Whats causing my tubby to run lean ????

[Munnsy]

i hope this is just a simple fix then
how far out would u expect it to be then?? advanced??
i have no idea what im talking about here lol

[jimGTS]

could be bang on, but also could be at 12, (2 degrees advanced)

[Munnsy]

you have lost me know lol
Is there a sticky on here to do cambelt change etc???
Something to refer to?

[jimGTS]

no no no, you certainly dont want to be messing with the belt itself...

its igntion timing were refering to...
you just angle your dizzy so timing is set to 10 degrees before top dead center (btdc)

just need a timing gun...maybe £15...thats it to carry out this test.



http://www.imoc.co.uk/forums/kb.php?mode=article&k=23

[Munnsy]

see how dangerous i am lol
it all makes sense now ,
guess i will be trying this sometime soon too then
where woul i be without imoc eh

[Kongaroo]

Thing is a few degrees of extra ignition timing isn't going to affect the measured AFR on the wideband by much (and the actual real AFR doesn't change if you alter the amount of ignition timing anyway).

However it would put you more at risk of getting knock.

From Ryan's post earlier it sounds ike you were getting some ECU knock response when coming onto boost.

Whilst I'm not suggesting that you definately don't have a problem somewhere I would say that is not all that unsual to get some ECU knock response (pulling timing/swapping to a less aggressive map) when coming onto or during boost. It's one of the protective mechanisms that a stock ECU uses to deal with a batch of bad petrol for example.

I take it you are running the car on high octane petrol like V-power (99.x RON) or one of the 100 RON fuels that are availabe nowadays rather than a 95 or 97 RON fuel?

If so then the car is actually running on pretty much what the ECU was intended to run in Japan anyway (Japan petrol is typically 98 or 100 RON at the pumps and not that mythical 102 RON figure that sometimes gets bandied about ). How does the car drive normally - do you get a lot of hesitation and stuttering every single time you boost?

It may only really be a problem if you are getting knock response constantly. If it's only now and again then it's probably just the ECU doing its job - achieving decent power by running at the threshold of knock.

So if you do find the base timing is actually ok then I'd consider checking the AFR with a wideband sensor installed into your downpipe - the wideband will come in handy later anyway for mapping the car

[Munnsy]

The car drives like a dream and i personally have never heard the knock although in all honesty im not sure what it sounds like (probably like a knock )
The car since i have owned it has always 100% been run on 99 octane fuel and servieced regularly to the book.
Ill have to get someone to check the timing etc then see how things pan out,
i have or just have put a payment down on power fc and then wideband is next on the list but its short term now is the problem,
Ill be honest im not too kean on driving it until i get this problem sorted
dave

[Lee @ 3S Service Centre]

your ignition timing will be set at 10 degrees as we set the ignition timing after every cambelt change.

lee

[Munnsy]

ok mate cheers for that lee
Rules that one out then, i guess i will check for error codes etc

[Munnsy]

right update, did error codes and absolutely nothing came up, however i do now have reverse lights lol
have ordered a walbro pump and am booking that in to be fitted, then really looking at getting my girl mapped on the power fc,
But surely this is hiding the problem rather than actually fixing it??
Really dont know what to do guys
i Suppose invest in wideband next??then see what the outcome is,
lewt me knoiw?
cheers
dave

[Ryan S]

right update, did error codes and absolutely nothing came up, however i do now have reverse lights lol
have ordered a walbro pump and am booking that in to be fitted, then really looking at getting my girl mapped on the power fc,
But surely this is hiding the problem rather than actually fixing it??
Really dont know what to do guys
i Suppose invest in wideband next??then see what the outcome is,
lewt me knoiw?
cheers
dave

i don't know much about mr2 yet but on my nissan 200sx i had the turbo replaced with a slightly bigger one, after that it was running lean, we did everything to sort it, coils, afm etc, eventually i replaced the fuel pump with a walbro and it was sorted!!!

[Munnsy]

well i guess you have a valid point matey, it is on the list but i was also thinking along the lines of fuel pressure regulator too??
Aeromative one seems very popular,
are these easy to fit?
thanks for youyr advice bud, and give it a few months and you will have a wealth of knowledge on the 2s
dave

[steve b]

right update, did error codes and absolutely nothing came up, however i do now have reverse lights lol
have ordered a walbro pump and am booking that in to be fitted, then really looking at getting my girl mapped on the power fc,
But surely this is hiding the problem rather than actually fixing it??
Really dont know what to do guys
i Suppose invest in wideband next??then see what the outcome is,
lewt me knoiw?
cheers
dave

i don't know much about mr2 yet but on my nissan 200sx i had the turbo replaced with a slightly bigger one, after that it was running lean, we did everything to sort it, coils, afm etc, eventually i replaced the fuel pump with a walbro and it was sorted!!!

Thats blindingy obvious though, a bigger turbo shifts more air so you need more fuel.

[Ryan S]

right update, did error codes and absolutely nothing came up, however i do now have reverse lights lol
have ordered a walbro pump and am booking that in to be fitted, then really looking at getting my girl mapped on the power fc,
But surely this is hiding the problem rather than actually fixing it??
Really dont know what to do guys
i Suppose invest in wideband next??then see what the outcome is,
lewt me knoiw?
cheers
dave

i don't know much about mr2 yet but on my nissan 200sx i had the turbo replaced with a slightly bigger one, after that it was running lean, we did everything to sort it, coils, afm etc, eventually i replaced the fuel pump with a walbro and it was sorted!!!

Thats blindingy obvious though, a bigger turbo shifts more air so you need more fuel.

na not at all, i went from a t25 to a t28 and the standard 200sx fuel pump can EASILY cope with that, uprating the fuel pump isn't a nessecary supporting modification when fitting the t28, but for some reason mine couldn't cope, must have been fecked.
even nissan couldn't figure it out with there diagnostic machine, the car idled fine, it was when it was under load the problem occurred. it was just by chance that i was fitting a new fuel pump and it cured the problem.

[RobCrezz]

i don't know much about mr2 yet but on my nissan 200sx i had the turbo replaced with a slightly bigger one, after that it was running lean, we did everything to sort it, coils, afm etc, eventually i replaced the fuel pump with a walbro and it was sorted!!!

Thats blindingy obvious though, a bigger turbo shifts more air so you need more fuel.

na not at all, i went from a t25 to a t28 and the standard 200sx fuel pump can EASILY cope with that, uprating the fuel pump isn't a nessecary supporting modification when fitting the t28, but for some reason mine couldn't cope, must have been fecked.
even nissan couldn't figure it out with there diagnostic machine, the car idled fine, it was when it was under load the problem occurred. it was just by chance that i was fitting a new fuel pump and it cured the problem.

I dont know where you heard that, a better fuel pump is most definatly needed to go from a t25 to t28. The standard fuel pump on S13s are turd. You should probably get your ECU mapped too, as the standard map wont work that well with a t28. H-dev do good chips. Are you not on SXOC?


http://www.h-dev.co.uk/product_info.php ... 200e26da7b

[Ryan S]

yeah i used to be on it, don't have my 200sx anymore, the car was chipped as well, got rid of it. preferred the mr2.

[RobCrezz]

yeah i used to be on it, don't have my 200sx anymore, the car was chipped as well, got rid of it. preferred the mr2.

Same here!

[Ryan S]

yeah i used to be on it, don't have my 200sx anymore, the car was chipped as well, got rid of it. preferred the mr2.

Same here!

200's are ok but have a tonne of grief trying to get more power from them, i was gonna put a ca18det in my mx5, that would be fun!!!

i had an n/a mr2 at the same time as my hundy and just preferred the way it looked. the power is so much better too!!!

i even preferred my mr2 over my rx8, they are very similar in terms of power and handling, although the rx handles a bit better it lacks on power, i had mines converted to a turbo and then sold it, i really had to try hard to enjoy the rx, but the mr2 i just love!!!

[RobCrezz]

yeah i used to be on it, don't have my 200sx anymore, the car was chipped as well, got rid of it. preferred the mr2.

Same here!

200's are ok but have a tonne of grief trying to get more power from them, i was gonna put a ca18det in my mx5, that would be fun!!!

i had an n/a mr2 at the same time as my hundy and just preferred the way it looked. the power is so much better too!!!

i even preferred my mr2 over my rx8, they are very similar in terms of power and handling, although the rx handles a bit better it lacks on power, i had mines converted to a turbo and then sold it, i really had to try hard to enjoy the rx, but the mr2 i just love!!!

Yeah I really liked the S13, the CA18 is a really strong engine if the big ends are looked after (regular oil and filter changes, never letting it go low), but its not as smooth as the 3sgte and i prefer the power delivery of the mr2 also. The S13 could make me smile so much though with the way it would go sideways with such ease