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> car is bucking under acceleration...any ideas?
era vulgaris
post Aug 27 2014, 02:04 PM
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My car has developed an extremely annoying bucking under acceleration. It started about a week ago, and at first it would only happen while accelerating out of a fast turn. But now it does it all the time while accelerating. It's like the car is oscillating between half power and full power, making it lurch-slow-lurch-slow-lurch-slow. It's like you're riding a bucking bronco or something. The only cure seems to be to get off the throttle completely, upshift, then slowly accelerate.

Anyone have any idea where I should start looking first?
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r_towle
post Sep 2 2014, 09:47 PM
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I would suggest a few things.
A new fuel tank sock on the return line at the fuel tank...
Check all your fuel lines.
Check all your wiring, make sure all the fuel injection wiring is properly connected and not loose...it happens.

Do new points, new plugs, and new wires, rotor and distributor cap.
Remove the advance plates and clean then inside the distributor...40 year old grease is like glue now...

Remove the if trigger points and blow out all the crap from the bottom of the distributor.

Full tune up
Set valves
Set dwell
Set timing
Check fuel pressure.

Now you would have eliminated a large number of variables...it's just a good place to start.
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era vulgaris
post Sep 3 2014, 09:05 AM
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QUOTE(r_towle @ Sep 2 2014, 11:47 PM) *

I would suggest a few things.
A new fuel tank sock on the return line at the fuel tank...
Check all your fuel lines.
Check all your wiring, make sure all the fuel injection wiring is properly connected and not loose...it happens.

Do new points, new plugs, and new wires, rotor and distributor cap.
Remove the advance plates and clean then inside the distributor...40 year old grease is like glue now...

Remove the if trigger points and blow out all the crap from the bottom of the distributor.

Full tune up
Set valves
Set dwell
Set timing
Check fuel pressure.

Now you would have eliminated a large number of variables...it's just a good place to start.


Plugs, wires, cap, rotor are all only a few months old. I've put in a new pertronix elec ignition and flame thrower coil also.
FI wiring has been gone through and all contact points cleaned.
Valve adjustment, timing, and dwell has been done in the last couple months.
All FI hoses are only a few months old, and routed correctly.
Injectors are all recently rebuilt - all bought here from a couple different forum members.
All 4 elbow hoses are new. The rest of the fuel hoses are relatively new (I didn't install them, but they're definitely not OE.)

I plan on having the fuel tank cleaned and a new sock installed by a local air-cooled shop here in town.

Is there a good guide somewhere to pulling and cleaning the dizzy? This is really the only other thing I haven't done.
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BeatNavy
post Sep 3 2014, 09:22 AM
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QUOTE(era vulgaris @ Sep 3 2014, 11:05 AM) *


Is there a good guide somewhere to pulling and cleaning the dizzy? This is really the only other thing I haven't done.

I say again (from page 1 of this thread), you may want to read this thread in its entirety, including the part about servicing the dizzy. It may help, it may not, but I found it useful for cleaning the dizzy.

In terms of pulling it: most people have to loosen up the timing barrel nut (or whatever you call that 10 mm thing that secures the dizzy in position for timing) and rotate the dizzy counterclockwise. Then you can get a 13 mm socket down there to remove the nut securing the dizzy in place. Once you get that nut out you can pull the dizzy straight out (after disconnecting wires, vacuum lines, etc). Depending on the type/shape of the O-ring seal, it may require some modest amount of force to pull out. Place something like a rag inside the hole so dirt that's hanging out there doesn't fall into the well. I have seen some people say they can get that 13 mm nut off without rotating the dizzy (and messing up the timing), but I was not able to.

When you put it back in after cleaning, notice that the gear is offset so the dizzy will only go back in one way. If you replace the O-ring, keep in mind it might be tighter to get it back in and may require some force.

Also, getting that 13 mm nut back on during reinstall requires dexterous fingers. May want to have your magnet ready to retrieve the nut a couple of times.
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era vulgaris
post Sep 3 2014, 10:49 AM
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QUOTE(BeatNavy @ Sep 3 2014, 11:22 AM) *

I say again (from page 1 of this thread), you may want to read this thread in its entirety, including the part about servicing the dizzy. It may help, it may not, but I found it useful for cleaning the dizzy.



Oh damn! Sorry about that. I got so wrapped up in the fuel system I forgot you'd linked to that thread.

Looks like that's just the info I need.

Is it necessary to replace the o-ring?
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Posts in this topic
era vulgaris   car is bucking under acceleration...any ideas?   Aug 27 2014, 02:04 PM
Mike Bellis   sounds like a lack of fuel.   Aug 27 2014, 02:50 PM
jt914-6   When you get the bucking worked out check your mot...   Aug 27 2014, 03:23 PM
Rand   Don 't know if the TPS would cause bucking to ...   Aug 27 2014, 03:45 PM
wndsnd   Car still have the Djet? Has the tank ever been c...   Aug 27 2014, 03:45 PM
era vulgaris   Motor mounts and trans mounts are still good. TPS...   Aug 27 2014, 04:32 PM
brp986s   Motor mounts and trans mounts are still good. TP...   Aug 27 2014, 07:31 PM
era vulgaris   Any chance a dying fuel pump would cause this? Ju...   Aug 27 2014, 04:52 PM
Mike Bellis   Any chance a dying fuel pump would cause this? J...   Aug 27 2014, 06:52 PM
scotty b   Check all of the vaccum lines. there is one in par...   Aug 27 2014, 07:18 PM
jasons   When my 2.0 did this, it was the trigger points in...   Aug 27 2014, 07:21 PM
mepstein   Mine did this. Did a LOT of things to try to fix b...   Aug 27 2014, 07:52 PM
warrenoliver   Could be a loose ground wire on your distributor p...   Aug 27 2014, 09:16 PM
era vulgaris   Check all of the vaccum lines. there is one in pa...   Aug 27 2014, 09:44 PM
BeatNavy   I think it's probably worth reading this thre...   Aug 28 2014, 04:30 AM
76-914   What's your fuel pressure?   Aug 27 2014, 09:46 PM
The Cabinetmaker   I'm surprised that no one has mentioned the f...   Aug 28 2014, 04:03 AM
dknechtly   There's a lot of good advice here. Make sure ...   Aug 28 2014, 07:55 AM
era vulgaris   So first I cleaned every contact I could find in b...   Aug 28 2014, 01:29 PM
Phoenix914   :headbanger: :Qarl: :driving:   Aug 28 2014, 03:43 PM
The Cabinetmaker   don't you love the simple fixes   Aug 28 2014, 04:19 PM
era vulgaris   Definitely! :Qarl:   Aug 28 2014, 04:40 PM
era vulgaris   Celebrated too soon :( Went for another drive t...   Aug 28 2014, 09:44 PM
PancakePorsche   Celebrated too soon :( Went for another drive ...   Aug 29 2014, 02:33 AM
era vulgaris   Got a friend bringing over his fuel pressure gauge...   Sep 2 2014, 05:35 PM
Rand   Disregard that since you have a carb now. You don...   Sep 2 2014, 06:20 PM
era vulgaris   Disregard that since you have a carb now. You do...   Sep 2 2014, 07:12 PM
r_towle   I would suggest a few things. A new fuel tank sock...   Sep 2 2014, 09:47 PM
era vulgaris   I would suggest a few things. A new fuel tank soc...   Sep 3 2014, 09:05 AM
BeatNavy   Is there a good guide somewhere to pulling and c...   Sep 3 2014, 09:22 AM
era vulgaris   I say again (from page 1 of this thread), you may...   Sep 3 2014, 10:49 AM
BeatNavy   [quote name='BeatNavy' post='2081511' date='Sep 3...   Sep 3 2014, 01:24 PM
914_teener   I would suggest a few things. A new fuel tank soc...   Sep 2 2014, 10:22 PM
era vulgaris   Couple of extra things I thought of: Check your...   Sep 3 2014, 09:08 AM
914_teener   :agree: I assumed you had already done this. Ge...   Sep 3 2014, 09:47 AM
BeatNavy   Sorry, a couple more things to note: you probably...   Sep 3 2014, 02:08 PM
era vulgaris   Sorry, a couple more things to note: you probabl...   Sep 3 2014, 04:05 PM
BeatNavy   Sorry, a couple more things to note: you probab...   Sep 3 2014, 04:18 PM
jacksun   hi, maybe the below will help? "Throttle Swi...   Sep 3 2014, 07:52 PM
era vulgaris   Aha! i finally got it. After a couple weeks ...   Sep 15 2014, 11:47 AM
BeatNavy   check the obvious shit first before diving into t...   Sep 15 2014, 11:56 AM
era vulgaris   But at least you learned a lot of things that co...   Sep 15 2014, 01:10 PM
dknechtly   Geesh, thanks for posting the solution. That...   Sep 15 2014, 12:16 PM


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