converting to carb, that f.i. pressure sensor is $$$$$$ Options

[fatlando]

My sensor is dead, so i thought i would just spend $40 bucks and get a new one...ha! was i wrong...so my mechanic buddy (i'm stoopid) recommended to convert to carbs.

I'm just doing a single carb set since i got a $400.00 budget.

I can't believe that sensor is $800 to $1200.....

anyway do any of you sell or know of a good deal? I found this on ebay which is just in my range..

what do you think?

http://cgi.ebay.com/progressive-weber-carb...1QQcmdZViewItem

[rhodyguy]

i'm still confused as to which fi component is bad. shane (red914) dumped the progressive and went to the dual single barrel set up (pretty cheaply iirc). seemed to help with the running of the beast.

k

[ArtechnikA]

QUOTE (Michael J @ Jul 31 2005, 12:15 PM)

So i'm sitting on the fence with no real strong opinion one way or the other about carbs VS FI. It worked for VW for a lot of years. I used to have a beetle ...

i installed a pair of SMALL dellortos on a 1,7 with SMALL venturiis. IMO it had no more or less power than the FI, it started and ran every day (unlike the FI) and had no better or worse mileage than the FI (except when the FI delivered 4 weeks per tank because the car was PARKED.)

but that was in 1980. no Internet resources, no online parts vendors. i PROBABLY wouldn't make the same choice today.

carbs are DEFINITELY a place where bigger is NOT better.

the single carb worked OK on a beetle because it was DESIGNED to. even so - no performace cars used it. the carb was a SINGLE barrel, and thus had pretty constant airflow through the venturi. it had (IMPORTANT!) a manifold heat riser that kept the mixture atomised on its way to the intake ports. it was HIGH which helped minimise the amount the air/fuel charge had to change direction.

low, no manifold heat, big plenum runners, progressive multi-barrel just can't work right on a little engine.

if you could find a set of 40mm Dells and run little venturiis you'd probably have a good solid system once you got it jetted right and synchronised. no amount of glowing ad copy will ever make a single progressive run right on the street. (you can imagine a scenario where they might run with ok power numbers at WOT on a dyno. but i need my car to perform on the street.)

[bing101]

Hey all this is Landos' Mechanic friend who by the way someone recommended "find a new mechanic friend"

I have done the research and have come up with this...

- FI is better at producing power/gas mileage and supposedly engine longevity due to carb setups not heating up the heads properly.

- Conversion to a carbed setup is a big no-no among 914 owners.

- If converting to carbs duals are better at producing power but not as good as a FI setup.

The reason a carb conversion was suggested was this...

- while trouble shooting an idle seeking problem...once started car idle goes up and down very consistently...MPS sensor was found to be bad (will not hold vacuum at all, doesnt slowly leak down, completely leaks by) initial research showed them to be quite pricey.

Based upon the price of a new sensor a single carb setup was suggested as it would have the car up and running for significantly less $$

I would love to keep the FI setup for him so let me give you guys some info on what i have found.


- Engine has been desmogged.
- 1 Air injector port is missing and there is just a hole there (what would you recommend plugging the hole with) could that cause the idle issue.
- Crankcase was overfilled with oil along with various vacuum lines mis routed resulting in oil getting sucked into other vacuum lines.
- MPS sensor is bad (would that cause the idle seeking) where can they had cheap?


If someone has a picture/diagram of a Desmogged 75 2.0 I could verify all his vaccum lines and make sure they are all correct.

Thanks guys, I aint trying to randomly trash a FI system but I am trying to help a friend get his pride and joy running again with a limited budget.

[bondo]

QUOTE (bing101 @ Jul 31 2005, 10:06 AM)

Thanks guys, I aint trying to randomly trash a FI system but I am trying to help a friend get his pride and joy running again with a limited budget.

(IMG:http://www.914world.com/bbs2/html/emoticons/smilie_pokal.gif)

This can be fixed for much less than going to carbs. Somebody here has a really nice diagram, I'm sure they'll post it soon. The MPS can be had used and tested for under $100. Just to get it running it'd probably run on a bus MPS.

Also, somebody recently bought a bunch of odd sized bolts or something for plugging smog ports from mcmaster carr, I think they still have a bunch left.

[Porsche Rescue]

Ok, so we're talking PNW guys here. Kevin, Al, Geoff, help these guys out and get the car running right. I bet Geoff knows all there is to know about a '75 engine.

[Michael J]

[QUOTE]it had (IMPORTANT!) a manifold heat riser that kept the mixture atomised on its way to the intake ports.

Thanks Rich, after a few cups of coffee this made all kinds of sense.

[TravisNeff]

That was me who dissed you. I said after that, I also said that obviously you are trying to find him a cost effective alternative to a brand spankin new MPS.

A single carb is a helluva compromise. Dual carbs, and toss in a carb cam it can be great. All I am saying is that for not a lot of money that MPS can be replaced with a good used one.

The cost of the carb, manifold, fuel pump, pressure regulator, distributor (if you are swapping) plus the time to install and tune - that can add up to a lot of money. Plus I haven't heard very many people with a single progressive carb say that they are satisfied with the all over performance, most of them say it sucks.

If there is a ton of stuff wrong with the FI, I can see the justification, but all that was said was that there was a bad MPS, time for a carb. To me that sounds like a bad descision.

[rhodyguy]

hi, i've sent lando a pm this am. his engine is a 1.7 correct? my take on carbs (40's). a used set will run 300 to 400. may or may not need to be rebuilt. may or may not include intake manifolds, add 35 to 50, used. linkage, prob not included, 85 to 240 new, (you get what you pay for). an 009 for an inexspensive dist. i have a good one that can be had for next to nothing (lando can mow my lawn (IMG:http://www.914world.com/bbs2/html/emoticons/wink.gif) (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif) ). fuel pump, buy a new self regulated, low pressure rotary from cb perfomance. the facet style makes a hell of a racket and you will need an adj fuel pressure reg and a gauge to varify the fp, more money. mho, the 2 barrel progressive is not the way to go, a used one is ntwtgx2. it adds up quick. this does not include the various jets and what not that will surely be required. btw i run 40's on my 73' 2.0 so i know what the play is.

that being said, there was a recent thread that was very interesting. it discussed the mating of l-jet compoments and d-jet items. a good, tested mps will run 150 to 200, and some sort of perfomance garrantee should be expected. pehaps less $. if lando hasn't pointed it out, the vaccum line diagram @ pelican in the 914 tech articles will detail every hose, size, length, and routing. line sources, williams oil filter service in tacoma (oh, TACOMA!!!)(cheapest source for high pressure fuel line and the correct clamps that i have found )should have what he needs, or small car performance, ovals, or too quick's out near me.

don't be too offended by the "get a new mechanic" line. we see many plans by folks, with bad suggestions from people less experienced with our stupid cars, and are pretty quick to correct in a less than polite manner. mostly because it gets people's attention. eventually, we are all forced to throw some money at these cars, we just don't want to see lando thow it in the wrong dirrection.

k

[rhodyguy]

plus... i may be totally off base. my guess is the air injection port needs to be plugged asap. personally, i would fix that before i did any vaccum leak chasing. the oil leak issue... the bottom of the car needs to be STEAM CLEANED. MONEY WELL SPENT!! i explained why and where to lando, and made a suggestion via pm. tracing down the leak will be MUCH easier. on top of the heat exchangers? guess-valve cover gaskets or oil return tube seals. on top of the oil filter, guess-oil cooler seals or a leaking oil pressure sender/switch.

k

[jr91472]

(IMG:http://www.914world.com/bbs2/html/emoticons/hijacked.gif)
it seems that folks seem to prefer Dell over Webers....

why is that if you don't mind?

end hijack........

[rhodyguy]

me? the totaled car i bought with an engine that has taken me to cal twice and lots of local driving, came with a set of webers.

k

[bing101]

Yes I agree that air injector port needs to be plugged ASAP. I will pm him and see if he still has any of those bolts left.

Regarding the oil leak, I dont think he has a true oil leak, it was due to the engine being overfilled with oil and that issue has been resolved

A rework of the FI system including new Vacuum hoses and possibly new seals where vacuum can be lost (fuel injector seals, throttle body seal, intake manifold seals, etc) will be my path to fix this FI setup.

Also does anyone have a source for those MPS sensors and a price. Its a 75 2.0

Thanks for the help guys.

[rhodyguy]

bing what? crosby? (IMG:http://www.914world.com/bbs2/html/emoticons/chairfall.gif) what's your real name. geoff (bleyseng) had one fs. tested i believe. maybe still in the classifieds. pm sent.

kevin

[echocanyons]

source

[Andyrew]

Um... Out of curiosity....

What kind of carb does that single carb take?

Because if its a holley carb... then you can easily convert a "single carb" setup to a computer adjustable holley efi setup....

Any comments?

[ArtechnikA]

QUOTE (Andyrew @ Jul 31 2005, 04:33 PM)

...you can easily convert a "single carb" setup to a computer adjustable holley efi setup.... Any comments?

you mean a TBI system?

you still have the issue of big, long runners and multiple changes of direction.

flat engines need port injection.

[bondo]

QUOTE (Andyrew @ Jul 31 2005, 01:33 PM)

Um... Out of curiosity.... What kind of carb does that single carb take? Because if its a holley carb... then you can easily convert a "single carb" setup to a computer adjustable holley efi setup.... Any comments?

I have a Holley TBI injection setup on my Mustang.. it sucks donkey balls. Big rich spot just off idle that makes it bog. It won't tune out no matter what I do.

They're also made for V8s and probably wouldn't even tune down to type IV fuel flow rates.

[TravisNeff]

I believe the single carb is a holley progressive (but what do I know), if you could put the injectors above the intake valves (as stock) that may be a decent alternative.

[Mueller]

QUOTE (Andyrew @ Jul 31 2005, 01:33 PM)

Um... Out of curiosity.... What kind of carb does that single carb take? Because if its a holley carb... then you can easily convert a "single carb" setup to a computer adjustable holley efi setup.... Any comments?

the single carb used is basicly a 2 barrel carb, the reason it's not the best for these engines is that the carb is too far from the intake valves, the air/fuel mixture bounces along the long intake tubes, what happens is that everytime this happens, some of the fuel will now turn from a vapor to a liquid and "stick" to the intake tubes and now you'll have a strange and incomplete air/fuel ratio....2 progressive carbs closer to the intake valves would be better.

I've seen the single carb setups on eBay for less than $300, what you could do is get the car running with the less than ideal single, save up your money and once you have about $1200 or so, use the remaining stock FI parts and install a modern programable FI system.

[Rand]

QUOTE

once started car idle goes up and down very consistently

Is it hunting pretty quickly? If so, that doesn't sound like MPS to me. Sounds like vacuum leak at AAR or along that path between air box and cold start valve.