Idle Mixture Adjustment

[Jonty]

Some people run without it plugged in mostly to stop idle hunting. If you do that you probably won't pass emission testing and expect less MPG.

No problem - no emission testing where I live

[Jonty]

Hi all

Just wanted to update you and all say thanks. I'm part way to a solution. My misfire was really bad today but limited to a local mech and ran a compression test. Result were:

155 - 1
145 - 2
150 - 3
155 - 4
155 - 5
155 - 6

So will take that as a pass (the mech was pretty happy with results). As part of doing that we check the plus and they looked all fine but when we started it it was clear it was only running 5 cylinders. We pulled the leads and noticed no reaction with cylinder 2 and discovered the lead must be dodgy. After wiggling it round a bit the cylinder came back to life and it drove perfectly home. Looks like I need to invest in some new leads. Does anyone know if I can change this without removing the manifold?

So next steps are to check dwell tonight and if that is till a bit wired then i will replace the o2 sensor when it arrived (which i will probably do anyway).

Thanks

[Jonty]

Hi all

Further update I’ve now tested dwell and it’s going closed loop and swinging between 35 and 25. My mixture bung has got stuck so when I free that up I can test giving it a slight tweak to richen up and see if that works. One other question, the one residual issue is that it takes the car 3 or 4 seconds of cranking to start warm or cold. The CSV is fine and the accumulator is fine so it’s not a “hot start” issue. What I find is if I start it cold then quickly shut off (so it’s still cold) it will fire straight away which makes me think it’s a fuel supply issue.

[Ron]

COOL!
Sounds like your O2 sensor is cleaning up. (Damn screws ;-)

Several ways to change the plug wires HERE. I'd do the cap and rotor while I was in there.

The hard start may go away after you put some miles on it. If not, the gauges are on the way...

[Jonty]

Thanks Ron! I did shut down and start it after 10 mins and it never went closed loop so I think the 02 sensor still stuffed but a new one not far away! Have just ordered new spark plug leads. I’m pretty sure I’m only a tire away from having replaced every bloody part in this car 😂

[Ron]

NP!

lol - The spare?

Just curious- With smoothness in mind only, does it idle perfectly in open loop now as in post 21 or significantly better?

[Jonty]

Yes it idles really well in open loop (pretty much the same as always). It was idle well in closed loop after I got home but never went back to closed loop after I started it again. I’m fairly sure it must be the 02 sensor and I’ve got a new one ordered. The misfire seems to be an unrelated issue due to the plug lead. I’ve also just ordered the cap and rotor as per your recommendation

[Jonty]

Hi all just wanted to close off this thread by saying all issues now fixed and perfect dwell readings. The main issue was a worn distributor cap and a dodgy spark plug lead. I also replaced the o2 sensor and everything fell back into place.

Thanks