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Discussion Starter #1
Ok, so the oil leak is now gone but I'm getting a rough idle and throwing the above codes since I put the engine back into my 9-5 Aero. Random mis-fires and evap leak.

I can't find what is causing this. The car runs great above idle but at idle it is clearly missing and stumbling. Everything on the engine is the same as it was before it came out with the exception of the limp home solenoid on the throttle body that I broke putting the engine back in. All of my experience says that this is a vacuum leak somewhere. So far I've checked:

  • All of the vacuum hoses coming from the throttle body to the PCV nipple including the check valve, to the FPR, to the turbo control valve on the firewall and to the release valve on the charge air tube. (I don't have the coolant bypass valve so I don't have those vacuum lines)
  • The EVAP lines going into the back of the throttle body as well as the line going into the turbo control tubes at the top of the COBRA
  • the Cobra was never off of the turbo so I know that is not loose
  • last night I wondered if I may have mis-timed the engine when I put the head back on but took the valve cover off and it is spot on
  • Also did a compression test and got 210/200/205/205, nothing wrong there
  • I also unplugged the brake booster pipe from the intake manifold and plugged it with a spare plug just in case I'm losing vacuum in the booster
I'm at a loss at this point. I didn't have these issues before I pulled the engine to fix the oil leak on the timing cover and now I do. I'm missing something. thoughts?
 

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Discussion Starter #3
didn't check that.

I think I'm going to make a device to pressurize the intake and see if I can figure out where it's leaking.
 

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there is a description in WIS how to check for air leakages.
It requires to plug the cobra. I found this at home improvement markets:
I am not sure if 50 or 63mm fits to cobra.
Then I dismount the tube from pcv to cobra and plug the thread of the cobra with a special screw. (I think it is M14 or M16 with a finer thread than normal. But for US market any metric screw would be some kind of special, and maybe a little hard to get)
I disconnect the tube from cobra to turbo control valve and feed pressurized air of 0.6 bar to the cobra.
Oil dip stick should be open.
I think WIS also recommends to disconnect some of the evap lines, but haven´t done so far.

With this method a lot if not all air leaks should be found.

edit:
Is a Tech 2 available to check certain signals and values of trionic?
I am not 100% sure that is a air leakage.
air fuel ratio controller adopts for smaller air leakages which should let the engine run quiet fine.
Could you make a test in the other direction: create an air leakage and check if misfire increases:
disconnect tube from PCV to cobra or
any small tube from intake manifold, except the one to the FPR (as this would also increase the fuel pressure)
 

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Discussion Starter #6
there is a description in WIS how to check for air leakages.
It requires to plug the cobra. I found this at home improvement markets:
I am not sure if 50 or 63mm fits to cobra.
Then I dismount the tube from pcv to cobra and plug the thread of the cobra with a special screw. (I think it is M14 or M16 with a finer thread than normal. But for US market any metric screw would be some kind of special, and maybe a little hard to get)
I disconnect the tube from cobra to turbo control valve and feed pressurized air of 0.6 bar to the cobra.
Oil dip stick should be open.
I think WIS also recommends to disconnect some of the evap lines, but haven´t done so far.
I did something similar today. Take the hose off the cobra, put a plastic bag over it and then clamped it back down to hold the bag.

Then unplug the PCV from the tube that goes across the front of the engine, and pump air in through that hose. Pressurized the entire system. Found a leak on the port that has two taps for the FPR and the turbo bypass control. Not huge. Took that off and replaced it with a spare that I had. now the whole system holds pressure.

Problem did not go away

Is a Tech 2 available to check certain signals and values of trionic?
I am not 100% sure that is a air leakage.
air fuel ratio controller adopts for smaller air leakages which should let the engine run quiet fine.
Yes, I have a Tech 2, just don't know what to look for
 

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there are several things to check:
measure resistance of evap valve (behind passenger frontlight)
activate this valve by Tech and check if it pulsates with 8 Hz, should only work with engine not running
there is another valve for evap leakage test at the filling line, also check resistance and try to activate it with Tech. I think I read somewhere that these valves sometime fail and get stuck?
in Tech you can read values, take pictures with smartphone, warm idle condition. As there are a lot you have to scroll down. I think with the soft button you can scroll down 10 signals at once so you don´t miss a signal

for misfire:
first read number of misfires in Tech
maybe a single cylinder has a lot more than the others, than it would be cylinder specific (ignition or fuel, most propably)
If you delete errors in Tech also misfire counters are reset
You can check if the counters increase in (poor) idle conditions (but I am not sure if in idle conditions the misfires are counted in this counter; could result in obviously misfiring engine but misfire counters remain at their value)

to exclude simple errors:
check electrode gap (we had misfire once and simply forgot to change spark plugs over a long time on this car)
maybe test another DI cassette if available
there is also a DI test available in Tech, but it might require to update software before (with global TIS)

edit: checked the grounding point at the thermostat housing?
 

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Discussion Starter #8
"edit: checked the grounding point at the thermostat housing?"

You had me there..... I was hoping at least. That's the only thing that would be impacted by me taking the engine out but I checked this morning and both grounds (one on the manifold and one on the thermostat) are both bolted tight.
 
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