EGR Question

[becketts]

Hi Guys,When I bought my Blazer 12 years ago the engine had already covered over 120.000 miles and the vacuum pump produced hardly enough to operate the demisters properly,I also noticed the hose that operates the egr valve was blocked off,being new to GMC diesel engines i didn't understand the reasons why and as the engine ran ok i left it alone.Move forward 11 years and last September the engine lost most of its compression because of piston rings failure!I couldn't afford a rebuild so a local garage installed a second hand engine of similar age that had less wear than my old engine and also had good compression.All was well for the first month then it started to emit clouds of black smoke on acceleration,IP is a new remanufactured one, timing is ok and the engine has plenty of power,I'm told by Jim who works for Oregon pumps that people disconnect the erg system on old engines where the vacuum isn't perfect to stop the engines carboning up and smoking badly,is anybody out there who would agree with that and if so whats the quickest and best way to decarbonise the engine and the safest way to block off the erg.

Regards
Paul

[john8662]

You'll want to disable the EGR and keep it that way. Here is what to do. Disconnect the EGR hose from the air cleaner, in place of the Hole in the air cleaner housing, you will need a small short carrage bolt and a nut and two washers and some RTV sealant. You will want to remove the air cleaner housing from the vehicle to do this properly. First take the RTV and be very generous and coat the entire bottom side of one of the washers. Then coat the bottom of the carrage bolt head (that seals against the washer). Place the bolt through the washer, then take the washer and bolt and stick them through the hole inside the air cleaner. Take your second washer and coat it again very generously with RTV sealant and then add the nut to secure this in place. You'll want to tighten the bolt to make a very tight permanent seal. This will keep your engine from being contaminated with dirt from the hose missing, Then install the air cleaner back on the truck. Find the hose that connected to the EGR solenoid, take a 3/4" length bolt small enough to thread in tightly into the hose (that did go to the air cleaner) this will stop the vacuum leak.

You really won't clean the carbon out of the engine, but running it clean like this will help it breathe better, and over time some of the crud will be burned off.

[TimK]

Paul,

Black smoke is caused by a lack of air for the amount of fuel being injected at the moment of combustion. Either you have some form of air intake blockage (such as a collapsed air intake hose or clogged air filter) or the timeing has shifted. An EGR not functioning properly or an engine with a lot of blow by can cause the intake to get very oily and sooty in a short amount of time.

TimK

[Robyn]

The new to you engine that you had installed may have had someone turn up the fuel screw some too. This will definately cause some heavy smoke when you romp on it.