The FI carb debate, Need your input to dedice what I need to do Options

[Type 47]

Back in the day the hot setup was to put carbs on and ditch the FI. Now everyone seems to be in the FI camp. So what's the deal? Back in the day did people just start having issues with a FI component and say F it I'm putting some nice dual 44 IDF Webers on this sucker?

My situation is that I'm starting to put everything together after rotisserie paint & body work. My spend is way over what the value of the car is...which I expected, but I haven't touched the engine yet.

Engine only has 62K miles on it. Had Webers put on it but just bolted on with no cam change.

I have no problem with cracking it open, putting in new bearings, and the right cam for the carbs...but everyone says put the FI back on.

The PO gave me a box with the FI in it...I'm not sure what version it is...what ever the 75' 2.0 had.

I've heard the carbs are a PITA to keep tuned.

the goal of the car is just to kinda recreate my 1st 914 I bought in 77', take the top off and drive down a nice twisty 2 lane on the way to a winery...I have other cars I get my need for speed with.

[r_towle]

Well, given it's not a daily driver, and the quality of fuel today is far worse then the 70's , I would suggest you consider getting the FI back on and working so each time you want to drive the car! it actually starts and does not require you to mess with dirty clogged carbs that the fuel has separated and turned to lacquer.

[Mblizzard]

Well I think I can give you some input. The FI system on the 914 is really pretty good when it works. My 2.0 I had in college was so jacked up that it routinely spit parts out the tailpipe in protest. But other than a cold start valve to go bad I never had issues with the FI other than vapor lock.

For the most part you will always be able to get parts for a Weber. The FI is a different story. But it can be done.

I did not change my cam so there was always going to be an issue with using carbs with a FI cam. Worked yes. It certain rpms it was a real kick in the head. But for me, it was a let down when compared to the FI.

So my take is that if you start from the case out with carbs in mind it can be done and done well. If you are like me and want a reasonable level of performance and dependability, it is hard to beat the FI.

[Type 47]

Well, given it's not a daily driver, and the quality of fuel today is far worse then the 70's , I would suggest you consider getting the FI back on and working so each time you want to drive the car! it actually starts and does not require you to mess with dirty clogged carbs that the fuel has separated and turned to lacquer.

OK, I'll treat the fuel...what happens to FI when you push lacquer through it?

[Jesco Reient]

Well, given it's not a daily driver, and the quality of fuel today is far worse then the 70's , I would suggest you consider getting the FI back on and working so each time you want to drive the car! it actually starts and does not require you to mess with dirty clogged carbs that the fuel has separated and turned to lacquer.

OK, So here is the deal, "r_towle" was very instrumental in my decision not to ditch the FI after I was ready to do so. Brad Mayeur was the original guy that pushed me to not go to carbs. I got really frustrated earlier this year and "r_towle" really convinced me to stick it out.
Now I install the key, turn the key, it starts well, drives well, idles well. Mission accomplished. Stick with the FI. do it right and you'll love it.

[mepstein]

I just started my 1.7 FI on the second turn of the key after 2 months of sitting. Idled perfectly. I did carbs once. FI is the best on a stock engine.

[Bulldog9]

I think its what you want, and what you have..... I think all agree that the FI cam is less than ideal if you just bolt on some carbs. If you have all the stock FI components and they are in good shape, I'd say it is probably a great idea to go back to FI. But why did the PO pull the carbs? likely he couldnt get/keep the car running well with teh FI, so you may have some tails to chase to get it straight.

No question FI will run smoother, start better, and in all conditions, but that assumes all elements are working correctly, and lets face it the older Bosh systems (even the simple CIS) get buggy over time, and are difficult to keep in tune.

Well maintained and properly set up carbs are NOT difficult to keep clean and run well. Of my 3 older vehicles (soon to be 4 when #770 is up & running) I add a bottle/dose of seafoam or similar to help counteract the ethanol and ethanol damage. Raby has been talking about an additive as well. As hard as it is to believe, my 1979 Yamaha XS1100 has 4 CV carbs, and are notorious for clogging. I bought the beast in 1983 with plugged up carbs, and after a rebuild/cleaning, have NEVER had to work on them again. Over 120K miles, 28 years (my Lord how can it be that long) and now for the last 4-5 years only ridden 3-4 times a year. Starts runs strong no issues. I keep waiting, but proper fuel habits and paper air filters have kept these running clean and strong.

#770 will run carbs, but only because the stock FI system (the entire fuel system other than the brain and harness end to end actually......) was toast and I diddnt want to go through the hassle when doing a complete rebuild. So because I was going from the ground up Carbs, and a matching cam was the easiest for me. I've looked at a couple aftermarket systems and may play down the road, but for now I'm content with Carbs.

***IMO, key with Carbs (especially) is the need for proper filtration. Too many use poorly or under or over oiled gauze or foam filters, or no filter with velocity stacks/metal grating and this really gums up the carbs, especiallly the IDF or DRLA. A good quality paper filter or an oild gauze with a pre filter is the only way to go with carbs if you want to keep them clean Thats my experience at least on my 3 carburated vehicles, two of which I've driven and maintainted for over 25 years without a carb issue.

[ben*james]

:fi:

It sounds to me like you want a reliable, low maintenance system. One where you start up the car and head down the road without having to tinker with the car. It sounds like you want to switch back to fuel injection. Opinion: fuel injection is the way to go.

I've had dual carbs and was either cleaning the carbs before too long or suffering the snap crackle pop burb sounds at stoplights that turned a lot of heads. I've never had that issue with any of my fuel injected cars.

This all said, I am not a wrench at all and don't have the slightest idea how to maintain or tune either system.

Perhaps the injected cars I've had we're set up well and never required work on my part, perhaps they are easier? I don't know.



Good luck (IMG:style_emoticons/default/driving.gif) regardless, enjoy the drive!

[rsrguy3]

I had a 2l 74 with the single carb setup. It ran OK and drove OK. After talking to James about it I chose to go with the stock efi setup but omited the brain in favor of megasquirt. Man did that thing work! It started and ran great sweet t -response and emmisions was a breeze even with second hand injectors. The coolest thing about the installation was it all looked stock. I'm so sold on MS now that its going on my 914-6 with Al's high butterfly Gasser system, it should seriously kick ass. On a side note the MS system will also support a full electronic ignition system as well. Send James a pm, I'm sure he'll be glad to give you the lowdown. If I had to put that old efi in with the old brain I would probably considder staying with carbs too.-Guy

[Mark Henry]

On a stock engine FI is best.
On a performance engine it's a toss up between carbs and aftermaket FI.

Stock engine and a performance engine are two different animals.

[rsrguy3]

I'm telling you it was a stock engine with stock efi the only difference was the brain and It rocked! It was bullet proof you guys might love the Bosch brain but there's no substitute for the constant management that wideband provides. The system had maps but was self tuning for optimal performance.

[DRPHIL914]

i have driven but now owned any carbed 914-s. I bought my '75 with the f.i. intact but need to be sorted out. It had a bad MPS(d-jet). i replaced it, the fuel lines injectors, filter and cleaned the tank put it all back together and it fired right up. i chased a vac leak for a while, but things need cleaning and re-sealing after 40 years!! i chose to stay with the FI because my only experience with dual carbs was a '69 Austin Healy Sprite back in college. always had issues with keeping them tuned. Had the linkage lock up on me once on wide open throttle (IMG:style_emoticons/default/blink.gif) .
It may be partly what you know, what you are comfortable with, but the FI is pretty straight forward. At some point i will probably go aftermarket FI, atleast programable and tune-able , especially if i decide to upgrade the 2.0 to a 2056 or 2270. right now i am happy with the way it runs, starts every time, and i get close to 35 mpg on highway, you wont see that with carbs on a f.i. cam.

i almost got rid of the FI when i was frustrated in finding an issue that ended up being a bad FI ground connector!! - i did put in a brand new FI wiring harness made by Jeff Bowlsby and have not had an issue since.

PW

[r_towle]

Well, given it's not a daily driver, and the quality of fuel today is far worse then the 70's , I would suggest you consider getting the FI back on and working so each time you want to drive the car! it actually starts and does not require you to mess with dirty clogged carbs that the fuel has separated and turned to lacquer.

OK, I'll treat the fuel...what happens to FI when you push lacquer through it?

FI does not seem to be as affected by the fuel issue, but carb bowls get filled up with solid materials if left too long.

I got into the habit long ago, when ethanol became a reality, of turning off the fuel supply while the engine is running and letting the carbs go dry.

Take a bit more to get anything going again once its drained, but it also keeps from an annual carb rebuilt each year.

I guess it really depends upon how much time you have to tinker and how you want to use the car.
If you are a typically busy person and would like to walk into the garage, pull off the cover and roof and go for a ride while you have an hour or two on a sunday....stick with an EFI system (stock is fine) to get that instant pleasure of driving.

If you are ok to tinker with the car for 30min to 1 hour each time you start it (it happens) then go for carbs.

If you swap the camshaft, want to go racing, have headers etc....stick with carbs or a finely tuned expensive EFI system from the aftermarket.

Given your original statement and driving intention, I would still suggest you consider restoring whatever FI system you have and enjoy driving the car.

Its honestly a very simple system to bolt in place, and there really is no tuning involved...it either works or it does not.
Then you diagnose parts of the FI system, no need for a AFM or any of that...
All the parts have a function...
All the functions have been diagnosed here 500 times....
Its really not terrible to figure out the issues, then you are basically done for the rest of the decade if you leave the motor alone...they just start and run.

rich

[VaccaRabite]

I had cArbs on a moderately built engine.
I HATED them. Three years I spends dicking and fiddling with the damn things. When they ran right they were awesome. But if the car sat for a month I had to play with them again.

I know they worked for a lot of people for a long time. But I don't want to wait and baby them on start up. I want to turn the key and drive. No more carbs.
Zach

[Type 47]

So much information...I had to go out of town for work and just got back.

Thanks all for posting your info and opinions. I do want a car that has a low PITA factor. It's not a performance car.

So that points to FI but the PO took it off for a reason (may not have been a good one) and most likely the system won't just bolt back on without a lot of effort to get right.

I have the Webers and to me rebuilding the engine to put the right cam in seems less difficult that trouble shooting the FI.

The MegaSquirt is something I will look into.

I think though in the long run a properly running FI system would be the best choice...that said I don't want to be constantly tracking down the next problem in the FI multi-component system...it's been in a box for 25-30 years.

No single direct answer here...a lot to think about.

Again, thanks for all the help, it is exactly the info I hoped I would find out.

[r_towle]

old FI diagnosis is simple.
Parts can all be had now with Foley selling rebuild kits for the MPS, and new TPS boards available for purchase...

all other parts can be purchased new.

So, the easiest way, in my opinion, would be a new wiring harness, test and plug in everything....

Done

rich

[Spoke]

I bought my 71 with the single progressive carb. (IMG:style_emoticons/default/barf.gif)

The mechanic who put it on for the PO said he couldn't get the FI running and didn't have time to figure it out.

When I purchased the car, I asked the mechanic for any parts from the FI: he couldn't find them. Fast forward 5 years and he's moving his shop and he has a box for me; the original FI parts; all of them!

I tested each part separately to find the MPS and the dizzy vacuum advance both to be leaking. Fixed both and the FI is working just fine now.

Go to FI.

IMO, most people have gone to carbs cause they can't figure out why the FI isn't working well. ALL modern cars have FI, none have carbs...hmmm (IMG:style_emoticons/default/idea.gif)

Cheers (IMG:style_emoticons/default/beerchug.gif)

[DBCooper]

...to me rebuilding the engine to put the right cam in seems less difficult that trouble shooting the FI.

Seriously?

[SKL1]

I put Solex carbs on mine WAY back in the early 70's to take care of some early FI issues plus I liked the look with the mesh air cleaners like the old 4 cams had. Used that system for a couple years then put on a turbo unit which worked pretty well for a few years with several other mods. When you've had a car for over 40 years you tend to play with it...

My '71 has Webers on it now with a different cam and big bore kit and it runs great. The '73 I'm currently restoring has a Webcam and Webers.

I actually like the look of the carbs and the cleaner engine compartment without all the FI wiring etc. I'm surprised no one else has ever mentioned that. Sure easier to keep clean. Luckily these are not DD's!!

[Type 47]

old FI diagnosis is simple.
Parts can all be had now with Foley selling rebuild kits for the MPS, and new TPS boards available for purchase...

all other parts can be purchased new.

So, the easiest way, in my opinion, would be a new wiring harness, test and plug in everything....

Done

rich

That's good to know...

here's a question that hasn't come up yet: What is a SWAG on what the cost might be replacing /updating the FI.

I bought my 71 with the single progressive carb. (IMG:style_emoticons/default/barf.gif)

The mechanic who put it on for the PO said he couldn't get the FI running and didn't have time to figure it out.

When I purchased the car, I asked the mechanic for any parts from the FI: he couldn't find them. Fast forward 5 years and he's moving his shop and he has a box for me; the original FI parts; all of them!

I tested each part separately to find the MPS and the dizzy vacuum advance both to be leaking. Fixed both and the FI is working just fine now.

Go to FI.

IMO, most people have gone to carbs cause they can't figure out why the FI isn't working well. ALL modern cars have FI, none have carbs...hmmm (IMG:style_emoticons/default/idea.gif)

Cheers (IMG:style_emoticons/default/beerchug.gif)

I'm pretty sure that something in that box of components does not work and that's why the PO took it off.

...to me rebuilding the engine to put the right cam in seems less difficult that trouble shooting the FI.

Seriously?

Yep, I understand that...not sure what's going in those boxes with the wires going to them.

I have a secret weapon though...my son. if he can calibrate the lane assist feature on the new Cayman he can help me get FI going.

I put Solex carbs on mine WAY back in the early 70's to take care of some early FI issues plus I liked the look with the mesh air cleaners like the old 4 cams had. Used that system for a couple years then put on a turbo unit which worked pretty well for a few years with several other mods. When you've had a car for over 40 years you tend to play with it...

My '71 has Webers on it now with a different cam and big bore kit and it runs great. The '73 I'm currently restoring has a Webcam and Webers.

I actually like the look of the carbs and the cleaner engine compartment without all the FI wiring etc. I'm surprised no one else has ever mentioned that. Sure easier to keep clean. Luckily these are not DD's!!

I agree with the look of the dual carbs.