Tropical storm today with absolutely torrential rain today. Looking to still get out to this afternoon....
New to me 78 NYB on its way but please Don't tell my wife
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commando1
Old Man with a Hat
"We need the rain"... 
cm23uoc
Old Man with a Hat
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But it's a dry rain.
Shop was closed this weekend due to some major work on that 55 Mercedes in the background. Component painting all weekend had all the cars out to protect them from dust and give room for the scheduled work..... And kept me at home.
Meantime, I’ve been kept busy by my wife, and when she’s not paying attention, working on putting together some research on the lean burn to help me sort through it.
More out of intellectual curiosity than an attempt to keep it, the second generation of Chrysler’s Lean Burn in this ‘78 is the original ignition control system for the car’s engine and should be capable of making it run satisfactorily. It’s never going to be either a high performance or overly powerful engine.... At least, not without changing a lot in and on it.
But because it is so maligned in the hobby, I’m not going to waste the effort to do a separate step by step of the system on a separate thread like I did on the ATC II.
This will be more of my own documentation of the troubleshooting I’m doing for future reference just like the rest of this thread.
First thing I’m doing is reviewing this thread for all the work done that could have influenced the current sad state of operation the car is in now.
Got the car in FEB. 12th and by the 17th had the carb out for rebuilding. The plugs, wires, cap and rotor were all changed just prior to the carb work. Additional work done to that point was: new battery, recoring of the radiator, top and bottom hoses for same, water pump and thermostat.
Car came in starting well but stalling upon any movement of the throttle.
Accelerator pump was not providing any gas at all upon movement of the throttle. Hence, carb rebuild.
Result: car fired up and off idle stall much improved. Stall was now an on power hesitation and not a stall. I decided to set this issue aside for later as it was enough to get the a/c compressor turning which was where my attention became focused.
Leak in drivers side carb float bowl repaired on March 1st. Car taken out to lunch on March 8th. No change in operation noted. Still a slight hesitation after initial warm up that became less of a problem as the temp got closer to normal operation temp. Engine ran smooth.
Second time into the carb occurred after leak developed on passenger side float bowl similar but smaller than the previous one on the drivers side on April 8th. Car running well otherwise up to then.
Repaired ground strap on firewall to block at this time. Repair for carb went a bit afoul and car developed running problems after that. Problem presents as a bad air leak. Found several vacuum leaks (one major and several very very minor) and repaired in attempts to correct on May 6th. Car still running shitty.
Condition as follows: car starts quickly and is initially smooth. Starting procedure, 1/2-3/4 pump of gas to prime cold and set fast idle and choke. Choke fully engages as does fast idle cam. As soon as choke starts coming off car develops slight and intermittent missing. Closing of the choke manually makes it better. Driving it stumbles badly and can stall as it warms up. When engine reaches full operating temp, problem diminishes. But engine feels much weaker and will not spin over 3000 rpm regardless of throttle position. Engine has also developed a bad backfire if the throttle is opened up suddenly and upon release of open throttle.... until engine warms up.
Started checking lean burn for faults found a few and corrected them on May 16th. Car runs a bit better and starts easily cold or warm but backfires less than before and has intermittent irregular stumble. Started getting a bit frustrated and I retarded the timing to get it running better..... knowing I am addressing a symptom temporarily and not solving the problem. Somehow, I’ve knocked a decently operating engine down to this. Back to square one.
Meantime, I’ve been kept busy by my wife, and when she’s not paying attention, working on putting together some research on the lean burn to help me sort through it.
More out of intellectual curiosity than an attempt to keep it, the second generation of Chrysler’s Lean Burn in this ‘78 is the original ignition control system for the car’s engine and should be capable of making it run satisfactorily. It’s never going to be either a high performance or overly powerful engine.... At least, not without changing a lot in and on it.
But because it is so maligned in the hobby, I’m not going to waste the effort to do a separate step by step of the system on a separate thread like I did on the ATC II.
This will be more of my own documentation of the troubleshooting I’m doing for future reference just like the rest of this thread.
First thing I’m doing is reviewing this thread for all the work done that could have influenced the current sad state of operation the car is in now.
Got the car in FEB. 12th and by the 17th had the carb out for rebuilding. The plugs, wires, cap and rotor were all changed just prior to the carb work. Additional work done to that point was: new battery, recoring of the radiator, top and bottom hoses for same, water pump and thermostat.
Car came in starting well but stalling upon any movement of the throttle.
Accelerator pump was not providing any gas at all upon movement of the throttle. Hence, carb rebuild.
Result: car fired up and off idle stall much improved. Stall was now an on power hesitation and not a stall. I decided to set this issue aside for later as it was enough to get the a/c compressor turning which was where my attention became focused.
Leak in drivers side carb float bowl repaired on March 1st. Car taken out to lunch on March 8th. No change in operation noted. Still a slight hesitation after initial warm up that became less of a problem as the temp got closer to normal operation temp. Engine ran smooth.
Second time into the carb occurred after leak developed on passenger side float bowl similar but smaller than the previous one on the drivers side on April 8th. Car running well otherwise up to then.
Repaired ground strap on firewall to block at this time. Repair for carb went a bit afoul and car developed running problems after that. Problem presents as a bad air leak. Found several vacuum leaks (one major and several very very minor) and repaired in attempts to correct on May 6th. Car still running shitty.
Condition as follows: car starts quickly and is initially smooth. Starting procedure, 1/2-3/4 pump of gas to prime cold and set fast idle and choke. Choke fully engages as does fast idle cam. As soon as choke starts coming off car develops slight and intermittent missing. Closing of the choke manually makes it better. Driving it stumbles badly and can stall as it warms up. When engine reaches full operating temp, problem diminishes. But engine feels much weaker and will not spin over 3000 rpm regardless of throttle position. Engine has also developed a bad backfire if the throttle is opened up suddenly and upon release of open throttle.... until engine warms up.
Started checking lean burn for faults found a few and corrected them on May 16th. Car runs a bit better and starts easily cold or warm but backfires less than before and has intermittent irregular stumble. Started getting a bit frustrated and I retarded the timing to get it running better..... knowing I am addressing a symptom temporarily and not solving the problem. Somehow, I’ve knocked a decently operating engine down to this. Back to square one.
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Lean burn research besides FSM.
The Chrysler Lean Burn engine control system
| Repair Guides | Emission Controls | Lean Burn System | AutoZone.com
All of these have one thing in common.
They all say rule out the typical ignition and carb issues before digging into the Lean Burn.
That makes sense and so that’s where I will start.......again.
Looking at the related events and work in the previous post, two things come to mind as possible causes for the current problems.
1) I warped or otherwise ruined the carb on the last rebuild (not my favorite) or
2) I miss connected the lean burn ground or broke the ground wire internally to it when reconnecting the ground strap. Not likely.
My motto... when in doubt, start with the simple **** first.
I checked the ground wire but haven’t checked continuity through the harness. I’ll start with that first. I have a few theories so far regarding that I want to check that make sense with what I’m seeing.
Don’t worry, I’ll get it!
The Chrysler Lean Burn engine control system
| Repair Guides | Emission Controls | Lean Burn System | AutoZone.com
All of these have one thing in common.
They all say rule out the typical ignition and carb issues before digging into the Lean Burn.
That makes sense and so that’s where I will start.......again.
Looking at the related events and work in the previous post, two things come to mind as possible causes for the current problems.
1) I warped or otherwise ruined the carb on the last rebuild (not my favorite) or
2) I miss connected the lean burn ground or broke the ground wire internally to it when reconnecting the ground strap. Not likely.
My motto... when in doubt, start with the simple **** first.
I checked the ground wire but haven’t checked continuity through the harness. I’ll start with that first. I have a few theories so far regarding that I want to check that make sense with what I’m seeing.
Don’t worry, I’ll get it!
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70NEWYORKER
Well-Known Member
If you have not yet done it, put a dwell meter on it. Make sure dwell is steady. I forget the dwell angle, but it should be near 40 or greater...and steady!
Thanks and correct. Rock steady.
Tropical storm/depression blew over enough to be outside this afternoon.
Went by shop..... still closed and full of cars.
Had to repair a broken bolt on the power takeoff coupling on the Citroën SM. Sucker sheared off leaving part of the bolt in the accessory drive wheel adapter which I would have to extract. So....I just got down to business and got to it. I knew it would be a pain in the *** to do and I was right.
My friend Dave Hume in Kentucky sent over a replacement set of bolts for me to use. We trade parts and stories.... great guy. He’s the Regional expert on Citroën’s and Maseratis in the SE.
Power coupling detached. Similar to BMW and Mercedes drive shaft couplings. Bolts to the adapter neck down to form shoulders to sit flat on the plate. I use two hose clamps to pre-load the rubber coupling in order to remove and insert the bolts in their proper alignment.
Close up of what happens if the bolt comes lose... it starts to wobble off the plate and fatigue shears it right off.
Tried a bolt extractor kit I had... no go
Ended up carefully drilling the bolt out and then.....
Using a tap to catch it and thread it through. That’s not a helicoil on the vice... that’s the threads of the sheared bolt.
3 hours later.., all done.
Since Jeff recently asked to see it... here she is at a show last summer at a Lamborghini/Maserati dealer in Fort Lauderdale.
Advert picture of the SM... ain’t she sexy??
Went by shop..... still closed and full of cars.
Had to repair a broken bolt on the power takeoff coupling on the Citroën SM. Sucker sheared off leaving part of the bolt in the accessory drive wheel adapter which I would have to extract. So....I just got down to business and got to it. I knew it would be a pain in the *** to do and I was right.
My friend Dave Hume in Kentucky sent over a replacement set of bolts for me to use. We trade parts and stories.... great guy. He’s the Regional expert on Citroën’s and Maseratis in the SE.
Power coupling detached. Similar to BMW and Mercedes drive shaft couplings. Bolts to the adapter neck down to form shoulders to sit flat on the plate. I use two hose clamps to pre-load the rubber coupling in order to remove and insert the bolts in their proper alignment.
Close up of what happens if the bolt comes lose... it starts to wobble off the plate and fatigue shears it right off.
Tried a bolt extractor kit I had... no go
Ended up carefully drilling the bolt out and then.....
Using a tap to catch it and thread it through. That’s not a helicoil on the vice... that’s the threads of the sheared bolt.
3 hours later.., all done.
Since Jeff recently asked to see it... here she is at a show last summer at a Lamborghini/Maserati dealer in Fort Lauderdale.
Advert picture of the SM... ain’t she sexy??
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78Brougham
"Chump"
What do you think caused it? Loose bolt, not hardened bolt, or out of balance some where?
Could be too much monkey strength tightening it the first time (2 years ago... not likely), not tight enough and just backed out. Just worked itself loose. Who knows. The rest were good and tight.
Couldn’t resist.
Went to the shop... I like it when it’s quiet.
Swapped the spark computer after verifying ground to it and a few other things.
Started right up. Not smooth in gear at idle but... no backfire, no hesitation off the line.
Need someone to stand on the brakes to set the timing... we’ll see if that can cure the rough idle.
Meantime: enjoyed a night drive.
Went to the shop... I like it when it’s quiet.
Swapped the spark computer after verifying ground to it and a few other things.
Started right up. Not smooth in gear at idle but... no backfire, no hesitation off the line.
Need someone to stand on the brakes to set the timing... we’ll see if that can cure the rough idle.
Meantime: enjoyed a night drive.
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commando1
Old Man with a Hat
I didn't know it was that Citroen. I simply must drive it. Once. Before I die.
Thank you, she's a beauty. I only ever got to poke at one and only just a little bit... what strange and wonderful machine.
As long as you can drive stick... she’s waiting.
ROTFLMAO
More background research on Spark Control Computer... pretty bleeding edge of technology at the time....
Unit Ignition System
CAR FORUM: Lean Burn system shows sign of age
Unit Ignition System
CAR FORUM: Lean Burn system shows sign of age
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commando1
Old Man with a Hat
For the first time, I actually want to go to Boca Raton.
What’s in Boca????? I’m in Coral Gables about 2 hours south of there.
Let’s you Jeff and I meet somewhere in the middle for lunch and you can buy us both a beer and then we can buy you one.
Tried the cruise control last night. It was NFG. Add to the list. Compared to the ATC II and The Lean Burn system, it should be easy. I’ve got a couple of spare parts and units... somewhere.
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