Mechanics do you prefer tbi or vortec to work on and for reliability?

How bout everything else on the engines like timing belts, water pumps, headgaskets, etc. How do they compare?

But also the opposite can be done to improve MPG and reduce emissions. Slowing both tip in and throttle response creates a software imposed restriction to limit jack rabbit starts or stomping the throttle to the floor.

I’ve read posts on other boards with people speculating how electronic throttle is causing the delays due to signal lag. Give me a break! A properly design DBW system could actually improve response over a cable based system. A uP can see not only the displacement of the pedal but the RATE at which it is being displaced. It can then predict where it is going to be in the future and start adjusting the throttle position based on that projection. But doing that is not in the interest of the vehicle manufacturer. Reducing emissions, increasing fuel efficiency and limiting mechanical stress are things they value more than providing uber fast throttle response… Given a choice, I’m on the latter end of that spectrum :smile:

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Not sure where that question comes from . They are made by different suppliers and I seriously doubt if there is any difference at all .

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more modern

more accurate

less moving parts

slightly better fuel economy

I could go on . . .

Not that common

far more common to have to replace the iac and/or throttle cable, if driving an older vehicle . . . at least in my experience

None of those GM engines you mentioned have timing belts

Please go on! I meant chain not belt, sorry

Since you seem to be interested in the older trucks with the 4.3, 5.7 and 7.4 . . .

They definitely had problems with the lower intake gaskets deteriorating

The 4.3 and 5.7 were especially bad

Not many problems with the head gaskets

Most of the time that coolant got into the crankcase, it was the lower intake gaskets crumbling, which sometimes allowed coolant to literally gush into the crankcase

pretty much all of them eventually had leaking engine oil cooler lines or trans cooler lines

water pumps are cast iron, no plastic impeller to worry about, but they only last so many years, then they start leaking. no big deal

every once in awhile, the distributor drive gear would wear out, resulting in no spark and no start. you can replace just the gear if you want to be a real cheapskate

the 4.3 and 5.7 had a few variations of csfi . . . central sequential fuel injection. The early version had a central injector body, nylon lines going to poppets at the end. Sometimes the poppets would get stuck or the lines would break. The newer ones had mini injectors at the end.

The 7.4 had true efi, but you have to remove the plenum to get to it. Slightly more reliable than csfi, in my opinion

On the 7.4 the egr pipe tends to develop a hole, which in turn can damage the engine wiring harness

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Thanks that’s the stuff i want to know. I replaced a few of the oil cooler lines on the 4.3, Real fun. Now how about the vortec problems?

I hope that was meant to be a joke

It’s pretty difficult to replace engine oil cooler lines on a 4x4 Jimmy/Blazer with the 4.3 . . .

You’re going to have be a LOT more specific

As @FoDaddy mentioned, “Vortec” could almost mean anything

How about you tell me exactly what engine, what truck, and what model year you’re talking about . . .

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Yeah it was a joke 91 blazer and 91 jimmy 4wd lol

The 90s 4.3 vortec in the jimmy or blazer and the 99 350 vortec in an escalade

Db, in fairness, the last half ton with a 350 was built 20 years ago. So it’s a given you’ll get trans cooler and oil cooler line leaks eventually. Heck, my wife’s 2013 Toyota seeps a little oil somewhere at 120k miles. Not enough to be a concern yet though.

I don’t know what people are doing to throttle cables to warrant needing replacement. They generally last longer than I want to keep the vehicle. I replaced one that was binding on a truck I bought with over 200k miles. But it had been used as a mud toy.

I agree that since the vehicle is older more things will need replaced. I took that as a given. Whether it’ll need more replaced in as many miles as a drive by wire truck, I don’t know. I figure it’ll work out about the same in most cases.

I think what you’re saying is any 1/2 ton truck with a 350 era motor (tbi or vortec) is going to be either worn out, already rebuilt, or so old (even if low miles), everything’s going to be prone to leaks. Which I agree with.


From the posts we get here electronic multi-port injection seems to be more reliable & easier for diy diagnosis and repair than tbi. I’d prefer a car w/a carburetor to one w/tbi.

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Well, that’s hard core old school thinking. I’ve owned too many TBI systems to recall. Very few ever had any real problems. When they did, it was easy to repair. FAR easier than any carburetor I ever owned. I even tore the carb and ignition system off a Wrangler and installed a Chevy TBI system. That thing ran trouble free for a decade before it was traded in on a new Rubicon. As opposed to the carb which was a frequent source of frustration…


The TBI on my '95 Suburban gave me no problems for 12 years, up to when we got rid of it. Much better than I’d expect a carb to do.