Messages

1

Saab 9-3 Sport Saloon / Convertible / Combi (Wagon/Estate) / Turbo X / AWD (2003 on) / Re: 93 V6 fuel pressure release.

« on: 27 April 2024, 12:39:39 PM »

Engine light was still off this morning, but came on again on the second journey back home.

The only small positive is that, if it is the fuel pump, if that is replaced, the level sensor will be replaced too.

2

Off-topic chat, Help, Advice, General motoring issues / Re: What I Did To My Saab Today.

« on: 26 April 2024, 10:36:11 PM »

After sticking a bottle of Forte in the Carlsson, I took the rear LH door card off and cleaned all the contacts in an attempt to cure the intermittent door lock failure.  It seems to be better, but still not 100%.  Getting the front door locks out is easy, getting at the rear door locks id much more difficult.  You have to remove the window mechanism first...

3

Saab 9-3 Sport Saloon / Convertible / Combi (Wagon/Estate) / Turbo X / AWD (2003 on) / Re: 93 V6 fuel pressure release.

« on: 26 April 2024, 10:28:57 PM »

I'm sure it will happen again.  The last two occasions the light stayed off for a few months.  But if I put some Forte in every 6 months or so, It might confir it's a restricted fuel line or injector.

Short of running 100% of the time with the fuel pressure recorder, there's not much else I can do.  Unfortunately I would have to keep an eye out as the scanner doesn't doesn't record.

4

Saab 9-3 Sport Saloon / Convertible / Combi (Wagon/Estate) / Turbo X / AWD (2003 on) / Re: 93 V6 fuel pressure release.

« on: 26 April 2024, 01:32:06 PM »

Two days on and the engine light is still off.  Fingers crossed...

Forte engine cleaner has arrived.  Two days late due to Royal Mail delays.  I might as well use it!

5

Saab 9-3 Sport Saloon / Convertible / Combi (Wagon/Estate) / Turbo X / AWD (2003 on) / Re: 93 V6 fuel pressure release.

« on: 24 April 2024, 07:17:43 PM »

Both of those thoughts have crossed my mind!!

6

Saab 9-3 Sport Saloon / Convertible / Combi (Wagon/Estate) / Turbo X / AWD (2003 on) / Re: 93 V6 fuel pressure release.

« on: 24 April 2024, 03:51:46 PM »

One stage further. and the two issues.

The P0089 fuel pressure code and engine light gets more odd each time.  Last night, as reported, the light was off when my wife drove to her concert.  When she went to come home the light was off in the car park and on leaving the event, but came on soon afterwards.   This morning I went out for fuel and, as expected, the engine light was on because I hadn't cleared it.  Then a quarter of a mile up the road it went off of its own accord.  So who knows what is going on.


The second issue with the fuel levels is a bit further on towards a solution, but has got a bit more confusing.  I disconnected the ECU and measured the resistance to each of the two level sensors at the ECU connector.  The WIS says they should be 40 Ω on full and 250 Ω on empty.

I measured with the gauge showing about ⅓ full and the resistances were...

Level on fuel pump sensor: 158 Ω
Level on second separate sensor: 121Ω

Which seems about right.


After I filled the tank, I checked the resistance again and they were...

Level on fuel pump sensor: around 23 Ω (It was wandering about from 21 Ω to 25 Ω, not steady)
Level on second separate sensor: 42.4 Ω which is about right for a full tank.

So the fault seems to lie with the sensor attached to the pump.  It can't be a broken wire in the resistance strip on the sensor as the reading is not zero, and it can't be a corroded connector in the line because that would give a higher resistance.  But it's reading below 40 Ω, so presumably the ECU is seeing this as out of range.  It implies that the float is going higher than expected, relative to the resistance winding.  All I can think of is that the sensor has become detached and is loose and moving about a bit.  But at least it's likely to have identified the sensor that's at fault, I think

It looks like a garage job to fix it.  To get to the tank, it's: 

Anti-roll bar off
Exhaust off
Propshaft off
Heat shield off
Rear diff unbolted and hung on a strap to lower it a few inches
Detach fuel filler
Remove fuel pipes
Undo main electrical connector
Unbolt tank and fiddle it out

That's too much for me these days.  I might even leave it as it is for a while.  Oh! for a hole in the floor like the 9-5.

7

Saab 9-3 Sport Saloon / Convertible / Combi (Wagon/Estate) / Turbo X / AWD (2003 on) / Re: 93 V6 fuel pressure release.

« on: 24 April 2024, 09:07:36 AM »

The level sensor feeds were the first thing I checked with the Tech2.  They arrive at the ECU separately, but Tech2 only sees the combined value. Actually it only reports the lowest of the two, which is why the gauge falls to zero when one goes open circuit.

It may be warm enough today to work on the electrics without dropping anything.  I’ll try.

8

Saab 9-3 Sport Saloon / Convertible / Combi (Wagon/Estate) / Turbo X / AWD (2003 on) / Re: 93 V6 fuel pressure release.

« on: 24 April 2024, 12:14:17 AM »

The V6 fuel system does not have a return pipe through a pressure relief valve.  The pump is electronically controlled and varies the fuel pressure under the control of the ECU.

I have cans of Forte engine and injector cleaner coming tomorrow. 

The P0089 fault in WIS does mention it being triggered by no fuel.  It also mentions a blockage in the fuel line.  I'm also thinking about a loose electrical connection.  The level sensor may have a a fault but separate to that, if one of the level sensor signals to the ECU is broken for a moment or two, the ECU may think the tank is empty and trigger P0089, it won't show on the gauge because that has a damped response.  Perhaps I can read the instant fuel level with Tech2...

She went out to a singing engagement tonight.  No engine light on the way there, but it came on as she started to drive home. 

9

Saab 9-3 Sport Saloon / Convertible / Combi (Wagon/Estate) / Turbo X / AWD (2003 on) / Re: 93 V6 fuel pressure release.

« on: 23 April 2024, 09:40:00 PM »

No, I didn't.   I'll double check the circuitry when it's warm enough for my fingers to grip the multimeter probes...

I have been thinking that the P0089 fuel pressure fault and the level sensor fault may be linked,  but I think that will depend on the fault being in the sensor attached to the pump, rather than the separate sensor in the other half of the tank.

I was also pondering if there's a pressure drop or spike when the pump starts up.  From my hydraulics background, I wondered that if there's a small blockage in the feed.  If it stops the flow briefly the pressure will be lower than expected at the sensor and could trigger a fault.  If the blockage releases suddenly, the pressure would surge and also trigger a fault.  That sort of blockage is typical of a sticking non-return valve.   Further reading required...

10

Saab 9-3 Sport Saloon / Convertible / Combi (Wagon/Estate) / Turbo X / AWD (2003 on) / Re: 93 V6 fuel pressure release.

« on: 23 April 2024, 05:15:26 PM »

Oh! ****

In a gap in the rain I went out, cleared the code, set the Car Scanner to show the fuel pressure.  Went out and retraced the route she did last night, then came home via the motorway and the supermarket.  The light stayed off.  So no data to compare.

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Saab 9-3 Sport Saloon / Convertible / Combi (Wagon/Estate) / Turbo X / AWD (2003 on) / Re: 93 V6 fuel pressure release.

« on: 22 April 2024, 10:11:08 PM »

Oh well!  She's home and the engine light is back on...

If it's coming on more regularly, I'll clear it, run with the pressure recorder and see if I can pick up the instant it triggers.

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Saab 9-3 Sport Saloon / Convertible / Combi (Wagon/Estate) / Turbo X / AWD (2003 on) / Re: 93 V6 fuel pressure release.

« on: 22 April 2024, 07:47:19 PM »

That's the consensus on the internet, but I've run a long record of pump pressure and it hasn't dropped at all.  There's no suggestion of hesitation at full throttle, so when it first happened, I changed the sensor and it seemed to solve the problem.  Six months later it was back and I heard a theory that the filter allowed very fine particles through which, over time, sat in the far end of the fuel rail.  It was suggested that I filled the fuel rail with fuel treatment, which i did and the light went off again for almost a year  Now it's back.

I filled the fuel rail again with the intention of leaving it standing overnight, but the failed battery meant that the treatment stayed in for 36 hours.  It's started and I've run it a few miles and the light is still off.  I felt the engine was running a bit smoother, but it was maybe my imagination.  The SWMBO took the car out and when she came home, said "What did you do to my car? It's running a lot smoother than is was".  Maybe the fuel treatment has cleared an injector, or maybe the new battery is helping.  She's out on a much longer drive this evening.  We shall see if the light has stayed off.

I'm hoping it stays dry enough to check the level sensors tomorrow, if the rain stays away, but it isn't looking promising.

13

Saab 9-3 Sport Saloon / Convertible / Combi (Wagon/Estate) / Turbo X / AWD (2003 on) / Re: 93 V6 fuel pressure release.

« on: 22 April 2024, 01:35:39 PM »

Nothing today.  It's cold and wet.  We had a frost overnight.

14

Off-topic chat, Help, Advice, General motoring issues / Re: Peeling lacquer

« on: 22 April 2024, 01:31:30 PM »

The problem you will have is that the exposed paint will be dirty.  Unless you get it really clean, the lacquer won't stick.  And, it's clear that the exposed paint is not suitable for getting lacquer to stick, as it hasn't stuck before.  So you will probably need to sand down to get a key, which will expose the metallic particles and alter the finish.

Maybe a good clean and de-grease and a coat of lacquer is all you can achieve, in situ.  But expect to have to do it again in a year.

15

Saab 9-3 Sport Saloon / Convertible / Combi (Wagon/Estate) / Turbo X / AWD (2003 on) / Re: 93 V6 fuel pressure release.

« on: 21 April 2024, 11:15:00 PM »

OK, so that points to a break in the sensor resistance at high level.  The resistance for a break being infinity, it would give a reading of empty.