Recently installed an 18T turbo, and ARD blue tune. After a hard pull at WOT I heard some popping, like predet or unburned fuel(note: this happened only after I put the blue tune in, at WOT); then after I let off the issue started. It started bogging and didn't want to let me go over 1/4 throttle or 2k RPMs, and I had to go 20 mph to get it off the freeway. It ended up dying in a parking lot a few miles down the road. The idle was surging and there was no CEL.

I put in my old stock ECU and it ran OK but still idled like this. CEL is from me unplugging the MAF and plugging it back it, not from the idle issue. Ran ok for 4 miles with the stock ECU, just didn't want a lot of throttle or it would cut out.

I've already tried unplugging the MAF, no difference. I'm thinking it's a fuel issue, either regulator or pump because no CEL was thrown but it smelled like it was running VERY rich after this problem started.

Here's a vid of the idle, stock ECU
Volvo 850R idle issue - YouTube


Vacuum seems good, solid 17-20 at idle. I checked everything under the hood as well.. No hoses popped off, injectors are seated firm, looks normal.

 

Oscillating idle usually caused by vac leak; make sure you didn't blow some hose(s) off.

I would also ck compression and fuel pressure.

 

The fuel pump would not be a likely problem if it was smelling rich.

The regulator on the other hand can rupture and allow the engine to suck in raw fuel through the vacuum hose connected to it. Try pulling the hose and starting the vehicle to see if any drips out the regulators nipple.

 

Excuse the finger...

Throttle body hose came off! Didn't rupture or anything, just blew off. Whew... I was worried for a second! I guess I'll be investing in silicone

 

And life is good again !!
Glad it was only a loose hose and not some electronic gremlin.

You know you're in trouble when you're trying to run new wire and you can't tell the new from the old !!

 

had the same thing happen to me after doing my pcv system. hit a rough spot in the clamp and then didn't tighten fully. whoops

 

That is my nightmare!! I hate wiring!

 

It seriously made my stomach drop. Like I thought something catastrophic happened at first, especially on the busy freeway on a saturday night, NOT GOOD

 

yea i know how you feel. mine died thankfully in my driveway but was blowing black smoke and wouldnt go over 30

 

Not even an honorable mention

 

I blew off an ic hose once, while I coasted to zero I died inside a little..