Is it too Rich?

deoxford · 12-04-2004, 03:27 PM

Today I took the car for a drive to the gas station, this was the first time it been out for a ride in a long time(10 years)
Any way I have two Proubems

1. I think the M/C is bad because it stops and the pedel is firm , then It gett soft and you have to pump it back.

2. THe car bucks really bad in first , If you let the clutch out till the RPM's get high. All the rest of the gears seem to be fine.
I was thinking that the MFI is too Rich , I noticed that I smell gas in the exhust..

What do ya'll think , to rich? How do you adjust it?

THe car is a 72 , with a 73 2.4T MFI

deoxford · 12-04-2004, 03:32 PM

Jim where are you?

tsuter · 12-04-2004, 03:49 PM

10years???? Get a full tank of gas, a couple cans of additive and drive it 400 miles on the highway before you do anything.
Maybe bleed the brakes first...sounds like air.

RoninLB · 12-04-2004, 08:02 PM

Quote:

Originally posted by tsuter
Get a full tank of gas, a couple cans of additive and drive it 400 miles on the highway before you do anything.

Maybe bleed the brakes first...sounds like air.

ditto.
There should be plenty of MFI adjustment available in search, after you do the best you can to clean out the fuel system with Techron or better. I don't remember who posted info on better than Techron?

Joehand1 · Joehand1's Garage

Was it cranked in those 10 years?

deoxford · 12-04-2004, 08:55 PM

Yes the I have run the engine over the last few weeks, and I ran it about 2.5 years ago when I pulled it fom the 73.

I scared to take it out on the hwy when it bucks so bad in first gear.

Also there is a one inch hose that goes to the MFI , I noticed it was loose when I wne to attach it . THe hose broke. Does that hose have to be in to make the MFI run correctly?

Zeke · 12-04-2004, 09:10 PM

Quote:

Originally posted by deoxford
Yes the I have run the engine over the last few weeks, and I ran it about 2.5 years ago when I pulled it fom the 73.

I scared to take it out on the hwy when it bucks so bad in first gear.

Also there is a one inch hose that goes to the MFI , I noticed it was loose when I wne to attach it . THe hose broke. Does that hose have to be in to make the MFI run correctly?

Yes. That hose comes off the heat exchanger and heats up the thermostat. With a cold T-stat, your pump is set at rich to help with warm up. if it never gets heated, you never get to normal on the mixture.

Please check your oil for the smell of gas and to see if it's thin. If it is, dump it. Then fix the hose and print yourself a copy of check, measure and adjust form the tech articles right here.

Jay Auskin · 12-04-2004, 09:30 PM

My '72 was sitting for 5 years. I bought it, rebuilt it, and it would idle really high. Now, it idles too low. The engine's characteristics changed dramatically after a few tankfuls. Also, make sure the tank is clean. If the inlet screen is clogged, it will never run right...and will probably stop running soon. If you haven't yet, check the tank...ask me how I know

deoxford · 12-04-2004, 09:56 PM

Is being too rich cause the bucking?

Grady Clay · 12-05-2004, 03:53 AM

Derek,
Now that I see your post, I’ll add some more.
Yes, heed the advice about the master cylinder. It can suddenly fail. Pull the carpet and floor board and feel in the pedal assembly and rubber boot at the master cylinder. Ian sign of brake fluid is cause to replace the MC. You will also want to replace all the bushings in the pedal assembly and the four rubber brake hoses at the same time. Also lube and cycle the pistons in the brake calipers.

Milt and Jay are right on. You are probably going to find rust in the fuel tank. There is a filter screen in the tank outlet fitting that can get clogged from the fine rust particles.

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

Here are some useful MFI threads:
“MFI thermostat spacers”
p. 1 end has CMA extension, p. 3 has nozzle, fuel flow, and fuel pressure.
MFI thermostat spacers

“More Fun with MFI and LM1”
How to use protractors for correlation.
More fun with MFI and LM-1
“More MFI”
More MFI
“MFI Problems”
MFI Problems
“MFI Speed Switch”
MFI Fuel Shut off solenoid questions
MFI tools
MFI tools for DIY'er

“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

E-mail to Grady:
Grady,
I have some problem with my MFI.... I think
I took the car for a ride today for the first time.
This engine has run setting in the drive way fro about 8 gallons of gas.
Well anyway when it is in first it bucks very badly till the rpm's get up and it gets moving.
I think that maybe it was running to rich.
I also noticed that the hose going to the thermostat was broken can that affect the richness that much?
Or do I need to adjust the mixture and if so how?
Thanks for the help
Derek Oxford
73 2.4t MFI

E-mail reply from Grady:
Derek,
Yes, the concentric paper hoses to the thermostat must be in good condition so the thermostat gets hot. The left heat exchanger and the large rubber hose also must be in good condition. You also may have diluted the oil with gasoline. This would be a good time for an oil change and inspect the sump plate.

Best,
Grady

evren · 12-05-2004, 04:54 AM

thanks Grady, I just bookmarked this thread for future reference...

deoxford · 12-05-2004, 07:51 AM

Grady,
I don't thgink the Gas tank and rust is the cause ,because I had the tank out and removerd everything from it. But I will but a filter on the hose.

I do beleive that the Thermostat is not getting hot , and there for I am stay rich......IF staying rich will make a car buck in first gear is the true?

I will do a oik change today also and get a new hose..

I will update as soon as I know

Grady Clay · 12-05-2004, 08:57 AM

Derek,

Notice that most of us are not addressing the “bucking” issue. There are more fundamental things necessary here.

If I were to prioritize things with the 911, they would be:

Don’t drive it until you have the brakes fixed. Crash car = 10 steps back or worse.

Change the engine oil and carefully inspect the sump plate screen. At the perimeter of the screen, between the screen and the case, is where anything unpleasant will accumulate. Smell the used oil away from the car. Can you smell gasoline?

Inspect the left heat exchanger for any air leaks. What is the condition where the three pipes emerge to the rear? Find a way to internally inspect the large rubber hose from the heat exchanger to the left side tin. That hose can fail internally yet still look OK on the outside. Mice nests are also a potential issue. You have the two paper/plastic thermostat hoses coming. Use the time to remove, disassemble, and clean the thermostat. There aren’t any special tools required and the instructions are in CMA (p. 37-38) and one of the above thread links.

Good that you have recently cleaned the fuel tank. When the tank was out, did you remove and clean the filter screen? Very important. No, you don’t need an additional filter in the fuel supply line. That will only increase the propensity for fuel starvation. Later, after you have everything running properly; replace the main big (expensive) fuel filter. Unless it tests restricted now, it is best to wait and let all the debris collect there and only then replace it.

As you go through this process, you will find us harping on CMA. That means Check first, Measure second, and only then Adjust anything. The issue for you right now is to get the 911 to run safely where it won’t hurt you or itself.
I wouldn’t touch the MFI without having all new ignition components; certainly cap, rotor, wires, plug connectors, distributor advance function, and regular plug changes as necessary during testing. While you are getting parts, do the fuel flow and fuel pressure tests. Bucking can be from insufficient fuel.

The common flaw in diagnosing and servicing the MFI is to assume something is OK and skip a step in CMA and extensions.

Best,
Grady

deoxford · 12-05-2004, 09:40 AM

Grady,
THanks again, I start from the top of your list and work my way down.
I will post what I find.. Also When can I buy the hose? I will be getting a new M/C this week .

Thanks again
Derek

Grady Clay · 12-05-2004, 10:08 AM

Derek,

The hoses are available from our host here:
http://www.pelicanparts.com/catalog/shopcart/911E/POR_911E_fuelij_pg4.htm#item23.

According to my ’72-’73 parts catalog they are:
901.110.295.00 for the inner hose.
901.110.296.00 for the outer hose.
These may supercede to later P/Ns.

While you are getting brake stuff, remember to get the four rubber brake hoses and the (6+) plastic pedal assembly bushings. Do some Forum searching on pedal assemblies – there is a “canary in the mineshaft” issue with the bushings.

Please answer questions even if it is “I don’t know but will try and find out.” All can chime in and help you. This is a very unique forum and there is a huge reservoir of skills and experience available to you for free.

Best,
Grady

c911s · 12-05-2004, 10:34 AM

Don't want to highjack someone else's thread, but I have a related question regarding MFI.
Recently bought a 73T with what appears to be a 69E engine and trans in it.
The previous owner had the car for 3 years and just drove it in the summers for about 3 months. He emissions tested it this fall and it failed the drive test for CO.
It idles ok when warming up and runs ok when not hot. After driving about five minutes when coming to a stop light and you take your foot of the acc to apply the brake the engine dies. Usually starts up with no problem, however a couple times, would not crank over for a minute or so, not the best situation when on a busy road! The warm up hose had a hole in it, I fixed that.
I can keep the engine running if I use the emerg brake to stop the car, while keeping the acc reving the engine; but it's a PITA to say the least.
The car needs lots of TLC, I have made a test run on parts order from pelican to see how CDN customs treats me, have 101 book and have read the threads on MFI etc.
I want to start at the tank end and restore parts, but would like to drive the car when the weather permits. Do not have enough time to start a complete restoration at present and have not finished my garage yet. I am going to replace plugs, wires, dist cap, rotor etc, but was wondering if anyone could offer insight to a probable cause?

Jay Auskin · 12-05-2004, 11:21 AM

Quote:

After driving about five minutes when coming to a stop light and you take your foot of the acc to apply the brake the engine dies. Usually starts up with no problem, however a couple times, would not crank over for a minute or so

Mine did that when my tank screen was clogged. This became progressively worse. More rust accumulated, and clogged the screen more. Waiting the minute or so allows the rust particles to fall off the screen, and allow for a little more fuel flow.

This is really easy to check. You just need a flashlight and a screwdriver. Remove the fuel sender, and look into the tank with a flashlight. You'll see right away if there's crap in there.

deoxford · 12-05-2004, 01:04 PM

Grady,
Thanks for the brake advice, I did replace all the rubber brake lines with SS, and Replaced most of the hardlines during the restore. I also replaced the front brakes with Carrera Brakes and new Rears , I did not do the M/C . I knew I should have and well I got lazy

As for the (6+) plastic pedal assembly bushings, I looking at ordering them also when I order the hoses on monday.

So this week the car goes back to the body shop for some little things , while it is there I am going to take the Thermostat off and clean it .
That way this coming weekend I can do the brakes agian, and the hoses.
Maybe take it out for a little ride is all goes well.

I will update the forum soon

c911s · 12-05-2004, 02:25 PM

thanks for the tip Jay. I have no way of knowing what may have been replaced on the car by previous owners. I suspect the tank is dirty, also suspect a lot more things could use updates. Wish my engine bay looked as good as some of the 'before' photos posted......

deoxford · 05:12 PM

Grady,
I hate to ask this question again but I don't know if the MFI is the cause of the BUCKING.. SO tonight I made a hose to replace the paper hose going to the thermostat , this does not prove anything ,the thermostat may not be working but..

I let the car warm up a bit and whated to see if it would buck still. well it did. It also bucked a little in second but not as much.

NOW this is the part that make me wonder, when I put the car in reverse it does not buck at all. IT will go smoothly in to reverse and no bucking..

So can the issue of running too rich not effect Reverse if so why.

I hate the ask this question again , I just what to make sure that the engine is the issue not the clutch or the trans.(remember I but the car together so maybe i did something wrong)

So if the engine is running rich it will buck and in reverse it will not?
I want to add that I checked to see if the fuel screen was clean and it was, Also The car Rev's up fine no sputter or anything like that.
Thanks again
Derek