LT1-LT4 Modifications 1993-97 Gen II Small Block V8

LT1 spit and sputter, better without MAF

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Old 01-14-2010 | 11:52 AM
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Default LT1 spit and sputter, better without MAF

95 Lt1. Ok so getting to drive it more since the snow is off the roads now. Started it, drove half mile to a mile, came to a stop sign and she started spitting and sputtering pretty good. Put it in nuetral and cleared it out. Back in gear and started rolling, same thing. Falling on its face. Now when its warm it has a miss around 2000rpm, but never anything like this. So I am in about an hour doing plugs because I know i need to. But as far as the issues when the motor is cold I was thinking O2's possibly? But then I found on alldata that the MAF is very sensitive to over oiling the air filter. So I unplugged it today when it was cold and drove it. Still my 2000rpm miss but Never a spit and sputter, never any hesitation. Also this is after market ram air. So here is another question, will a stock non ram air MAF differ from that of a ram air? Or is it all programed in the pcm. Pcm on mine has been flashed but not sure if air fuel was ever adjusted. With its unplugged, mas, I do not have the power up top noticably but I do not have the spit and sputter. So tell me what I am looking at. LOL Like I say this LT1 is all new to me. Oh and when i did the msd opti it helped my miss some. But not all of it. That is why I also figure on a fouled plug or two. Thanks in advance.

Last edited by Boman6760; 01-14-2010 at 02:52 PM.
Old 01-14-2010 | 11:54 AM
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You mean the MAF..

When you unplug it, it will run a lil rich..sounds like you have a plug or 2 out, change them and see what happens.
Old 01-14-2010 | 12:01 PM
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Ha yeah. Excuse my retardedness on that one. went about 36 hours on an hour of sleep so I am just now waking up from the aftermath. Thanks for the fast response. Gonna head out to the garage now.
Old 01-14-2010 | 03:03 PM
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Ok so an update. Changed the plugs. None looked to bad honestly but all were gapped at .060 intead of .050. They were NGK iridium plugs in it. I put standard TR55 NGK's in it. I still have a vibration around 2000rpm. I thought it was a vibration from a miss but now I am more and more unsure. It also still wanted to spit and sputter when I first started to drive and temp was low. Now after driving it a bit, I again unplugged the MAF. ALOT smoother. Pulled hard under WOT with no hesitation at all. Out of gear you can stab it and no stutter either. I still have vibration/miss but not near as bad. Right bank plugs- mainly white with light orange color, no deposits, clean as almost if not firing as much as left bank. Left Bank Plugs- Rust orange/red/white with some deposits. More typical of a hot good firing in my op. Now the left O2 has been changed. Not the right. Done by previous owner who decided right was to hard to do. Any ideas?
Old 01-15-2010 | 05:23 PM
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Anybody? I read that with the MAF unplugged and it runs better it is likely a sensor problem. Would it be O2's? MAF itself? Just lookin for ideas on were else to look.
Old 01-15-2010 | 08:45 PM
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Originally Posted by Boman6760
Anybody? I read that with the MAF unplugged and it runs better it is likely a sensor problem.
Not true. When you unplug one sensor you cause the PCM to go into open loop. The PCM then ignores any sensor input and runs off default or "limp mode" settings. Once a sensor is unplugged it breaks the circuit of all sensors. You cannot pinpoint a sensor problem by unplugging it. Do you have a SES/Check engine light? If so, the best way is to find out what codes have been triggered.
Old 01-15-2010 | 10:38 PM
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You need to get the maf cleaned before you continue. I'm not saying it's your only problem or even a problem at all, but you need to eliminate the simple obvious issues.

I agree with SSR^^^ you need to get the car scanned to view the sensors value's and to see if you have codes before you spend money needlessly.
Old 01-16-2010 | 01:16 AM
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to make sure you have every thing hooked up right at night with no light start you car up and look for arcing in the ignition coil and your spark plugs. If you do have arcing re check all connections for your wires and touch your wires to make sure none of them are breaking apart. "If you have long tube header they can burn the hell out of wire if you do not protect them the right way"
Old 01-16-2010 | 01:21 AM
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Oh and you might have just a little water in that msd opti. I hit a water puddle and had a problem like yours. I just drove it for about 3 days and dried out the opti. the gasket on the opti do not seal right if you are not careful on how you tighten it down
Old 01-16-2010 | 02:57 PM
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I'm with everyone saying that you should clean the MAF, then I would start checking plug wires, then I would check other sensors/ignition components.
Old 01-17-2010 | 04:07 PM
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Thanks guys. I cleaned the MAF and also the throttle body while I had the MAF off. The throttle body was absolutely the worst I have ever seen. It was pretty much caked with build-up. Doin this i also noticed the PCV was not even in the valve cover. So now I am into the process of just searching over the entire car seeing how everything on this car seems like it was done half way by the previous owner. Checked and rechecked wires and all. It seems to be running alot better after the MAF and Throttle body. It alway ran worse when it was cold, and its not been as cold lately so we will see and hope the issue is gone. Thanks for all the input again.
Old 01-17-2010 | 04:58 PM
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Pcv valve is on the drivers side of the intake manifold
Old 01-17-2010 | 06:06 PM
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He prolly means the check valve on the passenger's side.
Old 01-17-2010 | 10:00 PM
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Yes. i stand corrected. I am used to working on my Jeep, or other chryslers, mostly. PCV valve in in the cover on it. Seen that it was out on the firebird and just assumed it was also the valve. I have so far found water pump bolts extremely loose, the head of a rear main bolt that has been broke off and much more so I am slowly learning the LT1 v8 vs my normal dealing with a 318 v8. Between alldata and you guys on this site it has not been to bad though.



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