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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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Discussion Starter #9
Still rough/pulsing idle. I had the EVAP system checked at the Saab dealer this week. Didn't find any leaks on the EVAP and it seems to be working. They think I had a loose gas cap that has now "fixed itself" and say that my DIC is bad and that is causing the misfires. (I'm not sure I believe that)

They did find a problem with the wire to the boost control valve and MY OH MY, THIS CAR IS NOW FAST! Seriously if you're not getting what you think you should get from the car, check those wires!

What I've done so far:
  • EVAP system tested, no problems (done by Saab dealer)
  • Pressurized the entire intake system (see above) from top of COBRA to check for leaks, nothing. All of the check valves are holding as well.
  • new plugs, all of them were a nice light brown color
  • changed DIC with my spare that throws P1312 codes now and then, but functions. no difference
  • unplugged the brake booster at the intake and put a plug in the hole to see if it was the brake booster
  • pulled the valve cover off and checked the timing, dead on.
  • Compression 210/205/205/205 (warm)
The car runs great above 1500 RPM's, it's only stumbling/missing/whatever at idle.
I've not connected the Tech 2 to the car to count misfires.

I'm at a loss at this point, suggestions?
 

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New spark plugs. Check the gap..9-1.0 mm. Sometimes If the plug gets accidentally dropped into the hole it can close the gap enough that it will cause an annoying idle misfire that goes away driving .
 

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Discussion Starter #11
I did change the plugs and the gap on the ones I took out were spot on. But I'll pull them again.

I'm close to pulling the trigger for a new DIC but I am not convinced that will solve the problem.

As a reminder, the engine was running great with no issues before I took it out to fix the oil leak on the timing cover. In doing that the head was taken off, new head gasket, intake gasket, and exhaust gasket (as well as other stuff)
 

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Discussion Starter #13
yea, but I wonder why it would go bad during the engine removal/reinstall? (and same symptoms on two DICs)

but I agree, I can't think of anything else.
 

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Discussion Starter #14
I'm still chasing this one, cold start and idle has misfires, you can feel it. when you're above 1500 RPM the car runs great. I'm not getting codes anymore, I think the EVAP leak was the gas cap.

I'm going crazy trying to figure it out. I've checked everything. I'm going to pull the valve cover off again and check the timing becuase that is (in essence) the only thing that changed from before I took the engine out and when I put it back since the head was indeed off. If I'm off by one tooth (let's say I'm 14 or 16 pins between the gears) would that do the deed? Because last I looked the timing marks were pretty damned close but that was with the tensioner in and no slack between the gears.

Could this be a failing CPS? I have a spare and could change it if that's a possible suspect. But I can't see again how it would be an issue at idle and not at higher RPM

any other thoughts?
 

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CPS generates a sine wave signal. Amplitude depends on speed and distance to crankshaft wheel. Therefore higher engine speeds provides better signal quality. Could be a reason, but normally this problem occurs at very low speeds, this is the reason why it would be difficult for this sensor type to detect speeds at e.g. 20 rpm. But this only applies for healthy sensors, a broken one might show this behaviour at higher speeds.
Any chances that the oil pan was off and you knocked on the crankshaft wheel. We had this once that a mechanic somehow bended the wheel, either by trying to install a new sensor or the crankshaft was out, dont remember exactly.


Any chances that fuel injectors were dismounted and you created a leakage at a single cylinder by some dirt in the sealing? Apply some start pilot outside of each injector in idle.

What about the misfire counter?

I think I might remember a thread about misfires in lower engine speeds which in the end was caused by one tooth off in valve chain alignment, so it might be possible.
 

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Discussion Starter #18
@thaistatos

Yes, the pan was off. No, I don't think I bent the slotted wheel. I only took the pan off while I was doing the timing cover and it was on an engine stand at the time so it was upside down when I was working with the pan. Crank was definitely not out of the engine. Only the front timing cover, pan and head.

Yes, the injectors were out, the whole rail as a single assembly. Good call, I'll see if I can trigger something by putting propane next to the injectors and seeing if one of them is causing issues. Great suggestion. (and not something that I've checked) Maybe I should just go ahead and replace all of the injector o-rings? they're not that expensive and taking the rail out is not that hard.


I do need to re-read the misfire counter. I cleared it after I changed the DIC back to my "known good" one from the one that was having issues. But I've read that the misfire count doesn't increment at idle?
 

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Most propably misfire isn´t counted in idle condition, but it might be counted in low load range up to 1500 rpm. It was just an idea to check if there is a suspicious pattern. As it takes less effort than removing anything on the engine it might be worth a shot. Maybe you can watch the misfire counters while someone else is driving in low speed range.

Saab recommends to use some electronic cleaner on the injector connectors once they are disconncted, might help, might not.

O rings are 7,52x3,53mm, they should be made of viton to withstand the high temperature, especially the one at the intake manifold side.
 

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Discussion Starter #20
Yesterday I got my propane torch out and pushed some propane around all of the injectors while the car was running. no difference. So I'm not convinced I have a leak on one of the injecdtors

Today I hit a CEL, first one in a few weeks. Four codes. P0300 (random misfire), P0303 (misfire on #3), P0106 (MAP sensor circuit) and P1181 Fuel Trim Max Value, Air/Fuel too lean

My Tech 2 is acting up, the "enter" key is not working so I'm having trouble reading stuff to see what might be wrong.
 
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