Drivetrain New Clutch And Flywheel, Car Bucks?

[flashback87]

hey guys,

i basically finished up my explorer motor swap and am now able to drive my car. i put in a new valeo clutch ( i think thatis a king cobra) and new flywheel from advanced auto. now the car bucks at low rpm's and decelerating when i get below 2,000 rpms. i have to keep the car around 2,000 rpms when cruising or it bucks. if i fall below 2,000 the car will buck a little untill i apply more pressure to the throttle. i used to be able to drive in 4th gear in a 35 mph zone and have no issues. now i need to have it in 3rd. the same goes for a 25 mph zone. i used to be in 3rd but now need to be in 2nd. again, at higher rpm's it is fine and the bucking stop if i put it in netural or if i give it more gas.

the car now has a b303 cam and i tried setting the timing to 12 (when i put the timing light on it it bounced a round a little but the 12 marker was right by tht needle).

do i just need to break in the clutch? i have less than 100 miles on it, probably less than 75? could the cam be causing this? i did convert the car to MAF. Or do i just need to be cruising at a higher rpm?

any help will be greatly aprciated.

Thanks!

 

[flashback87]

Anybody? I also changed cap, rotor and wires yesterday

Thanks

 

[f8tlfiveo]

Cam might be the culprit..

 

[RangerJoe]

Is this your first time driving the car with the new motor? What makes you think its the clutch? I agree with above, could be your cam.

Joe

 

[ratio411]

What gear do you have in the rear?

 

[flashback87]

Thanks guys, I have only driven the car 3 or 4 times with the explorer motor in it. As far as I know my car has stock gears in it. The more research I do suggests the cam is the issue. I haven't gotten on it yet because I am still breaking in the clutch (that's gonna take awhile because the car is a hobby so I only drive on weekends/evenings). I guess I just have to keep the rpm up when cruising. That might get expensive

 

[Gearbanger 101]

Sounds like your engine timing is too far advance. Adding timing is great for picking up a little free power, but it hurts driveability. Before tearing into the engine, try backing it off a couple of degrees and see if the problem goes away.

 

[2000xp8]

A b cam shouldn't cause any trailer hitching.
You probably have an ignition related problem of some sort.

 

[flashback87]

i hooked up the timing light this evening, pulled the spout connector, warmed up engine and move distributor until the index was at 10 degrees. i took it for a drive and it seemed a little better when i was in fourth gear going about 37 mpg at 1600-1700 rpms. 3rd gear was still pretty bad at the same rpm. when i came back from the test drive i hooked my light back up and it seemed to be on the marker for 12 again ( i made that mark really think and white because that is where i thought i wanted it) so i loosed the lock nut and adjusted it a little more to wear the index pointer was to the left of 12 about 1.5-2 marks. i was not able to drive it after that but i wil try it tomorrow.

should i go below 10?

 

[pissedoff92]

no 10 degrees adv. is factory. unless you restabbed the dizzy a few teeth off.

 

[flashback87]

I am pretty sure I have my timing set between 8 and 10 with the spout unplugged but when I plug the spout in it seems closer to the white line I made for 12 btc. Now, the cheapy. Timing light I bought from harbor freight has a dial on the back with degree markings. Should I be leaving that dial set at 0 because that is what I have been doing?

Well retarding the timing didn't help that much. 4Th gear does not buck as bad in a 35 mph zone but 3rd in a 25 mph zone still bucks. Any other things I can check for?

Thanks!

 

[Gearbanger 101]

Are you sure it's bucking and not a slight engine miss? When was the last time you performed a tune up (plugs, wires, cap/rotor, etc)?

Some bucking on the other hand is going to be normal. It is after all a 20+ year old car. Mounts wear, U-joints wear, drive shafts vibrate, trans bearings wear, rear end gets loose, control arms distort and bushings rot. Things will get a little sloppy over time and become more noticable at light throttle when the engine is able to "coast" a little. Just the nature of the beast really. I have never owned a Fox that drove perfectly. Hell....they were perfect when they were brand new.

 

[pissedoff92]

If you have your timing marks visible you wont need the dial keep it set at zero. The only thing I can see on my balancer is a white line on the ten. so what I do is set my gun for 10 deg advanced on the dial and make sure my line is right at the pointer. If I bump it up same thing I set the gun and turn the dizzy so that the number lines up. and with the spout in I think it should be reading like 20 degrees total advance

 

[f8tlfiveo]

I would put my money on the stock gears combined with the cam.. Put 3:73's in it.. Bet the problem goes away.. Or just downshift to keep it away from 1500 rpm.. My cam that I just got ground from fti is matched up for my 3:55 gears at a minimum..I think the operating rpm is different on the b cam rather than the stocker.. Prob 1500-5500... With gears..

 

[flashback87]

Thanks, gears might be my winter project.

Could the bucking be caused by the act sensor? I did not drill a hole for the sensor in my explorer intake and it is just sitting on top of the lower intake. I was planning on relocating it to the air tube. Would this sensor just laying on the lower intake cause this?

Thanks!

 

[ratio411]

I believe it is your gears too.
I can't think of any stock gear that will act right with an aftermarket cam that has ANY lump to it at all.
You have to have a way to keep the rpms up other than the throttle, or you are just killing your economy.
Taller gears will get better MPG as long as you don't do much highway driving. In a urban or suburban setting, lower gears are the way to go for both power and economy. I assume you didn't cam your car for interstate driving anyway.

 

[ratio411]

Thanks, gears might be my winter project.

Could the bucking be caused by the act sensor? I did not drill a hole for the sensor in my explorer intake and it is just sitting on top of the lower intake. I was planning on relocating it to the air tube. Would this sensor just laying on the lower intake cause this?

Thanks!

Get'r done.
I have found that sensors cause all sorts of trouble you wouldn't think they could.
Get the sensor placed properly first, and then go from there.
Your car might be loading up on fuel, which could cause low rpm instability (surge), which could be causing the bucking as much as a miss would.

 

[f8tlfiveo]

That sensor tells the computer how hot the air is entering your engine.. I would imagine its prob not that. But it needs to be in your intake so you get accurate readings. Right now the computer prob thinks the air is cooler than it really is. Even putting it in your intake tube it will still be a couple of degrees off.. I put mine right in the #5 intake runner as close as I could to where the explosions happen. But the intake tube will be fine.( anything is better than laying on the intake)..

 

[flashback87]

thanks guys, good info!
i am goin gto move the act sensor to the air tube tomorrow.
One more question, since the engine i put in was out of a 2000 explorer, it has the gt40p heads and intake. so, there was not egr set up. So right now, i have the egr installed but i have the electrical connector disconnected and vacuum lines disconnected.

Just wanted to throw that out there to see if that could be an issue that would cause the bucking? I have been doing a ton a research on eger and gt40p heads but am still a little confused. It seems if i have the eleectical connector disconnected and the vacuum lines disconnected it is not functioning anyways and should cause a problem.

I am going to pull a plug or 2 tomorrow to see if i am running rich.

 

[f8tlfiveo]

I had a non egr intake and p heads on mine.. Just took them off last weekend.. I ran the same as you, just left the egr stuff there but keep it plugged in so the codes didnt show.. The valve opened and shut on the egr but nothing happened..