A Big Woosh And Then No Boost

[Jeff]

Hello all,

I am unfortunately, the worst kind of forum member. My last post here was when I bought my 9-5, nearly three years ago. Back then it had just over 182k miles; a couple days ago it rolled past 248k. Since my last post I have done all sorts of little fixes like the window rollers, the automatic shifter cable, two fuel pumps (yes I bought the tool), the water pump, brakes all around, and of course the normal stuff.

Now, on my way home tonight, about 2 miles from my house (thank the higher powers) I was accelerating (briskly) after turning off a main road when the normal turbo whine/whistle gets many times louder, I lost power and it felt like the engine was cutting out. I made it to the side of the road just as the CEL started blinking. I didn't smell anything though (windows down) so I let it idle for a moment, and the light stopped blinking.

I popped the hood, and prepared myself to see a horrendous mess, but there was nothing. I looked at the ground under the car and back up the road where I came from and I didn't see anything on the ground. Seeing as no vital fluids appeared to be gushing out and knowing what the turbo and associated hardware should look like, having taken it all off at some point or another, I decided to finish the drive home.

While rejoining the road I noticed a definite lack of power, and the turbo still sounded much louder than it did previously. The turbo gauge was now also reading in the yellow at maybe 1/4 throttle and into the red/orange at any more than that, and the ignition system seemed to cut out when in that range (which it is supposed to do I assume).

I made it home fine, yanked the ramps out of the shed, drove up, and shoved some cardboard underneath to catch any tell tale drips. After family duties I went back outside and found nothing but a little water (actually water, not coolant) which I gathered was from one of the drains for the sunroof or something, as it had been raining earlier. The coolant reservoir was still full, and the oil was not milky and the level was fine. I didn't see anything obviously disconnected though it is very cramped in the area where all of the turbo related things are.

I fired it up to take a spin to get a little more information. It backed off the ramps okay, and I shut it off to grab my code reader. When I turned it back on, it wouldn't idle without keeping the throttle depressed a little, and driving it was essentially impossible, leaving me to coast backwards down a small hill to get back to my driveway.

The codes were as follows:
P1110: Charge Air Bypass Valve (This has been appearing on and off for months, naturally)
P1312 + P1324: Ignition Coil Knock Detection CYL 1&2, 3&4: I assume this is a result of whatever happened, and the ignition cutting out to protect the engine
P1300: Misfire: Seems normal given the circumstances
P0101: MAF: Again seems symptomatic of whatever happened, but not ringing any bells for me

Here are a couple videos I took when attempting to drive the car again, hopefully they are helpful is assisting with a diagnosis.

https://photos.app.goo.gl/8o2hWcRGsFBAEP9X8

First start, not touching the throttle at all. Second start, keeping it running by applying some throttle.

https://photos.app.goo.gl/8NHED2Gk4AEfvGMj9

Trying to keep running both times, before coasting backwards into my driveway.


Thank you everyone for your time!

[Jeff]

For those following along at home I believe I have found the culprit, the MAF sensor.

I have another car, same year, model, and engine, as the one that was misbehaving. Having found that the diverter valve was indeed faulty, I swapped them between cars, no change. I swapped the boost control valve (three verticaly stacked hoses), no change. I swapped the DIC, no change. I traced all the related vacuum lines I could find and everything was intact. I then disconnected the MAF sensor, and it ran perfect. The boost however was limited to the lower half on the yellow section.

Is this to be expected with the MAF unplugged, a safe mode of sorts, or do I still have a problem elsewhere?

Thank you.

[nordwulf]

Tough problem to diagnose remotely. My first guess was disconnected vacuum lines and a faulty DIC as well. Perhaps it's worth it to take it to a Saab specialist and have it checked out with Tech2.

Perhaps the turbo just went bad internally but that's just another guess. Do you have the 2.3t or 2.3T engine? Has the turbo been replaced at all? The GT17 turbo usually lasts 100K miles and even the TD04 doesn't last forever.

[Jeff]

Perhaps the turbo just went bad internally but that's just another guess. Do you have the 2.3t or 2.3T engine? Has the turbo been replaced at all? The GT17 turbo usually lasts 100K miles and even the TD04 doesn't last forever.

It's the 2.3t. I don't know if the turbo has ever been replaced, but I know that I have not done it from 182k-248k miles. With the MAF unplugged the whole turbo subsystem seems to be working properly. After some more thought, I'm thinking the MAF is not the problem. The sudden nature of the problem doesn't fit my understanding of how MAF sensors go bad.

Putting together that the car runs fine without the MAF plugged in, and the definite increase in the volume of the spooling of the turbo, I'm thinking there is air getting into the intake after the MAF sensor somewhere. I will still swap the MAF with the one from my other 9-5 first just to be sure, but I think now I'm leaning towards extra air getting in somewhere. I had the intake apart when I did the water pump of course so maybe I didn't didn't get everything tight or nicked something in the process. That was a few months ago though.

Anyhow, I will report back what I find.

Thank you!

[Jeff]

So while following the path of the intake side of the engine, I found that the pipe from the output of the turbo to the intercooler was undone where it meets the intercooler. It looks like the hose clamp failed. I didn't have another one handy so I grabbed a zip-tie just to see if reconnecting it solved the problem. It did, and when I took it for a drive and built up some boost, the hose popped off again and I heard the same sound I heard originally. I will be picking up a new hose clamp tomorrow. I just wish I checked for something like this first!

Cheers!

[walawala]

great find! this used to happen on my classic 900. A big Whoosh and the intercooler hose would pop out. but the car doesn't run after that. I'm surprised the 9-5 could run with such a big air leak in the system.

[nordwulf]

This happened to me after I replaced the turbo on an earlier 2001 9-5 2.3t. But it was my error because I didn't tighten the hose clamp enough and the hose slipped off. I never thought a hose clamp could fail like in your situation so never thought of mentioning this.

Good to hear it was a quick and cheap fix.