Printable Version of Topic

Posted by: downrange Jul 16 2019, 02:16 PM

I am on my last nerve trying to get my 74 1.8 ltr L Jetronic fuel injected car started. Bypassed the seatbelt interlock to get the starter to work. Hot wired the fuel pump to get it working and still no go.

I am considering a carburetor conversion and see that Redline has a few kits. The dual carbs system has no choke and the single carb with electric choke has some distance from the cylinder heads. Anyone have any success they could share?

Posted by: SirAndy Jul 16 2019, 02:19 PM

Don't ...

Posted by: yellowporky Jul 16 2019, 02:37 PM

2nd the don't

Posted by: mepstein Jul 16 2019, 02:42 PM

Where in PA are you?

Posted by: Eric_Shea Jul 16 2019, 03:13 PM

I'll play along...

It seems the community has gone from:

1. Put carbs on - Early years when old schools couldn't figure out the FI
2. Don't put carbs on - Mid years when shade-trees dug in and became more knowledgeable than most old schools on FI systems. Parts were plentiful. They were/are correct.
3. Here and now...

Here & Now, harnesses are brittle, good parts are getting harder to find and, a good FI system requires a knowledgeable tech trained in the art of 50 year old FI systems. My take is, if your system is stock and you have all of the components, it may be worth a shot at saving it. That said, you can easily spend thou$and$ with MPS rebuild, TPS Rebuilds, leaks and bad wiring (a $500.00 harness from Jeff B. would be an EXTREMELY wise investment).

I guess my point is, I feel carbs can be a viable alternative as we are beginning to run out of stock FI resources. Good parts are just getting harder and harder to find and, it's an old system. ***They (carbs) will make less power when run on FI cams*** As you move forward plan on a motor rebuild with a substantial cam to take advantage of all that carbs can offer.

If you're considering an engine rebuild, I would go 2258 with the new stroker cranks out there and run either carbs or EFI the likes of The Dub Shop's Type 4 MicroSquirt system. An EFI system on a motor like that will change your world.

So...

*Try to keep it alive if you can.
*Don't feel bad if you have to go carbs but, look to the future and make sure you have your eye on the proper cam for the motor eventually so you can take advantage of them.
*Did I say look to the future? Modern EFI systems can be almost plug and play these days and they will reward you in technological leaps and bounds. It's amazing.

Posted by: lalee914 Jul 16 2019, 03:19 PM

You can find the factory workshop manual for the 914/4 fuel injection system and some manuals from Bosch for both the D and K jetronic FI systems here:

http://p914-6info.net/Manuals.htm

Hope this helps.

Posted by: porschetub Jul 16 2019, 03:37 PM

Keep it,I was able to download and print off a complete L-jet FI tech manual which is for a 912E but its essentially the same and very helpful reading.
IMO it important to know how it all works piece by piece and how all the parts should work together,this manual covers it all.

Posted by: dr914@autoatlanta.com Jul 16 2019, 03:40 PM

don't do it! Call me personally for tech advice and we can work through it!!

Posted by: jdamiano Jul 16 2019, 04:23 PM

Love my Redline Weber kit and Petronix distributor. Far less points of failure and it new!! The FI systems on these cars are just old. Can’t fix old. It’s a law of physics called thermodynamics. Keep the FI in a box somewhere safe in case the next caretaker of the car wants it. No shame it wanting new fuel and ignition systems.

Posted by: tejon007 Jul 16 2019, 04:31 PM

...completely agree with Eric.

It's not what you or I would or should do in such a situation...it's what's right for the owner to decide.

So, let's see:

Option 1: study-up or find someone that can diagnose an old FI system, including potentially fixing wiring and broken parts that may not be available -- but, can definately be an expensive option? (but, it might also be an easy fix after you know what's wrong)

Option 2: bolt on some carbs/manifolds in an afternoon and drive it, even though the cam isn't the correct one

Option 3: install modern FI (maybe install a crank sensor) and tinker with it some to set it up correctly. A little more work than installing carburetion and expensive.

Other Options: ??

Definately, if you put carburetion on, keep the FI parts in case you decide someday to restore it, which would not be difficult to do once you have all the working parts and the knowledge. New or rebuilt carb can get you back up and running and would be much less than converting to modern FI. Driving your 914 is a good thing!

Lots of 914s run dual carbs and IIRC, 914-6s had carbs on them too...

Posted by: bbrock Jul 16 2019, 05:08 PM

Convert it to a six, a Subaru, or even a Chevy V8 but for God's sake don't convert to carbs!

I'm with Eric on this. I've been at the point you are now and ended up with carbs. That was decades ago and if it happened today, I would take advantage of all the great info now available to better diagnose my FI to fully understand what would be needed to restore it to a reliable state. Then I would feel like I could make the best choice. Although I'd prefer an OE FI in good working condition, I'd still switch to carbs if it was the quickest and most cost effective path to a running and reliable car. It's your car, your time, your wallet, and your choice.

If you decide to go with carbs, I would stay away from the single progressive carb. I've tried those both on a 914 and a bus and got nothing but misery from them. Both those cars ran much better when I switched to dual single throat (34 ICT) carbs that used to be available very cheaply back in the day.

Posted by: thelogo Jul 16 2019, 05:30 PM

5

Posted by: Chi-town Jul 16 2019, 05:36 PM

The stock FI parts are over priced and don't really offer any advantage over a properly tuned set of carbs.

The old "different cam" theory is long dead as the part number is the same for our US market FI cars and the carbed cars in the EU market. Yes you can make more power with a performance cam but that's true on FI also.

If you do carbs purchase a new set of HPMX (no cold idle circuit to deal with) from Empi, open the up and inspect and clean them. Dorking around with antique used equipment is not worth it (especially ancient Italian Webers that weren't right from the factory).

Get a syncronizer and a wideband O2, set aside a day to drive around and tune then and you'll be very happy.

Posted by: SirAndy Jul 16 2019, 05:55 PM

That's why FI died some 40 years ago and nobody uses it anymore. Carbs rule today's automotive landscape for a reason!

Posted by: Chi-town Jul 16 2019, 05:58 PM

The stock 914 stuff is to keep it running and reliable.

I'd be all for converting it to a current FI setup but nobody wants to spend that kind of cash when carbs are $500

Posted by: jdamiano Jul 16 2019, 06:21 PM

You misunderstand the point. I don’t see anyone trying to make an argument that carbs are better than FI. Bosch were ahead of their time with the systems they made for the 914 and FI is superior to carbs. The point is 50 year old FI will never be as reliable as a brand new set of quality carbs and a new pointless distributor.

Posted by: Ansbacher Jul 16 2019, 06:22 PM

Get a good pair of Dellortos. Service them as needed. Make sure your intake manifolds are sealed top and bottom. You will have a great running car without FI headaches. If you use a 009 dizzy, you will not have to worry about any vacuum issues. Bob's your uncle.

Ansbacher

Posted by: mepstein Jul 16 2019, 06:31 PM

I learned long ago that just because I can’t fix something doesn’t mean someone else can’t do it. Just because the car won’t start doesn’t mean it’s time to trash the system. It could be something simple. You just may need a different set of eyes looking at the problem.

Posted by: SteveL Jul 16 2019, 06:45 PM

Please PM me your direct email, and I will send you the Official Captain Krusty L-Jet troubleshooting guide. He sent it to me years ago.
Thank you Cap'n.

Posted by: struckn Jul 16 2019, 06:59 PM

Bought my '74 1.8 9 years ago which has the single Weber progressive carb, had the cam changed for carb and it's run like this with no problems no tune ups of mechanical problems. The electric choke works great even in cold weather.
Here's a video coming home from Hershey Swap Meet climbing out of the river vally on the hill.

https://youtu.be/wMTxSHz_UKM

Posted by: SirAndy Jul 16 2019, 09:30 PM

I dis-agree.

The L-Jet system was used on more than just the 914 and the system is well understood and parts are readily available.

When i still had my 1.7L D-Jet i went through several months of trouble shooting and eventually merged 3 engine wiring harnesses into one good one and got the engine running as smooth as the day it came off the assembly line.

I've also had a warmed over 2056 with dual carbs and an aggressive cam. It had loads of power the few times it actually ran ok, but in terms of smoothness and reliability there just is no comparison. FI all the way.

Just try to start a carbed car jetted for sea level at 5000 feet up in the mountains and report back to me how much better than FI they are.

Posted by: Superhawk996 Jul 17 2019, 04:43 AM

I don't have a dog in the fight.

I had carbs on my 1st 914. Put an incredible number of miles on it without issues related to carbs. Ignition was usually the problem (bad points, wires, etc.). Carbs can be reliable.

As others have stated FI really is the better solution . . . no doubt . . . but it comes with cost and complexity. Just look at modern vehicles. They start at -20F with no issue and modern emissions couldn't be met without FI.

I'm a mechanical engineer with a background as an electronics technician that did repair down to component level (resistor, capacitors, etc.).

The biggest issue I see with the original FI and with issues on this site is wiring. You guys post pictures of wiring that makes me tremble in my boots. Especially the FI & engine harness wiring. This stuff has been exposed to the heat and elements for 50 years! Bad wiring and poor grounds will cause all sorts of intermittent problems that can make you want to slit your throat.

Second biggest issues is that these cars are OLD. Many of the sensors are mechanical in nature (MPS, AAR, decel valves, analog Engine Control ECU, etc). Things do wear out. Sure they can often be repaired or jury rigged but that takes time and effort. Lots of effort!

I believe that IF you take the time to properly sort out these issues the stock FI will be fine. I intend to put D-jet back on my project.

However, personally, if I could come up with the $$, I'd do the system below in a heartbeat. But. . . . you still have to fiddle with calibration, installation, wiring, etc.

http://thedubshop.com/dual-throttle-body-fuel-injection-package-with-ignition-type-4/

My personal reason for the above system is that I prefer the look of carbs and that system would at least get the FI into the digital age.

Posted by: DRPHIL914 Jul 17 2019, 05:58 AM

10 years ago this fall I bought a '75 2.0 d-jet car not running but figured we'd figure it out. I had never owned a 914 or a Porsche, but had a '69 Austin Healy 25 years before and knew I did NOT want to deal with the mess that was dual Webber carbs, and figured it was going to be a bit of a trip to sort it allout, but my first test was compression leak down and then starter fluid in the intake to see if it fired, as I had already checked and had spark at all 4 - simple - it ran , for a few seconds-
took it home cleand the system, tested some components and bam! BAD MPS-
and with new rebuilt MPS I was on the road-but over thenext year I proceeded to essentially replace all the smaller sensor components and vac and fuel lines , because as he said above its all OLD stuff no matter what - but I can tell you the issues ive had over the years were ususally related to some bad ground(FI grounds) or bad mechanical sensor (AR) failed CHT, what have you, but for past 5 years , trouble free and now with a 1123ignition distributor, like brand new. - most issues were wiring related and I replaced my harness with a new one with new connectors from Jeff Bowlsby , I did that fairly early in the process.
I am with Sir Andy on this in the long run MPG and performance will be better , way better with FI - and I have learned a lot - Yes carbs work and can be ok , but really not more simple than FI, clogged jets , floats etc.
- with that said, I had a BMW - 73 motorcycle, R90S and of course was carbs, and in MN it sat all winter , but really rarely had issue with it but I wonder what it would have been like to put FI on that?
but I digress-- do what makes you happy and you can deal with but do not fear the FI! I get 30mpg with my d-jet ., you wont get that with carbs.

Posted by: dr914@autoatlanta.com Jul 17 2019, 07:44 AM

George Hussey 1978 " do not remove the fuel injection". dr914 tech tips circa 1999 "do not remove the fuel injection" George Hussey 2019 "do not remove the factory fuel injection"

Posted by: dr914@autoatlanta.com Jul 17 2019, 07:50 AM

afc l jetronic fuel injection is MUCH simpler than mpc d jetronic fuel injection and is very easy to troubleshoot and repair. Parts are actually inexpensive for this car

Posted by: downrange Jul 17 2019, 08:21 AM

Mechanicsburg

Posted by: downrange Jul 17 2019, 08:25 AM

mschafer51@outlook.com

Posted by: downrange Jul 17 2019, 08:54 AM

Thanks for the offer. Will do before performing the operation.

Posted by: type2man Jul 17 2019, 11:36 AM

To the original poster, how long has the car sat before this problem happened? Or did this just happen from one day to the next. Also another thing to take into consideration is how good your mechanical abilities are? Fuel injection can get a bit complex, but so can adjusting a set of carbs to run properly. If you don't have great mechanical abilities and have to rely on someone to install the carbs or troubleshoot the FI, things can get expensive quickly....

Posted by: Rav914 Jul 18 2019, 04:26 PM

I'll dog pile on this one too!

I have a 1.8 (1.9 really) L-jet car. I went from:

1. Stock motor and FI to,
2. 1911 with Webers to,
3. 1911 with L-jet.

I prefer the L-jet to carbs any day. Much smoother idle and acceleration and better gas mileage. I feel like I lost a little bit of power, but it's what came with the car, so I feel it's worth any trouble it brings.

"Bosch Fuel Injection and Engine Management", by C Probst is a stellar book. Highly recommend.

Posted by: orthobiz Jul 18 2019, 05:37 PM

I've had three major bad running problems with my 1.8 1974 L-jet:

One was a stuck flapper in the air intake thingy.
One was a bad dual relay: car would run poorly for 30-40 seconds and then would konk out.
One was a fried engine harness.

Each problem fixed with replacement parts, a "good" used harness, a rebuilt air thingy and a new dual relay. Car running smoothly now.

Contact Tim about L-jet, he's an accessible expert. PM sent.

Paul

Posted by: downrange Jul 19 2019, 10:40 AM

Can you give me some info on the pointless distributor.

Posted by: mitchdiego1 Jul 19 2019, 11:00 AM

I have a 1976 914 non cat and I put a Pertronix Ignitor Electronic Ignition in my car just two days ago and it was like night and day the difference it made. "Djet"

Posted by: jdamiano Jul 19 2019, 04:29 PM

I run this Pertronix D186604 with their Flamethrower coil on my 2.0 with the Redline Weber dual 40 kit. I’m very happy with the set up. You will need a new fuel pump and it’s a good time for new fuel lines and filters.

Posted by: JamesM Jul 22 2019, 04:47 AM

I would (and have) save that $500 for injection every single time. Though depending on what you are starting out with you can do modern injection for under $500 if you know what you are doing. Even the best running carbs are still a compromise.

Why compromise?

Here is the rub though, from what I have seen, the learning curve for most people for a Megasquirt based system is pretty steep, I would say even steeper than figuring out l-jet/d-jet. If you have a stock motor and a complete injection system already, unless it is cost prohibitive to repair or you are worried about long term reliability I would stick with the l-jet.

Posted by: housepumpinpc Jul 28 2019, 07:23 PM

Thank you!!!