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One of my friend owned a 1988 Chevrolet Caprice equiped with the V8 305ci ( 5,0 L) type LG4 . The car has been imported from Canada and is in the Police configuration .

Having troubles with the EGR , he has removed the valve and now when starting the engine and when engine is cool he has a small black smoke ; He thinks that without EGR the engine runs more rich .
1°) Is it right that it's more rich ?
2°) Concerning the spark plugs is it necessary to change the AC Delco R45TS (origine) for cooler or hoter ones .
3°) If the change is necessary have you any recommandation for the spark plugs ( Brand and type ) ?

Thank in advance for your help

It would not go rich. Actually I think lean would be the direction it would go if anything.
If he removed the valve, hopefully he blocked off the port. Otherwise there will be a big vacuum leak.

The exhaust gas recirculation works by introducing an inert gas (exhaust gas) into the cylinders to reduce combustion cylinder temperatures, thus reducing the oxides of nitrogen produced. Eliminating it may increase combustion temperatures, but also allows them to contain more air fuel mixture to produce more power.

Read the plugs to determine if a change is needed.

Thanks Brule . I agree that to "read plugs" is the good way to go .
I have transmitted your answer and now wait for the comments .

What trouble was he having with the EGR valve? Did he fail an emission test or was the car stumbling on takeoff? Does the EGR valve have a bad diaphram? Did he plug the vacuum line going to the EGR valve and did he make a block off plate to cover the hole in the intake when he removed it? There shouldn't be any reason to switch to colder or hotter plugs regardless if the valve works or not, and as Brule mentioned the engine should not run rich without the EGR sysyem installed. EGR problems are usually caused by leaking diaphrams, carbon build up in the EGR passage inside the intake manifold, or lack of vacuum from the remote valve that controls vacuum to the EGR valve. We would be glad to help, but we do need more info!

Steve

killian96ss wrote:What trouble was he having with the EGR valve? Did he fail an emission test or was the car stumbling on takeoff? Does the EGR valve have a bad diaphram? Did he plug the vacuum line going to the EGR valve and did he make a block off plate to cover the hole in the intake when he removed it? There shouldn't be any reason to switch to colder or hotter plugs regardless if the valve works or not, and as Brule mentioned the engine should not run rich without the EGR sysyem installed. EGR problems are usually caused by leaking diaphrams, carbon build up in the EGR passage inside the intake manifold, or lack of vacuum from the remote valve that controls vacuum to the EGR valve. We would be glad to help, but we do need more info!

Steve

I do not have all these informations concerning the troubles with the EGR . I will ask and at the moment I will transmit to him your answer . Thanks for your support .