Hot start problem 2006 9-5 petrol Aero
Discussion
My car lets me down from time to time.
It won't restart within 15 minutes when hot, engine turns over fine, but won't fire.
If I leave it for 15 minutes, it starts fine.
Doesn't do it every time, only when I need to be somewhere, or at a petrol station.
Its 160,000 miles old, manual, engine rebuilt at 130,000.
Any thoughts what could be causing this?
I have known a similar fault on a diesel Mercedes be a failing crankshaft position sensor, but has anyone had this happen on a Saab?
It won't restart within 15 minutes when hot, engine turns over fine, but won't fire.
If I leave it for 15 minutes, it starts fine.
Doesn't do it every time, only when I need to be somewhere, or at a petrol station.
Its 160,000 miles old, manual, engine rebuilt at 130,000.
Any thoughts what could be causing this?
I have known a similar fault on a diesel Mercedes be a failing crankshaft position sensor, but has anyone had this happen on a Saab?
yep, very common.
you can test the CPS off the car but, given the faff to get at it, you may as well just change it. there's an "o-ring" washer affair that should come out with it. if it doesn't then you'll end up installing the new one with a double washer and it'll be too far away from the crank to count properly and the problem will appear to be elsewhere as it'll now not start at all.
considered consumables by many owners.
paul
you can test the CPS off the car but, given the faff to get at it, you may as well just change it. there's an "o-ring" washer affair that should come out with it. if it doesn't then you'll end up installing the new one with a double washer and it'll be too far away from the crank to count properly and the problem will appear to be elsewhere as it'll now not start at all.
considered consumables by many owners.
paul
paulmakin said:
yep, very common.
you can test the CPS off the car but, given the faff to get at it, you may as well just change it. there's an "o-ring" washer affair that should come out with it. if it doesn't then you'll end up installing the new one with a double washer and it'll be too far away from the crank to count properly and the problem will appear to be elsewhere as it'll now not start at all.
considered consumables by many owners.
paul
Thanks Paul - I will get a proper man in.....!you can test the CPS off the car but, given the faff to get at it, you may as well just change it. there's an "o-ring" washer affair that should come out with it. if it doesn't then you'll end up installing the new one with a double washer and it'll be too far away from the crank to count properly and the problem will appear to be elsewhere as it'll now not start at all.
considered consumables by many owners.
paul
in theory it's a 20 minute job but ....
it's not difficult, just fiddly. small hands are a great advantage if accessing from above. if accessing from below then you have to drop the undertrays, jack it, get the stands under etc so time consuming.
the sensor itself is fixed in with just a torx 30, hidden under a little flip off cover, and the multiplug. space to work is limited (approx 2 inches between the downpipe and the T30), hence the small hands. conventional ratchet won't fit in there, i use a ratcheting spanner with a bit holder.
the bolt can be really tight - if yours is then that would probably be the point to get someone in as if you chew it up it's a mare to rectify and access from underneath (ramp) will then be essential
i recall hearing of someone who, until they could get the new CPS, sped up the cooling time (and, therefore, the restart time) by spraying cold water from one of those nozzle-type bottles over things but that may be just an urban myth
paul
it's not difficult, just fiddly. small hands are a great advantage if accessing from above. if accessing from below then you have to drop the undertrays, jack it, get the stands under etc so time consuming.
the sensor itself is fixed in with just a torx 30, hidden under a little flip off cover, and the multiplug. space to work is limited (approx 2 inches between the downpipe and the T30), hence the small hands. conventional ratchet won't fit in there, i use a ratcheting spanner with a bit holder.
the bolt can be really tight - if yours is then that would probably be the point to get someone in as if you chew it up it's a mare to rectify and access from underneath (ramp) will then be essential
i recall hearing of someone who, until they could get the new CPS, sped up the cooling time (and, therefore, the restart time) by spraying cold water from one of those nozzle-type bottles over things but that may be just an urban myth
paul
Edited by paulmakin on Wednesday 7th February 17:44
Yes, I have done some reading and that point about small hands was made.
My wife has small hands (she's under 8 stone) and so has her daughter. Both live here, as do the grandchildren.
I have not yet, in five years, found a use for the grandchildren except for sweeping chimneys.......
So I will give it a try - it's all downhill to my local garage anyway.
My wife has small hands (she's under 8 stone) and so has her daughter. Both live here, as do the grandchildren.
I have not yet, in five years, found a use for the grandchildren except for sweeping chimneys.......
So I will give it a try - it's all downhill to my local garage anyway.
I changed mine recently for the same problem. It's really tight but I managed. What I couldn't do was release the old one from the cable grips so I zip tied the new cable to the old so now I have 2 CPS on the car but only 1 connected... Later that month I did an oil change, putting the car on ramps and could clearly see the CPS from underneath, would have been much easier from that angle....
Gave up trying to do the job myself, as it would clearly be easier with the car up on a ramp (as alluded to above).
Local garage had it in this morning and have just called to say job done.
I will collect it and see if it is fixed.....
Thanks all for your help and input.
Ditto on the Saabworld forums, where I had similar help and input.
Local garage had it in this morning and have just called to say job done.
I will collect it and see if it is fixed.....
Thanks all for your help and input.
Ditto on the Saabworld forums, where I had similar help and input.
Been there, got the T shirt - however the last time I did the CPS the problem re-appeared not long after.
It then started to tell me the key wasn't recognised and though the ignition side will light up, do all the checks etc, it refuses to crank.
No2 son is a techie and reckons the crystal in the key chip is on its way out and/or faulty.
Current solution has been to hot wire the starter solenoid. I've run a switched live feed through a dashboard switch to the low tension side of the solenoid and use this if it refuses to crank on the key.
Sometimes it will still refuse to start but remove the key, re-insert and crank on the switch - off she goes.
Only precaution on an Auto (as I discovered in a drive-through car wash last week) is always ensure the selector is in Park!!
I have subsequently on ANOther forum come across the fact that pressing the unlock button on the key four times over-rides the chip - could be true - never tried it.
HTH.
Cheers, Pewe.
It then started to tell me the key wasn't recognised and though the ignition side will light up, do all the checks etc, it refuses to crank.
No2 son is a techie and reckons the crystal in the key chip is on its way out and/or faulty.
Current solution has been to hot wire the starter solenoid. I've run a switched live feed through a dashboard switch to the low tension side of the solenoid and use this if it refuses to crank on the key.
Sometimes it will still refuse to start but remove the key, re-insert and crank on the switch - off she goes.
Only precaution on an Auto (as I discovered in a drive-through car wash last week) is always ensure the selector is in Park!!
I have subsequently on ANOther forum come across the fact that pressing the unlock button on the key four times over-rides the chip - could be true - never tried it.
HTH.
Cheers, Pewe.
So far it hasn’t let me down since the CPS was changed, but I haven’t been far. I will know more after 250 miles on Monday.
Intriguingly, I was getting endless problems with codes P1312 and sometimes P1334, both ignition cassette/spark plug codes. This was despite changing the ignition cassette for a known good one off my wife’s 9-5. Spark plugs are mint.
Since the garage reset the codes on doing the CPS, those codes haven’t recurred either. We shall see if somehow the two things are related..
I had noticed that my key works perfectly sometimes, and other times is a pain in the door unlocking bum. But it always seems to work on the ignition and immobiliser.
Inscrutable Scandinavian Saab....likes to keep me guessing.
Wife’s Saab doesn’t dare cross her.
Intriguingly, I was getting endless problems with codes P1312 and sometimes P1334, both ignition cassette/spark plug codes. This was despite changing the ignition cassette for a known good one off my wife’s 9-5. Spark plugs are mint.
Since the garage reset the codes on doing the CPS, those codes haven’t recurred either. We shall see if somehow the two things are related..
I had noticed that my key works perfectly sometimes, and other times is a pain in the door unlocking bum. But it always seems to work on the ignition and immobiliser.
Inscrutable Scandinavian Saab....likes to keep me guessing.
Wife’s Saab doesn’t dare cross her.
these are both misfire codes and usually signify a failing DIC. not necessarily though - what plugs do you have and what's the gap ?
you do seem to have been getting random misfires on all 4 though so initial thoughts would be the DIC. Although........, theoretically it could also have been down to CPS
check the underside of any replacement carefully as even a cracked DIC will continue to work well until it reaches the point of no return. i once fitted a hopelessly broken (as in bits of plastic literally crumbling off it) DIC to one of my aeros and it still started immediately and ran without a CEL.
take it out and look carefully at each coil-pack; cracking you'll easily see but also look for electrical tracing/arcing (usually seen as faint silvery coloured wiggly lines on the coil packs). i believe that there's a distinctive smell associated with the arcing but i've never been able to "sniff it out", even on badly denatured packs. i've also seen bench tested DICs with absolutely no cracking or arcing visible that have been well out of spec. very occasionally, the multiplug can break down so check the wiring at that end for breaks etc.
a failed DIC does not generate a definitive fault code, it's usually a process of elimination. the "7" in Trionic 7 is merely the number of parameters the system uses to keep things in line so you need to work backwards and rule stuff out until you hit the real issue - ie, eliminate 6 out of the 7 possible problems.
the CELs associated with misfires will recycle out (eventually, not immediately) so no need for a tech2 session once the DIC has been swapped.
if you aim to keep the car then go genuine if you opt for a new DIC, despite the ouch price. the ebay specials will keep you mobile but longevity is not their USP.
paul
you do seem to have been getting random misfires on all 4 though so initial thoughts would be the DIC. Although........, theoretically it could also have been down to CPS
check the underside of any replacement carefully as even a cracked DIC will continue to work well until it reaches the point of no return. i once fitted a hopelessly broken (as in bits of plastic literally crumbling off it) DIC to one of my aeros and it still started immediately and ran without a CEL.
take it out and look carefully at each coil-pack; cracking you'll easily see but also look for electrical tracing/arcing (usually seen as faint silvery coloured wiggly lines on the coil packs). i believe that there's a distinctive smell associated with the arcing but i've never been able to "sniff it out", even on badly denatured packs. i've also seen bench tested DICs with absolutely no cracking or arcing visible that have been well out of spec. very occasionally, the multiplug can break down so check the wiring at that end for breaks etc.
a failed DIC does not generate a definitive fault code, it's usually a process of elimination. the "7" in Trionic 7 is merely the number of parameters the system uses to keep things in line so you need to work backwards and rule stuff out until you hit the real issue - ie, eliminate 6 out of the 7 possible problems.
the CELs associated with misfires will recycle out (eventually, not immediately) so no need for a tech2 session once the DIC has been swapped.
if you aim to keep the car then go genuine if you opt for a new DIC, despite the ouch price. the ebay specials will keep you mobile but longevity is not their USP.
paul
Edited by paulmakin on Thursday 15th February 22:50
Thanks Paul, that is very interesting.
Having two 9-5s helps with eliminating problems.
I have replaced the DIC twice now on my 2006 Aero. One Ebay special from China failed completely one evening. RAC diagnosed it correctly.
Replaced it, and the replacement has not let me down yet.
The replacement DIC is actually on my wife’s car. Her Saab genuine one is on my car. Doesn’t matter which one is on which car, the engine management light comes on on my car, not on hers.
My plugs are the correct ones for the car, but NGK Iridium plugs. I will check exactly which model number, and the plug gap and condition at the weekend. Car runs smoothly and pulls well.
It will be interesting to see if the light comes on during my 250 mile drive on Monday. If it doesn’t, it suggests the CPS may have been the problem all along.
Car has 164,000 miles on it, and I intend to run it until it stops. Engine was rebuilt at 130,000, so it should be good for another 100-150,000. Cannot sell it - the suspension squeaks and creaks like a cave full of bats. All is fine with it, have had it all checked, but nobody can eradicate the noises, so the car is not saleable. I mostly do motorway miles, where the squeaking and creaking is minimal.
Needless to say, my wife’s109,000 mile 1999 car doesn’t squeak, runs perfectly and will last her another 30 years, given that she does less than 5000 miles a year.
Having two 9-5s helps with eliminating problems.
I have replaced the DIC twice now on my 2006 Aero. One Ebay special from China failed completely one evening. RAC diagnosed it correctly.
Replaced it, and the replacement has not let me down yet.
The replacement DIC is actually on my wife’s car. Her Saab genuine one is on my car. Doesn’t matter which one is on which car, the engine management light comes on on my car, not on hers.
My plugs are the correct ones for the car, but NGK Iridium plugs. I will check exactly which model number, and the plug gap and condition at the weekend. Car runs smoothly and pulls well.
It will be interesting to see if the light comes on during my 250 mile drive on Monday. If it doesn’t, it suggests the CPS may have been the problem all along.
Car has 164,000 miles on it, and I intend to run it until it stops. Engine was rebuilt at 130,000, so it should be good for another 100-150,000. Cannot sell it - the suspension squeaks and creaks like a cave full of bats. All is fine with it, have had it all checked, but nobody can eradicate the noises, so the car is not saleable. I mostly do motorway miles, where the squeaking and creaking is minimal.
Needless to say, my wife’s109,000 mile 1999 car doesn’t squeak, runs perfectly and will last her another 30 years, given that she does less than 5000 miles a year.
Interesting above re cranking issues. I had this last year, turned out the ignition switch was failing. I went through loads of scenarios including neutral switch. Eventually I put a multimeter on the ignition switch output and found the fault. I didn't bother replacing it and now have a start button hidden inside the centre console. 1 year down the line still good. I had an issue with airport parking last year as they couldn't start the car, I forgot to tell them about the switch!!
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