MFI adjusting tech manual

[Lexluther]

It here a book or manual I can buy to adjust my MFI injector pump? We now have it running, but that is it...it rev's up and you can drive it around the yard, but it is running way too rich. My friend took the pump apart in order to unstick the pistons, anow ther out of wack..

I have read alot of the .PDF manuals on this site, but they dont tell much on the inside of the pumps. Thanks

[MobileWrks]

http://www.auto-solve.com/mech_inj.htm

[HarryD]

Lex,

While I am not a MFI Guy. I have always heard that you need the "Check, Measure Adjust" manual. It is in the tech section here.

[Lexluther]

I looked and cant find it, anyone have the link?

[Wayne 962]

All you need to do is type "Mechanical Fuel Injection" into the search box at the top of this screen, and it pops right up (in the results section under technical articles).

I don't understand why people don't use the search engine?

http://www.pelicanparts.com/techarticles/911_MFI/TipMFI.htm

-Wayne

[Lexluther]

What kind of injection do I have?..K, L,....? I've been calling it mechanical injection.

[HarryD]

If you have the stock 2.4 liter engine, you have Bosch MFI. The "book" is here: http://www.pelicanparts.com/techarticles/911_MFI/MFI_check_measure_adjust.zip.

Post a picture of your engine compartment and, usually, it is pretty obvious what you have.

[Lexluther]

I know what i have, 2.2 litre, mechanical fuel injection, but the book i found said it was for "L", "K"...injections.....several injections with letters, NOT mechanical FI... Whats the link with the .zip supposed to do?.. Is there instructions on the site, or do i need a certain book, Does my mechanical fi have a " letter" name? Sorry, just a little confused.

[Lexluther]

I think I found the manual.... thanks.

[HarryD]

Hi,

Hope it helps. If you use the search button here, you will find a weath of information to both enlighten and confuse you. Read carefully and good luck.

[svandamme]

Originally posted by Lexluther
I know what i have, 2.2 litre, mechanical fuel injection, but the book i found said it was for "L", "K"...injections.....several injections with letters, NOT mechanical FI...

MFI on this board generally refers to the sequential injection system with a timed pump and individual throttle bodies.

the Jetronic mechanical injection is usually referred to as CIS


MFI is superior to CIS , in that it has the best throttle response(instant), but is more expensive and a bit more of a hastle to tune, doesn't lend itself well to changes in the engine(the pump has to fit the engine), it delivers fuel based on a space cam in the pump, wich is timed to the engine through a belt. because of the expenses, Porsche stopped using it in 74 for production engines although they kept using the system on race engines for at least another 8-10 years at which point they moved to ElectronicFI

CIS (the various Jetronic types) is more of a compromise to meet enviromental regulations, while still beeing affordable
it was used on anything from Porsches , Ferrari's to Volvo's and VW Golfs....throttle response is far from perfect, there's no individual throttle bodies , but it doesn't care what engine mods you do it (short of maybe very high lift cams) , is sort off self adjusting because it delivers fuel based on air mechanical metering




as far as i know , there are no books around that cover MFI , none except the Bosch service documents such as "Check Measure Adjust". Grady , how about you writing one ? i'm sure you'll have plenty of buyers 101 things to do with your MFI system ( or 101 things NOT to do )

[Early_S_Man]

The link MobileWrks posted is to a page explaining the Bosch CIS system known as K-Jetronic ... a rabbit trail you don't need to go down!

However, you already had the question posed by this thread answered days ago in your earlier thread ... had you bothered to check! Grady posted the link to Pelican's MFI page on 30 November 2005!

1971 911E Fuel injection problem

Soak the MFI pump in Berryman's B-12 Chemtool for a few days ... it usually frees up without having to do any dissassembly or adjusting at all! After freeing up, let the pump dry out ... then soak in Marvel Mystery Oil ... and turn it over a few times every day for a couple of days.

You don't need to be messing with internal adjustments to the MFI injection pump! All that will do is guarantee that it has to be sent off to a professional for rebuilding!!!

[Lexluther]

I have read this stuff, theres no real info there, it all runs around the subject but nothing to tell me how the "pump" actually works, even a couple of the breakdowns leave certain views out, For some reason Porsche is very cryptic anout these models, We did soak it and used 3 different chemicals, it was welded with varnish, had to be taken apart, and we will finish the job, once fe find some info on it. Thats why you have to send these off to have them "fixed".... If you had the info, or a better understanding of them, you could save yourself $1000... And they certainly dont want that..

[Lexluther]

I have read this stuff, theres no real info there, it all runs around the subject but nothing to tell me how the "pump" actually works, even a couple of the breakdowns leave certain views out, For some reason Porsche is very cryptic anout these models, We did soak it and used 3 different chemicals, it was welded with varnish, had to be taken apart, and we will finish the job, once fe find some info on it. Thats why you have to send these off to have them "fixed".... If you had the info, or a better understanding of them, you could save yourself $1000... And they certainly dont want that..

[svandamme]

fact of life ... mfi pumps that get stuck and seized up... aren't always fixable with a soak... they are quite delicate that way and once they are well out of wack , they need to be sent off to a shop...

trying to rebuild it yourself migt very well leave you with a lot of parts and then the real shops won't even touch it anymore...

[Lexluther]

I will say this, I will never pay $1000+ to have a pump basically re-adjusted, I will learn how and do it myself, change to carbs, or sell and chaulk it to a little experience. Someone on this forum had to figure them out, has anyone even tried? It would be so beneficial If a person "cracked" the pump code. Talk about tweeking! My brother uprooted EFI from a 302 early '90s and installed it , and the wiring harness on his '71 Mach 1, 351 cleveland!.... Purrred like a perverbial kitten! .....Injectors, mass air, computer..... To my knowledge theres no manual to show how to do that either...!

[svandamme]

good luck , you have all the tools to fabricate replacement parts then? cause you sure as hell can't order any...

[Lexluther]

what fabrication?..is something broke?.. TO my knowledge my pump needs adjusting, I am fairly sure nothings broke.

[304065]

Lex,

I admire your tenacity. However, in the US, only a couple shops like Pacific Fuel Injection (Gus Pfister) or Henry Schmidt at Supertec have the experience, special tools, and the required inventory of used parts to correctly repair MFI pumps. Bosch sold all of the repair equipment and the entire inventory of spares back in the 1980's-- ever since then, the pumps are repaired with a dwindling amount of NOS parts and usable spare parts from other pumps. And it was never important to Porsche that the MFI system be cheaply rebuildable-- why do you think the 911T came with carburetors?

Sure, there is nothing preventing you from taking it apart and trying to get it back together. But knowing how to do that, knowing all of the settings and having all the experience to do it right the first time and not trash the pump or blow your engine, well, it's a long shot.

You found the right book, though. As you can see on the first page of the Repair Manual, the instructions have been updated to cover the double-row ("VR6") injection pump, which is called "PED 6 KL" which I am guessing means, in German, "Pumpe Einspritzung Doppel-Reihen." The single-row pump you see on the cover is probably not familar to you yet, but the MFI gurus here will recognize it as the single-row pump from the early 906E and 910 engines. Porsche used this technology as far back as the early 1960's.

So in that manual, you can see all the special tools and wrenches and procedures that must be followed EXACTLY for the pump to work correctly. The rebuilders who have experience with these pumps, and also the facilities to test the injection output per stroke through the pump's 0-4000 RPM speed range, have the ability to do that. I'm not trying to discourage you from doing it, but just making you aware that cracking open that pump is not for amateurs: you do NOT want the thing to fail when the engine is at wide-open throttle under load, or you will be spending a lot more than $1000 to repair the engine!

It would be far better for you to look around on Ebay or junk yards for a good working '71 E pump, identified by the ID number ending in -010, the trouble is, you won't save that much over a rebuilt one. Perfect ones, that have been filled with Marvel Mystery oil to preserve them go for around that, so you might not be better off buying used.

Conversion to carburetors was a popular thing to do back in the 1980's because so many people didn't understand, or wouldn't take the time to learn, how to properly set up and adjust the MFI system. So you see lots of 2,2 E's running around with Webers, which costs about 10 Horsepower, and doesn't have the same throttle response, not to mention originality, plus you still have to get a set of Webers or PMOs and change the electric fuel pump. These days, with the availability of the kind of information we have on Pelican, a lot of guys are converting BACK to MFI, which is why the stuff is getting expensive.

Anyway, good luck with your problem. If I were in your shoes I would call Henry Schmidt at Supertec and arrange to send your pump to him, you will save money, time and frustration in the long run.

[svandamme]

Originally posted by Lexluther
what fabrication?..is something broke?.. TO my knowledge my pump needs adjusting, I am fairly sure nothings broke.

if certain parts are welded by varnish. then the individual pistons might not be in good shape either...that's not an adjusting issue

and then what John said...