Just bought this 93 Blazer with the 4.3 "w" CPI knowing it needed either the injector, fuel lines (nut kit), or EGR Valve repair. Turns out the fuel line had a pin hole in it, causing a rough idle due to the excess fuel allowed to drip into the cylinder(s). I will be replacing the injector unit as well as it appears to be original, just judging from the looks, and this vehicle has 110K on it. I also removed the EGR Valve and it appears to have already been worked on as it had the gasket with the screen in it which as I understand it would not be original. I'm attempting to "embed" photos here, hope it works.

The pictures were taken as the engine looked once the upper plenum and EGR Valve had been removed. I thought the inside was acutally pretty clean, no chunks or carbon build up of any kind. I reinstalled the EGR Valve using one of the screened gaskets again.

This job is extremely simple and straight forward. I've never done it before, had no manual, and it only took about half an hour to disassemble. My parts will arrive tomorrow and I'll re-shoot the photos with new parts in place for comparison.

Rod

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Nice pics.


You don't need to replace the injector. I had a '93 Astro with a 4.3L engine. I bought it with 60,000 miles on it. I burned only 10% ethanol blend cheap gas. Never replaced the fuel filter, rusted in place. I retired the trcuk with 286,000 miles on it, hydroplaned on a bridge, totaled. I never had any problems with the engine. Since then I have seen 4 S10-Blazers with roughly 190,000 miles on them, still original injectors. Keep em clean and they last a long time.

However, if your going to replace it. Get some pics and do a little write up on it. This site needs a bunch of tech info.

 

Well, all the parts arrived today. I will be installing them this evening. There has been one change in the plans. I've known about the aftermarket regulator for the injector unit, as I seen them on Ebay when researching what I would need for this repair. After all my GM parts arrived today, I decided to call down to the local O'Rielly store and inquire about a fuel regulator kit, low and behold, they had two in stock, cost is 29 bucks. I had them send one down and that is what I am going to try. As it appears, my original regulator doesn't appear to be leaking, but I've also heard they can be intermittent. My GM Mechanic friend tells me the injectors never give them problems, only the regulator, and suggested I give it a try. Since it is not that big of a job to get to these pieces anyway, I figure why not try and if it works, I just saved myself 230 bucks.

I'll take picture of the process and do a little write up with them. In the Plenum picture, the fuel inlet (pressure) line is the line towards the outside of the plenum, the pinhole is just beyond where the plastic line attaches, shooting horizontal towards the outer wall of the plenum (the cleaner spot in the upper left corner). For those that do not know this, there are two drain hole in the lower plenum, one on each side. In my situation, fuel accumulates over that read plenum bolt until it crests the hump, then flows to the center where the hole is and over loads the left rear two cylinders with fuel, causing the rough idle and strong gas smell. When the regulator leaks, it runs right down the center where the hole is on the right side of the lower plenum and feeds directly into the front two cylinders on the right bank. These two drain holes are not visible in my photo. The hole on the right bank faces towards the firewall, the hole on the left bank faces the front of the vehicle, directly to the left of the middle lower plenum bolt.

 

Okay now.. This is VERY interesting... Tell me - what engine do you have? Is it a Vortec V6? That sounds a LOT like my symtoms that I've been having, and when I changed my plugs today, I noticed that Cyls 2, 4, 6 (all the passenger side of the engine) were ALL carbon fouled. Would this be something common to that side of the engine that would cause that in all 3 cylinders?

Thanks,
Rex S.
('95 Blazer 4.3 4Dr, 2WD Auto)

 

Okay - Here's a pic with the upper plenum removed. The drivers side is pretty cruddy.. Normal? Probably... But the passenger side is CLEAN comparitively speaking... and there's fluid sitting in the bottom. Gasoline? Probably so.



Also note all the carbon buildup!!!



So, where so I look for the leak?

 

Your leak is the regulator, part of the injector (the round canister on the right side of the injector unit). They do offer just the regulator kit now, 50 bucks at O'Reillys (the part they sent me that was 29 was wrong). I just went ahead and installed the new injector regulator assembly. While your in there, get a "Nut" kit as well, that is the two fuel lines on the left side of the plenum, running from the fuel lines outside the plenum, to the injector.

It will cure what ale's your Blazer. Yes, I have the same engine. I would clear out that carbon build up as well. as you can see from my photo, mine had no carbon build up. You should probably do a tune-up on your engine asap after replacing your injector/regulator (cap, rotor, plugs, PCV Valve, at a minimum, plug wires if you can swing it, AC Delco’s are the way to go for the plugs and wires). This should help cut down on carbon build up. Also, it is a good idea to remove the EGR Valve, bolted to the lower plenum right in front, while you have your upper plenum off. make sure it isn’t plugged like that hole is in your picture. When you reinstall it, get a "screened" EGR valve gasket. I ordered two, one from O'reilly and one from GM, I used the one from O'reilly as it was less than 6 bucks and the one from GM was almost 20.

If your not setup to buy wholesale through a dealer, I'd get the complete injector, nut kit, and gasket set for the plenum, off of Ebay. There is a guy on there selling the genuine GM stuff, and usually offers the entire set bundle for 308.00. That is only a couple bucks more than I paid, but hundreds less than the average Joe walking in to the local GM dealer to purchase. The Nut Kit lists for around 90 bucks, and the Injector list for around 495.00.


I'll gather my pictures up and post shortly.

 

BTW, you may not see your regulator leaking, but the giveaway in your photo is the fuel line running to passenger side rear poppet, is cleaned off right under the regulator, plus you can see the gas tarnished streak right below the regulator on your lower manifold. You'll be amazed at how much better your Blazer runs.

 

Thanks for the info! I'll check into it tomorrow. My AutoZone is pretty good about that kind of stuff.. If they don't have it, then I'll run down to O'Reilleys, and will check the other info/sources as well...

I changed all 6 plugs this morning, and will examine the Distributor/Rotor/Wires again.. I just changed all those back about a year ago, though.... I cleaned out the EGR this morning, too... There really wan't anything there, but I cleaned it up with some STP intake cleaner, anyway.. and used some hi-temp RTV gasket sealer to hold the gasket in place again when I reassembled it.

Rex S.

 

Just refer tot he picture for text.



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And the rest....



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