Trying to check for exhaust restriction

sk66 · Post by **sk66** » Fri Dec 09, 2016 10:03 am

Over the last couple of days I did belts/timing/fuel filter/air filter/water pump/valve adj... it took me around 8hrs in the driveway, with breaks, and I'm pretty sure I spent a good deal of time removing the power steering bracket when I probably didn't need to.

The last thing I'm trying to measure/check is for a possible exhaust restriction. I attempted to use the vacuum measurement technique by connecting my boost/vacuum gauge to the EGR vacuum line. But I get nothing at idle or mid revs (~1500-2000)... I'm guessing the diesel vacuum system is significantly different than on a gas engine. Is there a way to use vacuum to check for exhaust restriction? Or is my vacuum pump dead?

Post by **Growlerbearnz** » Fri Dec 09, 2016 1:26 pm

Diesels don't make engine vacuum since they have no throttle. The vacuum that runs the EGR, brake booster, and aircon idle-up comes from a vacuum pump on the back of the alternator- that's the bit that has the oil return pipe going into the sump.

My favourite way to test exhaust restriction is to remove the exhaust system and replace it with a 2.5" side exit exhaust.

sk66 · Post by **sk66** » Fri Dec 09, 2016 1:58 pm

I'm considering a 2 "straight pipe" type of system; I understand that these things aren't very loud unmuffled. I should probably test that first...

gezzza · Post by **gezzza** » Sat Dec 10, 2016 9:10 pm

I had a 2' straight through system for a while and it was too loud for me. Cops pulled me over and gave me a defect notice for excessive noise along with a couple of other things. I got a resonator put on which did quieten it down a little but it is still quite loud if you floor it. Next time I would put a larger muffler on if I do it again.

sk66 · Post by **sk66** » Sun Dec 11, 2016 12:34 pm

Thanks Gezza!

theDriver66 · Post by **theDriver66** » Wed Dec 28, 2016 5:33 am

We've checked on the mufflers for delica with my dad, as his blew due to a piece of rust or metal that blocked the outlet. He wanted a muffler that would sound as close as possible to the one he had, so we checked online and found a nice aftermarket one (https://www.carid.com/exhaust-mufflers/). I must admit, the sound is close, yet a little louder. But he liked the way it was installed and now is totally happy with what he got.