OK
So over the last month or so, my car has developed a few problems.
-Really bad fuel economy (about 18L/100km)
-Feels like it is going to stall when its first started, or when i give it about 2% throttle application
-Blowing Black Smoke (Rear bar is covered in soot)
Now, reading through the forums, i thought, first place to start would be with the AFM as i recently changed that over to try and fix a different problem, it was sitting on around .390 OHMS. I plugged the connector back in, and now it wont stay idling for more than 3 seconds, it just cuts out.
Any ideas greatly appreciated
Its been in the car for roughly 3-5 months with no hiccup until now, and i'd hope it was OK, hate to of bought a duff one.
I did an oil change last weekend, but there has been a buildup of deposits on the rear bar for longer than one week
Changed it out, same deal.
With the AFM plug out, it refuses to idle.
With the AFM plug in, i have to jump on the revs to keep the motor going and as soon as i try to let it idle it dies straight away.
Really annoying as it was at least starting this morning before i touched the AFM, now one tiny adjustment has caused the car to be unstartable
Have throughly checked all hoses
Bit of an update, decided to wind the Cal Screw to find if that helped at all.
I wound the number from 385 right down through to around 90. At 90 the car will continue to idle, although roughly for a good 10 seconds, as opposed to one or two at 385.
Should i keep going until i can find an optimum place on the resistance front, or should i start looking at the screw behind the AAC valve?
It wont be the afm if you can adjust it to get it to kinda sorta idle. I would bring it back to 384ohm because thats what it is supposed to be.
I would be checking your AAC valve and TPS. For the idling issue. Even if the car is overfueling it still should idle.
Mostly the 3 things you should check for fuel usage are AFM(of which u have and its working) Temp sensor and O2 sensor. They are your biggest fuel consumption issues.
Then again I mite more more inclined to thinking you may have a spark issue if it wont idle and you cant find problems with the above. A dead lead/bad spark etc etc
Will have to look into those things tomorrow, i took the car out for a quick spin and after driving it, i stopped for a minute and let it idle, in gear and out of gear. It didnt lope or anything like it had been.
But i agree that dialing down the resistance is probabaly just a quick fix in the scheme of things.
If the engine wont idle without the AFM then assuming the ECU is properly
detecting this then you have a faulty fuel pressure regulator (FPR) and possibly
a flakey connection on the coolant temp sensor (CTS) provided the TPS is OK.
The RB30 ECU will comfortably idle without an AFM as its in 'limp' mode.
Fact it wont idle without the AFM suggests you have more than one fault,
and they dont have to fail at the same time.
Eg.
you have a flakey CTS for a while giving bad economy and a marginal TPS
connection which is mostly not noticeable, then when the FPR sticks and
wont bypass fuel - causing a very rich mixture - then the combination with
or without the AFM makes things stall..!
If you want to check the FPR and dont have a fuel pressure gauge then
get it to idle by whatever method you can AFM in or out. The tap hard the
FPR and see if speed/smoke changes.
Then if you find any change, swap it out and fix all the CTS, AFM, loom
and ECU connectors...
btw:
AFM cal screw is *not* supposed to be anywhere, the 385 or whatever figure
is some factory setting - it has to start somewhere *but* then you should tune
the cal screw for your car because the cal screw is the only way to tune the
EFI system on these types of cars assuming the sensors, ECU and loom is ok.
Quote:
Originally Posted by Munro-
It wont be the afm if you can adjust it to get it to kinda sorta idle. I would bring it back to 384ohm because thats what it is supposed to be.
nope. cal screw does nothing to afm output, its a separate circuit to provide
the ECU with a method of tune.
The 384 figure is a factory leftover from their tests, these afms are used on
a lot of cars, they could be anywhere on that setting and its statistical luck
that many that come from factory might be 385 and that figure happens to
be close to the mean setting the ECU needs - assuming the FPR is doing its
job, but the cal screw is the only (easy) method for correcting for minor
variations in FPR setting...
I agree though that the poster might have more than one fault and that
needs some thinking about and attention to investigate/repair something
that might not initially be the cause of a major fault...
who?
Quote:
Originally Posted by Munro-
errrrrr you need to go back and do a vl history course or maybe just even read a few tech threads on this site.......
Quote:
Originally Posted by monaro327
who?
if it was the thermostat it would be a very simple and quick thing to diagnose and it really doesnt have much bearing on fuel economy unless its opening way too early but I havent really heard of one of those since the bad batch they put out a few years back that opened when u farted on them, but it really is only a minor thing because eventually they get up to temp just takes longer. If it doesnt open well then thats another story and we both konw that it ends badly...
Neways back to the point.
There is a lot wrong with that car and Im doubting its just one big thing. Doesnt behave like osmething something can cause... I'd be interested to take a look and see just what is happening.
Can you take a video of it running on a fone or somethign and host?
Thanks to all who have posted, all of your comments have in some way come in handy to me today.
At the moment, the car is behaving itself and not dieing on me, so its doing what it needs to, transporting me around, but on monday or tomorrow afternoon i'll see if i can re-create issue and record it
