22R dieseling and running rough

Having trouble diagnosing why 1986 22R engine running real rough at idle and semi rough while driving. Diesels badly when shut off. Checked all the obvious; timing, all new ignition parts (cap, rotor, plugs, wires), fresh 91 octane gas, vacum lines appear ok (shot carb cleaner around... no leaks detected). Set valves to .008 intake and .012 exhuast (warm/hot).



How I got here... My son was driving and noticed engine getting hot. Well, it was the known Toyota 22R problem whereas the timing chain breaks the guide then starts chainsawing away at the timing cover until it breaks the water jacket wall. Yep, oil in the water and water in the oil. Sent the head out and had it rebuilt anyway. Put everything back together and now we have the dieseling at shut down and the rough idle and rough (slight) while driving.



One of the things that I noticed when tearing down the motor was the mixed oil & water got sucked up by the PCV into the carburator. There was chocolate milk all over the throat of the carb. It took my son and I about 4 weeks to get the engine back online and I'm wondering if perhaps too much time lapsed letting the milk sit in the carb.



Timing 0 degrees at 950rpm with distributor vac lines plugged off.



There is no smoke.

Engine has good response from idle

Engine has good power while driving.

No noises apparent

Exhaust is clean



So if anyone has had a similar experience and found a solution I would really appreciate hearing from you!



Thanks.

Reply 1 : 22R dieseling and running rough

Recheck for Vacc leak !!!!-------(and cracked lines)

Reply 2 : 22R dieseling and running rough

Isn't timing supposed to be 5 degrees BTDC at 800 RPM? Check the vacuum advance module for any leaks by individually sucking on each one of the hoses leading to the diaphragm. My truck started pining one day and I chased it down to a leaking diaphragm on the inner vacuum advance module.

Reply 3 : 22R dieseling and running rough

Replaced ALL vac lines (thanks Krusty) and actually found one going to the distributor to be bad. Don't know why spraying carb cleaner around didn't catch this. Then re-timed 0deg @950rpm per the book. Still a little rough.

Reply 4 : 22R dieseling and running rough

5 btdc @ 950 is spec. Put a vac guage on the outter distributor vac line and it's good. Put the guage on the inner (closer to engine) line and there's zero pressure. This may be correct, dunno. Went over everything again... still crap idle and dieseling on shut off. The vavles have been adjusted but maybe they're still off? Anyone have rough idle/dieseling caused by sloppy valve settings? Thanks.

Reply 5 : 22R dieseling and running rough

mine dieseled with the valves sloppy. once i adjusted them the diesling stopped. im running a weber 38 also an i believe im running slightly lean on my main jets. also an exhaust with too much back pressure can cause this too. most of the time diesling is due to a lean condition. check the egr as well. ive heard of people dropping down to a colder plug or adjusting the gap a little to help with this issue. bottom line is something changed or is out of adjustment and should be fixed.

Reply 6 : 22R dieseling and running rough

The timing on the 22r carburatated model should be 0 degrees at 950 rpm