 2% fuel...do the same for either situation. If knock goes away, add 2 degrees timing. Does knock/popping come back? If so, add 2% more fuel. Work your way up to max timing. If you're in a situation where you cant get rid of KR or popping without pulling a bunch of timing out, turn the alky up. I like to stay 2% richer than the point where I start getting KR. Even thats a little risky...4% is better for safety. Wherever your O2's end up, thats your happy number. 820's may be rich for one guy, but lean for another guy. My car LOVES 820's. If I even dip into the 700's, my car becomes alot more prone to knock and sensitive to weather changes. As for your crack, the most common place is where primary tubes 3 and 5 are welded together. That weld ALWAYS cracks, and that exhaust leak will make O2's even more worthless. Tune around KR and engine sound, not o2's.
 
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