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Discussion Starter #1
My issue is i recently did a tune up on my 88. It has a powerdyne supercharger and has its own belt and manual tensioner on it. The car has been sitting for almost 2 years. I drove it yesterday to a city about 75 minutes away. Midway through the drive i went to pass someone and i had no boost. Then later i went to pass someone and the boost was going in and out. Once i came to a stop and started again it was boosting fine. I was told could be a fuel issue. Please help!!!!
 

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Are you sure your boost gauge is working correctly, maybe that's whats cutting in and out. Could you feel the power loss ?
 

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Discussion Starter #3
Ya i could tell a major difference. When it would kick in i could feel it pushing me back and then it would just stop and then kick in again. The engine wouldnt even rap up as fast.
 

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I guess check your fuel pressure and make sure your belt is tight.

Maybe its a malfunctioning by pass valve
 

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Could be a bad belt if it has been sitting. I would start there!
 

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Discussion Starter #6
Thanks. I was told the fuel booster could be cutting in and out. I dont understand how that could cause it to loose boost though. Wouldnt it just lean out and misfire if anything. I do think the belt is probably loose because i had to take it off to do the water pump. Im gonna check both. Any other ideas.
 

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Thanks. I was told the fuel booster could be cutting in and out. I dont understand how that could cause it to loose boost though. Wouldnt it just lean out and misfire if anything. I do think the belt is probably loose because i had to take it off to do the water pump. Im gonna check both. Any other ideas.
Fuel booster? No such thing. Unless you mean the fmu, which I'm sure you do. Being lean can show up as a miss, but thatd be lean spots. If the car is just running leaner in general you wont be able to tell. The blower belt doesn't run off the serpentine so idk what you mean. If your belt is dried up it could slip under tension, fuel pressure can be dropping and you would loose power, or that crappy blower could be being crappy. Do you have a boost guage to actually tell that your droppin boost.
 

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Discussion Starter #8
Ya. The guage wouldnt go past 0. Then it would hit like 5 pounds and drop back down. I know those chargers have a bad rep but it came on the car when i bought it and it has less then a couple hundred miles on it since it was rebuilt. It was boosting fine when we started it was just after driving a while that it stopped boosting. But after stopping at a red light it boosted fine after that. It has its own belt and tensioner i know. I took the belt off to do the water pump and im thinking maybe i didnt put enough tesion back on it. It does mis in second gear sometimes. Dont know bout that either. I dropped it off for a new top and wont have it back for a week. Just wanted to get some ideas of where to start
 

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New top? When you run a fmu it's hard to trace fuel issues at wot. Start with the belt, then I would get a fuel pressure guage on there and do some wot pulls and see if it drops off. First off though, scan for codes. May tell you while the car is misfiring randomly. That could be your valvesprings going bad? You you have highmilage heads? The car will start to miss randomly at higher rpms but if it is the springs, it'll eventually do it in every gear under some load.
 

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Discussion Starter #10
The car only has 66000 original miles on it. The motor was rebuilt and supercharged at about 30000. It has edlebrock performer heads on it with roller rockers. I dont think it would be the springs but i guess it could. The person i bought it from inherited it this way and didnt take the time or energy to upkeep the car at all. It sat for over 9 months before i bought it. I am trying to get it back to being a reliable and high performing car again the way it was meant to be. I dont know that much about supercharged motors as this is my first one. Thats y i have so many questions. I did the plugs cap and rotor. It has taylor 9mm wires on it and they look to be in good shape. Thats y i dont understand the mis. And its very intermittant. It happens more if i just hammer it in second. If i ease it to the floor in second and then hammer it to the floor in third it doesnt mis.
 

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Could the belt be sliping? My supercharged foxbody sat for a year and when i first drove it the belt was sliping and it wouldnt build boost.
 

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Discussion Starter #13
Thats what im thinking the issue is for the boost. I was told the belt needs alot of tension on it and i doubt it still does.
 

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You said that you changed the plugs. When u did that did you use the right plugs meaning usually when its supercharged you go 1-2 heat range colder, not saying u did this , jsut throwing this out there
 

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Discussion Starter #19
I used the same plugs that i took out which were working fine. I gapped them at i think .035 or maybe .040. It had this missing problem before i replaced them but just the same only when the motor was cold and i hammered it to the floor in second. I know the plugs were autolites i think they are 43's or something like that. It has edlebrock performer heads.
 

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Discussion Starter #20
So i think i got the boost issue figured out. Now i drove the car home about 90 min and when i start it up the idle doesnt drop below 2000. i was using the cruise control on the way home dont know if it is still holding the throttle open or something stupid like that. i was drivin for a while and when i slowed down to make a turn and pushed in the clutch the rpms stayed at 3000. so i shut the car off and started it back up and it was fine. i didnt use the cruise anymore after that and now its still running funky. any ideas????
 
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