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View Full Version : Motorcraft/Autolite 2100 - SOLVED!


Captain Ledd
04-18-2008, 11:49 PM
does anyone have experience trying to tune these things?

Now I have the firing order right, new throttle cable (moves nice and smooth), and got everything plugged and adjusted.

Adjusted the idle mixture screws out to get about 18 inches of vacuum, turned them back in to just get the vacuum to fall back off and then turned them back out 1/4 turn. Also adjusted the accelerator pump linkage to the lowest slot on the connector arm thingy so it dumps the least amount of fuel in - only very recently, the below is with it at the 3rd of 4 holes from the bottom.

now for what it's doing:

It has no power, as in it feels like my 4 cylinder has more power (I did get to drive it around the yard today). when you try to throttle up (no load on the engine) it coughs, sputters, backfires (vacuum gage is of course going ballistic), until it's up to speed, and then runs perfect, flawless even, even up into the fairly high RPM's. Under load it's even worse. I stalled out almost every time in first gear in the T18 (4.56 gears and 33's). under load even when it's up to speed it has very little power it seems, and coughs alot.

I have no idea what else to adjust or tune on this thing. it came off a very well running and surprisingly strong 289 and never sat long at all, so I don't think it needs rebuilt. I know the person I got it from too so I know it wasn't manhandled.

The only other thing I can think of is since I know it's been rebuilt, had the HO cam put in it, if it might need premium? I don't think it'd do that though.

I almost thought the intermittent miss that has now cleaned up was a stuck or sticky valve. Most of that has since completely cleaned up except for when gas is being added.

Timing: I have no idea. it seems to run the best where I have it, I have a yellow paint line that doesn't seem to line up with much. there are 3 things that it could line up with: a hole that looks like a pointer in it, a "C" chunk out of the bracket - middleish, this is where is seems to tun sorta best around but not lined up with, and an actual pointer allll the way at the end (everything described is on passenger side of engine, from left to right)

I think that covers it..

Grandman
04-19-2008, 12:00 AM
From idle if you step on the gas it dont pick up , yet it is hitting on all eight when it does come up on rpms ?

If so it sounds to me like the accelorator pump is not pumping fuel , once the idle comes up its pulling fuel on vacuum . Take a look in the carb ( motor shut off ) pump the accelerator it should put a decent spray of fuel in . If not the little acelerator pump is shot . They were often a problem on ford carbs .

There should be 2 sprays one on each side of the carb .

If your not sure its firing on all eight when it is dead cold start it up for just 2 or 3 minutes . Check the exhaust manifold to see that it is equally warm at each port . If there is a port or two not warmed up your not hitting on those .

Captain Ledd
04-19-2008, 12:07 AM
From idle if you step on the gas it dont pick up , yet it is hitting on all eight when it does come up on rpms ?

If so it sounds to me like the accelorator pump is not pumping fuel , once the idle comes up its pulling fuel on vacuum . Take a look in the carb ( motor shut off ) pump the accelerator it should put a decent spray of fuel in . If not the little acelerator pump is shot . They were often a problem on ford carbs .

There should be 2 sprays one on each side of the carb .

If your not sure its firing on all eight when it is dead cold start it up for just 2 or 3 minutes . Check the exhaust manifold to see that it is equally warm at each port . If there is a port or two not warmed up your not hitting on those .

Actually we did almost all of this up to temp, 190°F or just below. By the time we got the blasted screws adjusted.

Though I did find it curious that the protective film that is supposed to burn off my headers, is only really flaking on the #5 cylinder.

I'll run back out now to see if the accelerator pump is in fact spraying fuel into the carb. I toned it down because I thought it might be dumping too much fuel in.

Captain Ledd
04-19-2008, 12:18 AM
Accelerator pump is working fine, even at the lower setting it's spraying in quite the little blast of fuel. Pretty even on both sides too.

Grandman
04-19-2008, 12:21 AM
My point with the headers , which makes it easier is when it is dead cold you can tell if it is on all eight , Headers only need to run a minute or less to warm up the pipe . at the port . Just making sure you understand what im saying .

Ill assume you did that , no question its on all 8 then , well then . HMMMMM id really need to listen to it .

Captain Ledd
04-19-2008, 12:24 AM
My point with the headers , which makes it easier is when it is dead cold you can tell if it is on all eight , Headers only need to run a minute or less to warm up the pipe . at the port . Just making sure you understand what im saying .

Ill assume you did that , no question its on all 8 then , well then . HMMMMM id really need to listen to it .

yeah... I'm gonna be nice and do that tomorrow morning. Neighbors might not really wanna hear open headers at 12:30 AM lol

Captain Ledd
04-19-2008, 10:40 AM
Took new video this morning. it has the banging similar to the earlier video's, but it's just the t-case shift lever banging against the body. As soon as I pull it away it stops.

This runs a ton better than last night for some reason. the only thing I changed was I blocked off a vacuum port that I swore I saw something fly out of when it backfired, but couldn't get any kind of vacuum from at all. And also moving the accelerator pump linkage down to the lowest notch. these are the only things I've done to it since last night.

The stumbling on acceleration used to be easily 4x worse and it took 2x, maybe 3x on occasions longer to get there. I can tell it's backfireing because I can feel it blowing on my hand when it is on the throttle. the pops at the end when I let off the gas are out the tailpipe.


http://www.youtube.com/watch?v=LU2BxEXTLAQ

This is the video from last night while cruising around the yard, running much choppier

http://www.youtube.com/watch?v=4VoZJd6CSXU

Captain Ledd
04-19-2008, 12:01 PM
My point with the headers , which makes it easier is when it is dead cold you can tell if it is on all eight , Headers only need to run a minute or less to warm up the pipe . at the port . Just making sure you understand what im saying .

Ill assume you did that , no question its on all 8 then , well then . HMMMMM id really need to listen to it .

well I figured it was running on all 8 because it was so much smoother and more consistent than with the alternate fireing order. I found this little pic to help describe what I just found out

http://www.mustangii.org/tech/engine/fo-351-400-302ho.jpg

This is how mine is currently set up. HO 302 fireing order. cylinders 3,4,5 and 7 are all not fireing. I burnt myself on the others, but these are only warm at best. Interestingly enough, they are all opposite eachother on the distributor. so I'm off to take that apart and see maybe whats up.

Captain Ledd
04-19-2008, 12:28 PM
*sigh... took the cap off the distrubutor, nothing looked out of the ordinary. threw the timing light on all the cylinders, every one of them is getting spark that at least with the human eye seems pretty steady.

now that the carb is somewhat adjusted (better than it was, well.. ish.. or something.. hell I don't know) I'm gonna play with the fireing order again...

Captain Ledd
04-19-2008, 12:40 PM
just realized something...

Cylinders 3,4,5,7 are the only ones different between the standard 302 order and the HO 302 order. they are the only ones not fireing. Crazy you say?

Standard
http://www.mustangii.org/tech/engine/fo-302-460.jpg

HO again
http://www.mustangii.org/tech/engine/fo-351-400-302ho.jpg

Now if it is still the other fireing order why in the hell did it run so much better and smoother with the one I have now (HO)...

Captain Ledd
04-19-2008, 01:22 PM
well I'll be damned. I wonder what the hell we did wrong the first time?! she runs like a champ now. with tons of power!

All it was was the fireing order. grrr...