Ford Distributors 101

[toohighpsi]

Although the factory Ford distributor is without doubt the best choice for use with the AEM EMS if you intend to keep a distributor, there still have been some issues with syncing when an AEM is installed. Recently a fellow ford enthusiast in PA (Chris) installed an AEM on his supercharged mustang and found a NO SYNC issue with the current distributor in the car. The car would sometimes start cold, but once you shut it off, it would not restart again. Removing the AEM and reinstalling the stock ECU would allow the car to fire right up and run.
Fortunately I was in PA for the Easter weekend and had enough time to run down to ChrisÂ’s place to check out the situation with his car. I took a stock TFI distributor that my brother had laying around for to see if switching the distributor would help. By the time that we got to ChrisÂ’s place he had already switched the distributor with another that he had borrowed from a friend. The borrowed distributor didnÂ’t even produce a RPM signal so there were more serious problems with that one. Chris pointed out that the distributor that was originally in the car had a problem because the shutter teeth on the wheel were hitting the hall-effect pickup.
Upon closer inspection it was easy to see that the black plastic hall-effect pickup had moved around so much over the years that the center bore was worn loose enough to let the pickup contact the shutter wheel. Also the pickup could rotate up to 1/16” due to excessive wear on the plastic pin that interfaces with the octane rod (small rod that locates the pickup’s rotation). Due to the fact that the EEC-IV still ran with this distributor, I feel this is a good example of the tolerance built into the factory ford controller. Unfortunately this pickup is the heart of all the ECU’s outputs and last time I checked; GARBAGE IN = GARBAGE OUT! There is no doubt that using such a poor speed signal could have an ill effect on the ECU’s ability (AEM or Ford) to correctly control spark for the engine. After seeing this I’m quite glad about the fact that the AEM will not sync with this condition…. There is a problem with the distributor and it needs attention!
After seeing these issues we took a quick look at the distributor that we brought with us, it had a fairly new distributor gear which showed little wear (about a year old), the hall-effect pickup was retained tight and had very little signs of wear. Nothing on the shutter wheel was contacting the distributor and the distributor spun smoothly. I will note here that conditions have been seen with the shutter wheels contacting the pickups when the hall-effect pickup is still retained tight. For this condition carefully bend the shutter teeth slightly until there was adequate clearance for the wheel thru the pickup.
We dropped my brother’s distributor into Chris’s engine and the AEM sync’d quickly and fired right up. We let it idle for about 10 minutes before turning the key off and attempting a restarting, which also sync’d and started fine. We ended up running the engine for about ½ an hour with numerous starts and no issues. So far it seems that the problem as been resolved. I think Chris will be replacing the pickup in his distributor to see if that cures the problem as we expect it to.

So, what did I (we) learn from thisÂ….

1. The AEM ford controller is a new player in an old market; there are a lot of fords out there with new engines and old ford distributors. Chris said that it’s possible that his distributor has over 150,000 miles. I don’t think the story is any different with my distributor either (which I had problems with) – I think I took it out of a van with a known 200K miles on it.

2. If you have a sync issues – or even if you donÂ’t – you might want to check the pickup:  Pull the distributor cap off, put your finger on the pickup and try to move it around. Use a flashlight and check the shutter teeth on the wheel to make sure there are no signs of rubbing. If there are any issues, replace the pickup itÂ’s fairly inexpensive at about $16 from AutoZone.

3. If all is well there, pull the distributor out and check the distributor drive gear. The later ford roller cam engine has a steel gear, which seems to wear well, but if it has over 100,000 miles on it, IÂ’d probably consider replacing itÂ…. If you are running a bronze gear you might need to check that more often as they seem to wear quite a bit faster than the steel OEM units. Check the bearing in the top of the shaft for looseness, if it flops around then it might be time for a rebuilt distributor.

Apparently these ford distributors are not maintenance free – at least if you are looking to have a repeatable signal from them, which is what the AEM needs to sync and provide perfect engine control.

Well, enough of my rambling, I just thought this information could be useful to some of the users out there when getting their cars running – or keeping them running.  

Later

[BLKMGK]

Wow, very good write up on the issues. I'll bet this is biting a few Ford owners in the butt with the stock ECU too. I cannot imagine how it couldn't be!

[cbecker]

Hi all
After Mike left my place I went to National Auto and got a new pickup.  The cost was $33.  After installing that and putting the distributor back in my car it synced and started right up and has everytime I have tried it since.
Thanks again for all your help Mike!

Chris Becker

[toohighpsi]

Cool, I was going to call you tomorrow to see if it worked out OK. Let me know if you run into anything else...

[JasonB]

Same thing happened with my installation only I just replaced the whole distributor.

[turbogt]

Hey Mike,

thanks for the writeup. i have an all stock '93 GT that i'm putting my aem on and it has a 160k on the motor. i'm going to look at the distributor before my aem computer gets here to make sure i don't have these issues! thanks again for the heads up  

[NastyStang]

I just wanted to add something here.. 

I found issues with replacing the stock TFI with an AutoZone (No Name) piece.  I kept getting cut-outs, timing errors, mis-fires with this TFI but with a old Used Motorsport TFI I had no problems.  I was able to sync, no problem, just under load it would cut out at 3k. 

This is a great post for a problem that hits a lot of Mustang guys.   

[foxbody95]

I have a supercharged 347 in a 90 mustang gt, and an msd billet distributor, I had to swap out the pickup inside of it to get the aem box to run my car.

I went to napa and bought an echlin(their brand name) pickup for a 90 ford 5.0 mustang, and installed it in the msd distributor and the the car runs fine.

all you have to do is press off the distributor drive gear and pull the shaft out of it to get the new pick up in the msd.  I would suggest using a press to get the gear off as hammering it might hurt the gear or shaft.

[piripiri]

Hafa Adai

 Could this be the same problem I'm facing now?
I'm trying to sync. timing to timing light but the box won't respond?
Trying to install onto a '90 ? w/summit crate 5.0 & powerdyne 9psi supercharger 24# inj. pro m maf. Any info would be appreciated! As you might have noticed I'm a Newbe!

[r.barn]

F*ck these damn distributors all together if you ask me.
Throw you a Ford EDIS system on there and go dizzyless, get the parts in a junkyard for $100.

ultimate in timing sync is always going to be a crank trigger
this lets you use an OEM Motorcraft crank trigger ....... even better, cause I'm done with MSD too.

[itow]

F*ck these damn distributors all together if you ask me.
Throw you a Ford EDIS system on there and go dizzyless, get the parts in a junkyard for $100.

ultimate in timing sync is always going to be a crank trigger
this lets you use an OEM Motorcraft crank trigger ....... even better, cause I'm done with MSD too.

Your sig says you have a 351w.. What stock ford DIS setup are you using with a 351w based motor??? I want to go DIS on my 427w...

[dennis17116]

GREAT INFO.  CAN YOU HELP ME WITH A TUNE ALSO?  THANKS

[gray86hatch]

GO EPM

just installed mine and after a little learning curve it idles better than ever. 

Sold off my dig 6 coil and distributor for about what the EPM costs. 

I got a good deal on coils $50, $250 on the EPM and $50 on conectors and wire. I bought the conectors and wire from Mike at EFI Conection. 

[beerfarm]

GO EPM

just installed mine and after a little learning curve it idles better than ever. 

Sold off my dig 6 coil and distributor for about what the EPM costs. 

I got a good deal on coils $50, $250 on the EPM and $50 on conectors and wire. I bought the conectors and wire from Mike at EFI Conection. 

I have been watching for coils on fleabay to do my conversion in the near future, the last set I saw went for over a hundred bucks!!!!...F-that.... looks like I have to start scrounging the yards! Getting to be a hot item!

[gray86hatch]

Look on Craigslist

I got mine on there.  Most don't know what they have. 

I am going to buy as many sets as I can.  at that price I will never loose $$

Tim