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Discussion Starter #1
WTF!!! My car bucks and jerks uncontrolably up to about 1700 or 1800 rpm. It will only stop when I take it out of gear. I just built up the 331 stroker with a set of TFS TW heads and TFS stage II cam. I have the C&L 76mm MAF that people say they've had problems with bucking and jerking. Some say though when they turn it a certain way that it stops the jerking....does anyone know if this is true and which way am I supposed to turn it in order to do so (I also have the fender wall filter so no disturbance from the fan is bothering the filter). Would a chip help stop this bucking and jerking? I need all the reasons that would cause bucking and jerking so I can try and run down this demon!!
 

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1) Make sure you have the right C&L sample tube for your injectors

2) List your complete combo for us to help, because many things can be causing your problem

3) Most bucking problems I've encountered come from bigger camshafts. The TFS 2 is pretty big as street/strip cams go for a stock compression 302. However, you have a 331 (and more compression too?), so it seems like that 224/232 type cam should be almost on the small side for a 331.

Give us some more info.
 

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Discussion Starter #3 (Edited)
Sorry......my combo is in my sig. BTW, my compression is about 10:1....and I do have the right sampling tube for my 19# injectors.
 

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I had the same problem as you. A dyno run showed me i was running a little lean. Posting my prob. here resulted in my finding out the stock A9L computer would be better than my X3Z cobra comp. guess what? it was, it fixed my car like magic. I dont know what you have or if it will work for you but it brought peace and joy to my life.:joy:
 

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Discussion Starter #5
I have the stock A9L computer. BTW, my fuel pressure is at like 50 because I have the 19# injectors.....I don't think i'm running lean.
 

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Discussion Starter #7
Well, the question is then can the 19# injectors be causing the bucking and jerking I'm getting? Other than that, the car runs VERY strong!
 

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re

I think its the CnL, I had a 73 MAF and it bucked like crazy, try tuning in the FP
 

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Not sure if your problem is injector related but you are at or above the limits of 19lb injectors.

Try turning the MAF and messing with fuel pressure. I'd try messing with the meter first.
 

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I would swap over to 30 lb/hr injectors and a bigger fuel pump on your 331 setup, and step up to a Holley or a ported RPM intake, while you are at it. Your Explorer will really make lots of torque, but your power curve will flatten as low as 4900 rpm.

I'm not sure if that is the bucking problem, but it sure couldn't hurt. Maybe you can borrow a Pro-M calibrated for whatever your injectors you have from a Buddy, and see if that fixes the problem. You always will have some low speed bucking with a big cam, however. I just push my clutch in :)
 

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Discussion Starter #11
Sure I can push the clutch in, but constant riding of the clutch like that...i'll have to get a new one in a year!
 

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Dude, its the CnL
This is infamous charcteristic of them.
By adj the timing and FP, you can minimize the bucking. Also try erasing the computer- disconnecting the battery and holding down the brake pedal for 10 sec, leave the battery off for a couple hours.
 

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24lb injectors
My car had the same problem and once I got the fuel pressure worked out it runs fine
Even though the injectors look like they are doing the job they are overworked. Eliminte the major things first. put the stock mass air back on and see if that helps. next try the FP and see what that does.

Good Luck
Tim
 

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injectors too small fuel pressure too high(will screw up your idle) you need to adjust it so you have enough at wot but not so much it adversly affects your idle quality. then you will be able to enjoy your cam lope
 

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I have heard of turbulence in the MAF sensor causing this kind of problem. Rotating the MAF sensor could move the element out of the turbulence area.

If there is a turn in your intake right before the MAF, this could be a factor as well. It needs a steady stream of air coming into it to be accurate.

If the problem is turbulence, you could detect it by probing the 'D' wire on the MAF and testing the voltage while the problem is happening. If the voltage varies wildly while the engine is bucking, then the problem is probably MAF related. The voltage should increase smoothly from idle (<1V) to WOT (~4V or so).

If you find erratic voltage, try rotating the MAF first, then consider straightening/modifying the intake between the air filter and the MAF.

Also, if the Throttle Position sensor has developed a dropout, then it could also cause this. I think it's the green wire, and you can test it with key on, engine off. probe the wire and test for a constant sweeping voltage from idle position to wide open throttle position (same range as MAF sensor). If there are any dropouts in voltage, then replace the TP sensor.
 
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