Foam pad on air filter?

[tyeriver]

I have purchased my first diesel, Chevy 94 C3500 6.5 w/150k miles.

Performed maintenance all normal items. Found foam pad on front of the air filter and discarded not knowing why that was there. First time putting stress on engine after maintenance (towing camper) I got a 'service engine soon' and it did not seem to be associated with the incline of the hill or the speed of the truck. (I do not have obdi to read codes yet). Also noticed some black smoke when stressing the engine.

Is this tied to finding a foam pad on the filter thus reducing the boost? Any and all recommendations for a newby is appreciated. Thanks

[Robyn]

Very likely you are seeing a failure of the wastegate system that results in Low boost.

The low boost will cause the black smoke.

Get a code reader or use a paper clip on the ALDL connector to flash the codes via the ses light.

Keep us posted and will get you on the right track.

The foam is a prefilter to knock out the big junk.

Best.

Missy

[DaveBr]

Being a 94 you have a panel filter. That foam pad is a pre filter that comes on the stock filter. GM put a snorkel between the inner and outer fender. If you remove your panel filter housing you will see the hole that goes into the inner fender. Look inside the hole and I'm betting you will find a dirty yellowish piece of plastic that curves toward the front of the truck. If it is there you need to reove it. This highly restricts the amount of air coming in and chokes turbo operation. There is on small bolt near the battery that has to be removed and you can pull the snorkel out the hole in your inner fender. This won't help your SES issue but will help your truck pull better.