911T sitting for 8 years... MFI not turning

[ken_kuchar]

Hi.

This is my first post. I have a 1973 911T Targa that I restored 15 years ago. With kids and life, it has sat for 8+ years. (I also have a 1973 911E Coupe, which I have been able to drive and keep running). Now the boys are in high school and college – and my daughter is in middle school, so I have more time on my hands to get my Targa running.

So, he's what I've done so far.
1) Changed the oil and oil filter
2) drained the nasty-smelling fuel (apparently I made some shellac over the 8 years, according to my chemical engineer friend) - picture
3) cleaned the fuel tank... oops, rust - picture
4) de-rusted the fuel tank; vinegar – didn’t work well, then electrolysis - this worked well (pictures)
5) again cleaned and then sealed the tank (POR 15)
6) got the fuel pump working by beating on it a bit and bench ran it enough with new gas to clean out any rust
7) replaced all the fuel lines, except the metal lines in the tunnel (flushed those out using the fuel pump and clean gas); this was a PIA without a lift
8) replaced the fuel filter
9) checked to make sure there was new fuel at the MFI inlet and outlet (didn’t measure pressure)
10) cranked it over, but it didn’t fire at all
11) checked to make sure I had spark; yep
12) noticed there was no gas smell on the spark plug
13) read about MFI and injector clogging… hmm… wonder if the MFI drive is even turning; nope.
14) MFI drive is not turning when I crank over the engine (it rotates about 15 degrees and stops while the engine continues to crank).
15) HELP
- ideas on why the MFI is not turning? I can’t see the bottom belt gear, but I assume it is turning and has worn down the belt in that spot because the MFI pump is seized)
- do I need to check the cold start system to get it to fire up?

Help is appreciated.

Ken

[ken_kuchar]

I'm still learning to use this tool. Sorry.

[ken_kuchar]

[Trackrash]

I think you will find that MFI pumps are very susceptible to corrosion after sitting for long periods. Probably time for a rebuild.

BTW, that tank looks really good. Any leaks?

[ken_kuchar]

There are no leaks in the tank. The electrolysis worked well, but it took like 2 weeks and each night I would file the iron anode and top off the electrolyte. The current would drop to zero and then go back to about 4 amps after cleaning the anode.

[Arne2]

I'm going to bet that the pump is gunked up inside and stiff to turn. In addition, either the drive belt, the drive gear (on camshaft end), or both are badly worn allowing the belt to spin free while the engine cranks.

I'd call Mark at MFI Werks to see what his lead time is. Plan on sending him the pump for cleaning and calibration at minimum. I'd also send all 6 injectors for cleaning and flow testing. Plan on replacing both drive gears and the belt.

[ken_kuchar]

This helps! Thanks.

[john walker's workshop]

Slide the belt off the pump or cut it off, then see if you can turn the pump by hand. Needs a new belt anyway.

[yelcab1]

Originally Posted by john walker's workshop

Slide the belt off the pump or cut it off, then see if you can turn the pump by hand. Needs a new belt anyway.

I sometimes do this out of frustration.

[jpnovak]

Given all the crud you found in the tank and that your fuel pump was also gummed up my guess is the same happened to the injection pump.

I would pull the injection pump from the car, take off the side cover and soak in a gallon can of Berryman's B12 Chemtool or other suitable solvent to soften and dissolve all the old fuel. Then lubricate all the springs and plungers and see if you can get it to turn properly.

The pump should easily spin by hand.

While the system is apart/off the car, buy a cheap ultrasonic cleaner from Harbor Freight and start to clean your injectors. Keep running them through with suitable solvent until the solvent is clean.

[ken_kuchar]

Fantastic! Thanks.

[356RS]

Originally Posted by jpnovak

I would pull the injection pump from the car, take off the side cover and soak in a gallon can of Berryman's B12 Chemtool or other suitable solvent to soften and dissolve all the old fuel. Then lubricate all the springs and plungers and see if you can get it to turn properly.

Taking the side covers off and soaking the pump in solvent will not get any solution into the plungers. Only way to get solvent into the cylinders/plungers is to fill the fuel head with solvent via the fuel banjo fittings. Fill it completely then plug the banjos.
Plunger to cylinder clearance is very tight, .008mm to .005mm. So if they are frozen it's unlikely that the solvent will help much but it's worth a try.

[ken_kuchar]

Update.

I removed the injectors and cleaned them with ultrasonic and Berryman's. They look good, anyway.

I removed the old MFI pump belt and it was toast. There were places where the teeth were worn off.

With the belt off, I could turn the MFI pulley by hand. It kind of stuck at one spot for a few times, but seems to clear itself and now turns easily by hand. So, before I pull the pump, I figured I try something... I turned the ignition on and could hear the fuel pump. I got out my drill and used it to turn the pump using a new belt. I was hoping that gas would shoot from the top of the pump where I removed the 6 lines to the injectors, but nothing came out. Is this expected?

Ok, and how the hell do I get to the one hidden nut on the MFI pump... I can't even see it?! Help.

[john walker's workshop]

You know the pump is timed, right?

[Jonny042]

I know enough about MFI to be dangerous..... but just to myself, not others. I rebuilt and tested and calibrated my own pump. Knowing what I know now, I will never let an MFI motor sit for long without running.

The oldest piece of advice in the book is only partially correct - checking to make sure the pump turns freely is great, but you need to make sure that the first time you turned the pump, the plungers (or some of them) don't stick up in their bores. If they do, it's not likely that any amount of fiddling without taking the pump apart is going to clear up the problem.

I would definitely recommend getting the pump checked out, at very least to make sure it's operational and all 6 plungers are operating in the full intended range. And the injectors tested to make sure they pop off with a nice "poof!" of fuel instead of dribbling out.

[356RS]

Originally Posted by ken_kuchar

With the belt off, I could turn the MFI pulley by hand. It kind of stuck at one spot for a few times, but seems to clear itself and now turns easily by hand.

When you turned the pump by hand and felt a hard spot, it was a plunger or 2 that was sticking in the cylinder. After you turned it a few times and it seemed to turn better it's because you forced the plunger up into the cylinder and it's stuck there now. So yes it would seem to turn easier without that stuck plunger in the way.
That nut in the left corner is a tough one. Remove all the metal fuel lines. I use a 1/4 in universal joint 13mm on a long 1/4 extension. I use a good light and mirror to see the nut and guide the 13mm socket down onto the nut.

[30westrob]

Originally Posted by 356RS

Only way to get solvent into the cylinders/plungers is to fill the fuel head with solvent via the fuel banjo fittings. Fill it completely then plug the banjos.
Plunger to cylinder clearance is very tight, .008mm to .005mm. So if they are frozen it's unlikely that the solvent will help much but it's worth a try.

I have returned to service, several pumps. As Mark said you must get cleaner into the fuel head. On the bench I positioned the the banjos vertically with short hoses and sprayed carb cleaner into them. Daily rotation and cleaner eventually resulted in spurts of cleaner from the top. It took approximately one week to get all 6 working. Rob

[ken_kuchar]

Thanks, guys!

[ken_kuchar]

update. Thanks to the help from this forum, I've made good progress. I'm spelling out the details of cleaning my gunked MFI pump in hopes this helps someone else.

1) Removed the MFI pump
2) Removed the side covers on the pump, turned the pulley by hand, and only saw 1 of the 6 springs going up and down. The others were clearly stuck.
3) Created a setup with 2 clear tubes connected to the fuel input and output on the MFI pump.



4) Filled the 2 tubes with Berryman's B12 and marked the liquid level. And watched it. Very slowly the level dropped, indicating the Berryman's was flowing into the MFI pump. At first, there was brown diffusing into the clear liquid.
5) Used my drill to slowly rotate the pulley and liquid dropped even more.
6) I let it sit with liquid for a few hours, turned the pulley, filled it back up, waited, and repeated this over the course of 2 days
7) then 3 springs were moving, then 4, then 5, then all 6.
8) I pumped more B12 using the drill and spinning it fairly quickly. After a while, the B12 started shooting out of the top of 1, then 3, then all 6.
9) I drained the pump (I'm sure the oil had some B12 in it), reassembled it, added new oil to the pump, put it back in, timed the belt, tightened it back up,...
10) with the injector lines disconnected, I sprayed brake cleaner through them, one at a time. Then I put in the cleaned injectors with new copper washers and connected the injector lines.
11) I turned the engine over for a bit, it sputtered and then it fired up and was running!!!! It sounds good and even idles well.

Thanks again for the help.

Now, for more help.

For a car that sat in a garage for 8 years, are the following things must do, nice to do, or not needed?

A: replace brake fluid - must do
B: rebuild brake calipers with new kit - ?
C: Master cylinder; rebuild or replace - ?
D: Transmission fluid replace - ?
E: CV joint re-grease - ?
F: Wheel bearings - ?
G: What else?

Thanks!

[Arne2]

To me, item E is optional, if the boots aren't torn. For C, don't rebuild, replace.