exhaust note sounds like a miss and slight surge

[d40ryan]

hey guys ive had a quick look and couldnt find anything with the same problem. the exhaust makes a surging sound like a miss. only happens under load low-mid range, highway driving in 6th and down low in 6th say if you were going to put your foot down to overtake in 6th. its also definatly more slugish as if it doesnt make the sound and you put your foot down it takes off like a rocket.

egt's sit quite high aswell i assume never checked what they usually are for a d40? 500ish sititng in 6th doing 100. egt probe about 7cm off back of turbo mid dump bend. if you put your foot down at 100 egts raise as quick as the speedo and wont do much over 130kmh anymore

boost doesnt seem to fluctuate to the note of the engine
useto have massive exhaust note change when it came on high boost has since stopped doing that and is now doing this

idles perfect starts perfect

2007 rx spainish d40 yd25 manual

straight through exhausts dumps under drivers rear door so you can really hear the exhaust note.

 

[bods]

07 I'd be looking at the boost solenoid VAC hoses to start with. Do you have a boost gauge? Sounds like it isn't making enough boost for the fuel going in. Those egts are way too high for cruising at 100 ks.

Sent from my SM-G900I using Tapatalk

 

[d40ryan]

yeah mate makes 19psi with foot to floor and lines have been replaced.

 

[bods]

Much smoke coming out the exhaust?

Sent from my SM-G900I using Tapatalk

 

[d40ryan]

No smoke at all. Very rare to see smoke from it.

 

[Black_Outlaw]

Things to look at:
Boost Solenoid and all the vacuum hose connections
Fuel Filter blocked, or leaking
SCV needs cleaning / replacing.

When mine had a hunt it was the SCV - cleaned with Liqui Moly
When mine was down on power - turned out the fuel filter was leaking where the water probe inserts into the bottom of the filter.

You should be seeing 21PSI of boost. If it's linear, then i'd go for the Boost Solenoid given up and is just on high all the time.

 

[ericcs]

as mentioned above, should be up around 21psi, and i vouch for the liquid moly diesel purge!

 

[bods]

Wouldn't have thought auto due to the mention of 6th gear...

Sent from my SM-G900I using Tapatalk

 

[d40ryan]

Very rarely does it hit 21 full load only ever peaks at 19. The last turbo useto hit 28/29psi no dramas this new ones always been low. fuel filters just been replaced.

Will try the liqui moly trick put half a bottle of injector cleaner through it and didnt seem to help

Have also just removed the dpchip and relearned the ecu and thats made it alot better still a ever so slight mid range hunt tho.

Also whats everyones egts sitting at since mine seem high?