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post #1 of (permalink) Old 05-12-2001, 08:09 PM Thread Starter
 
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Fuel Injection vs Carbd

Alright, i need to know all the good things about both the fuel injection and the carberator and all the bad things about them and the price differences between the 2 engines, the 4.2L and the 4.0L. I am basically trying to decide which to get and which will hold up, i also would like some opinions as if which one i should get and dont get carried away because i have a pretty good idea which one is better, but there is a budget of around 5K. thanks
andrew

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post #2 of (permalink) Old 05-12-2001, 09:06 PM
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Re: Fuel Injection vs Carbd

Ok, I'll bite...

Carbs

A carb is simple, it's mechanical, it's robust and doesn't break often. It requires little maintance other than cleaning. Engine modification is easier with a carb. You can adjust jets and needle valves, change the size of the Carb as didicated by the needs of the modificaiton. Those are the good points.

On the other hand, the carb is not as efficent as fuel injection, it does not work well in off-camber situtations.

Fuel Injection:

Fuel Injection is precise, and it increases fuel efficency. It works off camber and has been a reliable fuel delivery system. That's the upside.

The downside is for most people it's hard to understand and fix. It's electronic, so it's a mystery. It's VERY subject to dirt and stuff in the gas that gets by a filter. You NEED to carry extra parts, an extra electronic fuel pump is a good example and some sensors like the TPS are a must. If a sensor breaks... the system can be compromised at best, dead at worst. Modifications to the engine can be a real problem to an efi engine. The computer will vary conditions within a window. If ANY part of the engine is outside of the window required by the EFI then real big problmes can occur. Modification to the cam is about the best example I can think of this problem.

IMHO which is best is dependant upon your capabilities as a mechnic and a diagnostic technician. Me, I've a good understanding of electronics. Fuel Injectiion to me is simple, however give me a carb, and I can be reduced to a blithering idiot it a matter of seconds. But I'm learing about carbs and how they work and how to fix them. Someday my experiese will be equal in each area. But for now, I'd choose EFI any day!

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post #3 of (permalink) Old 05-12-2001, 09:31 PM
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Re: Fuel Injection vs Carbd

A complete "factory" fuel injection system would be best for most people. I tried the holley system, and it was more work than a carb for my application, plus I don't care for electronics, or anything that I can't fix with a few simple tools or buy in a junkyard. I have good luck with carbs and mechanical things, so I put-up with the downsides to avoid the unknown of the blackbox.

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post #4 of (permalink) Old 05-12-2001, 10:15 PM
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Re: Fuel Injection vs Carbd

EFI

Everyday; all the time - life in the fast lane.

It's not as hard as most people think - just buy the Haynes manual and read. Read. Spend a few weeks (no, I'm not being sarcastic) understanding how it works, what it does, what it needs, what breaks, and how to diagnose & fix it, and you'll <font color=blue>NEVER</font color=blue> go back to carbs. I'm sure Jeeps are a little different, but all I have to do to find out what's wrong with mine is put in a short jumper wire before turning the key on, and then count flashes of the Engine light. There are around 400 codes that it can flash out, which may sound bad, but it's actually a good thing: think of how specific it can be about the problem with 400 "words" to describe it.

I used to have the same trepidation dirtrod describes, but after throwing away an engine I had rebuilt 30Kmi before because of a flaw in a minor carb component (yes, the carb was rebuilt at the same time), I decided to switch. I'll never F#(& with another carb! It's SSSSSSSSSOOOOOOOOOO much easier, more reliable, cheaper to fix, more versatile, and more driveable.

My total cost, including new plugs, oil, coolant, filter, used gas tank, alt, PS pump, A/C compressor, air pump, fuel lines, Y-pipe, flywheel & clutch, air filter, engine harness, engine compartment harness, & an engine that (to this day) has never been opened (oil pan, valve cover, etc.) was $1300. It took me about 2 weeks to find an engine less than 5 years old with less than 80Kmi on it at MY price, and 1 day to pull it & all the other stuff of a few trucks at the junkyard, and I'd recommend it to anyone over rebuilding or installing a carbed engine.

I agree with almost everything LEVE says, except
<blockquote><font size=1>In reply to:</font><hr>

doesn't break often. It requires little maintance other than cleaning.

<hr></blockquote>


Mine was out of tune 30 miles after I tuned it, and ALWAYS needed something replace, fixed, or adjusted. A total PITA! The only time I spend under the hood now is when I feel like tweaking or adding something. The only problems I've had were a) forgetting to change the plugs for 80Kmi - they had burned to 0.14" gap before the computer couldn't handle it any more; & b) the coil burned out last weekend - $24.

Can you tell I like EFI yet? [img]/wwwthreads_images/icons/wink.gif[/img] You can see a pic of the swap in <A HREF="http://www.webphotos.com/default.asp?album_id=217
" target="_new">this album</A>.

Steve 83 Bronco 4.9L
<font color=red>Build it; Don't buy it...</font color=red>
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post #5 of (permalink) Old 05-14-2001, 10:02 PM
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Re: Fuel Injection vs Carbd

I was DYING to go to your album.... but NOTHING!!

can I get a little assistance?

DREW
IN2DEEP <font color=red>78 CJ5</font color=red> <font color=blue>302 FORD </font color=blue> [img]/wwwthreads_images/icons/shocked.gif[/img] <font color=red> T176/D300 REAR ARB 35" BFGS </font color=red>
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post #6 of (permalink) Old 05-14-2001, 10:27 PM
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post #7 of (permalink) Old 05-14-2001, 10:37 PM
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Re: Fuel Injection vs Carbd

I'm probably going to pull my carb'd 305, sell the 377 Chevy I have already built, and buy a stock MPI 4.0. Any other questions?

72 CJ-5: 305 Chevy; SM420; D-300; 30/44 with 5.38's, Warn axles, and Detroits
post #8 of (permalink) Old 05-15-2001, 01:24 PM
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Re: Fuel Injection vs Carbd

Are the Howell TFI setup and the TR upgrade compatible? I have done the TR upgrade on my '87 YJ 258 and am planning on getting the Howell setup next week. Just curious. Thnaks for the advice.

Donny

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post #9 of (permalink) Old 05-15-2001, 01:35 PM
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Re: Fuel Injection vs Carbd

Yes.

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post #10 of (permalink) Old 05-15-2001, 04:19 PM
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Re: Fuel Injection vs Carbd

I'll throw my $0.02 in here just because we seem to be getting a little injection biased here. [img]/wwwthreads_images/icons/wink.gif[/img]

I like a carb. I like it because it's simple (and not because I'm stupid, which I don't really think I am [img]/wwwthreads_images/icons/laugh.gif[/img][img]/wwwthreads_images/icons/wink.gif[/img]). My Jeep has a weber, and a GM HEI distributor. I carry a spare HEI cap, complete with coil and distributor pickup, and a spare mechanical fuel pump. If the jeep won't run, I can fix it. I can fix it with basic tools. I can replace the fuel pump without taking the tank down. (How exactly would you do that in the woods?) I can replace the entire ignition system in 5 minutes.

OK, so it gets a little worse gas mileage, and it won't run unspide down. Doesn't sound too bad to me.

A Jeep should be simple to repair, anytime, anywhere. If I'm in the middle of nowhere, like Orla Texas (and bonus points to you if you know where that is [img]/wwwthreads_images/icons/smile.gif[/img]) I can probably get parts for a GM HEI at the local Fred's auto parts, or whatever it would be, or a simple fuel pump for the jeep. Think they have a Mass Air Flow Sensor for anything? I dunno.

I heard a great comment this past week. "I like new cars. Especially when they get old." [img]/wwwthreads_images/icons/smile.gif[/img]

Just my opinion,
Pete

88 YJ - trails/beach trips only![img]/wwwthreads_images/icons/smile.gif[/img]
79 4WD F250-hauler/tower of my toys
70 Jaguar E-type - the best car England ever made. [img]/wwwthreads_images/icons/cool.gif[/img]
90 Honda CRX - Daily pavement-pounder. 42 MPG. [img]/wwwthreads_images/icons/cool.gif[/img]
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