I'm trying to determine the whether to stay with a faltering fuel injection on my slightly modified 2.0, or go with carbs, or aftermarket fuel injection. Thiw is an every day car and whe have lots of traffic in Atlanta. If carbs, what is best?

People are going to line up like the Hatfields and McCoys a real feud. The key issue is how modified is slightly. Give us some more details. If it modified much you will really struggle with the stock D-jet. So your choices may be Carbs or programmable FI.

At that point get ready for the salvos to start flying. Everyones got an opinion and most hold it pretty dear.

Me, I love my Megasquirt. However, it was a lot of work and even though it's DIY it wasn't cheap cause I had to redo mistakes.

Dave

I'm not going to take a side in the fued... yet.

I say, go with what you know... if you are used to FI... go for it! if you are like me and have never used FI before... go Carbs... you are the one who has to work on it... make it something you know... you will be much happier...

Ya that's really good advice. Go with what ya know. What I said about the cost of redos is really the cost of the learning curve. I was learning as I went.

Dave

Do you know why your stock FI is having problems?

Are you 100% sure it's fuel related and not spark related?

Not knowing the D-Jet too well, I swapped mine out for the L-Jet which I knew and understood much better. I did have to do some troubleshooting but that is how one learns, to me, it would have been boring if everything would have plugged in and worked perfectly.

My last 914 (current, but taken apart) will be running the Megasquirt like Dave has. For the money, I think the Megasquirt is the best option when it comes to Fuel Injection, it is a DIY project, but the support for it is amazing. You can use most all of your stock parts
(the parts that rarely fail or cause problems)

I don't know carbs that well, so that is why I lean towards the FI.

I view carbs as being "crude" and nothing more than a ventuir operated water sprikling can.

Electronic FI is precise, sure things can go wrong but normally its easy to trouble shoot.

We are here to help you one way or another

If you're starting new (no previous knowledge or either system) I think FI is easier to troubleshoot because there are more testing points. You can find out what's bad with a multimeter and you don't have to know the "sound" or the "feel" of failing carbs.

Go with what you know.

Djet is really easy as long as you don't have electrical problems like a bad FI wiring harness. The only things that can go wrong are the MPS, CHT or the vacuum hoses leaking.
What is wrong with it?

Geoff

D-jet is VERY goodfor a stockish engine. Aftermarket FI doesn't get you much in terms of performance over a stock D-jet.

Aftermarket FI can be set up so you can sit in your car and look at the cold hard facts about what is going on in your engine - you can get quantitative numbers that will tell you how hot things are, what your mixture is if you have a wideband O2 sensor - or just too rich/lean if you have a narrowband. It is tricky to get an aftermarket system running - (my experience is with Megasquirt) - but it's also nice because you know (and will understand by the end of the project!) what is going on, and you always know that if it's running badly - all you have to do is spend some time with the laptop to tune it up a bit.

Carbs - a lot of people swear by them. IMHO they are a little crude. The D-jet works with all analog voltage and resistance changes - carbs work by air pressure and flow and the physical dynamics of that.

My engine is a 2.2 liter 4cyl. with a bit of a cam in it. I have 44idf Weber carbs. If I had a stock engine I would probably use FI. It is definately quieter than my big carbs and you will get better gas mileage. I asked this same question awhile back and it seems the general feeling is, if the engine is stock, go with FI. If it is bigger than stock and you want more power, go with the carbs.
Cheers, Elliot

Thanks for all the replys so far. I know that this can be a gnarly subject. In terms of "go with what you know", I have been messing with 914s for at least 20 years and have read every article I can dig up on on the how and why of d-jet. I think the problem is with the wiring harness and uneven injectors. Sometimes the thing runs like a dream. Then it will buck like a bronco. When you add up the cost, It would be about equal to fix those things or get a new IDF setup. It Just seems that If I wanted to take the car on an extended journey I would figure carbs to be more nearly bulletproof compared with 30 year old electronics. On the other hand, My suspicion is that injection is going to be smoother, especially at low end. More to come

Drop $350 and have Jeff Bowlsby make you a beautiful new wiring harness. If the harness is messed up, you will have problems

Trigger points can be a ghost problem as well. They can look fine physically, make good clean contact at the points, and show a nice square wave on an oscilloscope and still be bad. Seems like every car has original trigger points and needs new ones. D-Jet will run great once you replace everything. Aftermarket FI has the advantage of being comparable priced and using modern technology. I don't know a price point, but we are close to having the test EMS from KitCarlson running and it looks like it's going to be a sweet alternative to D-Jet.

already replaced the trigger points and the temperature sensor, all the hoses and changed to electronic ignition. Also replaced the fuel ingector gaskets, plug wires, fuel filter.

have you replaced the fuel-filter lately?


depends on who you talk to. me, i HATE carbs.
my d-jet had a few issues, but i went through it step by step and now it runs like a dream.
starts right up too, no matter what weather you're in.
it's soooo much nicer!

only problem with the stock d-jet, you can't get much more power out of your engine. if you go with a agressive cam and other goodies you have to go carbs or aftermarket FI ...

Andy

Still pondering on this. My engine is out for a clutch redo and I want to fix everything "for once and for all" while I am putting it back together. So the first thing I did after pulling the engine was to take photos of everything, then I removed the entire FI,wires and everything. To answer one question, The guy who built my engine before I puchased the car says he put in a "mild trick cam" but that was all he would allow. Also a cast iron oil pump which is now leaking and has blown out one of the oil galley plugs. Yuk! Anyway I was encouraged by the suggestion that factory fuel injection is so good and durable' although one has to wonder how many more years it can be expected to hold up. I ran a continuity test on all the FI wires, and they all showed 0 ohms, but I'm not sure that means too much. I did notice that the connecter to the brain had one pin that looked like it had been arc damaged. That was the one that feeds the center terminal of the trigger points. Perhaps I found the source of my problems. Whadaya think?

Ain't never gonna happen. Ask about Dirk Wright and his disease.

It was just a joke, but I wish it could be true. My toyota tercel never gives me any problems.

hmmm, didn't see that you replaced the Thottle body switch. Old TB switches produce a bucking at 2500-3500 going from off throttle to back on due to worn traces inside it.

Djet for the money is better than carbs on any stockish engine. As mentioned, a new FI wiring harness is a good bet too. Intermittent FI problems usually mean a bad connection somewhere in the wiring OR bad grounds.

Geoff

I read somewhere that the car will run well with the throttle valve switch disconnected. So I have tried that. Didn't make much difference. I took the thing apart and inspected it carefully and metered its action and came to the conclusion that it was in primo condition.

Did look at the traces? Thats where the wear is, are they scored at all?

Geoff

Actually the thing looked almost new on the inside. I cleaned the traces with a cotton swab and rubbing alcohol.

ok, just asking dumb questions trying to fix something long distance

Thanks for trying. I'm thinking it's that questionable connection between the wiring harness and the brain.

can you use the 1.7 injection with a 2.0 if i was going to put on in my car.. sorry a little OT.

Yep, switch to 2.0l injectors, a vanagon throttle body, and a 2.0l MPS.
Geoff

I've put about 7k miles on my dual ida 44's on a stock 2.0 over the last year and a half. No problems, good mph, and they sound sweet. If you know how to tune them, once they are right, you are set, but all things being equal, the FI is smoother, but I would say more problematic, IE- 30+ year old wiring, vac leaks, 30+ year old semi-electronics etc..

-if you can make it work, FI is better, if I had to do it over again and I had started with the FI still in the car, I would have worked it until it was running properly, but I started out with the carbs already in, and so all I needed to do was to replace the fuel lines, the coil, the filter, and tune/ballance them.

I like carbs as they are mechanical and I prefer the roar at WOT. Plus I like the view of carbs in the engine bay. At WOT they have superior fuel atomization. They are a compromise because there are three fuel circuits to cover the whole rev range.
Mine run great and I get good MPG too.

I am going to go with the best of both worlds.....webber throttle bodies....44 or 48 idf throttle bodies, with megasquirt....

I do like the visual feedback of the megasquirt...only took a few nights to build. I did spend a couple of hundred bucks on it and the wb02 kit...but it was fun to put together and there are plenty of people to help build it...kind of like this board...

good luck, herb

I've about decided to go with carbs. The exclusive reason is durability. I don't think that I will be sticking my head in the engine compartment and pondering "What's wrong now?" Once the carbs are set up the only questions in that sector will be "Spark?" or "fuel." so now the question becomes:40 or 44 idf {unless I'm missing something}.
My computer just started doing this strange thing in which the spacebar acts like the backspace/delete key