The 98 (I calculated) is actually saving me about $2 per tank compared to 95, so obviously I want to keep running the fuel. Starting up is not a hassle, I just have to tap the accelerator, and once the choke kicks in shes right for the rest of teh day. I guess what I am worried about is, does this 'struggling' hurt my car at all, and could it live the rest of its life struggling on start up? Because, I want to keep using 98, not only because it is saving me money, but i heard it is better for my engine, although that I am unsure of for obvious reasons.
98 is not "better" for your engine. The "best" fuel for your engine is the lowest octane fuel it was calibrated for, because you only have one fuel map in your ECU. Any benefit would be down to the detergent additives they put in 98 that assist in cleaning.
I'd be interested to see if the improved economy was due to the 98 cleaning the fuel system and improving spray pattern on the injectors etc. I'd go back to 91 for a couple of tanks and see if it's cheaper to run on 91. In your car, it should be.
No EFI car should require throttle to start - that's indicating a fault. Is it doing physical damage? Maybe not, but it's not ideal. I don't know what the injector pulse width is on cold start with your foot on the throttle, but I reckon I'd be doing anything I can to avoid it.
I know I'm sounding arrogant and dismissive. I'm wondering if your car actually has a touch too much timing in it for 91 octane, so when you increase octane you're in fact getting closer to the correct tune.
I reckon Suzuki used to sail a bit close to the wind in terms of timing in Australia. I recall a brand new WT Sierra in about 1996 pinging like crazy practically straight out of the dealer on a warm day.
Our motors are all getting old now so there's plenty of scope for things to be out of whack. Nonetheless, an engine is still just a function of the chemistry of the fuel that's going into it.
Steve.
PS, if your interested in some really crazy fuel tech, do some reading on nitromethane. Whilst stoich for nitromethane is 2:1, because it packs it's own oxygen with it, nitro keeps making power as it gets richer, so apparently top fuel cars run as rich as 0.5:1. Yep, that's twice the fuel than air. You can't start the car on nitro though, as the mixture is so rich the motor will hydro lock when cold, so they start on alcohol, get the motor warm, then swap to nitro.
Joined: Tue Aug 08, 2006 11:30 pm Posts: 5517 Location: Holland Park
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Posted: Thu Oct 24, 2013 10:44 pm
Gwagensteve wrote:
It turns out hard cold starting is one of the primary reasons it's not recommended to run higher octane fuel than the manufacturer recommends.
If you go by that logic ie noticeable change in starting characteristic, then you most likely would also notice a change in the running characteristics. If it had that much impact on the cold start tune then the rest would also be out of whack.
I'd go back to 91 for a couple of tanks and see if it's cheaper to run on 91. In your car, it should be.
I used to run 95, I have never run 91 in it before. Did you mean for me to go back to 95 or go down to 91? Also, by cheaper do you mean more economical or for the economy vs fuel price it is cheaper?
Gwagensteve wrote:
PS, if your interested in some really crazy fuel tech, do some reading on nitromethane. Whilst stoich for nitromethane is 2:1, because it packs it's own oxygen with it, nitro keeps making power as it gets richer, so apparently top fuel cars run as rich as 0.5:1. Yep, that's twice the fuel than air. You can't start the car on nitro though, as the mixture is so rich the motor will hydro lock when cold, so they start on alcohol, get the motor warm, then swap to nitro.
That sounds intense!
Also. I should mention (not sure if 100% relevant), since swtiching to 10W-40 engine oil (from 20W-50) I now hear the timing chain rattle for about 2 seconds on a cold start. Mind you, it is a Repco brand oil filter, not a genuine suzuki. I will be going genuine on next oil change.
It turns out hard cold starting is one of the primary reasons it's not recommended to run higher octane fuel than the manufacturer recommends.
If you go by that logic ie noticeable change in starting characteristic, then you most likely would also notice a change in the running characteristics. If it had that much impact on the cold start tune then the rest would also be out of whack.
No difference in running characteristics, literally just that struggle on cold start. Oh, and better economy.
Just excactly what do you mean by struggle, is it that the car won't start in the first few cranks without putting your foot on the to peddle and you have to keep cranking it, or that it starts within a few cranks but doesn't idle well once it has and you have to keep pumping the go peddle. Or is it all of the above. Diagnosing a problem like this over the Internet is vertually impossible, what you call 'runs fine' someone else might call 'poor performance' for that engine. I don't mean to offend anyone. It could be coincidence that something went wrong at the same time you tryed the different fuel. Personally, I'd take it to a good mechanic and get them to diagnose it.
Just excactly what do you mean by struggle, is it that the car won't start in the first few cranks without putting your foot on the to peddle and you have to keep cranking it, or that it starts within a few cranks but doesn't idle well once it has and you have to keep pumping the go peddle. Or is it all of the above. Diagnosing a problem like this over the Internet is vertually impossible, what you call 'runs fine' someone else might call 'poor performance' for that engine. I don't mean to offend anyone. It could be coincidence that something went wrong at the same time you tryed the different fuel. Personally, I'd take it to a good mechanic and get them to diagnose it.
On a cold start, when I turn the key it cranks over perfectly fine, but when it starts it idles very low, and you can see it trying to keep running, sometimes it can't and the revs drop so low it stalls. If you look in the video, that time it struggled to keep the revs up a little bit, but then once the choke kicked in it revved up to about 1500 and it was fine. I pump the pedal to try and keep those revs up to stop it from stalling. BUT, this morning when I started it, the choke kicked in immediately and the revs shot right up to 2000 (then settled back to 1500) when starting it and it didn't struggle at all. So I think overnight someone snuck some voodoo juice in my tank
All in all, it seems a little sporadic, sometimes it stalls, most of the time is just struggles (like the video), and then randomly today, it just revved super high. Note that this is only on 98 fuel and is a completely new issue to me. Never happened when running 95.
Thanks Gus, I missed that link, I'm such a dumb ass. If you notice the oil light doesn't go out until the idle picks up, the second time it goes out strait away, because it still has oil in the system. You said at one stage that you have rattle timing chains when cold. The question I would ask is, is the lack of oil pressure the reason for the difficulty at initial start or vice versa ? These engines have a separate chain that runs the oil pump, this chain hasn't got an automatic tensioner only a guide,it can be tensioned manually I believe, this wears down and hence the chain gets loose creating a rattleing noise. You also said that you went to a thinner oil, this isn't a bad thing but it may mean that there is less oil hanging around at cold start. The test I would do is to disconnect the injector wires ( preferably ) or the coil lead, which ever is easier, I can't remember the set up they have. The idea is to stop the motor from firing, then turn it over using the key until the oil light goes out, then plug them back in and fire up the engine and see if it still does it, if not then maybe repeat the procedures after a few hours to confirm the findings. If it does then we need to look deeper. I hope this helps and if anyone can punch holes in my logic, please do, I like to learn new things and I won't take offence.
The fact that Steve says it is harder to start the higher octane fuel and Gus has this problem with only BP tells me that BP is closer to the 98 octane rating than other fuels, this makes me happy I've never had a problem with this fuel in any of my cars or my family's and friends cars, that equates to about 23 different cars, six of which are Suzuki's.
Joined: Mon Dec 11, 2006 10:30 pm Posts: 34842 Location: East Radelayed
Vehicle: SV420+SV620 Vitara's
Posted: Fri Oct 25, 2013 8:55 pm
too easy Kenn, thread got hammered with useless dribble from old mate & is easily missed.
karl to do what Kenn is suggesting, you can pull the F/I (Fuel Injection) fuse from the fuse box near the LHS strut top to stop the thing from firing on start up, should be clearly marked which one it is on the fuse box cover.
_________________ You're just hating because you don't understand
Thanks Gus, I missed that link, I'm such a dumb ass. If you notice the oil light doesn't go out until the idle picks up, the second time it goes out strait away, because it still has oil in the system. You said at one stage that you have rattle timing chains when cold. The question I would ask is, is the lack of oil pressure the reason for the difficulty at initial start or vice versa ? These engines have a separate chain that runs the oil pump, this chain hasn't got an automatic tensioner only a guide,it can be tensioned manually I believe, this wears down and hence the chain gets loose creating a rattleing noise. You also said that you went to a thinner oil, this isn't a bad thing but it may mean that there is less oil hanging around at cold start. The test I would do is to disconnect the injector wires ( preferably ) or the coil lead, which ever is easier, I can't remember the set up they have. The idea is to stop the motor from firing, then turn it over using the key until the oil light goes out, then plug them back in and fire up the engine and see if it still does it, if not then maybe repeat the procedures after a few hours to confirm the findings. If it does then we need to look deeper. I hope this helps and if anyone can punch holes in my logic, please do, I like to learn new things and I won't take offence.
The fact that Steve says it is harder to start the higher octane fuel and Gus has this problem with only BP tells me that BP is closer to the 98 octane rating than other fuels, this makes me happy I've never had a problem with this fuel in any of my cars or my family's and friends cars, that equates to about 23 different cars, six of which are Suzuki's.
Kenn.
Nice spot about the oil light, didn't notice that. I just drove my car for a god 40 minutes so it is still very hot, will have to leave it until this arvo to test anything. Quick question though, isn't this oil problem not related to the petrol type? So you think it could be a coincidence that it started doing this just after swapping fuels? Also, if it is any relevance, I have a MASSIVE oil leak, seems like it could be a rear main seal, which I sincerely hope it is not, strange thing is the dip stick doesn't go down
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