How to clean EGR valve passages. The 93 Isuzu Trooper 3.2 L DOHC V6 often has a working EGR valve and clogged holes in Intake manifold.
You have to the EGR valve (sometimes the Intake manifold to EGR Vlalve line also). After you remove it take a drill bit the about 20 % smaller than the actual hole of the outlet side and rotate the drill bit with your hand to dig out the carbon. Aditionally the line coming from the intake manifold to the EGR valve will clog near the connection to the EGR valve. I use either a single piece of copper wire or the wire that you would use to tie ribar together to clean the line. When your done cleaning take a piece of vacuum line and connect it to the diaphram side and **** on it... then plug the line well with your thumb. Grasp the valve and blow thru it... Air should blow thru it freely. Remove your thumb from the vacuum line and try blowing again.. No air should pass thru the valve.
Then reinstall the valve and start the vehicle with the vacuum line disconnected (but blocked off) Use another piece of vacuum line connected to the diaphram again and **** on the line.. The vehicle should die or run really bad. If it does this then you cleaned it correctly.
You should remove the EGR valve and scrape off the carbon deposits. Also remove the intake manifold and clean them all off. Scrape off cabon with flat-end screw-drivers or scraper. A can of carb/ Injector claener would help.
I just did one of these by punchung in the plug on the back side, rear of car until the front side of the plug lifted, I grabbed it with pliers and pulled it out, to put back in a little sealant and 3/8" extension and it went in nice and sealed fine. But it didn't solve my intermitant rich running problem!
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Matt at Woodside Auto tells me that on the 93 Isuzu V6 engines, often the EGR valve is OK and the intake manifold passages are plugged.
Tools: hand vacuum pump-tester, 22 mm wrench, 12 and 10 mm sockets, 4mm hex wrench.
Engine running test: To test EGR valve, pull a vacuum on the 2 mm diameter valve port. Plug the hose. Working valve and passages will make engine stumble.
Engine stopped test:
Remove valve and observe the diaphragm and stopper move when vacuum is applied.
Test intake manifold passage with vacuum tester or by blowing through a tubing.
This is the start of a 1 day "amateur repair"
This is how to clean the intake manifold passage from the EGR valve to the intake manifold.
Put down 6 rags to cover the holes in the intake manifold. Disconnect battery ground..
Assemble cleanout tools:. punch, drill and drills, 14mm dia. freeze plug and sealant or other replacement plug (see text), brushes, EGR valve cleaner(flammable, do not vacuum it up), shop vacuum, 3/8" x 12" vinyl tube for cleanup, broomstick and clamp to hold throttle wide open.
Unbolt EGR valve and push it aside. With 12 mm socket undo the 8 mm dia x 12 mm long bolt that steadies the Exhaust to EGR valve supply tube.
Using 4 mm hex wrench, remove 4 pc. hex screws holding the "V6 DOHC" nameplate. With 12 mm socket, loosen the accelerator cable bolt to reach the rear most hex screw.
Retrieve any fasteners dropped. See, rags help.
See underneath the name plate a hole closed with a 14 mm diameter freeze plug. According to myisuzuparts.com the freeze plug is not available.Try to buy one or devise a way to plug this hole.
I used a #10 flatwasher and a #00 black rubber stopper cut for a tight fit as a temporary plug.
Mark the center of the freeze plug with a scriber and a washer or hex nut dropped into the cavity. Center punch as close to the center as you can get and drill a cleanout hole. Max hole size is about 5/16" and do not drill deeper than 1/8"..
Don't drill too far. Right below the freeze plug the connection to the intake bore is two slant drilled holes, You can feel the holes with an ice pick. You can scrape the two small bores with a hand held 1/8" droll bit.
Set up the shopvac to **** chips out the EGR port. Use an ice pick and hand held drill bits to break loose the carbon crusties.
Block the accellerator pedal to the floor, remove the intake air tube. Put icepick in through the manifole hole to mark where the carbon chips are in the intake air path.
Cut the end of the piece of 3/8" vinyl to make a slanted end. Use the vinyl tube and shop vac to **** carbon chips out of the manifold bore. **** up all the crusty carbon stuff and metal flakes from drilling.
Plug the hole. The best fix would be another freeze plug. If you have access to a lathe, you can make a plug. A rubber stopper as I used is just a temporary fix.
Get all your rags out of the engine.
Engine top view of EGR valve and the clean out hole underneath the name plate.
The mechanics at Woodside Auto and Tire, especially Matt Coffaro told me that this Isuzu engine usually has a plugged intake manifold gas passage, and the EGR valve rarely fails.
Taking the intake manifold off does not help. The EGR gas pathway is right on top. The EGR related holes are only accessible by drilling out the freeze plug and scraping the pathway clean.
The mechanics at Woodside Auto and Tire, especially Matt Coffaro told me that this Isuzu engine usually has a plugged intake manifold gas passage, and the EGR valve rarely fails.
Taking the intake manifold off does not help. The EGR gas pathway is right on top. The EGR related holes are only accessible by drilling out the freeze plug and scraping the pathway clean.
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