Printable View
thanks iv got her to stay at idle now but still a bit slow at idle about 500rpm in drive, and sometimes it takes a second hit of the key to start went out fwding on sunday and it didnt stall which is good, so just going to see how it goes on starting and idling over this week,i can adjust the idle up more but starts a droneing noise very annoying so i have it where it just starts to make the noise,thanks luke.Quote:
Originally Posted by PhilipA
Good to hear .... To pick up the revs.. have you tried advancing it a bit?Quote:
Originally Posted by spook
Also, when you have a chance, do a compression check
Q>> How many k's has the motor done??
Mike
:)
no have not advanced her yet, the motor runs real smooth she has got 209 on the clock no smoke uses a little oil but not worried about that thanks luke..Quote:
Originally Posted by mike 90 RR
.... :D It's a young-en :D ....Quote:
Originally Posted by spook
Keep chipping at it ... and it will all come good :)
no worries cheers luke..Quote:
Originally Posted by mike 90 RR
The 14 CUX has a target for revs of AFAIR about 750 in neutral and 600 in D, and it will try to attain those revs with the stepper . That's why it is there eg to step up one when you put the air on.Also why its hard to pick an idle miss as the stepper steps up to compensate.
These revs are set in the ECU and cannot be changed except overriden by increasing the base idle.
This may cause high revs on cold start as the stepper adds steps according to the temp.
Complicated little devils aren't they.
Regards Philip A
... and throw in the variations of a stretched cam chain ....Quote:
Originally Posted by PhilipA
adds a floating + - 6 degrees of the cam and the Dizzy timing ... :angel:
Mike
:)
they are a pain in the ass cheers lukeQuote:
Originally Posted by PhilipA
[quote][QUOTE=PhilipA;1061986]If it has a stepper it is a 14CUX and has a MAF not flapper.
Actually it is quite critical. The TPS is the ECU's only knowledge of where the throttle plate actually is and this is where it gets its direction for the fuel map along with the MAF signal. It calculates both signals on an "X + Y" scale and applies the appropriate injector pulse. As the std system here doesnt use O2 sensors, its imperative to get it in its correct idle position.Quote:
The idle voltage of the TPS is not overly critical on a 14CUX as it can recognise a wide range of idle voltage for injector off on overrun.
You then have the later O2 units and modified ones like yours, that trim the fuel setting by looking at a third factor being oxygen content much like a "Z" axis.
Setting base idle with the TPS at the wrong point will give the ECU the wrong info. This is why it has to be set within .33-.35v. It makes no difference to the injector off but a whole lot of difference to injector on.
Even loosening the screws on an unmodded TPS and rotating it will alter your idle speed. Try it, go to the exhaust pipe and smell the difference in the exhaust!
If you alter the base setting at the plate screw, the TPS will also alter but not to where it should be hence its importance.
Every performance house in the UK working on Rovers make this adjustment and it is even in the factory manual I have.
Setting base idle with timing at 2deg will require the airbleed to be opened more to allow it to run. If you do this with the timing advanced to say 8 or 9 deg BTDC, this will have already increased the revs requiring you to close the airbleed screw and hence will starve the engine causing it to stall.Quote:
I wouldn't worry too much about the timing as you want it to idle where you want the timing set although I must admit mine has always been a bit temperamental on hot start as my timing is at 7 or 8 degrees.
The whole point of a base idle is to set the engine to its minimum stall point so it doesnt die when you shift the quadrant from P to D & R etc.
Hmmm... 900rpm is into the load fuel map, not idle. Would be most likely due to the fact that it runs abit on the lean side and wont have adequate fuelling when load is applied. Plus at this speed, the extra air solenoid would be closed slightly by the ECU as it is only there for the idle adjustment which is no more than 750rpm.Quote:
After I had a dyno tune and the guy added 5 degrees at 900 RPM , I could never get the thing to not stall when I selected R or D but it is moslty OK now with standard settings.
It shouldnt affect it too much providing its getting the right info. I am running 12deg static timing atm and have no issues with stalling. I do however have a hunting issue but this is due to a different cam in mine now. My whole setup has had to change to accomodate the cams different profile and idle qualities. Plus, I think my idle solenoid may have copped a slightly too hard a pull when cleaning it a few weeks ago. Youy only extract the plunger until it clears the guide notches, then you unscrew it from its drive seat. Mine..... :mad: decided to not need unscrewing and although it does thread, it doesnt thread up and stop like it used to. This makes me think its moving around a little and causing the ECU to constantly correct its position for idle.Quote:
The 2 degrees is mainly for low Nox to meet the ADRS. At 2degrees you have VERY conservative timing elsewhere in the rev range and they drive much better and give better economy with 7-9 degrees, although it may affect the idle stability when you put it in D or R.
Ironically, it settles down when the thermo fans kick in or I take it out of drive... ;)
Quote:
It is unlikely that the throttle plate will be out but anything is possible. That is why a dirty plate can affect it and why there is a bypass, so it is wise to check and clean before adjusting as Lovemyrangie said.
It doesnt hurt. At the end of the day, if you dont and after weeks of drama, swearing and throwing tools at things... not that I do.... a lot... you kick yourself for not doing it.
I need to check mine again as its the only thing I havent done since the cam change (practicing what i preach :p) but so I never ever ever have to do it again, I am going to pull the screw out, slot it from the top and make it adjustable from the top, just as it SHOULD have been in the beginning. Thats my justification for not doing it when I had the engine apart putting the cam in.............
....... and I'm sticking to it!!
I am glad to hear it now goes well.
Me too!
Quote:
Actually it is quite critical. The TPS is the ECU's only knowledge of where the throttle plate actually is and this is where it gets its direction for the fuel map along with the MAF signal. It calculates both signals on an "X + Y" scale and applies the appropriate injector pulse. As the std system here doesnt use O2 sensors, its imperative to get it in its correct idle position.
You then have the later O2 units and modified ones like yours, that trim the fuel setting by looking at a third factor being oxygen content much like a "Z" axis.
Setting base idle with the TPS at the wrong point will give the ECU the wrong info. This is why it has to be set within .33-.35v. It makes no difference to the injector off but a whole lot of difference to injector on.
Even loosening the screws on an unmodded TPS and rotating it will alter your idle speed. Try it, go to the exhaust pipe and smell the difference in the exhaust!
If you alter the base setting at the plate screw, the TPS will also alter but not to where it should be hence its importance.
Every performance house in the UK working on Rovers make this adjustment and it is even in the factory manual I have.
Well , my bootleg photocopy of the 1987-1992 Paper Workshop manual says the following at test 17? of the injection test procedure
TPS- Check throttle potentiometer
Throttle closed 0.085-0.545 volts with smooth swing between closed and open.
Open throttle 4.2-4.9 volts.
The desctription of the Throttle Potentiometer function at the start of the chapter on injection in the manual indicates.
My understanding is that the TPS does not set the position in the base map on idle, the MAF does this, along with input scaling from the temp sensors. The TPS is like an accelerator pump in that it richens the mixture dependent on the speed of voltage increase (as stated above in the Workshop manual). If it were so critical how would the ECU allow overrun cut off on TPS's set to the upper end of the scale? as they would never see 0.33-0.35Volts. ie how would the ECU know that the throttle was closed ie LIFT UM FOOT.Quote:
The throttle potentiometer is mounted on the side
of the plenum chamber inlet neck and is directly
coupled to the throttle valve shaft.
The potentiometer is a resistive device supplied
with a voltage from the E.C.U. Movement of the
throttle pedal causes the throttle valve to open,
thus rotating the wiper arm within the
potentiometer which in turn varies the resistance in
proportion to the valve position. The E.C.U.
lengthens the injector open time when it detects a
change in output voltage (rising) from the
potentiometer.
In addition the E.C.U. will weaken the mixture
when it detects the potentiometer output voltage is
decreasing under deceleration and will shorten the
length of time the injectors are open.
When the throttle is fully open, the E.C.U. will
detect the corresponding throttle potentiometer
voltage and will apply full load enrichment. This is a
fixed percentage and is independent of
temperature. Full load enrichment is also achieved
by adjusting the length of the injector open time.
When the throttle is closed, overrun fuel cut off or
idle speed control may be facilitated dependant on
other inputs to the E.C.U.
If you rotate the TPS , particularly quickly then of course it will richen or lean the mixture as that is what they do.
The Rover V8 site ://www.britishv8.org/Articles/Rover-14CUX-EFI.htm also just repeats the Manual info plus a bit. BTW, just because British tuners do it does not mean it is correct. If you look at the above site's next para on O2 sensors it is wrong, as the sensors are fed 12v, and do not work opposite to other narrow band sensors .
RPi Engineering specify 0.33-0.35 but I do not know where they got the info from .
Quote:
Find the Throttle pot on side of plenum. There are three (3) wires coming from this unit to a multi plug. Do not disconnect. Wire colors are Red, Green, Yellow. Red from volt meter to red wire of pot. Black wire from volt meter to Green of pot. Volts should read .33 to .35 volts if not, loosen the two (2) screws that hold it in position and turn it to get the correct voltage. If you cannot get the correct voltage setting, undo and remove the throttle pot, make the fixing holes elongated and you will be able to get the right voltage.
Now I recall I set mine at 0.33-0.35 using the Rpi info on the old manifold but it did not seem to make any difference.
I would appreciate it if you could quote the wording in your manual as I am intrigued that it would change.
Regards Philip A