Uneven idle on my 73 440.... Any ideas?

[73 T&C]

Gentlemen, I need a little help please....

I have a 440 in my 73 Town&Country with an uneven idle and I've run out of ideas as to what it may be.

Engine fires up cold or hot on first turn of the key with proper starting procedure (one pump and hold part open when cold and hold open part way when warm). Engine is smooth off idle with a little gas and at slightly higher rpm higher rpm (too high for idle).

Current uneven idle occurs when warm or cold. Engine holds uneven idle at 650 to 700 rpm. Idle is irregular in its unevenness as in not a regular miss.

Car has about 63000 miles.

Here's what I've done so far.....

First, it is in proper tune with new correct plugs and nos Mopar suppression wires.

All vacuum hoses are correctly routed and I checked them all for leaks. OSCA valve is working and not leaking as is vacuum advance, EGR, thermal valves on block and radiator.

Checked the brake booster... No leaks.

New nos ballast... No change.

Timing is checked and within spec at 8.5 degrees BTC.

I rebuilt the thermoquad. No problems found.

Any ideas? What should I check.

Thanks.

 

[Pete Kaczmarski]

If the car did this before all of the things listed were done....does it have stock distributer? if so check the coil for proper connections and output. How dors the act act while driving and under load and full throttle. Check and let us know.

 

[commando1]

Your rebuilt TQ still needs to be fiddled with to smooth out the idle.
I had the identical problem.

Step one: Make sure secondary air door is adjusted to be fully closed at idle.
That's the easiest one and then we go from there.

 

[73 T&C]

If the car did this before all of the things listed were done....does it have stock distributer? if so check the coil for proper connections and output. How dors the act act while driving and under load and full throttle. Check and let us know.

Yes car did this before any work. but didn't pull as strong as it does now after the tune up.

Distributor is stock unit.

If it helps, all the above we're done about 3 months ago over a few weeks trying to chase this issue down. Will check connections and output at coil and report.

Car pulls like a freight train under load, no stumble off idle, puffs a little smoke at initial full throttle stomp. Very responsive. No missing, love that full throttle kickdown sound through the thermoquad. Very distinctive.

 

[73 T&C]

Will do and report. Honored to have your help....

I checked the secondary door at rebuild and door opens and closes as it should. Adjusted it to open under heavy load with spring tool to open a bit slower as it was running a bit lean on initial full throttle ( very slight bog) but only a touch more tension.... Worked great.

Car is heavy heavy heavy and needs moooooooore gas

 

[commando1]

Will do and report. Honored to have your help....

I checked the secondary door at rebuild and door opens and closes as it should. Adjusted it to open under heavy load with spring tool to open a bit slower as it was running a bit lean on initial full throttle ( very slight bog) but only a touch more tension.... Worked great.

Car is heavy heavy heavy and needs moooooooore gas

Ok. Good. Next step.
Sadly from here on it becomes a real pain in the *** because the car has to come off each time because all the next steps are internal and the only way to get at the internal stuff is by disassembling it.
I think (only think!) your stock primary jets are .101". You have to check to be certain.
It actually may be too rich. The idling going up and down may be from loading up and then burning off.

http://quadrajetparts.com/carter-ca...jets-rods-thermo-quad-jets-c-158_161_165.html

I ended up using .091".

 

[73 T&C]

Your rebuilt TQ still needs to be fiddled with to smooth out the idle.
I had the identical problem.

Step one: Make sure secondary air door is adjusted to be fully closed at idle.
That's the easiest one and then we go from there.

Door closes and remains closed at idle.

 

[73 T&C]

It actually may be too rich. The idling going up and down may be from loading up and then burning off.

i think that I may not have described the unevenness. The engine runs uneven in that it shakes irregularly on its mounts. It will run smooth for a bit then shakes, then smooth then shakes shakes, settles, shakes, settle shake sake shake all in fairly quick succession.

I will try changing main jets as you suggest since it makes sense. I'll also get some preparation h because your right...it going to be a pain in the ....

When you made the reduction in jet size did you change the metering rods in parallel? Do you recall what the steps in size you made to get to the final .092?

Assuming that the jets are .101 won't increasing the base metering rod dim accomplish the same leaning of the mix at idle without changing the of power mix?

Let me know.

 

[73 T&C]

If the car did this before all of the things listed were done....does it have stock distributer? if so check the coil for proper connections and output. How dors the act act while driving and under load and full throttle. Check and let us know.

Checked the coil leads and they were tight. Output was good. Swapped a new one to check.... Problem persists. Changed the ballast as the back was letting the resistor coils show.. Problem persists.

 

[commando1]

i think that I may not have described the unevenness. The engine runs uneven in that it shakes irregularly on its mounts. It will run smooth for a bit then shakes, then smooth then shakes shakes, settles, shakes, settle shake sake shake all in fairly quick succession.

I will try changing main jets as you suggest since it makes sense. I'll also get some preparation h because your right...it going to be a pain in the ....

When you made the reduction in jet size did you change the metering rods in parallel? Do you recall what the steps in size you made to get to the final .092?

Assuming that the jets are .101 won't increasing the base metering rod dim accomplish the same leaning of the mix at idle without changing the of power mix?

Let me know.

I never had to change the metering rods. From what i could determine from the more learned than myself, the metering rods were not a likely suspect. As it turned out, they were right at least in my case. Those metering rods are a real PITA in that many times during reassembly, they fall off the linkage and you can't see it. I had to bend the linkage slightly to make sure the rods stayed on.

I bought the leanest set of jets possible. I did that because I'm cheap and impatient and didn't want to buy a zillion sizes one step at a time. I have a set of '# Drills', #43 - #35. My plan was to start at the leanest jet available and drill up to where the plugs had the perfect ash brown tips after a full throttle blast and a quick shutdown. Fortunately I only had to go one step up which saved me a ton of R&R's. I said .092 earlier. I meant .093.

BTW, make sure the your acc. pump arm "S" link is not on backwards and the connector rod to it is in the correct hole to get full throw.

Lastly, what finally did put the cherry on top of the ice cream was when I drilled out the idle enrichment circuit one step larger. I never heard of anyone or reading anywhere to do that but I gave it a WTF and * BANG * , 650 RPM rock steady!!

 

[commando1]

Or you could just throw on Bob's Edelbrock....

 

[1978 NYB]

Edelbrock 1411 electric choke (750 CFM). Right out of the box and bolt on. No adjustments necessary on mine (Edelbrock 1406). I have 9000 miles on it now and haven't made a single adjustment. Of course you'll need a few low cost accessories to hook it up. I even have the cruise control hooked up. I know very few people that can keep a TQ working right.

http://www.jegs.com/i/Edelbrock/350...&cagpspn=pla&gclid=CLu7haLhsbYCFQdU4AodlmoApg

 

[commando1]

I know very few people that can keep a TQ working right.

So, who are the other two?....
LMAO

< Sent from my tablet >

 

[73 T&C]

I know very few people that can keep a TQ working right.

Still planning to be on that small list of few for now. Thanks for the advice, source and pictures of your great install...... If all else fails.... Then maybe.

Ok I'll admit it. It's a weird fetish I have for these particular wagons.

This ain't my first rodeo with a 73 440. I learned a lot on my parents town and country when I first started driving under the tutelage of a mechanic from the local Chrysler dealer named Martin Armstrong back in the late 70's. His specialty was carbs and especially thermoquads. He was known in the shop as one of their best. He was twenty eight and moved away from a bad marriage before I could learn too much. So I've seen when thermoquads work properly and have had similar experience on my last 73 440 when a few years back I bought a wagon matching my parents...

This current one is a replacement to that last one I got three years ago because that T&C developed bad rust in the cowl, floors and tailgate.....but not before it helped me build my current house..... I would take it to the lumberyard and the guys in the back would fill it to the roof. when they asked if i could make it i would start it up and the dealer installed load leveler would right the car right before their wide eyes.... too much fun. That car i kept running as smooth as a new rolls royce. (worked on one of those for a friend)

I was missing it when this current pristine example crossed my path. My wife calls it my " Midlife Chrysler" .... My girls call it "Das Vagon" and especially hate it when I take it to drive them to school. Maybe it's because I pull up with all the windows down playing the oldies on the factory five speakers kinda loud....

I also have a 73 roadrunner with a thermoquad topped 340 that now runs like a top. In the middle of a restoration of that one for the second time (cowl rust on this one too). Mores info on that car on forbbodiesonly under 73runner name. Getting pictures together for its own thread now.

Other cars I've had include some deusies including: 76 Seville, two 73 satellites, 75 eldorado, 71 Mark III, 74 Citroen SM, 96 Deville, two Jaguar XJS' 88 and 89, a 97 BMW M-3, 01 Bmw740i sport, 04 and 08 BMW 750li's all were new or very low mileage that I got , restored and flipped..... Or was allowed to keep by the boss as long as I give her a cut of the sales....

I've ordered a few different jets and rods to give it the commando treatment this Sunday. Also want to check the threads in the bowl for leaks under the jets.... Would also yield a rich uneven condition that commando1 is after... Wouldn't be the first time a jet gets over tightened either.... Sometimes I don't know my own strength and who knows what the last guy did...

So hopefully, commando 1 will be able to add one more to his list of two... Besides himself.

 

[73 T&C]

I bought the leanest set of jets possible. I did that because I'm cheap and impatient and didn't want to buy a zillion sizes one step at a time. I have a set of '# Drills', #43 - #35. My plan was to start at the leanest jet available and drill up to where the plugs had the perfect ash brown tips after a full throttle blast and a quick shutdown. Fortunately I only had to go one step up which saved me a ton of R&R's. I said .092 earlier. I meant .093.

BTW, make sure the your acc. pump arm "S" link is not on backwards and the connector rod to it is in the correct hole to get full throw.

Lastly, what finally did put the cherry on top of the ice cream was when I drilled out the idle enrichment circuit one step larger. I never heard of anyone or reading anywhere to do that but I gave it a WTF and * BANG * , 650 RPM rock steady!!

thanks commando. All good advice. Rock steady is as it should be on these mills. Liked the wtf move on the idle circuits. May start with that.

Accel pump arm link in as per pix in "da good book o Mopar".

Already pulled the #1 plug... Not the perfect light brown ash.... A little sooty.... Running a little rich. Uneven might also be a leak/crack under the jet around jet thread inserts.... Getting a phenolic base cleaned up tonight already ... just in case. ...Hoping we geterdone Sunday.... If I get my jets in time.

Btw. How much does that new yorker weigh? Just curious for jetting purposes... I can look it up but am sure you know off the top of your head.

thanks.

 

[1978 NYB]

So, who are the other two?....
LMAO

< Sent from my tablet >

Mike (Newp) and you............that's it. I'm sure there are others.

 

[commando1]

Btw. How much does that new yorker weigh? Just curious for jetting purposes...

Das Book says it's almost 48 hundred pounds.

Mike (Newp) and you............that's it. I'm sure there are others.

I was being facetious. VERY facetious. I have no idea WTF I'm doing when I dive into the bowels of that Rube Goldberg device. I'm just "Monkey See -Monkey Do" with the manuals next to me and watching the YouTube videos.

 

[1978 NYB]

Das Book says it's almost 48 hundred pounds.


I was being facetious. VERY facetious. I have no idea WTF I'm doing when I dive into the bowels of that Rube Goldberg device. I'm just "Monkey See -Monkey Do" with the manuals next to me and watching the YouTube videos.

Since having a brand new 1973 Challenger with a TQ it's been downhill with those carbs. I had 2 replaced under warranty....ended up with a Holley then and Eddie's now. Of the two, the Holley was the easiest to work on. No complaints from me on the Eddie's.

Newp, Mr.C., and you have had some nice results with TQ's.

 

[monaco75]

Stan, do you know/have any good books on rebuilding, tuning the thermoquad?

I found this one on amazon-
http://www.amazon.com/Carter-Carbur...r=1-1&keywords=how+to+rebuild+thermoquad+book#_

Think I'll be getting one, along with a big block rebuild book for my rebuild.

 

[73 T&C]

Das Book says it's almost 48 hundred pounds.


I was being facetious. VERY facetious. I have no idea WTF I'm doing when I dive into the bowels of that Rube Goldberg device. I'm just "Monkey See -Monkey Do" with the manuals next to me and watching the YouTube videos.

I got the facetious part.... My monkeying is similar.

Das Vagon weighs in at a petit although buxom 5600lbs not including driver and a full tank of gas. Figure an even 3 tons....

Leaned out the idle circuit a bit (1/8th turn in) on both sides one at a time....

right side no change....

left side a little better... Fluctuation and unevenness still there but less so by about 1/2. Rpm now holds at between 650 and 675...... I think we're on the right track.

Ordered new needles with jets just in case the previous repairs done before I got it were too aggressive in the "cleaning". I remember that the needles looked a bit too shiny in some spots and I think it was the left one at that.

Planning to start at .097 to start with new needles that match original OEM specs.

hope I get the parts in by tomorrow or it will have to wait till next week.

working on the chronometer today..... After 40 years of service it just stopped.... Got one from a 74-76 imperial/new yorker with the same internal mechanism but different case on eBay for 10 bucks plus shipping. Had it up and running for two days and it kept perfect time for two days....

I love it when everything works perfectly and it drives me nuts when it doesn't.

My wife says I'm an anal retentive sob that loves his cars more than her.... I tell her no dear....its just that I can fix them when they don't work right.... and they show immediate appreciation for my efforts.......

Javier Salman aka 73T&C