Fuel injection issues? Possibly run carbs? Options

[bmtrnavsky]

My 914 has been sidelined since 2012 for a number of reasons but was parked not running. Pulled it out of mothballs and hauled it over to the local vintage Porsche mechanic who said my impulse sender had no signal. He said he was unable to source parts for it and was unsure if replacing that part would get it back on the road his recommendation was to convert to Weber 40's. I'm not rich so I understand his hesitancy to open what could be a very expensive can of worms.

So here is where my questions start

I'm just looking for a solid running reliable car that I can drive on trips and maybe autocross 2-3x per year.

anyone have a source on the impulse senders? can they be rebuilt?

Is the Carb it advice good?

I have a basically stock 2.0 with hydraulic lifters and a very mild cam.

Will I have to change my cam to convert it?

what's the best carb? I have seen 34's 40's and 44's people seem to do all three are there pros and cons to each setup?

Can I get this conversion done for around $1500 in parts and is it a achievable project for an average mechanic? I suck with electrical but I have plenty of tools and am not afraid to learn as I go. I have done head gaskets and other mid level projects before.

[brant]

which motor and injection system are on the car?

you can learn fuel injection
there is a lot of experts around here
I am not familiar with your mechanic's term of "impulse injector"
as there is no part with that name... so the mechanic is talking about something with a different name...

possibly the MPS
manifold Pressure Sensor

but there are other items it could be.
I'd look up brad anders website and read it 3x
then go part by part and test each of your Fuel injection components

some description of how it was "running poorly" when it was parked would help also

If you fix it yourself... your probably talking about a few hundred dollars
you may do other maintenance things like changing out all of the vacuum lines while your there... and that could cost a little extra... but should not run up to the 1500 limit your expecting for the carbs.

The Fuel injection system is not very happy with cam lift.
so depending on which cam you put in... that may matter also

brant

[BK911]

I swapped over to carbs for the same reason; parts were just hard to find and I got tired of trouble shooting the FI system.
Now parts are a LOT more available, and the FI knowledge is more accessible.
However, I still do not have ANY regrets making the swap.
Cleaner engine bay and easier trouble shooting.
You can pull your existing FI and put on a set of carbs with minimal effort.
I went with the EMPI HPMX 40s.
Pretty easy install.

[nditiz1]

You can carb it!

You will not need to change the cam, you should as the one that is in it is probably setup for FI, but you don't need to. You did say it is a mild one. Which one is in there?

You can do it for under $1500 depending on your mechanics labor rate. The carbs run close to $1000 I believe for a set of 40 Webers. 40 Webers are what you should go with. You will need a different Fuel pump or a really good regulator to drop down the FI pump. The linkage is where you can spend a lot or a little.

Tangerine Sync Link - Set them and forget them $300
CSP - good quality center pull system $150
Hex bar - Cheap garbage. Will work at first then start to deteriorate free when you buy a kit

The $1000 kit should also contain the manifolds. You may need to buy the phelonic? spacers/gaskets between the intakes and the heads.

So you can see you get pretty close to the $1500 mark in just parts. I feel carbs are very reliable and simple.

BUT but BUT but BUT...

FI does work well when it has no vac leaks or wire issues and was meant for that engine. It is reliable once it is all working. You can probably get almost a completely refreshed FI system for $1500 or under. I don't like dabbling in the dark magic as my brain is too simple to work with complex wires and hoses and wires and thingies. From what I have worked with is runs nice. The jury is still out on whether I like djet or ljet more. If you replace the wire harness and the vac lines and test all the components individually, replacing the ones out of spec, you should be pretty close to a reliably running car. Also, learn the items yourself since most mechanics don't know the simplest spell in an ancient old magic.

[bmtrnavsky]

which motor and injection system are on the car?

you can learn fuel injection
there is a lot of experts around here
I am not familiar with your mechanic's term of "impulse injector"
as there is no part with that name... so the mechanic is talking about something with a different name...

possibly the MPS
manifold Pressure Sensor

but there are other items it could be.
I'd look up brad anders website and read it 3x
then go part by part and test each of your Fuel injection components

some description of how it was "running poorly" when it was parked would help also

If you fix it yourself... your probably talking about a few hundred dollars
you may do other maintenance things like changing out all of the vacuum lines while your there... and that could cost a little extra... but should not run up to the 1500 limit your expecting for the carbs.

The Fuel injection system is not very happy with cam lift.
so depending on which cam you put in... that may matter also

brant

The part was the impulse sender that he could not find. So far I have not been able to either but said part does seem to exist. I googled it and found it for lots of other cars. for the 914 its NLA. Is there ayone that sells used parts for this?

[Superhawk996]

. . . . local vintage Porsche mechanic who said my impulse sender had no signal.

The blinker fluid is also hard to come by.

Signed:
Resident smart (IMG:style_emoticons/default/bootyshake.gif)

Time for a new mechanic in my opinion. I've been in the automotive industry for 27 years and have no idea what is meant by an impulse sender in the context of a 914.

It could be interpreted to be any sort of Hall Effect sensor (Crankshaft, camshaft, speedometer, ABS sensor, etc.). Of which, the 914 Fuel Injection system has zero.

Could it mean:
Injector trigger points? Maybe -- but can be obtained with some work.

Ignition points -- These are definitely available so suspect that isn't what he means.

Source for trigger points in a pinch - not completely unavailable.

[brant]

all of the FI parts are out there...
even if it means rebuilding the MPS yourself with a diaphram from CFR

but I still have no idea what an IMPULSE sender is.
that is the wrong word for what ever part he is trying to describe.
maybe call the mechanic and get him to explain what an "impulse sender" does... then we can translate it into the correct term to help

I like superhawks idea... he might mean the trigger points in the distributor

like I said... anything can be found, even if its in the form of a good used one...
but you have to know the correct label for "impulse sender" before you can search one.

if you found something on the internet, maybe send us a picture of it


also... as a warning... there are very few mechanics left that still know this injection system. most of those guys are long gone, and all cars quit using Djet sometime in the late 1970's

so I would be highly suspect of any mechanic's diagnosis
unless they specialized in old volkswagens, most of them have no clue

even if its the "impulse injector" and you buy one... your mechanic could be far off.
I'd test it myself before spending the money. How did he test it? How did he diagnose it? Like I said... most mechanics have no clue when it comes to antique fuel injection
and that is likely the reason that most mechanics just want to sell you a set of carbs...

because 99% of them don't know how to fix it.

brant

[Superhawk996]

On a more pleasant note:

If you are limited on monetary resources, carbs are a very viable option but if you are unable to do the work on them yourself, you will quickly find that they they too can be maintenance intensive over a couple years time which could put you right back at the mercy of a good mechanic as they age and need rebuilds.

Getting harder and harder to find mechanics that are good with carbs (IMG:style_emoticons/default/sad.gif) .

[dr914@autoatlanta.com]

keep the fuel injection call for advice, do not incur needless expense, do not devalue your car and make it unreliable

My 914 has been sidelined since 2012 for a number of reasons but was parked not running. Pulled it out of mothballs and hauled it over to the local vintage Porsche mechanic who said my impulse sender had no signal. He said he was unable to source parts for it and was unsure if replacing that part would get it back on the road his recommendation was to convert to Weber 40's. I'm not rich so I understand his hesitancy to open what could be a very expensive can of worms.

So here is where my questions start

I'm just looking for a solid running reliable car that I can drive on trips and maybe autocross 2-3x per year.

anyone have a source on the impulse senders? can they be rebuilt?

Is the Carb it advice good?

I have a basically stock 2.0 with hydraulic lifters and a very mild cam.

Will I have to change my cam to convert it?

what's the best carb? I have seen 34's 40's and 44's people seem to do all three are there pros and cons to each setup?

Can I get this conversion done for around $1500 in parts and is it a achievable project for an average mechanic? I suck with electrical but I have plenty of tools and am not afraid to learn as I go. I have done head gaskets and other mid level projects before.

[brant]

which motor and injection system are on the car?

you can learn fuel injection
there is a lot of experts around here
I am not familiar with your mechanic's term of "impulse injector"
as there is no part with that name... so the mechanic is talking about something with a different name...

possibly the MPS
manifold Pressure Sensor

but there are other items it could be.
I'd look up brad anders website and read it 3x
then go part by part and test each of your Fuel injection components

some description of how it was "running poorly" when it was parked would help also

If you fix it yourself... your probably talking about a few hundred dollars
you may do other maintenance things like changing out all of the vacuum lines while your there... and that could cost a little extra... but should not run up to the 1500 limit your expecting for the carbs.

The Fuel injection system is not very happy with cam lift.
so depending on which cam you put in... that may matter also

brant

The part was the impulse sender that he could not find. So far I have not been able to either but said part does seem to exist. I googled it and found it for lots of other cars. for the 914 its NLA. Is there ayone that sells used parts for this?

please tell us what year and motor you have
there are 2 different (stock) fuel injection systems for a 914

one is called Djet
the other is Ljet

different components and theory
so you have to tell use which system you have



EDIT
I just saw your signature
if its stock components for a 1973 2.0
then you have a Djet system


sorry I didn't see that previously.

[PCH]

The good news: it's probably something really simple to fix.

The bad news: it will take less time to install the carbs than it will take you take you diagnosis the problem with the FI.

[JamesM]

I'm just looking for a solid running reliable car that I can drive on trips and maybe autocross 2-3x per year.

You probably don't want carbs then.

Yes they will work, but they will be neither as solid running or as reliable as sorted fuel injection.

While the engineering behind D-jet is pretty complicated the actual troubleshooting and maintenance of it is pretty simple once you familiarize yourself with it. As stated, check out Brand Anders D-jet site. There are really only a couple major components that will cause serious issues and they are fairly simple to bench test.

[Lockwodo]

I'm a newby here and am working on getting the FI system on my '74 2.0 up to snuff. Not that complicated. Anyway, Brad Anders has a discussion about the tradeoffs between the stock D-Jet FI system and carburetors which has some interesting information and perspective:

https://members.rennlist.com/pbanders/carbs.htm

[mtndawg]

I've owned a car with carbs and a car with stock FI. The FI required less maintenance and tinkering. If you already have the FI, just clean it up and make it work.

[914werke]

What hasn't been brought up (in this thread) that bears repeating ....
FUEL! The fuel mixes today SUCK unless you are fortunate & buying
non-ethanol fuel.
Unless you are driving the car daily these fuels exacerbate the challenges with carbed cars.

[burton73]

All I can say is with my Porsche cars with FI, they start right up. It never mattered if my car sat for 6 months with a battery tender on it started right up. This is with fuel for California. I say FI is best. I am thinking of putting FI on my RAT Eng. that has carbs now

Yes, this engine was in one of Oscars cars



Bob B.

[r_towle]

Carbs FTW
I do believe an impulse sender is what we call a bar tender up here on Mass.

All joking aside, just fix the FI
It’s most likely something stupid simple.

[r_towle]

Looking at your location quickly I found
Modern Aircooled
And
Victory motors
Koby
And a few others

Houston has a decent Porsche car culture so I suggest you might want to look around for a shop that remembers how to work on your era of air cooled classic Porsches and VW because the FI is basically the same.

[emerygt350]

It can only be the trigger points (although impulse has such a nice star trek ring to it). I would suggest spending 400 on a 123 ignition as the triggers are getting to unobtainium and that will also address the points issues. The rest of the djet is available and reliable and we can help you sort it out.

Just fyi, my 73 2.0 djet was near basket case due to well meaning mechanics. It cost me about 1000 dollars to get it running perfectly. 4 injectors, rebuilt mps, new hoses, cleaning, and some new boots and gaskets, the new 123dizzy, and more gauges than god.

[930cabman]

I swapped over to carbs for the same reason; parts were just hard to find and I got tired of trouble shooting the FI system.
Now parts are a LOT more available, and the FI knowledge is more accessible.
However, I still do not have ANY regrets making the swap.
Cleaner engine bay and easier trouble shooting.
You can pull your existing FI and put on a set of carbs with minimal effort.
I went with the EMPI HPMX 40s.
Pretty easy install.

Ditto for me. From my perspective working with 50 years old electronics is just too problematic. I have done the conversion with several cars and never looked back.

Sure, when the Bosch FI system was new, it was unbeatable, but she has her issues when old.