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CEL 7 flashes (air/fuel mix) & gas brand

790 views 10 replies 3 participants last post by  SaabKen 
#1 ·
I notice during the past 6 months my CEL (7 flashes, air/fuel mix) came on, each time soon after the car is filled up with a different brand of gas than my default of Shell octane 87 or 89 (quietly referring the the missus ....).

CEL would stay on for a few weeks before going off, even if on the very next tank I go back to Shell gas.

I don't see how Trionic 5 or anything else in the fuel management system would be calibrated so sensitive that even with a slightly different gas formulation it would cough up a CEL error code.

Is this something anyone else has experienced ? Any idea as to why this might be ?
 
#2 ·
For what it's worth...

A few years ago, the station attendant dropped my gas cap and slightly cracked the plastic. Within a few minutes after fillup, the CEL light was on, and stayed on until the cap was replaced.

Doesn't sound like your problem, but check that your cap is airtight.
 
#3 ·
Robinb said:
For what it's worth...

A few years ago, the station attendant dropped my gas cap and slightly cracked the plastic. Within a few minutes after fillup, the CEL light was on, and stayed on until the cap was replaced.

Doesn't sound like your problem, but check that your cap is airtight.
Hmm. Actually my cap (black part) is missing a small piece of its outer bezel where the green dial part fits in. So if I were turning to tighten the cap, the green dial would stop at a certain point and start racheting. I would grip the black part to tighten.

That could be the answer, esp. if the missus filled the tank and didn't tighten the cap the way I do it.

However I'm not seeing the CEL connection with a loose cap, is there extra vacuum in the fuel pressure or quantity as a result ? Shouldn't the fuel pump and/or the throttle body compensate in some way ?
 
#4 ·
When the problem happened to me, I read somewhere that the CEL light, although mainly associated with emission control, would also come on if there was no pressure in the gas tank because e.g. the cap was cracked (or missing!).

As usual, the CEL light took some time before it turned off after the new cap was fitted.
 
#5 ·
Stupid question Ken but is it possible that the station you got fuel from is using a higher ethanol concentration than the Royal Dutch Shell fuel you usually use? Could the ethanol confuse the O2 sensor?

I am getting conflicting stories here in the good ole US about E in the gas. I know the EPA mandated a higher concentration in marine gas and that caused a lot of older boats with fiberglass fuel tanks to need replacing. The alchohol dissolves the resin in the older boats. That's how I found out about them sneaking in ethanol in our fuel down here. Some pumps are clearly marked that the fuel may have x percentage of ethanol in the mix, I don't know about your areas rules or whether they are doing this or not, all I know is fuel is poorer overal than it was just a few years ago

You are probably on track with the fuel cap but I was just curious...... John
 
#6 ·
Not stupid question, John.

But yeah that is a possibility. I'm not even sure how much or if Canadian companies/refineries Shell, Chevron, Esso (Exxon/Mobil) and Petro Canada add any significant amounts of ethanol in their formulation. And even if so, how much ethanol is tolerated by Saab's ECU.

I know one thing and that is even at 87 octane, Shell gas gives my car the best and smoothest performance every time.

Funny while driving home yesterday from work, CEL came back and stayed on. Maybe I'll go get a new gas cap anyway just to see what happens.
 
#7 ·
Posted by SaabKen: even at 87 octane, Shell gas gives my car the best and smoothest performance every time.
I'm pleased for you, but I thought your first post about 87 octane was in jest. Was I wrong?

I spent over 7 years as a chemist in oil refinery laboratories, and was involved with gasoline blending & testing. 87 octane regular was regarded as the ultimate low-end product, the one where small quantities (500-1000 gallons) of foul-smelling/high-sulphur/high tar refinery by-products could be safely dumped without going off-grade or losing reputation. The thought of putting 87 octane into a performance turbo engine gives me the shivers.

I haven't said a word of this to Matilda, so maybe the gas cap is all you need.
 
#8 ·
Robinb said:
I'm pleased for you, but I thought your first post about 87 octane was in jest. Was I wrong?

I spent over 7 years as a chemist in oil refinery laboratories, and was involved with gasoline blending & testing. 87 octane regular was regarded as the ultimate low-end product, the one where small quantities (500-1000 gallons) of foul-smelling/high-sulphur/high tar refinery by-products could be safely dumped without going off-grade or losing reputation. The thought of putting 87 octane into a performance turbo engine gives me the shivers.

I haven't said a word of this to Matilda, so maybe the gas cap is all you need.
Maybe it's best not to tell Matilda ..... don't ask, don't tell, right ? :eek: I do put 89 or 91 from time to time, just not "regularly" enough ;oops:

Soooooo ...... when are ya gonna finally make it out to an SCWC meet ? Next meet is Feb 28th (always last Saturday of every month), this time at Coq. IKEA. See site for details.
 
#10 ·
Robinb said:
Might be able to see you on Feb. 28th.

But the SCWC site says "Next meeting January 31st, in Richmond".

Sooo.. where exactly at Coq. IKEA, and what time?
Ooops sorry. Site updated now.

Go around back onto Woolridge, turn left into lot, under flag poles. 10:30am
 
#11 ·
Robinb said:
Might be able to see you on Feb. 28th.

But the SCWC site says "Next meeting January 31st, in Richmond".

Sooo.. where exactly at Coq. IKEA, and what time?
Hey Robin, it was a pleasure meeting you today. Love your Aero .... a real keeper. Look forward to next time, and a local run later in the Spring.

Cheers
 
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