after installing new lifters (which took care of my clicking problem) we are now trying to properly time the engine and fine tune my new 2150 (thanks gronk). base timing was set at 8 degrees. not 100% sure on idle rpm (no tach) but we managed to get it quite low. however, as soon as we hooked up the vacuum advance, it jumped to approximately 25 degrees at idle.
a trip around the block indicated that under load it advances itself so far it almost wants to die; it's necessary to back off the gas a bit to keep it running. there is no evidence of knocking or pinging and other than having to back off the gas, it runs smooth as eggs.
vacuum lines are set up properly, computer is bypassed correctly.
any thoughts? the vacuum advance seems to be far too high, but i am not sure what it should be. i didn't see anything of much help in the tsm, unless i missed it, nor was it mentioned in the timing article in the eaglepedia.
oh, and if anyone has some good mixture settings to try for the carb, that would be much appreciated. it's guesswork at this point.
thanks
Vac advance for dissy is ported correct.
it's from the port directly below the choke housing. is that correct, or did i hook it up backwards?
which port on the carb is ported vac?
(http://i383.photobucket.com/albums/oo276/capnmudguru/2012-02-07_00-10-17_569-1.jpg)
this is where it's currently hooked up...that was the only remaining port on the carb. the other was the elbow that leads to the air cleaner housing that was already capped when i got it. so by process of elimination i assumed this was the correct port as it's supposed to be directly from carb to distro if i am understanding this correctly.
we set base timing with vac advance unhooked and port on carb plugged. after half a pack of cigerettes a 20 minute drive home and pacing back and forth in the house the "falling on its face issue" just leads me back to the carb and just having to do some fine tuning (by the way gronk its a very nice piece and i shouldve definatly got one off you when i built mine lol) its not knocking pinging nutn purrs like a kitten. off the stop sign idle circut is fine and accelorator circut is fine but once the squirt burns off i had to get out of the pedal to keep it running, no biggie just some fine tuning needed. in park throttle responce is good and crisp, hold at approx 2000 and cracking it was one the money. we let it idle for at least a good 30 minutes or so and the temp guage didnt go above the colder end of the green line. wich that could be somthing else (had heat tho) it would start fine didnt knock even on shut down didnt diesel or knock. it just kind of weirded us out as soon as we plugged the line in it jumped that much.
just realized we forgot to disconnect the 2nd connector from the ignition box (2-wire)
could this be the source of our issue?
Did you bypass the plug to the ECM, it sounds like it's still controlling the spark.
You don't have the 3-wire plug on you ignition, do you?
What is your elevation? I will respond with correct timing deg for you. Note: To set timing, you must disconnect the vacuum to the distributor and make sure your choke is OPEN all the way and your fast idle cam has dropped so you are riding on the curb idle screw.
Set your timing at 650RPM and you will be good to go.
I'm assuming you have PCV hooled up and all manifold vacuum sources sealed tight.
there is the one with 3 wires going to it (orange wire from distro spliced to green where orange continues on the other side, if that makes sense) and 4 going from connector to box. the connections look just like they do in the diagram:
(http://www.amceaglenest.com/~iowaeagl/guide/images/b/bf/Finishednutter.jpg)
the other is the 2 wire connection.
gronk, all pcv is hooked up and all other vacuum is good. new caps on unused ports, new hoses on everything still in use. elevation according to wikipedia for clovis, nm is 4,268
Set timing at 12-13deg at 650ROM, choke open, engine warm, etc.
Use a vacuum gauge (manifold) to dial in the mixtre screws/timing after you reach a good base.
still need to disconnect and jumper 2nd connector to ignition box, correct? or is this not necessary with the n u t t e r b y p a s s ?
and what numbers are normal for the vacuum advance after it's hooked back up?
I am running an MC2150 off of a mustang. I have a GM HEI distributor which is run off of manifold vac (on top of manifold behind carb by the firewall). My carb only has i port on it which is for the choke pull off. My engine is timed to 8* BTDC with the vac line plugged. When I tried to run the car off of the ported vac the engine ran like POO! I switched the vac line to manifold vac and it smoothed out and stopped stalling. I have run the car this way for 2 years now. I had the vac line plumbed like this before I switched to the HEI (but with the MC2150) and the car still ran fine. Perhaps a different configuration in the carb?
im still not understanding why if we are in the correct port its pulling full vac advance at idle lol. does one of the wires that plugged into the distributor from the ignition box run to the computer some how? i know a newb question but i havent done anything with the stock ignition i went straight with the HEI
AMC used two setups, one with a separate wire on the ignition module - the yellow grommet ignition module and the one with the the ECM spliced into the wires between the sensor and the ignition module - with a blue grommet. The blue box is much more common, that's what the diagram above shows. Sorry if it was confulsing, but asking about unplugging the other connector made me wonder, the yellow box also has a third 3-pin connector that needs to be unplugged.
This is where the wiring should end up:
(http://www.justanswer.com/uploads/amedee/2008-10-06_220530_1.gif)
My understanding is that the start wire to the module retards the timing to make starting easier, but you need that plug. The other plug goes to the coil and to the sensor.
If the wiring is all clean and good, and nothing is plugged in backward then try a new module. The timing will jump around on a dying module, especially after 20-odd years.
Also, if you have advance at idle, you're on a manifold source or you have your idle set way too high. Factory setup used a ported source with no idle vacuum, but everyone had a setup at one time that used temperature switches and regulators between vacuum ports and the distributor. If you have any of that disable it until everything is working correctly.
First, I would try running with no vacuum to the distributor. Make sure it's disconnected at both ends.
Second, if it still feels like the timing is changing then look at the wiring and make sure it's correct. You may have a wire that is shorting out somewhere.
Third, I'd go get a spare box. Worst thing is you have a $25 spare part in case it goes bad. They may even be able to test your old one.
Anything other than the stock carter BBD non-n u t t e r e d should be runnning PORTED vacuum for the distributor. I can argue this all day but the simple fact is, you want the distributor to be non-advanced at idle (no hg to dist advance) and you want full advance at WOT (Wide Open Throttle)
If you have a setup working pulling manifold vacuum to the advance you are compensating for something failing elsewhere. I have tooled on too many Jeeps/Eagles to count and even when running great w/ manifold vacuum to the distributor and an owner that swars by it, It always runs better when I configure it properly and correct the other PCV/ntake/vacuum leak/issues under the hood.
Base Idle should be at 650 (720 for automattic's) and tining (with no advance) starts at 8-9deg and advances 1 degree (still with no vacuum to advance) for every 1000'increase in elevation. Example, I live at 6000' elevation, I set my base, non-advanced istributor to 14-15deg at 650RPM.
hooked up a vac gauge today and compared advance to vac pressure, and according to the distributor curves chart in the tsm we are dead on where we need to be.
now on to the other issue of fine tuning the carb. when stomping on the gas the engine still wants to die. checked the float and it looks good however i am pretty new to carbs so i am not sure where to begin looking or adjusting. i know you jetted it correctly, where else should i look?
lol we both read that tsm 3 or 4 times and the chart said at 13 (what we have at idle) inches of vac should have 24 degrees advance. it didnt specify what rpm though. were obviously missing somthing here :banghead: could that vac diaphram on the distributor be bad? could i even have the distributor 180 out? i think we can rule out the ignition box the numbers are consistant every time. in park the car purrs like a kitten throttle responce is great doesnt knock nothin. driving it is when we start to have a issue. cruzing around its great. tromp on it and after the squirt from acceorator pump burns off (aprox 2500 we havent hooked up the tach yet) it falls on its face and have to get out of it to keep it running... so if im correct its doing one of 2 things. its either running out of time or running out of fuel. it doesnt backfire when this happens or knock when its about to. if it is the carb i know its already jetted for alttude
The TSM isn't going to be dead accurate once you swap carbs/distibutors. The TSM referrs to the stock configuration.
Right now, what is your timing set at (in degrees) at 650RPM with the advance disconnected and the ported vacuum port capped?
Post some installed pics too if you can and I'll liik them over in detail.
Looking at the pic you posted earlier too and I don't see the choke wired to 12V. If the choke is not wide open with the fast idle cam dropped and running on the curb idle screw (properly set) you cannot set timing or idle properly. I might have looked at it wrong, but I just noticed that. The choke should open on its own within a few minutes of running.
I know I'm probably going to need help on this later so I'm just commenting to make sure this thread is easily accessed.
I have to ask if that's a Holley or Motorcraft. Holley sometimes has manifold vacuum at that port and Motorcraft is ported. It's easily checked with a vacuum gauge. It should be near zero at idle. If there is a port for the EGR valve, you can tee off that for vacuum advance.
Quote from: GRONK on February 08, 2012, 05:38:30 PM
Anything other than the stock carter BBD non-n u t t e r e d should be runnning manifold vacuum for the distributor. I can argue this all day but the simple fact is, you want the distributor to be non-advanced at idle (no hg to dist advance) and you want full advance at WOT (Wide Open Throttle)
If you have a setup working pulling manifold vacuum to the advance you are compensating for something failing elsewhere. I have tooled on too many Jeeps/Eagles to count and even when running great w/ manifold vacuum to the distributor and an owner that swars by it, It always runs better when I configure it properly and correct the other PCV/ntake/vacuum leak/issues under the hood.
Base Idle should be at 650 (720 for automattic's) and tining (with no advance) starts at 8-9deg and advances 1 degree (still with no vacuum to advance) for every 1000'increase in elevation. Example, I live at 6000' elevation, I set my base, non-advanced istributor to 14-15deg at 650RPM.
Should that read ported vacuum for non-nuttered?
Drrrrrrrrrrrrrr... Yes. Only the Carter BBD (non n u t t e r e d) runs manifold vac. Sorry about the confusion. I know what I meant :)
yabbut... we couldn't read your mind! LOL!
Quote from: GRONK on February 09, 2012, 12:38:51 PM
Looking at the pic you posted earlier too and I don't see the choke wired to 12V. If the choke is not wide open with the fast idle cam dropped and running on the curb idle screw (properly set) you cannot set timing or idle properly. I might have looked at it wrong, but I just noticed that. The choke should open on its own within a few minutes of running.
we had choke tied open for timing setting just to be sure, not in picture though. the port the distributor is hooked to increases vacuum as throttle opens. at this point i am thoroughly confused - is that ported or manifold? sorry to be so noobish.
idle screw you are referring to is on the back by throttle linkage correct?
hooked up a tach. idle rpm is 650, 8* base timing w/o vacuum hooked up. choke open. pulled computer completely today, definitely not a factor.
If the wiring wasn't bypassed, you could still have a problem. How about the knock sensor? It's tied directly to the ignition box AFAIK.
wiring was bypassed correctly. we finally figured out there is an adjuster screw in the vacuum advance itself and we are much better.
we got it adjusted to whare we have about 10 degrees at idle (with the vac plugged in) and peaks out about 35 at 2000 rpm. and we were actually able to put some miles on it too! we drove it from his house to mine about 15-20 minutes away. car felt like it was surging and still falling flat mid range almost as if it was working too hard definatly wasnt as bad as it was before lol. got it in my drive and popped the hood and the exhaust manifold had a slight glow to it. temp barley got into the green line... ive got another ignition box here out of my 84. could it be the box thats causing the surging? as far as the glowing goes too lean? idle screws are about a full turn from closed. they were initially set at 2. car definatly doesnt load up any more lol.
Quote from: projectscreamingeagle on February 10, 2012, 03:04:33 AM
we got it adjusted to whare we have about 10 degrees at idle (with the vac plugged in) and peaks out about 35 at 2000 rpm. and we were actually able to put some miles on it too! we drove it from his house to mine about 15-20 minutes away. car felt like it was surging and still falling flat mid range almost as if it was working too hard definatly wasnt as bad as it was before lol. got it in my drive and popped the hood and the exhaust manifold had a slight glow to it. temp barley got into the green line... ive got another ignition box here out of my 84. could it be the box thats causing the surging? as far as the glowing goes too lean? idle screws are about a full turn from closed. they were initially set at 2. car definatly doesnt load up any more lol.
Based both on the hot manifold and the surging, I'd suspect the box. Misfires and unburnt fuel/air mix in the exhaust can overheat the manifold.
But first, check all your spark plugs and see what they look like, that will tell you something right now.
we've got a known good box that will be swapped in today. i will check plugs as soon as i get home.
This is a great thread. My Spirit had Gronk's kit on it when I bought it. It ran terribly and I never got it straightened out properly before stealing that engine for my MPI SX4.
One thing I did find was that the distributor hold down clamp was never tightened by the previous owner. Its embarrassing how long it took me to figure that out. The distributor was free to vibrate and spin freely. That is a simple reason your timing would change value randomly.
Could also be a leaking intake manifold, bad PCV valve, bad plug wire, mis-config on plug wires, etc.
pcv valve is good. we sprayed all around looking for leaks and found none. could be plug wires, but they were changed when i did tfi upgrade. i've heard they can be bad out of the box. just a simple resistance check, or is there a better test?
at this point my list of suspicions is:
bad ignition box
bad plugs and/or wires
still need to dial in proper vac advance but i think that will be easier once electrical issues are ruled out/eliminated
The only time I have ever seen glowing red exhaust manifolds is when a friend put the distributor in 180* out on an Olds V8 - we drove it for quite a few miles before it got real doggy , got out and opened the hood and they were glowing cherry red...................not saying that's your issue , just commenting.
How did the car run before the carb swap? In my experience a glowing exhaust manifold has typically been a timng issue. A couple possibilities could be either the outer ring slipped on the crank damper or possibly your timing chain might have jumped a tooth.
car didn't run great before carb swap. however, we have some findings to summarize:
1. assuming anything is supposed to be easy is a bad assumption.
2. having a tach is very important -- idle by ear is only so accurate. (however, we were VERY close.)
3. setting timing properly by altitude is vital.
4. there is a vacuum adjuster screw in the distributor. it needs to be set up to get proper advance.
5. glowing exhaust manifolds are not good. in our case, this indicated that we were running far too lean.
6. church or other vacant facility parking lots make excellent testing grounds to avoid irritating the neighbors.
7. vacuum gauges are underrated. go get one.
8. constant :censored: jokes improve morale.
9. removing the computer after it's bypassed (and the associated wiring "brain stem") is an extremely liberating feeling. (don't forget to re-connect the yellow wires going to the 2-wire connector on the ignition box or you won't start.)
10. seafoam is amazing. it really does work.
11. paint works excellent to identify timing marks.
12. a/c hoses and heater hose should be removed if possible to pull valve cover with ease.
13. removing the head and lifters and reinstalling head and lifters was far less frustrating than these timing issues. and easier. and even though the tsm does not state that priming is necessary, it is an excellent idea. a priming "tool" can be created using an old distributor shaft and a drill (be sure to rotate in the direction of the engine and DON'T hit the cam gear.)
14. there is no such thing as an overabundance of assembly lube.
15. keep face and limbs away from carburetor while timing. backfires can hurt.
16. speaking of things that can hurt, exposed wiring on the coil to distributor can bite pretty hard. it's funny as a spectator, though.
17. swivel sockets are amazing and will save your sanity.
18. don't drop intake bolts onto your motor mounts. this is a frustrating area to retrieve them from.
i am sure there were plenty other excellent lessons. if anyone would like any clarification on any of the above points i will definitely elaborate.
final note of what we did:
-installed new lifters (this was the easy part)
-timing set at 12* base (due to altitude -- gronk explained this excellently earlier in the thread)
-carburetor mix set 2 turns from all the way in, fairly rich (may adjust later -- seems to work well for now)
-distributor vacuum advance adjusted at least 10 turns from initial setting (set to carter settings, but we are unsure of original/specific settings)
-idle set at 750 rpm
-choke still needs to be properly set up, we are running it tied open at the moment
-new spark plugs -- old were disgusting and covered with trash, even though they were fairly new. buildup due to poor performance with the carter and our various attempts at tuning. highly recommend changing, this will make things easier. these were what was causing our surging.
-computer completely removed -- there is a yellow wire that runs to 3 or 4 wires spliced together that needs to be hooked up to the ignition box if you remove all the wiring. this will be fairly easy to identify as it is the only bundle like that.
-installed aftermarket tach. will likely replace at some point with something mounted inside the dash, like the clock -> jeep tach conversion thread.
we still need a little fine tuning, mostly with the vacuum advance -- this involves a LOT of trial and error, even after timing is properly set. there were a few good threads we found on some jeep forums that posted distributor curves and other such information (links to follow later).
at this point the car is now definitely drivable and the performance is definitely above the carter's. carb conversion is, of course, highly recommended. new lifters were a great improvement as well, although we did not replace the cam as most people recommend -- i will be rebuilding this motor at some point in the future and changing out the cam/matching lifters when that happens.
hopefully this helps out some of you that may have run into these issues or have hit a roadblock. any questions or clarification needed, just ask.
I would like a video of #15 and #16 : ) - #10 is so true - great stuff.
Sounds like you have more of the bugs worked out - great percervierence (sp) .
Good story too : ).
One thing I forgot to mention that occasionally plagues AMC 6 cyls (until the 4.0L came along) and that is cam walk. They put in a cam button from the factory to overcome that trouble. It's an "easy" add-on to the 4.2L with the cam bolt and timing cover from the 4.0L (and a miteaswell timing set)