Converting a throttle body van to carburetor.

First you need to determine how much of the ignition is controlled by the engine management system that also controls the fuel injection. Then you'll know the scope of the project... (or even if it's possible on the cheap, although being a '90 it probably at least still has a distributor) if there are any emissions tests in your area it won't pass after you're done.

Seriously, throttle body injection isn't that difficult to learn, fixing it is the path of least resistance and lowest amount of money. Basically instead of a carburetor jet(s) it has an injector(s).

You'd need an intake manifold, carburetor, non EST distributor and automatic transmission, all from a small block Chevy.

WHY? That throttle body will run better, get better mileage and over all out perform ANY carb you could put on it. The TBI is simpler than any carb as well.

If you can rebuild a carb learning TBI is simple.

Not mentioning the small item of it being against federal law for you to do what you suggest. And it will be illegal to operate it on any road that you don't own.

Oh well, there are a lot of old used vans around here for sale, I really haven't started looking yet, maybe when the weather warms up I might get out and look around.What I would like to find is a Dodge van, same body style as my 1978 (or earlier year Dodge van) long body van with a 6 cylinder or small 318 V8 engine and manual shift transmission, no power steering, no power brakes.I don't know why I am even thinking about buying another van.My van runs ok.I only drive it to the food store two or three times each month, round trip three miles, and to the discount tobacco store once every two months, round trip ten miles, and to a veterinary supply pet store once each three months for Pro Pac dog food for my little doggy.I don't enjoying driving anywhere anymore.Yep, I think I will forget that 1990 Chevrolet van.Too much money/trouble for the amount of bread. cuhulin

I don't think any 2 barrels will bolt up to the intake if it's the same engine as my 90 Chev truck. To swap intakes, you might need the not-vortec, but not-classic either - the center bolt hole angles were changed. They make kits to install it, and/or an aftermarket intake.

But, why bother? My 90 is probably on the original TBI, starts in -30, runs fine. I don't need to mess with jets and accelerator pumps or chokes.

Oh... you'll need a fuel pressure regulator if you go carbed. Your engine probably lacks a mechanical fuel pump boss and the pressure in a TBI is too high for a carb. (13? psi vs 6-7psi.)

What's wrong with the engine?

You must be nuts. My friend had a 78 Dodge van with a slant 6, manual steering, manual brakes. He bought it for $1. He overpaid.

My 90 Chev could beat that van in a drag race with me towing my race car and the park brake on. And it would stop better too.

But hey, it's your call. My other buddy has a 72 Nova ... and if he could marry it, he would.

Ray

The guy who owns the 1990 Chevrolet RV van doesn't know what is wrong with the engine and I don't know either.About a month ago, he knocked on my front door.He said he installed new spark plugs, and I think he said he installed a new fuel pump.I suggested he get a can of spray Gumout carburetor cleaner and spray the throttle body, he said he did that.

I think I read somewhere that on some of those Chevrolet vans there are two fuel pumps, perhaps three fuel pumps on some of those vans.My 1978 Dodge van has a good old tried and true mechanical fuel pump, which I replaced with a new one about six years ago because the old one had worn out.Mechanical fuel pumps are the best, in my opinion.I also read somewhere about three weeks ago that a new throttle body for that year model Chevrolet van with a 350 engine starts out at $303.00.If I knew what is wrong with that engine, I would step over there and help him work on it.I know Zero about throttle body/fuel injection.Although my

1960s Mercedes Benz four cylinder diesel engine which I bought from J.C.Whitney back in the 1970s does have fuel injection.Next time I go to the food store, if I think about it, I will stop off at the library and see if they have any repair books on that year model Chevrolet van. I just don't have any idea what is wrong with that engine, I am looking for ideas.Give me good old carburetors anytime! cuhulin

Ask him what it was doing before he put in the new plugs and pump. There really isn't much that can screw up on a TBI engine.

Also that van will have ONE fuel pump.

Post what the answer is and we can start from there.

Why the auto transmission? Why would not a carb conversion work with stick?

Get the guy selling the van to fix it before you buy it. or Running that old Dodge into the ground is probably the best and cheapest thing to do since you don't put on very many miles and its running fine now. GM's with the electric fuel pump in the fuel tank are notorious for fuel pump failure. What do you want to pay $30 for a fuel pump for the Dodge or $500.00 for a fuel pump for the GM.

In fact, a more common question is who sells the best kit to convert this or that carbureted vehicle to TBI.

TBI *was* a transitional technology but it worked pretty well (partly because the complexity is palmed off onto the computer and its inputs; the TBI itself is simple as a stone axe, consisting of little more than a couple of fuel injectors squirting into an evolutionary vestige of the air horn of a 2-barrel carb) and can give a better level of engine control.

I also side with those who think asking your neighbor what is actually functionally wrong with the vehicle (which is not the same question as

-- or even well related to -- what parts he replaced!) would be an excellent next step in the discussion. Remember, every used car is being sold by somebody who thinks his life would be better without it. Your job is to find out just why, and decide what that means to you.

My point is that there's no reason to be scared off by TBI per se nor its control loop -- just a new learning experience. (It does have enough expensive parts in complicated interrelationships to want systematic troubleshooting rather than scattergun replacement of everything or hunch-based replacement of one wrong thing after another.)

--Joe

The next time I holler at the guy across my back yard fence, I will try to get more details about what is wrong with the van's engine.I have his phone number, but I rather talk to him face to face.We are having some stormy weather here right now. cuhulin

Because his crankshaft isn't drilled for a pilot bushing.

Try this website for lots of Chevy & GM repair info:

Here's where it explains GM throttle body injection:

I hope your library has the good repair books, like the factory or Mitchell manuals, because I couldn't make heads or tails of my car's fuel system from just the Haynes and Chilton books.

Thanks, I will check out those chevythunder sites. cuhulin

well, I have the GM shop manual for my 90 truck, so I can probably help you if need be - scans of diagnostic pages, etc...

the TBI setup ends up looking a lot like a carb - with the air cleaner on, you almost can't tell the difference.

Of course, if it's knocking and has 2psi of oil pressure, that's not a TBI problem...

Ray

What I've been told (and which jibes with small-sample anecdotal experience) is that the latter is somewhat dirt sensitive and you shouldn't draw that tank down too far -- definitely not the vehicle for people who don't start looking for a gas station until the little red light comes on. (Which of course is asking to get better acquainted with the auto club no matter what you drive.)

Five bills should be parts and labor. The latter scales with the fullness of the tank (guess who filled 'er up with premium and a couple bottles of dri-gas when the driveability problems started...) and the type of vehicle. Pump itself seems to $150-250 depending on vehicle and generation.

Cheers,

--Joe

Not on some of the newer modular fuel pumps.. They run in the order of $500 from NAPA. Heaven only knows what a dealership might charge for unit plus install.