Battery, Brakes and MFI. What I've been doing and some questions.
 

Well, it’s been about a month since I got my 911 and I thought I would share what I’ve been up to. Upon delivery, it had some issues and would not start. Got a bit delayed on working on it because of family stuff so the first 2 weeks was a period of admiring and sitting in it going ‘VRROOM VRROOM’. I'll put up some pics this weekend.

The batteries were bad so I went with the Odyssey 925 single setup. It’s in the drivers side battery box and fits great with plenty of room. I need to put something around it to snug it up.
Rear brakes were stuck so I rebuilt all 4 calipers. I pulled both rear off then could not get the pucks out so I had to put them back on and use the pedal to push them out a little. I wasn’t sure how far they would come out before I had a big mess of brake fluid so I went slow and careful. Worked great but still had a devil of a time getting them the rest of the way out. Afterwards, they cleaned up nicely. Fronts were in much better condition and went smoothly. I ended up flushing the system with normal brake fluid, draining, and then proceeding with ATE Super blue. Motive Power bleeder and I was done in no time flat. Very easy to use. Just be sure and keep and eye on the reservoir. It’s easy to forget that part when all you have to do is turn the bleed screw. Brakes are a little spongy and will do a final bleed on Saturday using pedal method.

Now for the ‘fun’ part…. The MFI needed tweaking. I have Check, Measure, Adjust and have read through it a few times. The problem is I don’t have a CO meter or timing light. I know, I know. I will get those soon but couldn’t wait so I make a few tweaks on the fly. Before doing any adjustments at all, I started it and it would not idle for crap. Popping out of the intakes and bucking and snorting. Over 2k rpms, it would smooth out and sound good. So, I thought I would richen the idle mixture using my handy-dandy MFI adjustment tools from our host. I went 2 clicks at first and it was better. 2 more and even better then 1 more for good measure. Idles great but a little hard cold starting. Nonetheless, I let it run for 15 minutes or so varying the rpms gently and letting some heat build up. Things look good, sound good and I feel good so I load up the son and go around the block. First drive went GREAT! Ah, to be behind the wheel on a Porsche again was wonderful. My wife was at work which is 3 miles from home. I went on over the her work and back and it went well. Took the boy to school at noon and gassed it up with 91 octane pump swill.

The next day, I took it out again for a short jaunt and then that night took it out for another. Idle is still great but I’m having some intake backfiring at speed. Also, when I let off the pedal it backfires which indicates the stop microswitch is suspect. Is that correct? As for the run mixture adjustment screw, CMA says it’s located behind the only allen screw on the face of the pump. I suppose someone chaged it out over the years because they are all slotted. I could not find a pic anywhere so could someone please put up a pic pointing to the correct screw? TIA

Now for some q’s…
Where did you get your CO meter and timing light? And you MFI owners that maintain them yourself, what other MFI specific tools or otherwise should I pick up?

I bought my timing light and a set of feeler gauges from Harbor Freight. I think my MFI adjustment tools and a synchrometer are on the way from Pelican. Im still looking for a gunson gas tester or a cheaper functionally equivalant device. I'll probably just get one off of the bay.

Did you clean the thermostat on the front of the pump yet? Is all of the ductwork from the heat exchanger hooked up to feed hot air to the t-stat? Is your cold start working? I just went through all of this about a week ago and got it documented with the help of Milt, Warren, and Grady in this thread.

Don,

The backfiring upon deceleration could be the microswitch, the rpm transducer (aka speed relay) and / or cut off solenoid. I too had this problem and posted the question below (one of my first posts, btw). If you scroll down the post Early_S_Man provides some invaluable schooling on the matter...

If you follow the steps outlined in CMA you will be able to diagnose the problem quite quickly... there is a nice clean, high rez copy of CMA which can be downloaded from the link in my signature area.

So far my MFI toolkit includes: gunsun gas tester (ebay), the '3 tools' (pelican), digital multitester, and synchrometer (pelican), digital timing light (had it already).

http://forums.pelicanparts.com/porsche-911-technical-forum/69716-mfi-troubles-backfires-deceleration.html

Don,

I bought my Craftsman CO analyzer from Sears, but I am not sure if they sell them any longer.

I also bought my Craftsman advance timing light from Sears, but I wouldn't recommend them unless the item is on sale at a significant reduction ... Sears simply isn't competitive these days with non-sale pricing! I used to plan all major tool purchases around the sale catalogs, back when they were still in the catalog sales busines! But, then some cost-cutting bean counter convinced management to discontinue catalog sales ... right when Internet catalog sales were taking off like a rocket! Go figure ... why any company would abandon a major portion of their customer base!!!

I purchased a Gunson Gastester off the internet from some guy in Florida.

Synchrometer from local overseas imports.

Timing light with tach and digital advance, I found both features useful.

As for backfiring on decel, I recommend reading Warren's posts as someone above suggested. I found when I purchased my cars, both of my RPM transducers were not working, due to corrosion of the transistor legs.(Repaired with standard transistors per Warren's and others advice).

Sears stores are mostly a "front" to their real business, Credit Cards. They make gazillions more via credit card distribution and handling other company's credit department. An old friend of mine worked for thet department for years.

I put together a 3 ring binder with tech articles printed out for reference. I'm guessing part of my car's problem is that it just needs to be cleaned/checked/adjusted/maintained etc...

It's getting there and I'm lovin' it. Thanks everyone!!

Re: Battery, Brakes and MFI. What I've been doing and some questions.
 

You might want to check this thread. I had the same problem with a spongy pedal after rebuilt calipers using the Motive. It turns out the Motive was working perfectly but you need to remove the pads when you bleed. I would use the Motive for the final bleed.
Bleeding rebuilt calipers


Adjusting the MFI by ear scares me a bit. I would hold off if I were you until you have the proper tools. :eek:

Thanks Sunday,
I am being very careful and not poking around too much in the MFI area. I have a LOT to learn.

I'll try the brake pad thing this weekend.