Holy Cow ... Sputters and stumbles at 4000+ rpm

[svwilbur]

My 2000 use to look like that, rich in the back 2 cylinders and it was caused from the lever that pushes the nozzle down for choking.
On the rear the lever was a bit loose and would allow the nozzle to drop down a bit from vibration and it would run rich.
I bend the lever out a bit to take up the slack and it is much better now except when my choke cable gets bumped up out of the holder and then it is rich again. Two different issues, same result.

[msampsel]

[msampsel]

Day 2 of sputter free roadster driving. Drove 6 miles with foot on the gas no hesitation.
Thinking it is the streetfire coil I installed on Sunday. On Sunday drive, sputtering and missing.
Switch to the Streetfire from a 20 dollar china made coil from O'Reillys at first it still missed and hissed and sputtered.
I tried to keep accelerating and at 5000 rpm it felt like a turbo boost kicked in.

All good for 6 miles after. Today I synched the carbs and set the mixture, started at 2 turns and took little tweaking to
get to a good mixture. Drove it 6 miles with no incidents! Waiting on the new referbed nozzle to arrive with
fingers crossed, hoping the coil was it!

[Linda]

If you still have a points distributor I think you have the wrong coil..... if it is a 12 volt hi output unit with an internal resistor?
Check with the gurus
Linda

[bakerjf]

Hope you've finally nailed it down!

[Gregs672000]

Day 2 of sputter free roadster driving. Drove 6 miles with foot on the gas no hesitation.
Thinking it is the streetfire coil I installed on Sunday. On Sunday drive, sputtering and missing.
Switch to the Streetfire from a 20 dollar china made coil from O'Reillys at first it still missed and hissed and sputtered.
I tried to keep accelerating and at 5000 rpm it felt like a turbo boost kicked in.

All good for 6 miles after. Today I synched the carbs and set the mixture, started at 2 turns and took little tweaking to
get to a good mixture. Drove it 6 miles with no incidents! Waiting on the new referbed nozzle to arrive with
fingers crossed, hoping the coil was it!

It does sound like you found it! Or at least the area (bad wiring that is connecting now?). It's possible that she sputtered for a bit as it cleared the over rich plugs and got them firing strong again. Woo hoo!

[toplessdottie]

Day 2 of sputter free roadster driving. Drove 6 miles with foot on the gas no hesitation.
Thinking it is the streetfire coil I installed on Sunday. On Sunday drive, sputtering and missing.
Switch to the Streetfire from a 20 dollar china made coil from O'Reillys at first it still missed and hissed and sputtered.
I tried to keep accelerating and at 5000 rpm it felt like a turbo boost kicked in.

All good for 6 miles after. Today I synched the carbs and set the mixture, started at 2 turns and took little tweaking to
get to a good mixture. Drove it 6 miles with no incidents! Waiting on the new referbed nozzle to arrive with
fingers crossed, hoping the coil was it!

So I gotta ask.... because I'm expienceing the exact same 4k stutter (fuel system is good, just installed an duralast coil. Perhaps I need to upgrade to StreetFire).
http://www.autozone.com/ignition-tune-u ... ckfit=true

After you replaced your coil, it was still continuing to sputter around 4k? And then you forced it passed? Keeping the accelerator down even as it sputtered? And then it "corrected" itself and shot off?

I'm trying to determine if there is a chance my symptoms are due to electrical, before i start messing with the carbs that were tuned 2 years ago.

Thanks

[msampsel]

Day 2 of sputter free roadster driving. Drove 6 miles with foot on the gas no hesitation.
Thinking it is the streetfire coil I installed on Sunday. On Sunday drive, sputtering and missing.
Switch to the Streetfire from a 20 dollar china made coil from O'Reillys at first it still missed and hissed and sputtered.
I tried to keep accelerating and at 5000 rpm it felt like a turbo boost kicked in.

All good for 6 miles after. Today I synched the carbs and set the mixture, started at 2 turns and took little tweaking to
get to a good mixture. Drove it 6 miles with no incidents! Waiting on the new referbed nozzle to arrive with
fingers crossed, hoping the coil was it!

So I gotta ask.... because I'm expienceing the exact same 4k stutter (fuel system is good, just installed an duralast coil. Perhaps I need to upgrade to StreetFire).
http://www.autozone.com/ignition-tune-u ... ckfit=true

After you replaced your coil, it was still continuing to sputter around 4k? And then you forced it passed? Keeping the accelerator down even as it sputtered? And then it "corrected" itself and shot off?

I'm trying to determine if there is a chance my symptoms are due to electrical, before i start messing with the carbs that were tuned 2 years ago.

Thanks

When I replaced the coil, it still sputtered from 1500 to 4000 rpm for about 500 yrds (probably from fouled plugs), once I reached around 4 k to 5 K the sputter quit and all has been good. I installed my referb nozzle, and a capacitive discharge unit (MSD Street Fire) and tuned it (discovered my ancient service tach is not compatible with the MSD control ) and hope to drive it today again.

Hope it was electrical and fixed. Will let you know if the stutter monster returns. Never had such a persistent issue with this car in the 44 years I've owned it.

[toplessdottie]

I'm sure it's been immensely frustrating for you. But thank you for taking the time to documenting, and posting it here!! It's appreciated!

Happy Roadstering!

[msampsel]

So I drove it again today no sputter up to 7300 or so and all good up to 6000 and multiple times to 4 k. So far so good 12 miles today

[msampsel]

Took a 50 mile trek today without incident.
No stumble at any rpm. Got up to 209 degrees climbing. Still no problem with engine running

[Gregs672000]

Call it good! Problem solved! Ya da! etc etc

[msampsel]

Call it good! Problem solved! Ya da! etc etc

Hope so! I remember getting a pseudo trouble free 75 miles or before and at Solvang.
And then weirdness. Another 30 miles of no issue and I'll call it good.

[AidanDawn2000]

Day 2 of sputter free roadster driving. Drove 6 miles with foot on the gas no hesitation.
Thinking it is the streetfire coil I installed on Sunday. On Sunday drive, sputtering and missing.
Switch to the Streetfire from a 20 dollar china made coil from O'Reillys at first it still missed and hissed and sputtered.
I tried to keep accelerating and at 5000 rpm it felt like a turbo boost kicked in.

Can you give the link for the coil that fixed your sputtering? Unfortantly my U20 just developed this problem and now it feels like I'm bouncing off a rev limiter at 3500rpm

[msampsel]

Can you give the link for the coil that fixed your sputtering? Unfortantly my U20 just developed this problem and now it feels like I'm bouncing off a rev limiter at 3500rpm

MSD Street Fire coil 5525 summit racing.
Sorry not so good at pasting links with iPhone.
The coil I purchased is intended for use with a capacitive discharge (CD) MSD system. Summit carries them and was free shipping too.

Not sure if the coil alone is the right long term solution and I wanted a new toy. Might try calling MSD to see if coil alone is okay. It is ceramic filled (no fear of oil leaks with our horizontal mounting) and compatible with the ballast resistor. Ballast is no longer used with the CD system though.

Looking at just under $200 for the Street fire system. You could spend more and get the 6ALN
some roadster owners covet. Coil alone is 40 and free shipping too at summit on this coil.

I must admit I'm not entirely sure it was the coil as I also changed my carb jet and tuned carbs again. Still, 911 forum guys rave about the MSD system being better than the original p-car CD.
And s new toy ...

Checking your spark at night looking for blue color (across plug gap with new plugs) might give you a clue on electrical.
Might just be your condensor or something else though. Condensers are about 6 bucks.

Another option is try the coil and see.
If no fix with just coil then do not get the CD system? Depends on how you value your time and money.

Sorry if this got a little too long.