Posts: 33
Thanks David T! For better or worse, I won’t be getting lambda operational anytime very soon. My car’s had an old aftermarket exhaust for years with a rusted-in o2 sensor. Until I’m ready to put in a shiny new dpi exhaust, it’s more like lambDON’T for me (I’m here all week).
In the meantime, I just want to get it smooth enough to not stall when using the AC.
Location: Leonardtown, MD
Posts: 8,885
My VIN: 03572
The Volvo unit I use will connect right up to stock hoses and electrical connector but it is a smaller diameter so will not bolt up to the stock bracket. I don't use any bracket and it stays put just fine. I think Dgo sells it new.Originally Posted by deloreandmcxii
Location: Northern NJ
Posts: 8,517
My VIN: 10757 1st place Concourse 1998
I would try the old O2 sensor anyway. hey, maybe it will work! If it doesn't it is not that big a deal to remove an old, rusty one. Take it to an exhaust shop and they will use an acetylene torch. It will come right out. You will never get the car running smoothly without it. It will run WAY too rich. All of these engine systems were designed to work together so for the engine to run smoothly they all need to be working correctly.
David Teitelbaum
Posts: 33
Lambda is on the list! It just doesn't directly effect my enjoyment of the car, so it was lower than some other things.
The car runs smooth as heck... after warmup and with the AC off
Location: Olathe, KS
Posts: 1,510
My VIN: 11596
Regarding a good smoke machine, I had really great success using this one:
https://www.amazon.com/AutoLine-Pro-...xpY2s9dHJ1ZQ==
Sorry about the long link. Anyway it comes with enough smoke liquid for probably two sessions but you can also use USP mineral oil which they carry at CVS.
I put the smoke into the engine using the hose that connects the oil filler cap to the air cleaner cover. You will also have to seal off the air meter flap because it's not a tight seal and smoke will come out. I did this by cutting a latex balloon and zip tying it around the meter housing. See the picture below. Actually the next time I did it, I removed the backfire guard so that the screws wouldn't push into the balloon and tear it. I found a couple minor leaks this way. The first thing that started to leak was the oil dip stick seal but that's OK because it's not part of the intake system anyway.
PXL_20220608_001002441.jpg
Andy Lien
VIN 11596 Jan 1982 build - owned since Nov. 2000!
Total frame-off restoration completed 2021-2023
Photography and Backpacking is life.
Was Fargo, ND
Now Kansas City
Posts: 33
Perfect! Thanks Andy!
Waiting on a new idle motor to see if that helps. Will investigate vacuum leaks after that.
I am now dreaming of a winter project of a new exhaust and getting kjet fully operational (would be the first time in 20+ years!)...
Location: Olathe, KS
Posts: 1,510
My VIN: 11596
I was also able to rule out vacuum leaks to the front of the car using a MityVac which can draw a vacuum and you can watch the gauge on the tool to see if it falls. If you hook it up to the black hose that goes into the hose barb fitting on the rear of the passenger side of the intake, that is the source for all vacuum to the HVAC and brake booster. You can pull a vacuum from that hose to rule out the whole front of the car. You would have to rotate the mode switch to each position one at a time and re-check the vacuum since it's possible that it only leaks in one position.
Andy Lien
VIN 11596 Jan 1982 build - owned since Nov. 2000!
Total frame-off restoration completed 2021-2023
Photography and Backpacking is life.
Was Fargo, ND
Now Kansas City
Posts: 33
DeLoreanGo is FAST.
The new idle motor did improve the Hunt-with-AC-On somewhat. It still hunted some, but I think because it is clean and new it responds faster - the result is the min and max of the hunt is reduced. Was ~500-1000 and would often stall, with the new motor it became ~600-900 and it even settles into 750, if you remain at idle for a moment.
At the 600 range the engine still does it's shaky "I'm gonna stall" dance when you snap the throttle closed from high RPMs - Even though it doesn't quite stall, I still didn't love that.
So I cheated and gave the curb idle a tweak. I would have used the (gasp) brass screws, but one of mine is snapped off.
The result is a bit high idle without AC: ~900 cold up to ~1000 warm. But ZERO threat of stalling with AC on: a nice solid 750.
I'll probably move the curb idle back down in autumn when I don't need the AC.
And that is good enough for now! Thanks everyone for chiming in!
Posts: 33
Someone talk me out of this shady idea for a temporary improvement
Wire up a relay to disconnect the idle microswitch when the AC is on.
Location: Leonardtown, MD
Posts: 8,885
My VIN: 03572
Just to let you know. The idle micro-switch cuts off the ignition advance. It does not stop the idle ECU from trying to control idle RPM. So are you disconnecting one wire from the idle switch? Removing power to the advance solenoid will turn advance on at idle.Someone talk me out of this shady idea for a temporary improvement
Wire up a relay to disconnect the idle microswitch when the AC is on.
Try the same test pulling the advance hose off the ignition distributor. (plug the hose so no vacuum leak).
Last edited by Bitsyncmaster; 08-10-2022 at 06:57 PM.
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Dave M vin 03572