MFI, points question
 

I have a 2.5 with MFI and points. Yesterday the car wouldn't start. This is after being more difficult to start since the colder weather has come. Now, everything on the engine is new and I have total confidence in it.
What I am curious about is:

can a coil fail out of nowhere?

is there a breakerless ignition set up I can buy for this engine?

can you fuel foul plugs with MFI?

I have changed the CD unit. I pulled a plug and found it to be wet so I am confident that I have fuel delivery. I let the car sit overnight and it wouldn't start this morning either. A low battery from lots of cranking maybe contributing to that also.

The cold start fuel line from the top of the fuel filter assembly to the MFI stacks is not hooked up. I plan to do so this weekend.

Any advice you guys have would be greatly appreciated. I will only have this engine for 6 months but while I do I want to understand such things to make sure it's a reliable one for me.

Thanks ahead

James, have you checked to see if there is spark? You can pull a plug wire and use an old plug grounded to the block. Watch out for fuel fumes.

If you have no spark you need to verify that the points are working. Pull the 3 pin connector at the CD unit and use a MM set to Resistance between the trigger wire and ground. rotate the engine by hand. Teh resistance should be infinite when the points are open and zero when they are closed. if this works you could have a bad coil or CD unit.

If you get always open or always closed your points are bad. I have used the Crane optical points conversion. It drops right into a Bosch dist and only has three wires to hook up. never worry about points again.

Make sure you clean ALL connections on the ignition system.

thanks Jamie. I will check after work to see if I have spark. I can't imagine the coil failing when it worked an hour before? I also changed the CD box to a known to be good unit. I inspected the points and they seem to be in good condition. I need to validate this also by turning the engine over manually and seeing if they open and close. It sux because I need a car to get the things I need to fix the car... :-D
I will change the coil to eliminate that issue. I also need to set the cold start thing up. The car has been getting harder to start over the last month. I attributed that to the slightly colder weather but what else could contribute to that?

If your plugs are wet, wait on hooking up the cold start fuel line. I hope that sucker is plugged off good. To be sure it doesn't work, remove the center fuse on the rear 3-fuse panel.

I remove the fuse on hot days if I'm going to restart and the motor is still hot. I plan on putting switch in the circuit if I don't hook the whole thing up to an activating button in the cab.

I'm with the spark thing. Weak or no spark is not good. Get that dialed in before tinkering wiht the MFI. If it ran before, then the MFI is not maybe a prime suspect. MFI doesn't change on it's own too frequently. It's more of a gradual process.

so you checked the points gap and it's ok ?

I have not checked the GAP will do tonight, I did have the cap off yesterday and the points "looked good" as in they were not burnt and they seemed new (everything else on the engine is new or rebuilt to my knowledge) .

Zeke, are you saying that I should not use the cold start thing? I have not to thus far.. but she has been getting harder to start when cold..??

James.... the others who have posted here are much more learned in this than I, so take this as only one person's experience... as someone who lives in a northern (cold) climate, a functioning cold start system has made a considerable difference in starting my car. My engine may very well have been out of tune at the time, but once I hooked up the system I went from many many cranks to just one.

Again, follow the others first… and I certainly don’t want to be responsible for setting your car in flames!

Good luck.

I live in FL and use the cold start. Do you have an inductive timing light? If so, you can check for spark without removing or disconnecting anything.

James,

If you follow this advice and blow up your engine don't come crying to me.

Connect everything up normally. Charge the battery OVERNIGHT.

Go to any gas station and buy a can of dimethyl ether starting fluid.

Squirt a SMALL squirt on the outside of your air filter. A SMALL squirt, like half a second on the nozzle. If you squirt too much, you will blow up the engine, cause voter fraud and lose the world series.

With a fire extinguisher handy, crank the engine over.

I disconnected the cold-start squirter on my '71 and the car WILL NOT start on its own when cold without the ether trick.

Good luck! Semper Fi.

James,

To answer your questions:
Yes, a coil can fail out of nowhere but is fairly unusual. Is there any sign if failure (oozing at the low voltage terminals?)

Yes, there are lots of ignition systems available. That is not where to go now.

Yes, you can fowl sparkplugs with MFI. I think the first MFI 911 built by Porsche probably fowled its plugs. Every MFI owner should have several sets of good clean plugs for diagnostic purposes.


On to fixing the problem:

Cold start problems are not easily diagnosed in downtown LA unless you have an environmental chamber. LA is not the same as Evansville/Louisville.
First, trickle charge the battery so cranking isn’t an issue.
All you need to do is verify that you have spark as BK911 suggests.
Install some new/clean sparkplugs.
Yes, reconnect the cold start system. Be aware of its potential problems (like not turning off or leaking.)
You will probably also need to check the thermostat operation.
With a fire extinguisher handy, you can probably start the car with starting fluid.
Once running, you know you just have a cold-start problem. Easy to fix.

The “art” of MFI is to have everything work properly without drowning the engine with fuel. Things work great with too much fuel but there are bad consequences. The most serious is diluting the oil with gasoline.

Here is my library of MFI info. I suggest you keep copies and study it.

Check Measure Adjust (CMA)
http://www.scatliff.mb.ca/pelican/MFI_Check_Measure_Adjust.pdf

“MFI Size Chart”
http://forums.pelicanparts.com/porsche-911-technical-forum/117171-mfi-induction-chart.html

“MFI thermostat spacers”
p. 1 end has CMA extension, p. 3 has nozzle, fuel flow, and fuel pressure.
http://forums.pelicanparts.com/porsche-911-technical-forum/169445-mfi-thermostat-spacers.html

“More Fun with MFI and LM1”
How to use protractors for correlation.
http://forums.pelicanparts.com/porsche-911-technical-forum/179707-more-fun-mfi-lm-1-a.html

“MFI Problems”
http://forums.pelicanparts.com/porsche-911-technical-forum/173700-mfi-problems.html

MFI tools
http://forums.pelicanparts.com/porsche-911-technical-forum/170242-mfi-tools-diyer.html

“Mechanical Fuel Injection” site with OK stuff:
http://www.my930.com/MFI/TipMFI.htm


Early_S_Man posted this” Here are several threads on the subject ...

Changes in Pelican's server have invalidated several links ... I suppose I need to go back and chart all of them, then edit and revise the links ...
Several people posted multiple threads on one problem, and that unecessarily complicated keeping track of the various threads!
http://forums.pelicanparts.com/show...ght=mfi+warning
http://forums.pelicanparts.com/show...fi+speed+switch
http://forums.pelicanparts.com/show...=rpm+transducer
http://forums.pelicanparts.com/show...&threadid=78685
http://forums.pelicanparts.com/show...mfi+speed+relay
http://forums.pelicanparts.com/show...tch+replacement
Good luck! Warren Hall
Pelican Tech article:
http://www.pelicanparts.com/techarticles/911_MFI/TipMFI.htm


Good thread on fuel pump, filter, tank on Early S Forum
http://d240157.u39.zeonhost.com/forum/showthread.php?t=4147&page=1&pp=15

List of MFI rebuilders/experts:
http://www.early911sregistry.org/Resource-MFI.html

“Any good MFI people out there” on EarlyS
Hot starting issues.
http://early911sregistry.org/forum/showthread.php?t=4355

I’m sure there are more.


Best,
Grady

James, I'm still fairly new to MFI myself. The folks on this board have been a great help in getting me squared away with mine. One thing I have noticed, and you will see some of the MFI gurus here alluding to, is that they do tend to run rich. As a result, they can foul plugs. There are a number of threads dealing with the correct plug to run in the older MFI cars; just search on "MFI spark plugs" or something like that. The consensus seems to be to run a bit hotter plug to help combat the fouling and to deal with today's gas. It made a difference in my car. I wish I had the number of the plug handy, but I'm at work so I can't check right now. Anyway, you didn't mention the color of your wet spark plug. If it was all black and sooty, in addition to being wet, you will probably never get the car started until you clean or replace them. Once in that condition, they can take days in a cold engine to dry, and even then the spark can be kind of weak. If everything else seems o.k., maybe take a look at that.

thanks fellas. I have the car on the charger. I think that I don't have a spark. The coil and points look ok. I don't have an extra set of plugs and doubt anyone local would have the ones I need. I sprayed carb cleaner in the aircleaner opening and with the charger connected and car turning over as normal she didn't start. I will verify in the am but I suspect I dont have a spark. Either that or the fuel pump failed? Is the fuel pump fused? I checked all fuses and they look fine. I sure do miss my 3.2! and can't wait for my 3.6! 5 months and counting!
Thanks guys and keep the advice coming!

Semper Fi!

(John you gotta earn the stripes to invoke that one!)

Thanks Jeff. Please post that plug when you can so I can order a set ASAP.

What I am saying is that if the hose does not go where it's supposed to go, take out the fuse.

When you get ready to hook the thing back up, make sure the hoses are in good condition and CLEAN. All stacks need to get the same amount of gas.

You can't call Tyson about this?

Here's one thread.

I have called him but he does this all day and heck if I can query you fine people for some ideas, all the better!

UPDATE

It is raining here and I dont have a garage yet so I can't do much until it clears. I was not able to yet get the correct "hot" plug info so if someone has it that would be a big help.

James,

Any local auto parts store should have an appropriate sparkplugs. You should query Tyson for the exact preferred plug. I would use NGK BP7ES for trouble shooting and in winter weather and BP8ES for summer and highway use. These are very common plugs.

Carb cleaner works ok for cleaning plugs. After cleaning, an hour in the oven at 300F helps.

Best,
Grady

thanks Grady, I will run out and get those now.

ok, got the plugs, thanks again Grady. Its getting dark now so I will check for spark and switch the plugs in the am. Would a fuel pump fail that suddenly?