MPI with Vacuum Advance

[autoxer]

Ok so it seems all my problems are coming from not having a true ported vacuum for the distributor. I have spent hours reading through tons of posts on this subject but have not found any that really say how, where, or if they got it to work properly. It seems the only way to do MPI correct is to have ECU controlled timing. Any input would be great.

My setup: Magna Intake, msd 75lb injectors, FIP fuel only, MSD 6a, 19c turbo, 272 cam, Stock dizzy

 

The problem:

My spark knock only goes away with racing fuel or if I hook distributor vacuum lead to straight manifold vacuum but,

if I do this my timing is at 34 degrees advanced and it has no power. Currently have it hooked to OVCP right in front of Throttle Body but then I get spark knock as soon as I hit 10psi boost. Got to be timing related I have eliminated everything else. So whats everybody doing with a stock dizzy and MPI or am I the only DA trying to make it work?

 

 

Considering a 5 gallon can of gas and a match at this point :hangman:

 

 

 

Thanks to everyone I have bugged about this and for all the help......thus far.

James

[Indiana]

What's your base timing set at?

[autoxer]

What's your base timing set at?

Well the way I have it now it is at 10 degrees but I have been as low as 5 degrees with no change, but if I hook to straight manifold vacuum instead of OVCP its 34.6 degrees altough I did change distributor location and got it down to 24 degrees but didnt seem to make any difference so I went back to hooking vacuum upto OVCP.

 

James

[substock]

Well the way I have it now it is at 10 degrees but I have been as low as 5 degrees with no change, but if I hook to straight manifold vacuum instead of OVCP its 34.6 degrees altough I did change distributor location and got it down to 24 degrees but didnt seem to make any difference so I went back to hooking vacuum upto OVCP.

 

James

 

 

i had this problem, at idle i couldn't get my timing below something like 30*(hooked to the plenum for vac).

 

what i did was take the distributor gear off and rotated it 180* and put the pin back in to hold it.

i have a full range of timing at idle now and have it set to 10* at idle.

here was my post where i was told about it

http://www.starquestclub.com/forum/index.p...amp;hl=substock

[Minagera]

hmm might have to do this myself. I am having the same problem on my MPI car running stock ignition.

[JamesR]

I'm running Magna MPI with SDS fuel only and stock ignition and haven't any problems with my vac. adv. My vac. source is a port off the throttlebody like the stock TBI. I'm using a ford tb from Australia which came from Glenn. I believe it came off a ford falcon, not sure what US ford came with the same tb. Here's a pic of the port.

http://home.fuse.net/remo/sq-vacsource.jpg

Edited September 26, 2008 by JamesR

[autoxer]

I'm running Magna MPI with SDS fuel only and stock ignition and haven't any problems with my vac. adv. My vac. source is a port off the throttlebody like the stock TBI. I'm using a ford tb from Australia which came from Glenn. I believe it came off a ford falcon, not sure what US ford came with the same tb. Here's a pic of the port.

http://home.fuse.net/remo/sq-vacsource.jpg

OK so cool does anybody know anyone I can get this Throttlebody from? Or can someone tell me how to get in touch with Glenn?

 

Thanks James

[substock]

OK so cool does anybody know anyone I can get this Throttlebody from? Or can someone tell me how to get in touch with Glenn?

 

Thanks James

 

i originally tried on my mustang tb to make my own port similar to that

drilled the side out where the hex bolt is on the side, it had a port inside the tb and after the tb for vac, placed a barb fitting in the hole i drilled

but to much to my hopes it did not work,

 

thats why i ended up doing the gear on the distributor.

[Lusion972]

I'm perplexed...did you guys switch to a caravan igniter and lock the distributor?

[substock]

I'm perplexed...did you guys switch to a caravan igniter and lock the distributor?

 

 

Lusion,

they are just talking about fuel only, there is no need to lock the distributor down unless your running ignition through the ecu.

 

there are 2 ways to setup the igntion for fuel only with an msd.

 

caravan ignition module with the 8910 tach adapter through this diagram

http://www.26liter.us/gallery/albums/userpics/10171/msdfipinstall.jpg

 

or

 

keep the stock distributor as is(without the caravan module) use the 8920 tach adapter and use this diagram

http://www.26liter.us/gallery/albums/userpics/10123/msd_install_with_8920.jpg

[JamesR]

OK so cool does anybody know anyone I can get this Throttlebody from? Or can someone tell me how to get in touch with Glenn?

 

Thanks James

 

I'm not sure if Glenn is accessible any longer. His webpage has been down for years. Glenn sold modified Magna manifolds years ago from Australia. By the way, the TPS on my throttle body rotates counterclockwise which shouldn't be problem until it goes bad. Also, my tb is 65mm and has BOSCH written on the flange. I hope this helps. Maybe its the same tb from a turbo Merkur or T-bird?

 

 

I'm running the stock ignition with ignitor box and all, but with a MSD box. I kept the ignitor box for extra insurance. I maybe not running the best setup, but its been working great for me for over 5 years know. If I wanted more horsepower I would go with a programmable ignition computer.

Edited September 26, 2008 by JamesR

[Lusion972]

hold up...now yall got me confused...I am not gonna use MSD, I am just gonna convert my dizzy to a caravan igniter and run it that way. I will be running MS for fuel only...the igniter runs directly off the battery so all this extra stuff isnt necessary.

[substock]

hold up...now yall got me confused...I am not gonna use MSD, I am just gonna convert my dizzy to a caravan igniter and run it that way. I will be running MS for fuel only...the igniter runs directly off the battery so all this extra stuff isnt necessary.

 

if your not going to run an msd, there is no need to use the caravan ignition module.

just leave the stock ecu in and the stock ignition box will control the timing.

[Lusion972]

lol...dude, the wiring harness, ignition box and ecu is out of there...lol, I was under the impression that you didn't need MSD because the ignition coil got its power directly from the battery/alternator.

[questian]

lol...dude, the wiring harness, ignition box and ecu is out of there...lol, I was under the impression that you didn't need MSD because the ignition coil got its power directly from the battery/alternator.

Hey man!!! i'm no ignition professor but must say that i had the same problem with my 14g spinning @ 16 psi, i dont know if it is because the air was hotter compared to a20g but my car would ping like mad,here is what i did, dont know if will help you but give it a try take your vac line from the dist and move the dist all the way down towards retard then reinstall vac line and take that baby for a spin and then you can adjust it back up to where it runs and feels the best without pings i have done the same thing to mine and i slamm my pedal to the carpet @18 with 20g and it does not knock,my ignition is stock with blaster 2 coil and megasqt 1 v3.0 mnse and i have no performance issues related to ignition may not be the most hyped set up but the machine pulls hard.

[Lusion972]

if I could get the bracket for the edis vr sensor I would go that route but dont know where to get that bracket from

[quest96]

Did you eliminate the stock igniter and use the 2 wires from the dist. directly to the wires on the msd? I was only runnig feul at one time and I tried it that way and it didn't work. So I used the stock igniter along with the msd and the tach adapter for the tachometer. I think it has to do with the dwell. Give it a try. I think there was a few diagrams on here. Hope this helps...

[quest96]

If you look in the pic that james sent, you'll see his igniter box in the pic. That's probrably why his works. As for as ported vacum that just means before the throttle plate.

[Indiana]

The amount of vacuum at idle should be in the same range as a stock system is otherwise your range of movement from the vac advancer unit will be limited although you could still set the base timing correctly. You'd end up with much less ignition advance when you push the throttle but still have the mechanical advance working properly and if it was so far off the boost retard may also be limited -meaning that's asking for trouble.

[JamesR]

If you look in the pic that james sent, you'll see his igniter box in the pic. That's probrably why his works. As for as ported vacum that just means before the throttle plate.

 

Yes, stock ignition with MSD.

[Lusion972]

ok...MSD is not necessary but nice to have I guess...

 

I have removed the entire wiring harness, the ignition coil is powered directly from the battery/alternator so no need for the ignition box or harness that went with it. The stock dizzy will not fire with out the caravan igniter...we gotta have an igniter. So, convert the dizzy to the caravan igniter with part number cr125 and cr 120...run it directly to your ignition coil and there you go...its all you need. No need for an MSD or anything else like that.

[quest96]

I wouldn't use the caravan igniter. I tried that and had nothing but trouble. It would run ok but I think I had some isses under load. I went back to the stock igniter with a msd and it worked great. You don't need the msd but you can use it with the igniter.

[autoxer]

:thread20jacked8wq:

 

 

Back on subject:

I have drilled a small hole in the bottom of my ford Throttle body about a 1/4 inch in front of the throttle plate on the cooler pipe side and drove in a piece of 3/16 inch brake line that is about 1 inch long and hooked vacuum advance hose from distributor to it. This seems to be working as ported vacuum and everything seems to be working proper at the moment. Thanks to all of you for your ideas and suggestions. I will keep you all updated as I start to krank up the boost and see if it continues to work. Also will take some pics of this mod and post them soon.

Thanks again James

[Shelby]

question whats the first name of the vacuum advance unit

 

"VACUUM " now some one tell me how much vacuum their engine has with 5 lbs boost,,,with 10 lbs boost ,, 15 lbs boost ?????? or even WOT??? @ idle ????

 

"0" - nota - sip

 

the vacuum advance unit is design'd to NEVER see full vacuum it only see's partial vacuum and only durring part throddle petal movement , thats it the only time it funtions,,and it does NOT have to work at all ,,it was design'd to assist the engine when changeing rpms to work along with the fuel enrichment funtion of the tps(quick ) movement the ecu gives an extra shot of fuel and at the same time the dist timeing is advance'd to enable the engine to gain rpms and not stumble under the rich fuel mix

and the max vac signal it can see is aprox 12-14 inches NOT full intake vacuum . your engine will run just fine with out any vac advance unit

you are not helping any thing by indroduceing full intake vacuum to the dist,if you check specs it says advance @10 inches and @12 or so inches no where will you find a spec for 19-21 inches of vacuum

 

now those of you saying you have early spark knock,, you usually get this because the dist mechanical advance system is advanceing too early due to weak springs or two small springs not one small and one large , you certianly do not want full advance by 2k -2500 rpms , advance should be in steps not all at once , and any spark knock under boost you get certianly is not from the vacuum signal to the vac advance unit,, cause there is no vac signal under boost , your advance curve is all mess'd up

 

two things do not change the max amount of advance and the base timeing , boost retard is a seperate issue

 

the caravan igniter ,, strange some would say it don't work,, has kept many a caravan on the road for many 100's of k miles WITH OUT ANY MSD UNIT ,

explain that if you can

 

many seem to have the wrong idea about the MSD ignition system,,it is not what you'd call a true igniter ,it'd be clearer to say it's a reveribrator for the ign igniter system , each ign pulse is taken and recreate'd 3 to 5 times causeing multipul ign fireings ,this can increase the plug fireing time so more fuel is burn'd but has a tendency to confuse the ecu by it not being able to read the rpms correctly there by makeing the tach signal adaptor nessarry,, it's not for the tach only that this adaptor is need'd it's for the tach and ecu , i have not seen any actual proof that it increases the ign coil out put voltage , do not confuse spark plug burn time with ign coil out put voltage

 

only one igniter is need'd to trigger the ign coil , what the MSD is doing in this case is useing the caravan or oem igniter to make the trigger signal stronger so it can make stronger ign pulses , i have not seen one wire'd up to use the dist pick up only with out a helper igniter not saying it can't be done just i have not seen one wire'd that way

 

lots of confuseing information out there esp from people and sites that sell products

but the truth is only one igniter is need'd , now if your into trying for an 8 sec 1/4 an 500 hp,,you will want to do any thing and everything you can but for most all that is not need'd ,,those trying for the 8 sec 1/4 can work out what they need for them selves, they have the knowlege and experiance to do so , i'm only trying to help those that just want a good runing car , one has little to do with the other

Edited October 13, 2008 by Shelby

[CaliConquestAlex]

I would recommend ditching the stock ignition and converting to EDIS 4. The MK1 crank pulley is for sale on ebay with the EDIS trigger wheel attached. The Ignition system works sooooo much better than the stock distributor.