9-5 starts and stalls; backfires; turbo started working

[bobthebuilder]

So, I finished my top end rebuild a few weeks ago and started driving the car a bit. It's been starting right up and driving okay with the exception that the turbo gauge won't go past the white area. The engine power has been leisurely...

Today, I had a sudden burst of power - turbo gauge jumped to the red - followed by a backfire. The engine immediately shut down and I coasted to the side of the road. When I restarted the engine, I could feel a dramatic increase in boost in the brake pedal, the engine would not idle and pressing on the gas would keep the engine running but dropping into Drive killed it right off. Several attempts and no change in this. I opened the hood and saw the charge tube off the top of the throttle body. I snapped it back on, and voila! the engine started and run, idled normal and I was able to drive away. For about 1/2 block. Then it started over. I snapped the tube back on, and if I was easy on the throttle, I could carefully drive home.

Once home, I secured the charge tube better, and drove down my street. I gave it a little gas and saw the turbo gauge jump to the red and accelerate was more dramatic. Yeah, this is what 220HP is supposed to feel like! Then, a bang under the hood, much louder, and the engine quit. I pulled over and looked under the hood. The charge tube was secure. Hmm... so what was that noise? It started back up and I drove about 300 feet and it did it again. This time, no amount of coaxing could get it running. Turning the key caused the engine to catch and start, then immediately shut down, like there was no gas. I do have suspicions about the gas gauge, but I had just put $20 of gas in over the weekend, and didn't drove over 10 or 12 miles since then. AAA got me home - world's shortest tow - 4 houses down the street.

I am at a complete loss with what is going on. I'm reading here about AIC's (which I believe is built into the throttle body on this car - 2004 9-5 Arc), DI's (I have two spares), CPS, vacuum leaks and complete turbo failures. As noted above, I've never had any turbo boost since getting it running last month. That unexpected boost today kind of tells me it is generating some sort of boost - maybe too much, which is causing the charge tube to blow off. I would appreciate feedback on what could be going on here. Thanks for any and all help!

[Finding41]

If there is a leak from the turbo it will stall. As you have found out. I would check the blow off on the turbo it's self. Is it stuck open? Is the vacuum hose connected? Is it connected to the other thing on the other end? What about the 3 other hoses on the other thing.... (I can't remember what that is called... It's black and near the top of the cobra pipe.) Is the blow off that connects to the cobra attached properly? What about the rubber gasket in there?
Note: If that rubber gasket (O ring) is missing.... It may be stuck in the turbo! Or in a valve...
A quick compression test will tell you that last one.
Good luck!

[bobthebuilder]

Thanks Marty. One thing I noticed is that the wastegate (the diaphragm thing with the arm on it) has never moved since I got the car. I've tried to move it by hand and it seems to be stuck. The one on my daughter's 9-3 moves somewhat easily and she has good turbo boost. Last night, I took pliers and tried to force it to move. It finally moved about 1/2" or so and snapped into position and stayed there. Then it snapped back with resistance. Hoses are connected to it. I'm wondering if the wastegate moved completely from one position to the other, and "the other position" is where it stalls, then it snaps back? It is always in the "left" position when I look at it from the front of the car. The horizontal pipe that connects to the cobra is in place and the o-ring is behind it. However, that pipe can easily be lifted off, even with the retaining screw in place, so it is not a tight seal. I haven't had a chance to check the other things you mentioned but will. I can't get to the car to work on it for a few days.

[Finding41]

Ahh yes the waste gate actuator is the thing that moves the gate. (I've been working on sail boats for the last few months and have my head stuck in that terminology...) It is has a hose that goes to the black thing with the 3 other hoses.
You can take the acuator off by removing the 2 bolts and the clip. I would gently work the waste gate arm back and forth. Use some PB blaster to help free it up. If it doesn't move freely that's one of the problems. (I'm guessing it is stuck open a bit.)
The pipe that goes into the cobra being loose is a problem. There is supposed to be a small piece of metal in the shape of an L that the short end goes into the hole. You can make one out of a small piece of metal that looks like an L. The bolt holds it down.
On my 04 9-5 I rebuilt I have put a spring on the waste gate actuator going to the waste gate flap holding it closed a bit more. It still works fine but what the spring does is keep the boost a bit longer. (I found that mod on the English saab site.)
Check my rebuild my 2.3T thread for pictures of that mod.

[bobthebuilder]

Finally back from a 9 day business trip. I pulled the turbo off the car today for an inspection. The wastegate valve moves but it takes a lot to pull the rod out, more effort than my 1999 9-3. The wastegate ? (the flapper thing on the exhaust side of the turbo) lever sometimes sticks. It hangs sometimes to open, but moves freely once it's past the hang. If you move it all the way to the right (when the lever is horizontal), it hangs and does not return to close without a little effort or a wiggle. The wastegate shaft, while it moves freely, has a squeak when moving, which tells me something is binding. And when that turbo gets up to a thousand degrees, it could bind. So, I'm thinking the turbo and maybe the wastegate valve are the problem. If that wastegate hangs open, it could easily overboost. I'm headed to Pull a Part in the morning. They have a 9-3 and two 9-5's on the lot. If the turbos are still on the cars I might get lucky - I have no idea if they are the Mitsubishi turbo that I have until I take a look. Mine is a TD04HL-15T.

[Finding41]

Don't rule out the vacuum thing that operates the waste-gate. (waste-gate actuator...?) It may stick as well.
I have the same turbo on both my 9-5's.
Good luck.

[bobthebuilder]

No luck at Pull A Part - they are all Garrett units. I ordered a used turbo from a boneyard in Oregon. It is in much better shape than mine. Wastegate port opens and closes easily and the wastegate valve arm can be moved in and out, and it moves the wastegate port, with minimal effort. Put the used turbo on and fired up the 9-5. It's not doing the backfire thing anymore, but still runs poorly. It will not idle, and misses a lot while blowing some (not a huge amount) black smoke out the tailpipe. It will clear up at 3000 - 4000 rpm, but as soon as I let off the gas, it misses, blows black smoke and nearly stalls. Hitting the gas results in more missing and black smoke until 3000+ rpm. I did't try to drive it. During all this, the turbo gauge is moving between white, yellow and red, sometimes pegging the red at the far right. I can hear the turbo whistling.

Here's what I've done to trouble shoot: Checked all vacuum lines. I found one off (that long skinny one from the bypass pipe to the firewall - it was off at the firewall), that made no difference in the way it ran once reconnected. Took the BCV apart and cleaned it. Replaced the MAP sensor with another from a donor. Replaced throttle body with another from a donor. Tried the "bolt in the top hose" to bypass the evap system at the BCV. Checked plugs and regapped them to 1mm. They are proper NGK. Swapped out the DI unit twice (I have two spares). No change. Pulled fuse 27 (ECU), waited 20 minutes, put it back in. The engine ran good for about 10 seconds, then did the missing and black smoke thing again.

Today, I took the MAF out and cleaned it. Pulled fuse 27 again just for fun. Put it all back together, and it ran great for 30 seconds, then back to the missing and smoke. I pulled the wiring harness off the MAF and tried again. Now the engine runs smooth, idles (at 1200 or so, which is a bit high) and seems to behave itself except I don't think I have any boost. I only drove it up and down the driveway (maybe 100 feet). Didn't take it on the street as I didn't have time for another tow home if I needed one. Seemed like the turbo is really winding up (audibly), at least on that really short drive. Couldn't tell on the boost gauge or car movement if there is any boost as it was such a short distance. I reconnected the MAF and it immediately went back to missing and black smoke.

So, I'm thinking the MAF is bad, but am looking for confirmation, because in the back of my mind I'm thinking there could be something upstream or in the sensors elsewhere that is affecting how the MAF performs. I found a new OEM MAF for $120 which isn't too bad, but I don't want to throw parts at it. If the MAF in my daughter's '99 9-3 is the same, I can swap it out to confirm. I don't have another source of a MAF to swap out with (pending another run to Pull A Part...).

Thanks for all the help. This forum has kept the 9-5 project car moving along!

[bandasaab]

Hi, Did you solve the problem? My 2000 9-5 Aero is doing exactly the same thing + it seems to destroy the spark plugs. Your reply is much appreciated.

[bandasaab]

Just did a trouble shooting and the car runs fine with MAF sensor disconnected. I tried with the MAF sensor feom another 9-5 and the car did the same. So, it's not a faulty sensor.