SOLVED 96 Volvo 850 rpm's "governed" at 2.5k Topic is solved

Post by **matthew1** » 07 Oct 2017, 08:47

Jim, put an ear to the front of the engine. Down low on the front too, around the intercooler. You might be able to hear the leak. A stethoscope will help. Or a smoke test to see where it's getting drawn in.

Erik's post is as good a theory as any on how the engine management works in this unmetered air condition.

To add to it, when you go past 1/2 throttle, the already heavily trimmed (to +++fuel) state just goes off the map entirely. It's already way out of normal, probably even at idle.

I experienced exactly this. 1/3 throttle it was fine, but when the turbo spooled, stumbles, coughing, no power. Like an old car with choke activated while warm.

I can't remember what codes I got, but I'll look back at my photos. (I used photos to take "notes", like shots of the OBD scanner.)

Post by **matthew1** » 07 Oct 2017, 08:54

Oh yes, I remember now.

Rereading my Volvo 850 Blown Intercooler thread:

I'm getting around 15mpg around town and NO CODES. A BLOWN INTERCOOLER triggers no codes. I learn something every day, I guess.

No codes.

Post by **matthew1** » 07 Oct 2017, 09:02

Another possibility: the wide, short hose on the throttle body blew partly off.

Post by **erikv11** » 07 Oct 2017, 09:51

And that final intercooler hose, on the throttle body, also has a bad habit of splitting in a way that the split opens up when the rpms get high.

Post by **JimBee** » 08 Oct 2017, 09:32

I edited the first post as to what I found, as follows:

thanks to the MVS wizards who pointed out where I should be looking. Neil, abscate and Erik filed some clues; Matt hit the bullseye recounting his own 850 turbo experience.

On mine, the lower hose on the intercooler had come loose and was about to fall off the nipple. A nice 5 minute fix and now back to full strength

Post by **scot850** » 08 Oct 2017, 09:37

Glad you found the issue and it is nice to get a cheap and easy fix too! Well done.

Neil.

Post by **abscate** » 08 Oct 2017, 11:31

Nice - Volvo Horns for you.

Rinse repeat of mine last year

viewtopic.php?f=1&t=76489&hilit=1999+induction+leak

Of course, if I had been maintaining this car on a preventative maintenance (PM) basis instead of run to failure (RTF) , I would have replaced those nasty hose clamps years ago and saved myself hassle.