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View Full Version : Weird problem with 4.3l blazer...?



Joe H
10-28-2007, 08:19 PM
Ok, I'm not much of an engine mechanic. I was hoping someone here might have some experience with a problem like this.

It's a '92 S10 Blazer I picke up for a steal a while back. It's a 4.3l with throttle body fuel injection. It has always ran well, as beat up as it is. It's my fishing truck, as I like to fish waaay out in the wilderness and sometimes leave my truck several miles behind for a day or two.

It runs fine when in park, you can rev the heck out of and it sounds good with no trace of smoke. It runs fine when accelerating, again no smoke. The problem turns up when I have to stop. Every time you stop or slow down alot it produces HUGE clouds of thick dark grey smoke. When I take off again it spits, sputters, pops, and backfires for a second then runs fine again. It seems to be dumping alot of excess fuel into the intake when you deccelerate.

This is driving me nuts. It's real embarrasing, kinda dangerous too since the smoke is so thick it's hard to see through.:laugh:

Anybody out there got any ideas?? Fuel injectors shot out? I ran a code check and got "TPS voltage high". Ok, but I've had it for 2 years and it's always said that.... It may be the culprit, but I thought I'd ask for ideas before I started shelling out $$ replacing sensors.

denrep
10-28-2007, 08:26 PM
Are you using brake fluid too?
Maybe a master cylinder or booster failure is letting brake fluid get sucked in the intake.

David R
10-28-2007, 08:28 PM
TPS must be around .45 volts at rest. Too high to the computer means it will run like crap and burn even more gas. I think its wore out, by the color of the smoke and the fact that it does it decelerating when the vacuum is high.

If its a true throttle body, you can get the injectors rebuilt at napa for about $20.00 each. New ones are around 100 each. If its a Vin W engine, it has a spider for the injectors inside the plastic intake manifold with a big plug in the center. I am going on its true throttle body injectors not port injected.

Does it use much oil?

Do you know how to set TPS?

David

David R
10-28-2007, 08:29 PM
It sez you are on line, I will go to chat. I own a garage.

David

Joe H
11-01-2007, 07:19 PM
I still haven't got around to checking it out... I will this weekend.


Hey Denrep, I did check the brake fluid, and it is a little low. I popped off the vacuum hose, and it does look kind of wet.

Joe H
11-02-2007, 12:16 PM
No, it doesn't burn oil.. I've never had to add any oil between changes.

It even does it if I throw the transmission in neutral before I start slowing down..

Joe H
11-05-2007, 07:28 PM
FIXED!

I checked out the TPS, it was at 5 volts with no throttle! I replaced it.

I changed the oil too, it had picked up some gasoline. No more smoke!:cool2:

Thanks for the help guys, especially you David!

neex
01-17-2008, 11:47 PM
I've worked on several of these motors and as soon as you say you 'picked up some gasoline in the oil' I started thinking... leaking fuel regulator or spider/popet injectors. I would highly suggest taking a fuel pressure reading and seeing if it holds for 5-10min. If this is the Vortec 4.3W series, you should be at around 58+ PSI at the test shraeder valve. I'm glad you sorted out your TPS situation but I fear you might be in for a spider repair or replacement.

Good luck.
Andrew.




FIXED!

I checked out the TPS, it was at 5 volts with no throttle! I replaced it.

I changed the oil too, it had picked up some gasoline. No more smoke!:cool2:

Thanks for the help guys, especially you David!

SWells
01-18-2008, 02:08 AM
That kinda reminded me of a sniper....picked it off in one shot. Good call David!

denrep
01-18-2008, 02:19 AM
Are you using brake fluid too?
Maybe a master cylinder or booster failure is letting brake fluid get sucked in the intake.

I can't recall if I offered any guarantee with this diagnosis! :D :waving:

russellmn
02-06-2008, 09:09 AM
nice call, I was gonna say the same thing. FYI, the VORTEC 4.3l wasn't available in '92, I don't think it came out 'til around 94-95.

Joe H
02-06-2008, 01:13 PM
Yeah, it's not vortec. It's a TBI. It's been running great ever since. Thanks again!

turboblown
02-13-2008, 12:15 AM
All 4.3s are called "vortec" in GM's in-house terminology that came from a design feature of the combustion chamber. They've always been called Vortecs since the mid 80s. GM liked the in-house name so much that they officially named the new "spider" injected 4.3 the Vortec in 1993. GM's engineers named the 4LEx series trannys the "RG" series, which stood for "Rolling Grenade." "Civic" came from a Honda in-house name of the "Crown Vortex Controlled Combustion" (CVCC) technology on their 70's engines. The engineers pronounced CVCC as "Civic". The CVCC tag made it onto the cars, followed by the now-familiar name "Civic."

Just as the modular 4.6 Ford is a "Romeo", the Mustang is the "Fox" and even the 351s had names like "Cleveland", "Midland" and "Windsor" (the plant where these engines were built)

Many manufacturers use in-house names like this either as a joke or for a legit reason. Motorola produces one radio that comes in several different model configurations. The in-house names are "Guppy", "Marlin" and "Piranha." In the 70s and 80s, their in-house names for all of the models were named after words and characters from Star Wars. Some of these in-house names made it to the nameplates in production just as "Vortec" did for GM.

Many names that we see everyday evolved like this. "Hummer" comes to mind.