exhaust 1991 5.7 L

[schjoth]

Hey - Do any of you guys know what could cause at excesive backpressure in the exhaust - Engine is mercruiser 5,7 efi 1999. I have a suspicion that a high backpressure is triggering the MAP sensor to think more load is on the engine... and I end up with at rich fuel condition ???

 

[chiefalen]

Re: exhaust

Maybe the riser is all clogged up or a flapper / shutter fell down and is blocking the exhaust.