 should I junk my fuel injection for my 1.7 for dual 44idf Webers, Fuel injection versus carbs |
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| MrPurdy |
 Jul 27 2020, 09:00 AM
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#1
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Newbie  Group: Members Posts: 1 Joined: 27-July 20 From: Oceanside, CA Member No.: 24,541 Region Association: Southern California  |
Hello,
I recently bought a 1973 Porsche 914 with a 1.7 and fuel injection. The car ran ok when first purchased, However, I went to start the car, it would not fire up. Got spark etc, but no fuel. I noticed most of the fuel injection wiring harness is brittle and or have cracked wires. I have tried cutting out the old wiring where I can, however to no such luck.I would like to keep the car fuel injected, however, I can't find where to buy a new wiring harness and or don't want to assume that is the only cause. I recently have been discussing with other past owners of the 914 and two have said to go with Dual Weber 44's or 48's? if I went this route, do I need to change out my distributor and Cam? I know the fuel pump will need to be replaced. I would like some input and or advise from someone who may have already traded out the fuel injection for carbs. Lastly, Im an old VW guy and know carbs but the wiring on this fuel injection seems it could take me down the rabbit hole to more problems and cost. Thanks Mark |
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| KELTY360 |
Jul 27 2020, 09:18 AM
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#2
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914 Neferati Group: Members Posts: 5,031 Joined: 31-December 05 From: Pt. Townsend, WA Member No.: 5,344 Region Association: Pacific Northwest 
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| nditiz1 |
Jul 27 2020, 09:26 AM
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#3
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Senior Member Group: Members Posts: 1,188 Joined: 26-May 15 From: Mount Airy, Maryland Member No.: 18,763 Region Association: MidAtlantic Region
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From someone who loves running carbs this is what i would do.
1. Contact Jeff Bowlsby and get a new fresh harness 2. Install harness and continue to diagnose - tons of help and info out there. FI can be difficult but with a methodical approach you can replace each piece to diagnose the issue. 3. Throw in the towel so you can drive the damn thing and purchase a set of weber 40s, 44s on a 1.7 will need to be choked down a lot. |
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| Frankvw |
Jul 27 2020, 09:32 AM
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#4
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working on my first 914 ! Group: Members Posts: 651 Joined: 13-April 16 From: Holland, the Netherlands Member No.: 19,896 Region Association: Europe |
I also have a 1973 1.7 ... and I also come from the VWs.....
I had to get used to the system but it is actually a really interesting and good thought out system. Try to solve the issues first. If you go for carbs....that saves a lot of injection issues for sure (duh) but 40s are large enough. Good luck with your 914 ! Welcome. |
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| Root_Werks |
Jul 27 2020, 10:08 AM
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#5
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Village Idiot Group: Members Posts: 8,321 Joined: 25-May 04 From: About 5NM from Canada Member No.: 2,105 Region Association: Pacific Northwest
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I would keep the FI if possible.
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| ClayPerrine |
Jul 27 2020, 10:18 AM
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#6
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Life's been good to me so far..... Group: Admin Posts: 15,474 Joined: 11-September 03 From: Hurst, TX. Member No.: 1,143 Region Association: NineFourteenerVille
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(IMG:style_emoticons/default/agree.gif)
The stock cam in a 914 is not good with carbs. It will get lousy gas mileage, poor performance, and you will have gas smell in the car from the open evaporative emissions system. Plus, you will have to choke the carbs down a bunch to get them to work. Lots of changing venturis and jets. And if you go up and down mountains a lot, you will be constantly re-jetting the carbs. The D-Jet system is dirt simple for a fuel injection system. Lots of people on here can help you troubleshoot it and get it running. And I agree with replacing the harness first. Jeff's harnesses are da bomb and will save you hours of troubleshooting. Or you could go with a megasquirt system. Use the stock intake parts, replace the injectors with megasquirt compatible and hook the harness up to the existing sensors. There are even people on here that will give you a base program to upload to your MS. Then use tuner studio and an wideband O2 sensor for the self-tune program. My $.02 Carbs - No. Stock D-Jet - Yes. Megasquirt - Yes, but expensive. |
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| brant |
Jul 27 2020, 10:28 AM
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#7
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914 Wizard Group: Members Posts: 11,625 Joined: 30-December 02 From: Colorado Member No.: 47 Region Association: Rocky Mountains 
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wrong cam (requires rebuilding the motor)
wrong distributor wrong fuel pump and 44's, or 48's are way too big for a 1.7 I think 40's may actually be too big, but can be choked down to make work. |
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| 914sgofast2 |
Jul 27 2020, 10:29 AM
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#8
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Senior Member Group: Members Posts: 617 Joined: 10-May 13 From: El Dorado Hills, CA Member No.: 15,855 Region Association: None |
If you go to carbs, you will lose horsepower unless you also disassemble the engine and install a new cam that is better suited for carbs. Then you will spend hours tuning and jetting the carbs to cure the inevitable flat spots and cold starting problems. You will also need to replace the distributor with a 123 unit to get maximum power from the carb conversion. Search all the threads on this forum about people trying to get their cars to run properly with carbs . Much easier to replace the FI wiring harness with one from Jeff Bowlsby or rebuild it yourself. The Djet FI is a very simple and unsophisticated fuel injection system compared to modern ones. You can do most of your troubleshooting with a volt ohm meter and a vacuum pump. No need to buy a proprietary computer program from Porsche or Bosch to read and clear “check engine lights” and codes.
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| 914Sixer |
Jul 27 2020, 11:42 AM
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#9
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914 Guru Group: Members Posts: 8,886 Joined: 17-January 05 From: San Angelo Texas Member No.: 3,457 Region Association: Southwest Region
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Just say NO to carbs!
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| windforfun |
Jul 27 2020, 12:00 PM
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#10
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Senior Member Group: Members Posts: 1,796 Joined: 17-December 07 From: Blackhawk, CA Member No.: 8,476 Region Association: None |
No. KISS.
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| thelogo |
Jul 27 2020, 01:20 PM
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#11
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Senior Member Group: Retired Members Posts: 1,510 Joined: 6-April 10 Member No.: 11,572 Region Association: None |
QUOTE(MrPurdy @ Jul 27 2020, 08:00 AM)  Hello, I recently bought a 1973 Porsche 914 with a 1.7 and fuel injection. The car ran ok when first purchased, However, I went to start the car, it would not fire up. Got spark etc, but no fuel. I noticed most of the fuel injection wiring harness is brittle and or have cracked wires. I have tried cutting out the old wiring where I can, however to no such luck.I would like to keep the car fuel injected, however, I can't find where to buy a new wiring harness and or don't want to assume that is the only cause. I recently have been discussing with other past owners of the 914 and two have said to go with Dual Weber 44's or 48's? if I went this route, do I need to change out my distributor and Cam? I know the fuel pump will need to be replaced. I would like some input and or advise from someone who may have already traded out the fuel injection for carbs. Lastly, Im an old VW guy and know carbs but the wiring on this fuel injection seems it could take me down the rabbit hole to more problems and cost. Thanks Mark 1st off i love carbs but ... Youre at a crossroads, ive been there before You cant just go to carbs . unless you use a set of baby single throat webbers . those bolt right on and while not perfect .not bad . my opinion also need fuel pump But to really do carbs . 40s and up you have to rebuild the engine to take advantage . plain and simple You could do djet . but 1st find a witch doctor to help . And its no longer reliable because its fuckin ancient Not because its not a great system . So if you can afford . build a killer carb engine . If not the others will be more budget friendly but not as spunky. I would put baby webbers on my 1.7 in a second ( djet also starting giving up) but i lucked my way into a big /4 So thats what i would do |
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| JeffBowlsby |
Jul 27 2020, 02:58 PM
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#12
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914 Wiring Harnesses Group: Members Posts: 8,510 Joined: 7-January 03 From: San Ramon CA Member No.: 104 Region Association: None
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| porschetub |
Jul 27 2020, 04:04 PM
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#13
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Advanced Member Group: Members Posts: 4,701 Joined: 25-July 15 From: New Zealand Member No.: 18,995 Region Association: None |
(IMG:style_emoticons/default/agree.gif) with all comments,end of the day by the time you buy carbs and all you needed parts you could bring the FI up to standard and have a better running driving car.
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| jdamiano |
Jul 27 2020, 04:14 PM
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#14
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Member Group: Members Posts: 335 Joined: 18-March 18 From: Jacksonville Member No.: 21,981 Region Association: South East States |
44s are to big you would run rich no matter how you jetted them. I can’t speak directly to the 1.7 but I love my carbs on my 2.0. I got the Redline 40 Weber kit with a Petronix distributor. Any loss in power is offset with reliability. It’s less complicated and brand new. I would stick with EFI if you want to maintain originality or aren’t willing to buy all new parts for your conversion to carbs. I have all the EFI in a box in case the future caretaker wants to put it back on.
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| rgolia |
Jul 27 2020, 04:28 PM
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#15
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GeoJoe Group: Members Posts: 704 Joined: 5-February 10 From: PA Member No.: 11,329 Region Association: North East States
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Totally agree with all the comments. When I switched, 1981, it was the thing to do, know one new how to trouble shoot the FI system. I was stranded many times on the side of the highway with the FI, that is why I switched. Car had 75k miles. Put another 70 on the car with the carbs and was never stranded, but it did not run as well and got less MPG. Now it is rebuilt into a very nice street 2056 and the carbs can finally sing like they should. The guys at Tanagerine Racing did a great job on it.
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| ctc911ctc |
Jul 27 2020, 04:28 PM
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#16
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Senior Member Group: Members Posts: 893 Joined: 9-June 18 From: boston Member No.: 22,206 Region Association: North East States
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I was there once upon a time, I stuck with FI and I am glad that I did - once I got it running correctly (took a while) it is a stock car with dozens of experts. If you go with carbs you are trail blazing - very few people will have your setup.
If you stick with the FI, grab the plenum and make certain it is tight - this is the source of countless trouble when addressing the FI systems.....then the MPS....... GOOD LUCK! CTC911CTC |
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| thelogo |
Jul 27 2020, 08:22 PM
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#17
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Senior Member Group: Retired Members Posts: 1,510 Joined: 6-April 10 Member No.: 11,572 Region Association: None |
it is a stock car with dozens of experts.
CTC911CTC [/quote] You heard the man ................................... Dozen of experts... (IMG:style_emoticons/default/screwy.gif) (IMG:style_emoticons/default/pray.gif) (IMG:style_emoticons/default/av-943.gif) So if your f.i go's down there are about ...12 guys in the world who can fix it .... Id say thats about right ... Its unfortunate but its accurate. Ask 12000 mechanic s about djet . 1 of em may be able to help |
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| saigon71 |
Jul 28 2020, 05:55 AM
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#18
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Senior Member Group: Members Posts: 1,999 Joined: 1-June 09 From: Dillsburg, PA Member No.: 10,428 Region Association: MidAtlantic Region
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I'm not at all anti-carb...but:
Since your stock FI is mostly complete, I would recommend sticking with it as it is the best bang for the buck solution for a stock engine with a stock cam. I've got a stock 2.0 D-jet system on a 2056. I put about 8,000 miles a year on my car. The system isn't perfect, but I find it highly reliable for a street engine. Once you get it tuned, you just drive it. I haven't had to do anything mechanical to my engine in 2 years - haven't even tuned it up and I just drove it 750 miles in 2 weekends. There is a bit of a learning curve, but worth it in my opinion. This resource will supply most of the info you need: https://members.rennlist.com/pbanders/DJetParts.htm While written for a 2.0, many of the components are the same. At one point, parts prices became prohibitively expensive (particularly the MPS)...but over time, as demand rose for FI parts, solutions have been found. Start with a wiring harness from Bowlsby and go from there. 1.7 FI parts aren't too hard to find. Let us know what you decide. |
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| ClayPerrine |
Jul 28 2020, 06:51 AM
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#19
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Life's been good to me so far..... Group: Admin Posts: 15,474 Joined: 11-September 03 From: Hurst, TX. Member No.: 1,143 Region Association: NineFourteenerVille
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[quote name='thelogo' date='Jul 27 2020, 09:22 PM' post='2837708']
it is a stock car with dozens of experts. CTC911CTC [/quote] You heard the man ................................... Dozen of experts... (IMG:style_emoticons/default/screwy.gif) (IMG:style_emoticons/default/pray.gif) (IMG:style_emoticons/default/av-943.gif) So if your f.i go's down there are about ...12 guys in the world who can fix it .... Id say thats about right ... Its unfortunate but its accurate. Ask 12000 mechanic s about djet . 1 of em may be able to help [/quote] There are lots of D-Jet experts out there. It was used on everything from Mercedes, to Volvo, VW, Audi, all the way to the Chevrolet Cosworth Vega. So there are people out there that can help fix it. And it is dirt simple, so you can learn how to repair it yourself. It is not rocket surgery. Carbs are like doing accounting with a pencil and paper. D-Jet is like doing accounting with a mechanical calculator. Current EFI (megasquirt) is like doing accounting with Microsoft Excel. The accuracy and efficiency goes up with each new improvement. Clay |
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| 76-914 |
Jul 28 2020, 07:00 AM
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#20
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Repeat Offender & Resident Subaru Antagonist Group: Members Posts: 13,504 Joined: 23-January 09 From: Temecula, CA Member No.: 9,964 Region Association: Southern California
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Better yet put a Subaru in it. (IMG:style_emoticons/default/stirthepot.gif) (IMG:style_emoticons/default/biggrin.gif)
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