Lean - rich

Al Shore

Al Shore

Hi again,
fitted my air/fuel ratio gauge yesterday, took it out for a drive to see how things are running (vids to follow when I've got a friend to hold the camera).
As i expected it was running rich contantly with the red qg injectors an induction it, only time it stopped was when really ragging it up to bout 6500rpm, then it was bouncing from optimal to rich an back again like a yoyo.
So this morning i toook out the injectors replaced with the standard blue ones, again quick 10 mile drive and it was leaning out, like so bad I pulled over an put the red ones back in (rather be flooding with fuel than risk cracking a piston eh :p)
So I now have a few options, need to downgrade the injectors an match with either a new tb or get the balance right with this universal induction kit I have, I did think 1.8's were a bit overkill but you never know til you try hey :p
I'm about to give it a damn good service now I've been able to go out an buy le shiznich to do so, hoping maybe some fresh sparks will help a weeeeee bit.
Think 1.3 crank, cams, etc are next in line too just need to make some bartering with the scrapppy some want over 100 for a set of damn cams!
Think i'll offer them 50 for the block an see where we end up (hopefully not at the bottom of a canal :p)
any idea's? (except drop in a 1.4:p)
 
You could probably do with dropping the fuel pressure with those red injectors really eh, mine is about 1 bar at low throttle, and ideally a bigger t/b when booting it, mine,s an SR 60mm one :)
 
oooh didnt realise the fuel pressure was adjustable at standard, anything to do with the u clip on the fuelrail by any chance?/ if not how do I go about this?
didn't realise there was a difference in the micra TB's either, will have to go finding some micra's in the scrappy when I'm back have a play with some different ones,
I was looking at the QG MAF's but when I compare them to the CG10 there does seem to be some differences in shape, if not plug so might be worth checking out if footprints match/ or if I can get it put together nicely :p

Thought I'd better try an get it sorted out, back workin in town tonight, don't want to be driving round brindley place stinking it up of unburnt fuel hehehehe
 
ahhhhh engine code sr hehehehe
I was gonna say i've just been doing some reading on old posts and i've seen alot of people fitting adjs fuel regs but mainly on turbo'd engines, I feel it drawing me closer :p
hehehe just spent about half an hour tryna find your blog on micrafiles.au, reckon you can drop me a link?
Will have a gander see what I can replicate, if stock is running at about 3psi i reckon dropping it by about .7 should do the trick, but I'll have a fiddle and see how it comes up best :p
 
Its awkward to link stuff on this tablet tbh :) the pics and stuff will be in "ghetto turbo, or another n/a" threads
And you need extra differential between low throttle (high vacuum) and high throttle (low vacuum) really, so that the fuel pressure is held down when cruising and pottering around, and then cranked up to about 3 bar at wide throttle
 
hehehe, i thought I'd heard of this issue before,
bookmarking the page, this looks tricky, good job I've got a spare fuelrail lying around, can do some tests without having to remove it first :p
any ideas of a good place to get spare springs + such prob a scrappy? will get this one to pieces find out dimensions and start collecting variants

A job for another day now I think, long night of drunken fools with more money than sense ahead hehehe
 
Nah, its pretty simple :)
Basically the stock reg drops the pressure by half a bar at idle to stop/balance the vacuum in the mani from literally sucking the fuel out of the injectors.
And you can use the mani vacuum to your advantage, to drop the fuel pressure further (1 bar or more) at low throttle, so that the bigger injectors dont overfuel at low throttle (which is the usual problem when running oversize injectors)
 
frank said:
Basically the stock reg drops the pressure by half a bar at idle to stop/balance the vacuum in the mani from literally sucking the fuel out of the injectors.
and you can use the mani vacuum to your advantage, to drop the fuel pressure further (1 bar or more) at low throttle, so that the bigger injectors dont overfuel at low throttle quote]

Sorry, I understand how the vacuum can suck the fuel out,
but I dont quite get how the reg works, is it due to amount of pressure being placed on a plate of some form so as it gets the pull from the vacuum it gives resistance hence slowing the flow, and as you increase throttle it releases the pressure, hence allowing more fuel to flow? (or visa-verca)
Click to expand...
 
The stock reg has 2 functions eh, to limit the pressure and return any excess, and also to lower the fuel pressure by half a bar when the throttle is closed/part closed, when the is half a bar of vacuum in the mani.
So in effect the pressure at the injector nozzle is always the same.
And a proper rising rate reg will add extra fuel pressure as you open the throttle ( and extra extra pressure under boost :))
 
hehe sorry for the delay in reply, forgot that I was off to wales on sunday :S just got back, will have a look into this, might havetofind a diagram of the internals with force arrowsto kind of pound it through my skull, but I'll get the jist eventually, then will look into these springs, would a weaker spring lower the pressure, stronger spring raise?
Have had a quick gander at adjustable ones available onlineif i were to go for one is there any specific thing that I'd need to look at in order for it to fit the micra or are they pretty universal?
 
Just beware of the term "rising rate" , my apparent 1.7:1 ebay one only corrected the manifold vacuum (just like a stock one) matt has a 12:1 one on his atm (euromicra)
 
Al Shore said:
sweet, ta frank!
Click to expand...
Np :)
In theory a 12:1 reg will crank up the fuel pressure twelvefold as you open the throttle, so instead of the stock increase from 2.5 bar to 3 bar of fuel pressure, it theoretically goes from 2.5 bar to 8.5 bar ! (or if you are using big injectors, from 1 bar increasing to 7 bar of fuel pressure) :)
 
wher are these 12:1 regs? I've never seen documentation for one.
 
Al Shore said:
Hi again,
fitted my air/fuel ratio gauge yesterday, took it out for a drive to see how things are running (vids to follow when I've got a friend to hold the camera).
Click to expand...

What kind of gauge and what sensor does it use?
 
Saw one of those at that show. I didn't realise they worked WITH the stock reg in place. omg.
 
Al Shore said:
hi, its a generic piece, works off the lambda wire at the ecu, not the expencive kind with sensor in the mani :p
Click to expand...

Right, ok don't take this the wrong way then, but its a pile of trash. They don't work, well that's not true,they do work, they just don't tell you anything useful, and have no place in car tuning.

What they show you is weather your running richer or leaner than the ideal CAT operating parameters. Put it this way. Cats operate best at AFR 14.7:1 if you are richer than this say 14.5 or less then it shows rich. If you are leaner say 14.9 then it shows lean.

Chances are when it says RICH you are not actually rich at all, as to be honest its not rich unless your running less than 12.5:1, and so what you see is only with reference to the cats operating conditions. Do not modify or change anything based on the read out of such a gauge. You will be completely barking up the wrong tree.
 
Ed said:
Right, ok don't take this the wrong way then, but its a pile of trash. They don't work, well that's not true,they do work, they just don't tell you anything useful, and have no place in car tuning.

What they show you is weather your running richer or leaner than the ideal CAT operating parameters. Put it this way. Cats operate best at AFR 14.7:1 if you are richer than this say 14.5 or less then it shows rich. If you are leaner say 14.9 then it shows lean.

Chances are when it says RICH you are not actually rich at all, as to be honest its not rich unless your running less than 12.5:1, and so what you see is only with reference to the cats operating conditions. Do not modify or change anything based on the read out of such a gauge. You will be completely barking up the wrong tree.
Click to expand...

Lol's, I didnt think it would be too accurate, but I hoped it would give me a rough idea of whats going on in regards to the mix, was looking into replacing my lamda with a wideband version for a more accurate read, but if the meter itself is just running a basic system it probably wouldn't do too much good.
I still think that an adjustable fuel pressure reg might help, ie, if i reduce the pressure slightly the ecu might stop running this fueltrim malarky and turn off my check engine light :p
Thanks for the heads up! :)
 
No wont even give you a rough idea I'm afraid. You need to get something like an Innovate LC1 kit. All these ones do is tell you if your richer or leaner than the cat wants you to be :)
 
Have you read your fault code to see whats going on? The 1.4 ecus are VERY adaptable and only flag up problems if you actually have a problem.
 
I was thinking about gettting it done, but with the feedback from most places it doesnt seem to be worth it, unless i took it to nissan, or got a very expencive code reader myself :p
It's the 1.0 coilpack, so it might just be getting a bit jumpy, as i say, i did put the original 1.0 injectors back in only to see that is was "running lean" (according to the gauge) with the induction kit,and the last thing i wana do is be running lean everywhere, so I replaced with the 1.8's
maybe original injectors with the pressure pumped up a tad?
or maybe i should start saving for a wideband 02 sensor kit :D anyone know a better price than £130?
 
you should put it all back to one piece. Your problems are probably due to lambda sensor issues. I can tell your totally guessing with what you are doing. The ecu on those is fully adaptive, it will compensate for anything you do. Thus its simply NOT worth bothering with. If you want it done right, then I can supply a remapped ECU thats optimised for performance/economy rather than just economy alone.

You will be wasting your time with that car doing anything else.
 
Al Shore said:
Lol's, I didnt think it would be too accurate, p! :)
Click to expand...
Its only accurate enough to keep the lambda value between 0.97 and 1.03 in order to pass emissions tests ;)
If you want to check you,re running 12:1 afr at wot then yes its a "pile of trash" :)
But if you want to check the lambda is working ok and the ecu is closed looping at cruise, and various other diagnoses, then my 10 quid gauge has been a very handy tool
 
frank said:
Its only accurate enough to keep the lambda value between 0.97 and 1.03 in order to pass emissions tests ;)
If you want to check you,re running 12:1 afr at wot then yes its a "pile of trash" :)
But if you want to check the lambda is working ok and the ecu is closed looping at cruise, and various other diagnoses, then my 10 quid gauge has been a very handy tool
Click to expand...
yeah I was worried about the emmissions a wee bit, especially once I smelt the fuel :p
And yes ed, I am a complete noob, I suppose I'm just a bit too optimistic, with computers there's usually 2 ways of doing things, cars don't seem to be the same unfortunately,.
I was hoping to be able to wait until I'd compiled a heap of turbo parts before I had to hit out for a remap, but maybe not,
see I never really wanted to spend too much on the 1.0 engine, I just wanted to have a play with it, and get used to doing bits and pieces whilst saving up for a donor vehicle (and my friends' skills and time *notcheap*) so that when doing to big jobbie I could do a few bits myself at least hehehe.
I was gonna say, it (the gauge) doesnt have a numerical readout *coughcrapcough* simply varying degrees of lean optimal and rich. but it does give some interesting reads with differing driving styles etc.
so how much were we talking for the remapped ecu? £500?
 
frank said:
Its only accurate enough to keep the lambda value between 0.97 and 1.03 in order to pass emissions tests ;)
If you want to check you,re running 12:1 afr at wot then yes its a "pile of trash" :)
But if you want to check the lambda is working ok and the ecu is closed looping at cruise, and various other diagnoses, then my 10 quid gauge has been a very handy tool
Click to expand...

Can't argue with that at all! That's what they are perfect for. Just not tuning :)
 
Al Shore said:
yeah I was worried about the emmissions a wee bit, especially once I smelt the fuel :p
And yes ed, I am a complete noob, I suppose I'm just a bit too optimistic, with computers there's usually 2 ways of doing things, cars don't seem to be the same unfortunately,.
I was hoping to be able to wait until I'd compiled a heap of turbo parts before I had to hit out for a remap, but maybe not,
see I never really wanted to spend too much on the 1.0 engine, I just wanted to have a play with it, and get used to doing bits and pieces whilst saving up for a donor vehicle (and my friends' skills and time *notcheap*) so that when doing to big jobbie I could do a few bits myself at least hehehe.
I was gonna say, it (the gauge) doesnt have a numerical readout *coughcrapcough* simply varying degrees of lean optimal and rich. but it does give some interesting reads with differing driving styles etc.
so how much were we talking for the remapped ecu? £500?
Click to expand...

Yes the coil pack ones are more expensive initially. There is alot of R&D work behind the, They can be reprogrammed later however for different maps, as and when needed. The 1.4's pick up a lot of power, Nissan really did their best to de-tune them.
 
yeah, I wasn't meaning to belittle the price, I appreciate the work that must go into it, I know a bit about computers, but I wouldnt touch an ECU if you paid me :p
Time to start saving a bit for the right equipment :D
 
Ed said:
Right, ok don't take this the wrong way then, but its a pile of trash. They don't work, well that's not true,they do work, they just don't tell you anything useful, and have no place in car tuning.

What they show you is weather your running richer or leaner than the ideal CAT operating parameters. Put it this way. Cats operate best at AFR 14.7:1 if you are richer than this say 14.5 or less then it shows rich. If you are leaner say 14.9 then it shows lean.

Chances are when it says RICH you are not actually rich at all, as to be honest its not rich unless your running less than 12.5:1, and so what you see is only with reference to the cats operating conditions. Do not modify or change anything based on the read out of such a gauge. You will be completely barking up the wrong tree.
Click to expand...


rich and lean are purely opinion things. the location of stochiometric is not a myth, but is indeed elusive. my brother has written a dissertation on fuel chemistry, and having read through it and infact helped with the research, i can tell you FACTUALLY that you won't find stochiometric ratio for ANY FUEL unless you know exactly what proportions of what fuels are in it.

also worth mentioning is the fact that fuel companies have different mixes dependant on seasons, eg spring summer autumn winter. people think they know about fuel and go for higher and higher octane fuels, but the problem is they start to resist detonation at higher octane levels. to counter this you need something with a high cetane rating (like lead....... which was added to fuel as an anti-knock additive) which essentially brings your octane rating back down, while keeping the explosivity.

a final note:
look at fuel treatments. you will find that clean-burn diesel additive has C9-C12 hydrocarbons in it (petrol/meths/turps etc) and injector system cleaner is the same. yes, it seems every fuel additive is just some highly refined petrol.
 
tomwest said:
rich and lean are purely opinion things. the location of stochiometric is not a myth, but is indeed elusive. my brother has written a dissertation on fuel chemistry, and having read through it and infact helped with the research, i can tell you FACTUALLY that you won't find stochiometric ratio for ANY FUEL unless you know exactly what proportions of what fuels are in it.

also worth mentioning is the fact that fuel companies have different mixes dependant on seasons, eg spring summer autumn winter. people think they know about fuel and go for higher and higher octane fuels, but the problem is they start to resist detonation at higher octane levels. to counter this you need something with a high cetane rating (like lead....... which was added to fuel as an anti-knock additive) which essentially brings your octane rating back down, while keeping the explosivity.

a final note:
look at fuel treatments. you will find that clean-burn diesel additive has C9-C12 hydrocarbons in it (petrol/meths/turps etc) and injector system cleaner is the same. yes, it seems every fuel additive is just some highly refined petrol.
Click to expand...

I don't get your point on any of that post above at all? How does it relate to the topic/normal person in the real world?

people think they know about fuel and go for higher and higher octane fuels, but the problem is they start to resist detonation at higher octane levels. to counter this you need something with a high cetane rating
Click to expand...

That doesn't even make sense? Why would you want to counter a fuels resistance to detonation? Cetane by definition relates to diesel fuel, and is of no relevance here at all, all K11s are petrol.
 
yes cetane does relate to diesel, but you'll still find some in petrol (like it or not). they're all refined from the same crude oil.
 

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