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Discussion Starter · #1 ·
I'm go in to provide as much background information along with my findings and observations, as I can think of.
2007 9-5 Aero with 116,xxx. Original engine and transmission. Full service history. I'm the second owner.
Parts replaced under my year and a half ownership: battery, All vacuum lines, PCV hoses and check valves, boost control solenoid, boost bypass solenoid, solenoid(firewall mounted), turbo charger, upstream 02 sensor, MAP sensor, MAF sensor, CPS sensor, SEM DIC, OEM plugs, air cleaner, along with a TB cleaning.
Aside from the DIC, most of this was done for preventative maintenance purposes and peace of mind...
One day, I reved to around 4,000 rpm, to pass a car on the highway, I felt the car hesitate along with what sounded like a release of high pressure from the engine compartment, followed immediately with power loss and a flashing CEL.
My first thought was a defective DIC, but this episode "sounded" different to me, from the first time I blew the DIC.
As it sits, it runs tremendously rough at idle. My neighbor(a competent mechanic) hooked up his computer, finding code P1300. He also said the car was metering 21g of air @900rpm, essentially dumping a ton a fuel. Thought that would explain the rough idle. Unplugged the MAF sensor and cleared up tremendously. Replaced MAF sensor couple days ago(I believed it was original) but right back to horrible misfire and blinking CEL.
Additional thoughts would be helpful. I've been working from a Saab workshop manual, but I'm still pretty green to a lot. I'm fine with constructive criticism as long as it remains constructive and pointed on task.
 

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Make sure the black plastic pipe that is held onto the top of the throttle body with a hose clamp didn’t blow off
 

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Discussion Starter · #3 ·
Thank You for your reply.
Before I made the thread, I was sure to research some of the probable causes. I did read that as being a possibility. It was one of the first points, I checked. Seems tight and free of leak.
 

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Discussion Starter · #5 ·
Thanks for your thoughts. That's about where I thought to try next, though I'm apprehensive to do so because it ran about normal as I initially unplugged the MAF sensor. My thinking was/is a bad DIC would still manifest itself despite a faulty MAF. As I noticed the car ran better after unplugging it, I'm at pause to purchase another unit.
Disclaimer I likely have an incomplete understanding of the trionic system, so i hope others will chime in on my reasoning.
 

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Change spark plugs first, they are cheapest parts to throw away.
 

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Discussion Starter · #7 ·
I installed a brand new OEM set two nights ago. Didn't help. Thanks for commenting
 

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Did you check your brake booster vacuum hose? I broke mine one time and still attempted to drive the car. It would drive, although it idled extremely rough and also threw the P1300 code. A sudden release of pressure sound like you described would fit well with that hose popping off or breaking, especially where it connects to the booster itself back by the firewall. SAAB Brake Booster Vacuum Hose 5331095 | eEuroparts.com®
 

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Discussion Starter · #9 ·
I havent, yet. That seems a logical place to look. Thank you for your input.
Also, Can anyone comment(in addition to the MAF sensor) another avenue to look might be temp sensors? I haven't yet replaced the air intake temp sensor or the coolant temp sensor. My resources tell me they will be at play with the edu effecting fuel trims.
 

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Not sure of the exact cause of the P1300, which according to my list decodes as "torque limitation signal low", but the symptom sounds as if it's blown a hose off the intercooler. A pal experienced similar when the hose from the turbo to the I/C let go. Clamped it back on and all was well. This can be seen/repaired from underneath water the under tray is removed.
 

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I havent, yet. That seems a logical place to look. Thank you for your input.
Also, Can anyone comment(in addition to the MAF sensor) another avenue to look might be temp sensors? I haven't yet replaced the air intake temp sensor or the coolant temp sensor. My resources tell me they will be at play with the edu effecting fuel trims.
I should add that when I replaced the brake booster hose and pulled it off the booster, there was a sudden "release of pressure sound". That's what made me think of it after reading your initial description.
 

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Discussion Starter · #13 ·
That's a good thought, but no. Not near. There's a shop in a neighboring city About 4 hours away
 

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Discussion Starter · #15 ·
Thank you. To my surprise, Looks like a few local leads to call. Well done.
 

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Good stuff, in my experience having a local shop to bounce things off of, buy parts and borrow parts can be invaluable.
 

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Discussion Starter · #17 ·
Here's a quick update. The car still throws code p1300 with blinking CEL, but runs beautifully when I unplug the MAF sensor. My research of this leads me to believe the ECU uses a default map in the ECU when there is no sign of Signal from the MAF. The ECU uses a "speed density" value along with additional MAP and O2 values to sort of get by. This makes sense to me. Additional thoughts welcomed.
I looked over the car for the obvious disconnected vacuum lines- nothing. Charge pipe for throttle body- fine. Brake booster hose-ok. I replaced the air charge temp sensor along with the MAF sensor(as stated originally). I'm less inclined to believe its the DIC because it runs great if the MAF is in plugged. Logic tells me, if the DIC was bad it will run poor regardless of bad MAF sensor. It doesn't. It runs well so I'm putting that on the back burner, for now.
I'm currently looking into ECU voltage outputs to the MAF, shorts And faulty grounds. Can someone give me a MAF wire diagram? I'm looking to see the ground runs through the ECU or to the chassis. I can't find the right diagrams for this car.
Thanks for your thoughts.
 

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What brand was the replacement MAF sensor? Can you put back the original sensor?

Even a basic ODB II reader with real-time readouts should be able to show what flow MAF is reporting.

From your description, it sounds like the MAF is reporting an incorrect value, either due to MAF problem or air leaks. If it's air leak(s), the problem would manifest more at idle than at high RPM/load. A minor leak would have a major impact on idle air flow, but not so much when the airflow is high. With the MAF plugged in, does the engine smooth out when you put a light load on it? (Don't trigger the flashing CEL, that's not good for your catalytic converter.)
 

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Discussion Starter · #19 ·
Thank you for your reply. Ill respond to your questions sequentially and ill do so to the best of my ability.
The MAF was bought through eBay from Saab Forever.com as a direct OEM replacement in new condition. The original MAF sensor was reading @ 21gr. Of air @900rpm. The new sensor read 18gr. @900rpm, so the condition has been consistent between the two sensors. Idle is particularly bad with increased rev needed to keep from stalling out. I would say its marginally better, yes. I am concerned for the catalytic converter so testing has been limited to a few short interludes. For more context, check out my original posts.
Thanks for your willingness to help.
 
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