69 mfi adjustment
 

I am working on a 69 911e motor and would like to make it a bit more driveable. Let me say that the motor runs strong like a race car. For the past 5 years I have used it only 2 or three times a year. To go to FCA race events, never had a problem on the track, but now I would like to drive it more often. I would like it to make it more street-able, user friendly and still run strong. I have been working on this motor for over 10 years and never played with the fuel injection because that is what the hayes manual says.
Here is a list of the motor upgrades:
K&n filter
Bosh distributor with optical pick up
Bosh coil
Crane cams optical ignition
Perma Tune hid unit
Firebraid wires
S type Platinum plugs
Sebring exhaust

I recently came across the tech info for the injection and am not sure what to do. From what I’ve read, these things don’t need any normal adjustment and if there is an issue it is most likley not the injection. So, check everything else first and then double check. I have done that and it runs great but it back fires every time I let off the gass, the fuel pump has a gremilin, a cylinder looks to be running a little ritch, is hard to start when warm, heats up in trafic, never runs good cold. It will drive and idle fine even when cold but I need to keep the revs above 3500 to go any where.
The cold running looks easy to fix by getting new thermostat hoses, I have never had them on. Will this affect my over all performance? Is it running rich all of the time? Will that hurt the car? It runs good and I don’t want to mess with a good thing.
The warm start issue is confusing. I don’t have the thermostat hooked up so why is it hard to start. I think if I make a dash switch for the enrichment solonoid? The one that pumps gas in to the air cleener. That should fix it. Squirt some gas and it fires right up.
any sujections would be great.

Welcome aboard! SmileWavy

You've come to the right place. 1st off, ignore the "Here be Dragons" wording of the Haynes manual. It's rubbish advice. Everything that you'd ever want to know about the wonderful MFI system is right here in the Pelican Technical Articles section. It is perfectly possible to tune and adjust your MFI and it's really no more difficult then tuning carbs. It's just different. The important thing is that there is nothing that you can do to the injection system that will generate more HP in your stock engine beyond making sure that it is functioning correctly and tuned correctly. Your car's MFI system is essentially the same system that was used on the 906's, 908's and 917's with a few sub-systems tacked on to help it run well at idle. Unlike later injection systems, none of these enhancements hurt the top end performance in any way! Focus in on the Check - Measure - Adjust document (CMA).

1) First you need to size up what you have. Are all of the hoses there?

2) The symptoms that you describe sound like someone has mucked around with the system and possibly disconnected the cold-start and cold-idle systems in the interest of "improving" the MFI. They failed. It's a common "upgrade" which is done to The systems are there for a reason and disconnecting them doesn't make anything better.

3) The only "modification" which is generally recommened for the early MFI system is to disconnect the cold-start system that trickles fuel down the stacks -- it's a fire hazard. In the case of my car (also a '69E), there is a simple switch that you can add which will peg the adjustement rack to full rich when cranking the engine cold which works a lot better and doesn't risk an engine fire.

4) As far as improving the driveability of your car, I'd recommend you check into an MSD ignition system. It makes a pretty big difference in the 2-liter engines and less of an impact in the later engines since their combustion chamber is better designed. The multiple sparks do wonders for improving the engine's part-throttle transition in the 1500-3000 RPM range. Above that engine speed the system doesn't perform any better then the factory electronic ignition system.

Be sure to post pictures. Are you registered on the E-Registry?

Thanks for the reply. I have read through all of those files and am fairly confidant that I can do the work needed. I have the mfi tool kit but it looks like I will start out by checking the linkage- butterfly valves with a flow meter. That procedure looks easy enough.
The thermostat hoses were never hooked up? I got the top two years ago but never installed them cuz I couldn’t find the one that hooks up to the heat exchanger. Will these hoses only help cold starting or will they improve over all performance. The thing runs great I just want to improve the starting and cooling.
The switch you talk about. I was thinking of putting a momentary switch in the dash and use it to trigger the ground on the enrichment solenoid, to spray gas in the intake. It has never functioned and I plugged the hose up a long time ago. How did you wire up the switch? Did you need to use a relay?
Or are you talking about the servo? Thing. That pushes on the throttle and has an adjustment screw. That thing never worked and I lost the screw years ago. When the car starts it idles fine every time. I don't think I need to hook that thing up? I just want it to start every time and I know if I squirt fuel it will start no problem.
The msd looks like a cool upgrade but I don't know if I need it. On the freeway the car runs over 3,000 rpm and msd will not help there. I am curious how it would help when the motor is cold. If I want to start the car cold and drive away I need to keep the revs up and feather in the clutch. 5 min later and it runs like a champ. Will the msd help with that or is that an injection problem?
How about the heat in traffic? It never got too far over 210 but it did stress me out. Normal driving it will run around 200. Is this normal? I am thinking about getting one of those oil filter heat sinks. They advertise 10% less heat. That is just what I want. I am also thinking of adding a fan to the oil cooler
I am not on the registry. My E died years ago due to a head on collision. I think I got some bad advice. I ended up scraping the car and putting the motor in a 67 912.
I appreciate the help. This would have been great when I got the car years ago. It was my first car and I was not confidant working on the thing. The worn out bosh distributor and points made me hate to work on it. It was like shooting in the dark.
Thanks again for the help and I will get some picks up today.

Usually what people do is disconnect those systems and then richen up the MFI just enough so that it will start. The problem is that this can make MFI so rich that it fouls plugs and washes the cylinder walls with gas -- both of which then give MFI a bad name.

Quote:

The switch you talk about. I was thinking of putting a momentary switch in the dash and use it to trigger the ground on the enrichment solenoid, to spray gas in the intake. It has never functioned and I plugged the hose up a long time ago. How did you wire up the switch? Did you need to use a relay? Or are you talking about the servo? Thing. That pushes on the throttle and has an adjustment screw. That thing never worked and I lost the screw years ago. When the car starts it idles fine every time. I don't think I need to hook that thing up? I just want it to start every time and I know if I squirt fuel it will start no problem.

An easy way to rig a cold start with a 2.0 MFI is to run a switched 12V wire to the cold start solenoid. ('70's and later cars don't have this solenoid on the MFI pump.) I did it on my car and I've heard it is similar to what the factory used to do on some of the race/rally cars.

In the case of my car, I spliced a wire from the start circuit at the ignition switch and ran it to an unused switch on the dash. From there I ran it back and connected it to the cold start solenoid on the MFI. When the switch is closed the solenoid gets 12 volts as long as the starter is engaged. This 12v pegs the MFI's rack at full rich and the engine starts with just a couple of cranks. It's much neater then pouring raw fuel down the stacks.

I just make sure to open the switch after starting the car since trying to hot start the motor with the switch closed will result in the motor flooding.

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The msd looks like a cool upgrade but I don't know if I need it. On the freeway the car runs over 3,000 rpm and msd will not help there. I am curious how it would help when the motor is cold. If I want to start the car cold and drive away I need to keep the revs up and feather in the clutch. 5 min later and it runs like a champ. Will the msd help with that or is that an injection problem?

First off, all of the early 911's need some hand-throttle to keep them idling while the engine is cold. As the engine warms up the idle speed will increase and you can back off on the hand throttle. That being said, you shouldn't need to drive around with the engine idling at 3000 RPM.

Quote:

How about the heat in traffic? It never got too far over 210 but it did stress me out. Normal driving it will run around 200. Is this normal? I am thinking about getting one of those oil filter heat sinks. They advertise 10% less heat. That is just what I want. I am also thinking of adding a fan to the oil cooler.

That sounds about right for a 2.0 E. Mine rarely breaks through 210 except on hot days, but then I don't track the car. The "Cool Coller" is a waste of time. As far as a fan to the oil cooler, does your car even have a front cooler? If it does, AND its running up above 210, you might have something else going on. That's an awful lot of heat out of a 140 HP E motor. The factory didn't install external oil coolers on the 2.0E's because they didn't need them. The oil cooler attached to the engine was adequate.

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The worn out bosh distributor and points made me hate to work on it. It was like shooting in the dark. Thanks again for the help and I will get some picks up today.

That's when it makes sense to update the distributor with an optical trigger kit. Set it and forget it.

i got a page up for the car. a bunch of before picks :) i have a lot of work to do and it is mostly cleaning and painting. i would like to start driving the car soon.
http://www.cardomain.com/ride/2342860

:) thank you. i am learning :) that makes a lot more sence. it is called the enrichment solonoid, i was thinking of the thing on the filter. this is exactly what i need to figure out.
for the heat thing.

i do apreciate the advice on the oil cooler. it looks too good to be true.
i think that is the cooler i am talking about. the main oil line from the tank goes in to it, it's aluminum and says behr. it is tiny but it does have fins like a a raidiator. it was just a thought. i live in the bay area, ca and there is all ways stop and go trafic some where. i hate sitting on the freeway and watching the temp needle go up. normal driving it stays cool, even on the track it never got over 210 but sitting in stop and go traffic for longer than 20 min and it gets hot. some times it takes and hour to go 5 miles.
you have been a great help. thanks again.
here are some picks, to show you what i'm up against.
http://memimage.cardomain.net/member...860_4_full.jpg http://memimage.cardomain.net/member...60_11_full.jpg

ditch the platinum plugs and go with Bosch Supers. platinum plugs foul too easily for MFI in my humble opinion.

It sounds like you're talking about the cooler that is mounted on the engine. That is already blown by the engine fan. If you look at the fiberglass engine shroud, there should be a channel that flows air back to that cooler. That channel I believe was on all but the earliest of the 911's.

i got the brakes back on and gave her a bath :) she needed it.

i have tried many different plugs from ngk to bosch. the ones in now are the green platnum. i think they are for the s model engine? they are low profile and have a needle like electrode. they are expensive but work the best

i might be paranoid about the temp problem? it only did that once in the middle of summer and i think i had an exaust leak? like i could tell over the glass pack. it is allways in the back of my mind but i think my focus should be in ather areas.
here are a few better picks.
http://memimage.cardomain.net/member...60_36_full.jpg http://memimage.cardomain.net/member...60_38_full.jpg

It looks a lot nicer now!

i tried adjusting the idle today. the adjustment hole in the fan shroud is on the wrong side? i had to get a dremmell and cut one. i want the idle to be 800-1000rpm and now it is at 3,000. i did the recomended 2 clicks leaner took it for a drive and dam. it woulde't go any where and stalled out when i let off the throttle.
long story short, my fuel pump went out :(
the thing will still start and run but not good. i know it's the pump cuz that familiar pump whine is gone. i have a replacement but my dad took it cuz it was in a box of stuff he thought was for his ferrari. he is on vacation and won't be back for two weeks. boo hoo.
so i am looking for a cheep pump i can use to tune in the car. till then i'll just keep cleaning :)

i did some more reading in the check measure adjust book. the enrichment solonoid looks to be hooked up to a delay relay . did you try to use this first? the book dosen't say how long the relay stays open but i'm thinking not longer than 30 secconds.
i also found that there is a switch on the peddal box that helps stop back fire when you let off the gas. i need to hook that up.
my fuel pump should be here next week.

i finaly got a fuel pump in this week end and had some time to tune it in. it started up fine and idled good. i drove it around the block and it started smoking at idle. i turned the idle screw back two clicks leaner and it cleared up, mostly. i went two more clicks and it runs great but has a high idle. like 1,600 rpm? i want it to run like this but idle at 800-1,000 rpm.
i need to check the injector pump belt timing before i try any other tuning. i know i got it right when i replaced it but it could need an adjustment. the low rpm smoke could indicate that the injection is ahead of the cam? i'll have to check it out? i know when the injector timing is off it will smoke like crazy. the timing could be adjusted to bring down the idle but i have the timing set perfect. it has good power from 3-5k rpm and screams from 5-7k.
everything else looks to be in good shape. the linkage is tight but free. timing is good, advance good. i would like to check the idle screws and butterfly positions but i think that will be the final adjustment. it still has cam cover oil leak but i plan to get turbo valve covers and tefflon gaskets. i don't want to catch on fire.
i want to get this thing on a dyno. it runs strong and i want some numbers to brag about :) it is advertised at 140hp stock. i think the upgrades got me 20-30hp? sport exaust, K&N filter, crane ignition. i would like to find out
i'll clean the motor and take some picks soon. i have to wait a week to get an insurance quote cuz the VIN is only 6 digits??? :(

superhighperf;
I hate to break this to you, but I doubt that you found 20 to 30 HP. If you did you'd almost be driving an 2.0S, and those engines had significantly different cams, porting and CR, not to mention a whole host of other details in order to get up to 170 HP (DIN). If you come in between 140 and 150, you're doing pretty good. The sport exhaust may even net you a slight loss in HP (AKA: Torque) between 3000 and 4000 RPM.

It will be interesting to see what the dyno says. I'm happy to hear that the fuel injection is running better! SmileWavy