View Full Version : T-Bird Bucking... Help?

04-27-2003, 01:21 AM
Yeah, so I recently purchased(a few days ago) an 89 SC 5-speed that was in seemingly good condition until today. I was on the high way getting up to speed in 4th gear when all of a sudden it started making a crunching noise, bucking and the boost gauge started going crazy. I pushed in the clutch, and put it into 5th. The same thing happened. All of this happened while going about 60-70. I slowed down to around 50 and put it into 4th. Everything was normal again for about 3 minutes and then it all started again.

After traveling about 5 miles constantly taking it out and putting it back into gear, I got off the high way and started towards home. And again, the bucking pursisted. Now, in 1st gear, when the tach got to around 3000-3500 rpm it would crunch and buck until I put it into second.

I really don't know too much about the mechanic's of cars, so I have no clue what the problem is.

Anybody know what the problem could be? All help would be appreciated.


04-27-2003, 01:43 AM
what kind of boost are you making according to the guage?
what does it do when it goes as you put it "crazy"

also whats your vaccum at idle

to me it sounds like your leaking boost but please answer the above q. so i can make sure
then i will tell you how to fix it

04-27-2003, 01:46 AM
did your tach seem to be reading right? i had a problem like that and turnded out to be the plug for the coil pack wasn't locked in all the way. when it started bucking the tack went all the way back to zero. what do you mean by crunching sound?

04-27-2003, 01:48 AM
Idle the boost is a little less than 20 (18 I'd say).

I'm not sure what the boost was when it started bucking, but by "crazy" I mean it was going up and down(quickly) while bucking.

04-27-2003, 01:50 AM
Originally posted by Thrty5thSC
did your tach seem to be reading right? what do you mean by crunching sound?

Yeah, the tach seemed to be reading correctly.

It was just an awful crunching sound, similar to when you grind a gear on accident.

04-27-2003, 01:57 AM
hmm, deos everything seem to be in order under the hood? check out your balancer. maybe it started to fall off. possibly hitting the crank sensor . could you tell were the sound was coming from? front, back undernieth?

04-27-2003, 01:58 AM
whats your max boost under wot. (wide open throttle)

also at idle you motor is under vaccum not boost. boost only accures during driving or reving you motor at idle

also you might want somebody to look at you boost guage wile your driving (it would be a really stupid way to crash)

04-27-2003, 02:03 AM
Originally posted by Thrty5thSC
hmm, deos everything seem to be in order under the hood? check out your balancer. maybe it started to fall off. possibly hitting the crank sensor . could you tell were the sound was coming from? front, back undernieth?

It sounded like it was coming from the front, like right infront of the shifter.

I wouldn't really know if everything looks right under the hood because I don't really know what 'right' is.

04-27-2003, 02:11 AM
When were the plugs wires and fuel filter last changed? Look on the wires, if they say 1989 change them. Use Motorcraft plugs and stock wires. No Bosch platinum's only Double platinum plugs will do (unless you like changing them every 5000 miles).


04-27-2003, 02:23 AM
the only thing i can think of is maybe you have a problem with your clutch? or maybe the tranny?

04-27-2003, 11:34 AM
If your blower snout seal is leaking oil on to the CID cap it can cause the bucking issue. OR if the cap is bad.

THE CID is where the distributor would have been up front behind the water pump on top of the timing chain cover and under the the blower snout.

It has a cap with 2 screws. If you pull the cap and clean/replace it and any oil/dirty off the pickup (be careful and gentle) it may cure the issue.

04-27-2003, 02:21 PM
I've had that type of problem twice. The worst was a clogged pass side cat and I didn't know how to check them at the time and ended up having Ford do it and paid through the nose. You have to get under the car and hit them with a rubber hammer and listen for any rattling fro inside the cats.
The other time turned out to be a stuck Air Bypass Valve, behind the SC, and all I had to do was spray it with WD40. Check those before you start tossing cash at other possible fixes. Good luck

04-27-2003, 10:47 PM
i'm with vancouverBC, check the easy stuff first. you got me stumped on the crunch sound. hope it turns out to be an easy fix bro. sorry i can't help ya out.
good luck

04-30-2003, 10:40 AM
Thanks for the advise, everyone.

It turns out it was a bad alternator though. Just swaped it in and everything's working well.

Thanks again.

ben m
04-30-2003, 11:26 AM
i have concluded that almost anything makes our cars do that! plugs, wires, cam sensor crank sensor, coilpack, DIS, HB, vacuum leak, and now an alternator!?!?! what gives?

04-30-2003, 12:25 PM
ben m, don't forget the fuel pump too! That was my problem, getting on the gas it would buck like crazy. Or maybe it was the fuel filter. Come to think of it, my alternator was bad at the time too! Oh well, I replaced everything at the same time, so I guess I'll never know...:D

04-30-2003, 12:30 PM
here's what happened you were getting up to speed in 4th gear
the alternator bearings started to go out so your alternator put so much drag on the belt (i'm suprized it didn't shread your belt)
that it slowed your motor/supercharger down
when the rpms lowered slightly
it freed again alowing you to get back to the point were the alternator was going out

ben m
04-30-2003, 12:51 PM
would that cause hard starting some of the time, but not all the time? i don't hear any noise though. i've replaced the fuel pump, DIS, cam sensor, coilpack, checked codes (212)?, cleaned the t-body, checked the crank sensor, plug wires, plugs, oil, filter, etc. this all seems to be helping a little, but not fixing the problem, thats why i'm always on the posts that say "hard starting", or "bucking" or whatever. if anybody can give me some insight it would be much appreciated! thanks.
ben m

04-30-2003, 09:25 PM
Get new ignition wires and plugs!
Mine did the same thing when i bought it and
it was driving me nutz all i did was do a tune up
on the plugs with new wires and bam the car
pulled like a champ.

2 Hot 2 Handle
04-30-2003, 11:41 PM
check for codes...then post back!
as stated above several things can cause an SC to buck.

ben m
05-02-2003, 07:10 PM
code 212 was what i pulled, thats the EEC wasnt gettin the tach signal. what that means, i don't know. already changed plugs and wires, i've got only one more idea, the harmonic balancer/ crank ~~~. sens. thanks for the feedback, if you guys help me fix it i'll kiss all of you...er, your girlfriends!:D thanks guys.
ben m

05-02-2003, 07:46 PM
212 usually comes back to a bad cam sensor or wiring for the sensor. It will also cause hard starting sometimes.