Need MFI help or advice...PLEASE

[ed martin]

Thanks Matt. I actually heated the thermostat with a clothes iron. Got to be careful with open flames!

[Shuie]

OK, I just read through 101, the haynes, and the little tech specifications book on timing. I have a better idea of how you are supposed to actually do this now. Im looking up old posts on the breakerless ignition systems as well. I'll keep you guys updated.

Thanks again everyone

[Grady Clay]

targa911S,
I agree with you.
Best,
Grady

[Rot 911]

Originally posted by sithot
So, what's the consensus on plug choice?

Tom

NGK I'd run BPR7ES. If you don't have much of a fouling problem you could even go a bit colder with BRP8ES.

[304065]

What do the spark plugs look like?

[Shuie]

Originally posted by john_cramer
What do the spark plugs look like?

I never pulled them. When it came time to really check the ignition out, I brought it to the shop.

I didnt have the plug removal tool, and I had visions of dropping a plug inside the valve cover after trying to use the wrong tool.

[304065]

From time to time the cool factory plug removal tool becomes available on Ebay. Also, HAZET makes a great one, not cheap, but does a fine job of getting inside those valve covers, available at www.samstagsales.com

A true "plug cut" check requires you to run the engine under load at WOT and then shut it off immediately to get a sense of the right mixture. That's pretty impractical, but once when I was having typical "MFI system is rich" issues it turned out that I had a bad ground from chassis to engine. The plugs were covered in black soot, and when I would rev the engine, I would get the telltale "pop" of the plugs beginning to foul. Once I replaced the ground, the spark came back and the plugs cleared.

Also, I highly recommend the use of an MSD box, like a 6AL, for MFI. Really keeps the plugs clear.

Good luck! This thread is like being in a room with the best MFI guys in the world!

[Grady Clay]

Shuie,
It's Friday, what do you hear back from your shop? All us MFIs want to hear. Perhaps you should take all the info you have and talk?
Best,
Grady

BTW, I hope it was just the ignition points closing up.
G

[targa911S]

Ditto that!

[Matt Smith]

BP6ES, MSD
Could be a bit hot though, so I think I'll go BP7 soon
Ditto MSD, but don't tell Paul or Warren I said that

MFI is a complete package, so the emphasis should definately be on following the CMA to the letter, and in order!
But...with regard to dialing in the mixtures or 'playing with the pump' this may well be the eventual soloution if the car is new to you or a toyota mechanic has had a go in the past.

My car kind of ran ok when i bought it, but had a big mid range flat spot, and then leaned out as the car warmed up, to the point of constant stumbling.
Fix consisted of lotsa advice...and eventually correcting and recallibrating the pump to compensate for the fact that the main pump rod was about a centimetre/ 1/2" different to what it was supposed to be.

The learning process was half the fun.

Plug watching is tricky in a car that wants to run rich, as the Mfi T does, and becomes all the more tricky when you have to run unleaded 2004 pump gas in a 1972 Porsche. We get nice octane ratings here -up to 98 from the gun- but that's a waste of time and money when your motor runs 7.5 to 1 compression which is roughly the same ammount of pressure it takes to squash your pillow.

[Grady Clay]

Matt,
There are many ways to enter the CMA tree. If you have previously dealt with some of the normal basics, there is no reason to repeat until you exhaust other options.

I might use BP7ES in the winter or for testing, but it’s a little too hot for normal summer use in a good running ‘T’, even at our 5280’ altitude. A BP6 is suitable for driving around the ski areas in winter.

The MFD CDIs are great and powerful. We get to use them because we go through spark plugs so fast while we use up oil/gas mixture.

You bring up a good point from down under. Virtually every MFI has been adjusted, screwed with, tinkered, and more (expletive deleted) since new. It is a real challenge to get the system back to properly running. Yes, the other big issue is that nothing is new. There are many other issues that must also be perfectly correct before you adjust your MFI.

Yes, the fun is in the learning …. And the passing it on to the next generation.

BTW, Is your Mini a 1275S? Union Jack on the roof? Cool Minilites!

Best,
Grady

[Matt Smith]

Hi Grady, and welcome.

Better not hyjack this thread, but no, my Cooper is a 998. It's actually my first car, bought in 1987 and I just can't bring myself to sell it! No Union Jack either, although I did execute such a paint scheme on my best buddy's red '66. Great stuff!

The only problem with learning how to drive quickly in a Cooper is that it spoils you for life. I've NEVER driven another car with such sharp steering, although I guess I should find some seat time in lotus 7 someday.......

[Jim Richards]

If I remember correctly, I'm running BP7ES plugs in the 73E and I recently added an MSD 6A. Will add Pertronix Ignitor to it if the wife's honey-do's abate. To Matt's and Grady's point about the MFI systems being mucked with over the years, the previous owner had our 73E running at a CO of 11+% and the airflow out of balance from stack to stack. I've improved things a lot since then but am following this thread with great interest as there is lots of great advice here!

[FA-18C]

Jim, did the MSD make any difference other than the fact it replaced a dead Permatune?

[Jim Richards]

It's maybe a bit smoother all the way to red line, Chris. But, as you pointed out, the primary reason was to replace a dead Bosch box.

[Grady Clay]

Jim & others,
A high power CDI is worthwhile (and possibly necessary) on marginally running MFI. It keeps the plugs firing in adverse conditions. This lets you to continue tuning even when you are way too rich or trouble shooting some problem. As soon as you drop a cylinder, you have to start over with new plugs. Everyone who has MFI knows the two most expendable items are spark plugs (rich fowling) and engine oil (fuel dilution.) These are also reasons why twin plugs are desirable. There is “No Substitute” for NO gas in the oil when tuning.
Several sets of plugs are a useful tuning tool. I have sets of BP6ES that I clean well and then dry in my oven.

Who else has tricks?

Best,
Grady

BTW, a high power CDI will eat plugs in the long run. Once everything works right, I think a short duration spark and Platinum plugs work great, just not for tuning.
G

[FA-18C]

Good stuff Grady. Although I continue to pick away at other areas to enhance performance since the PO spent 8K rebuilding this motor 7K miles ago, I would like to keep it close to original. From the other MFI thread you all have convinced me to keep the MFI, and after the TH bodies are rebuilt, I will next install hydraulic tensioners. The next pile of cash will go to houndstooth seat inserts. So I have a rough plan, but where a reasonable investment can make a decent impact, I'm all ears.

Appreciate the great advice and info. Grew up in Lakewood BTW. My brother had good friend Kent who was a Porsche wrench out in Wheatridge I think and helped him tweak his car. Sometimes I miss Colorado!!

[Shuie]

Bumping to say thanks again to everyone. Car is actually running again. WHHHOOOOOHOOOOO!

Points had closed up, and the 'new' Permatune is putting out a weak and inconsistent spark. My wrench adjusted the points, set the dwell, and put a known working Bosch CDI in the car and she is running fine right now.

So what do I do now? MSD? If I go to a petronix/breakerless, I can use the permatune for target practice right? Ive got a Bosch 3 pin Bosch CDI that I pulled from my running '73 that I can use for now.

[Early_S_Man]

Tom,

You don't say which engine you have, but it will probably take two heat ranges to cover both fall/winter and spring/summer ... adding a third for track/DE events

NGK 'plain' copper core, Bosch copper core and Champion copper core are the choices I have had good luck with ...

*****************************************

For 911T engines ... NGK BP-6ES winter or cool weather, BP-7ES summer hot weather
Champion N6-YC cool/moderate/hot temps, N4-C very hot temps
Bosch W7C cold/moderate temps, W5C hot weather

-----------------------------------------------------------------

911E, 911S/RS spec engines ... NGK BP-7ES cool temps, BP-8ES hot weather, BP-9ES very hot/track conditions
Champion N-4C very cold, N-3C hot/moderate, N-2C very hot/track conditions
Bosch W5C cold temps, W4C moderate, W3C very hot/track conditions

[sithot]

Originally posted by Early_S_Man
Tom,

You don't say which engine you have,

Stock 2.4 S. Looks like you have me covered.

Thanks,

Tom