Engine, Fuel or FI problems, spitting and sputtering again Options

[ClayPerrine]

Ideally you should have low pressure at high vacuum (idle) and higher pressure at low vacuum (acceleration) Do you have another pressure regulator you can swap with to check values at low and high vacuum conditions ? In summary what you are looking at is low pressure at high vacuum (idle 28 psi) high pressure at max throttle (32 psi) and somewhere around 30 psi at cruising.

I do not have one. I'll check the web. Maybe I can find something not too expensive. I bet they are not available new, are they?

Is my vacuum backwards? I had 10" at idle and 20" at 3000 rpm which seems right to me... the air is being sucked into the engine faster when it is high RPM.

PM me your address.. . I will send you an L-Jet pressure regulator.

[malcolm2]

PM me your address.. . I will send you an L-Jet pressure regulator.

done... Thanks

I did find that they aren't too expensive. the 1.8 L-Jet version is $45 to $85. Not knowing for sure, yours should help diagnose.

on PARTS GEEK dot com

[pilothyer]

Once you get to the over-run condition (Cruise) vacuum picks back up, but when you step on it vacuum drops and fuel rail pressure rises to enrich the mix.

[ClayPerrine]

PM me your address.. . I will send you an L-Jet pressure regulator.

done... Thanks

I did find that they aren't too expensive. the 1.8 L-Jet version is $45 to $85. Not knowing for sure, yours should help diagnose.

on PARTS GEEK dot com

It will be on the way tomorrow...

[malcolm2]

PM me your address.. . I will send you an L-Jet pressure regulator.

done... Thanks

I did find that they aren't too expensive. the 1.8 L-Jet version is $45 to $85. Not knowing for sure, yours should help diagnose.

on PARTS GEEK dot com

It will be on the way tomorrow...

OK, I finally got around to installing your Pressure Regulator this afternoon. Thanks for the donation.

Fuel pressure doesn't really look that much different. idles at 35, needle bounces. I rev to 3500 and hold and the needle steadies, still at 35. Release the accel cable and it bounces around, then steadies again.

Gonna take a night drive after dinner. Then drive it to work in the AM. Then back home and monitor the hill climb.

I have driven a lot on my old regulator the past few weeks. No return of the spitter-sputter problem.

[timothy_nd28]

You adjusted the AFM too rich. You really need a AFR gauge to readjust the AFM. On my 1911 build, I relaxed the AFMs clock spring 3 gear teeth. I remember you told me before that you went more than that on your AFM. Replace the plugs, keep the stock gap for now, and drive it for a few days with the AFR gauge attached, document the ratios you see and what speeds you see that at.

[malcolm2]

You adjusted the AFM too rich. You really need a AFR gauge to readjust the AFM. On my 1911 build, I relaxed the AFMs clock spring 3 gear teeth. I remember you told me before that you went more than that on your AFM. Replace the plugs, keep the stock gap for now, and drive it for a few days with the AFR gauge attached, document the ratios you see and what speeds you see that at.

I was wondering about that today.

Glad you chimed in. I don't have an AFR , I used a work buddies last time. He lives 45 minutes away, and does not work here anymore.... I need to see if he will UPS it to me... (IMG:style_emoticons/default/confused24.gif)

I still have the black duct tape holding the plastic cover down and I did use a paint pen to mark the original spring setting. Picture edit coming soon...

I looked up my Air : Fuel readings from 2 years ago.... I do believe that was after we moved the AFM spring.
1000 rpm idle = 17-ish:1
3000 rpm parked = 14.2:1
4500 rpm parked = 13-ish:1
4500 rpm driving up a hill = 12:1

I remember the forum saying I was a little rich at the time... shooting for 13.7 - 14.2 on the hill climb, right?

[malcolm2]

BTW: My work buddy has the AFR device coming to me. I got lucky, a neighbor works with him now.

Close up photo of my AFM.... I did not remember exactly how many teeth I stopped at, but it looks like 9. I am going to go back thru the Itinerant-air-cooled instructions to see where I stand now. this thing still scares me....

Any other thoughts?

[malcolm2]

BTW this may not be related. But I drove the car to work for 2 days now and the only change I have made recently was replacing the (what I assumed to be original) fuel reg with another used (assumed good) one.

I noticed this week, that my CHT is back where I remember it had been since I began driving in 2013... 350*F. for the past few months after the last sputtering event, it has been in the gap between 300 and 350.

Seems odd to me.