rev problem
07-06-2005, 11:21 PM
#1
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Location: sacramento california
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rev problem
i recently aquired a 79 280zx 2+2 and i replaced my sparkplugs. started it and it worked fine and reved to 6k rpm.. i put degreaser on the engine and hosed it off. now it idles funny and wont rev past 3k rpms and it boggs down.. any suggestions on wat the problem may be?
07-06-2005, 11:45 PM
#2
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Location: Escondido (San Diego) California
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You got the TPS (throttle position switch) wet. Unplug it, dry out the contacts and plug it back in. (It's the little black box on the drivers side towards the front middle of the engine, on top facing out in front of the fuel rail... has a plug coming in from the top). Sorry I don't have pictures for you.
Rod.
Rod.
07-07-2005, 11:21 AM
#5
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may i ask
say figuring that u know that.. im looking to do some not cheap but the lower end up's on my car. i want to put some new exaust on it. im gana fabricate my own cool air intake. but wat kind of exaust would you recoment if u recoment any. i will evuentally get new manifold and pipe but for now im just looking to get the exaust part. any u would suggest.
07-07-2005, 09:10 PM
#8
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Unless you're going to be pushing at least 250HP, you don't need or want 3" exhaust. 2.5 is more than enough for even a modded 280ZX. You do need some back pressure or you'll actually lose horsepower. I run 2.5 on mine and it's a perfect balance.
Rod.
Rod.
07-07-2005, 10:07 PM
#9
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hrrm
alright well for now im not replaceing the pipe. im just foring for the exaust section itself at the rear. i dont want anything super expensive. i dont want the supid ricy coffee can bs. i want a deasent inexpensive brand name.. or soemthing you would suggest. leme know
07-07-2005, 10:44 PM
#10
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3" is really oversized. Especially if it's not a turbo. Turbo's don't like backpressure at all but with NA you need that backpressure to help the engine breathe. It's what keeps those cylinders filling and expelling. Not a problem at high RPM's, but in the lower range you're going to lose out if you don't have any backpressure.
07-08-2005, 12:48 AM
#11
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Actually, you'll get better throttle response with a 3" but you'll loose a significant amount of torque, not horsepower.
2.25 on a stock motor is about all I'd go for with a normal street muffler. With a high flow, low restriction muffler and no catalytic converter, I would probably keep it down at 2". Using mandrel bends will do more for a stock motor than a bigger pipe.
If you're planning for future mods, then you need to get what you expect to use in the future so you don't waste your money doing it twice, but you should expect to loose torque and off the line response until the rest of your mods are complete to compliment your exhaust.
2.25 on a stock motor is about all I'd go for with a normal street muffler. With a high flow, low restriction muffler and no catalytic converter, I would probably keep it down at 2". Using mandrel bends will do more for a stock motor than a bigger pipe.
If you're planning for future mods, then you need to get what you expect to use in the future so you don't waste your money doing it twice, but you should expect to loose torque and off the line response until the rest of your mods are complete to compliment your exhaust.
07-08-2005, 01:58 AM
#12
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true true true .... backpressure makes all the diff ...the msa header comes with a 2.5" piece that runs right to the cat .after i removed the cat i seen a big drop in the pulling power....... after my cat i had a few leaks in the stock piping where it was going into the to MY canister muffler...once i got and new piece in and welded up i could here the backpressure come back, little leaks are bad news ....i think that on my n/a motor.. if i had 2.5" all the way back to the canister it would lag me out ...iam sure of it ...that 2'' piece that i added to make my canister stick out seems to add some backpressure ....really i think there should be more ...most stock cars will jump out on me off the line .....but not in the top end 
we will see if they jump OUT at the start after i put this MT trany in
we will see if they jump OUT at the start after i put this MT trany in
07-10-2005, 07:22 PM
#13
Originally Posted by ThermalWake
alright well for now im not replaceing the pipe. im just foring for the exaust section itself at the rear. i dont want anything super expensive. i dont want the supid ricy coffee can bs. i want a deasent inexpensive brand name.. or soemthing you would suggest. leme know
07-10-2005, 09:46 PM
#14
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Location: Near Houston
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hey, is there supposed to be an actual plug-in to go into the tps? I have two small connectors that connect to two little prongs. there are three and the third one has nothing plugged into it is this supposed to be like that.
07-11-2005, 12:43 PM
#15
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Sounds like somebody butchered the plug at some point. NAPA sells the exact plug type (same as the injector plug ins) for a couple of bucks. I think the third post stays bare. If your TPS weren't working... you wouldn't be driving. Splice in a new plug and keep that area dry and you'll be ok. Also, if the plug ins for your injectors are green and crusty where the contacts are... replace those too, Less resistance means better performance.
Rod.
Rod.
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