Stuttering at 3000 rpm

BassettBritts · 05-08-2021, 12:59 PM

I just got my 83 SC running after not being on the road since 2004. New fuel tank, fuel lines, fuel filter, fuel pump, and accumulator. New plugs, plug wires, coil, and valves adjusted.

I got it to crank right up. I've driven it about 4 times with up to an hour. Now I'm getting a stuttering at around 3000 rpm. Any ideas?

ahh911 · 05-08-2021, 03:52 PM

Frequency valve running? The black connector at the engine firewall plugged in all the way?
Relay under passenger seat?

My connector at the rear was not connected and I had stumbling and poor running between 2500 and 3000rpm, plugged it in and the FV ran then leaned it out.
Phil

BassettBritts · 05-08-2021, 04:32 PM

Quote:

Originally Posted by ahh911

Frequency valve running? The black connector at the engine firewall plugged in all the way?
Relay under passenger seat?

My connector at the rear was not connected and I had stumbling and poor running between 2500 and 3000rpm, plugged it in and the FV ran then leaned it out.
Phil

Thanks Phil, I'll check it out.

Bill Douglas · 05-08-2021, 08:49 PM

Unlikely... But it doesn't cost anything to look.

My car ('82 engine) had a similar sort of missfire for year. It turned out I hadn't seated the distributor cap correctly.

BassettBritts · 05-09-2021, 03:13 AM

Quote:

Originally Posted by Bill Douglas

Unlikely... But it doesn't cost anything to look.

My car ('82 engine) had a similar sort of missfire for year. It turned out I hadn't seated the distributor cap correctly.

Thank you. I'm open to checking everything.

ahh911 · 07:56 AM

When I re-assembled our engine and put it back into the car, it started right up, ran ok. Then after several drives I noticed lots of surging stumbling at ~2500 rpm especially when the engine was a little cooler. Well, then I put a multimeter on the O2 sensor and saw it needed richening at 2500 rpm so did that. Anyhow, it just wasn't right and when I finally looked at the FV it was not running. I had knocked the black connector for the O2/FV system up a little and it wasn't seated right. I plugged it in, checked the O2, and FV duty cycle and "corrected" the mixture. No surging since (been over 2000 miles). So I'd agree it's unlikely, but seeing as the O/P has just had it rebuilt, it's possible in this sort of scenario. EDIT: Excuse me, I just noticed that the engine wasn't recently re-installed, my mistake, anyhow, worth a look since it's been since 2004.
Phil