My girlfriend has a 1995 S10 Blazer with the Vortec 4.3, 166,000 miles, and is starting to suffer from poor gas mileage. I know that the EGR is getting gunked up (occasional CEL, stumbling idle), and that it needs plugs and wires. After a bit of searching, I see that replacing the rotor and cap probably needs done as well.

I've never worked on a 4.3 Vortec before, but I have done similar work to my 1995 Taurus SHO (dissassembly of intake, de-carbon, cleaning EGR passageway, plugs, wires, valve cover gaskets, etc).

I'm looking at some pictures from a thread where the upper intake plenum has been removed, and it looks pretty straight forward to remove it, clean it out, etc.

I guess what I'm asking for is some pointers for performing this maintenance. (ie. any trouble some plugs to remove, things to look out for.)

Thanks in advance,

Adam
Des Moines

 

Welcome to the site Adam!

First thing, you do not need to remove the upper plenum to clean the EGR passages.

The more difficult plug to remove is the #3 plug (center plug, driver's side). The steering arm is in the way. I was able to use my normal deep socket with my wobble extension to get it loose, then just used a standard spark plug socket with a wrench to get it the rest of the way out. If you cannot do this or do not have a wobble extension, you can loosen up or remove the steering shaft cover to get a little more room.

A good seafoam treatment (do a search) will clean out the carbon in the intake and cylinders as well as off of the valves. This should be done before replacing the plugs as it may shorten the life of your plugs.

As always, make sure to check the gap on your plugs before putting them back in. I have found that the cheapest/longest lasting replacement plugs have been the AC Delco Double Platinum. If you don't mind changing your plugs every 2-3 years (depending on mileage), you can go with a set of copper plugs, but they will have a drastically shorter life than the DPs. Do not get caught up in all of the hype over the gimic plugs like the Bosch +2 or +4. They don't work as advertised after as little as 200miles.

A good tune up should include the plugs, wires, cap/rotor, cleaning the EGR valve & tubes, as well as ($$$ dependant) the O2 sensors. For O2 sensors, I have personally seen the response from several (Bosch, Warner, & AC Delco) and AC Delco had double the activity of the other two. I have experienced failures of direct fit and universal Bosch sensors as well as the Warner direct fit. IMO, they are both absolute crap in a GM application and not worth the card board box they are shipped in. AC Delco's are all I use and recommend for any GM application. I can purchase them at ~$10 more than the others at my local AC Delco retail store.

Good luck and if I can think of anything more, I'll let you know.

 

i've researched a bit and have a couple questions.

1. Where do I look to find the engine VIN? W or Z
2. What weight of oil is preferred for summer driving

I told the g/f to be sure to set some money aside for a tune-up this spring, I just hope she's ok with the $$$ that I tell her this evening, lol.

 

The 8th charactor in the vin is the engine code.

 

crap, one more question...

when using seafoam to decarbon the top end, i'm a little confused here...do i just dump it in the throttle body opening? or use the PVC valve? I've been searching and can't really find a definitive answer.

btw, thanks for the help.

 

I ran it through the PCV hose on my '00, but the '95 is a CPI motor which is different. I do believe that I could have poured it straight down through the throttlebody if I had of only unplugged the MAF sensor. The CPI throttlebody is horizontal making pouring anything into it a major pain in the rear.

I went to Walmart and purchased a set of small funnel from like the kitchen utensile area and used one of these to pour the seafoam into. First 2/3 of the bottle, keep the motor running (may need a helping hand with that), but then on the last 1/3, pour it in all at once, then let the engine die off and sit for a good half hour.

 

will any cap/rotor work? i'm looking up parts and there are quite a few different types listed.

 

Swartlkk has it right about that center driver's side plug. What i did was just move of the orange cover for the steering arm up and out of the way then a little wiggling and you can get your extension through the wheel well. Good luck.

 

i'll be performing this maintenance this coming weekend, and needed to ask a couple of questions.

do i absolutely need to do the cap/rotor?
if so, how hard is it (never done it before)?
does anybody know the part number for the egr gasket w/ screen?

the blazer doesn't seem to be having any ignition issues, aside from poor start-up times due to old spark plugs. i surveyed the engine compartment and with the distributor wayyy in the back, i didn't want to have to do anything to if if not absolutely necessary.

thanks in advance.

 

Hi, Adam.
The cap and rotor isn't all that hard. Believe me, if I can do it, anyone can. Of course, I had to sit on the engine to get to the thing! Just use a small socket with a screwdriver handle extension. I forget the size but it's around 5/16". Might be metric. Just replace one plug wire at a time and you should be OK. Rotor just pulls off the shaft, no tools needed there.