Right then, I'm writing on behalf of my mate who has just got a Z TT import. the only problem he has is the tick over is really low and alittle erratic. Nothing bad but how do we increase the rev's?? Is it just a case of disconnectiong the the throttle sensor (if thats the right sensor( the one on the right TB)) and it will reset itself or do you just adjust the idle screws.

 

P.S He's joining the club next week ;)

Right then, I'm writing on behalf of my mate who has just got a Z TT import. the only problem he has is the tick over is really low and alittle erratic. Nothing bad but how do we increase the rev's?? Is it just a case of disconnectiong the the throttle sensor (if thats the right sensor( the one on the right TB)) and it will reset itself or do you just adjust the idle screws.

 

P.S He's joining the club next week ;)

 

 

2 things to try mate

 

ajust the screw on the IAA unit at the back near battery or remove and clean the valves

 

and or ajust TPS on throttle body passenger side make sure you have a voltmeter to ajust as close as poss to 0.42v between 0.4-0.5v seems to work fine though

 

look on http://www.twinturbo.net for pics and a how to HTH ;)

oh and leave the lead of the battery over night or even an hour or so to reset the values on the ECU

NO NO NO the screw on the idle unit is for the BASE IDLE. This should be set to ~650 rpm. The ECU controls the idle rpm via the IACV unit (idle valve). Check the yellow connector on the idle unit for corrosion - seen a few of these not even connected... Idle unit is at the rear passenger side of the plenum, you may need to lift/shove the loom around a bit in that corner to get to the connector ;)

Jonce, take in part the advise given by Greg, however the following advice...................

 

Quoted by andyduff:

"NO NO NO the screw on the idle unit is for the BASE IDLE. This should be set to ~650 rpm. "

 

Is NOT correct and will potentially lead to uneven tick over, the base idle is exactly that, the lowest idle speed the car should run at with no high load electrical bits switched on or air con on, the engine at normal operating temperature and the electronic idle at its smallest setting of 15% open.

 

When correctly set up the car should idle without the electronic idle adjust disconnected ( or set to default off by a ConZult unit) at a target of 800 rpm.

 

With this set correctly, reconnecting the electronic idle adjust ( or canceling default off via a conZult ) will give a now steady 850 rpm tick over with a max. opening on the auxiliary air valve of 15%

 

In use the auxiliary air valve opens wider with the throttle, when the throttle is snapped shut the revs reduce slowly in a controlled manner back to base setting of 850 rpm any lower setting will give rise to the revs dropping too low and the ecu over compensating and opening the auxiliary air valve too wide, and then again lowering it, this cycle will often especially on a cold engine lead to a high rev followed by a low rev to a high rev to a low rev and on and on etc. until the driver intervenes.

 

As a demonstration of the above setting principle, it can be observed on the last two editions of the ConZult system that when entering the idle setting mode, the auxiliary air valve is disabled this is so any adjustments made are not invalidated by the ecu adjusting the auxiliary air valve open setting in response of any manual adjustment been made, also to note is the needle setting on the conZult screen has a target band showing the mid point to be 800rpm.

 

Also when entering the power balance screen again the auxiliary air valve is disabled to prevent surging of the engine when cylinders are switched off by the program to measure rev drop, if the base idle was set to 650 rpm the test would NOT work as dropping a cylinder at this low rev would reduce the tick over to less than 500 rpm which would not allow for a valid test.

 

 

Setting of base idle is simple when done correctly if badly advised or just incorrectly done it will be a pain in the ass driving with an uncertain tick over that will race one moment and cut out when braking the next.

 

Hope that helps

 

Jeff TT

Jonce, take in part the advise given by Greg, however the following advice...................

 

Quoted by andyduff:

"NO NO NO the screw on the idle unit is for the BASE IDLE. This should be set to ~650 rpm. "

 

Is NOT correct and will potentially lead to uneven tick over, the base idle is exactly that, the lowest idle speed the car should run at with no high load electrical bits switched on or air con on, the engine at normal operating temperature and the electronic idle at its smallest setting of 15% open.

 

When correctly set up the car should idle without the electronic idle adjust disconnected ( or set to default off by a ConZult unit) at a target of 800 rpm.

 

With this set correctly, reconnecting the electronic idle adjust ( or canceling default off via a conZult ) will give a now steady 850 rpm tick over with a max. opening on the auxiliary air valve of 15%

 

In use the auxiliary air valve opens wider with the throttle, when the throttle is snapped shut the revs reduce slowly in a controlled manner back to base setting of 850 rpm any lower setting will give rise to the revs dropping too low and the ecu over compensating and opening the auxiliary air valve too wide, and then again lowering it, this cycle will often especially on a cold engine lead to a high rev followed by a low rev to a high rev to a low rev and on and on etc. until the driver intervenes.

 

As a demonstration of the above setting principle, it can be observed on the last two editions of the ConZult system that when entering the idle setting mode, the auxiliary air valve is disabled this is so any adjustments made are not invalidated by the ecu adjusting the auxiliary air valve open setting in response of any manual adjustment been made, also to note is the needle setting on the conZult screen has a target band showing the mid point to be 800rpm.

 

Also when entering the power balance screen again the auxiliary air valve is disabled to prevent surging of the engine when cylinders are switched off by the program to measure rev drop, if the base idle was set to 650 rpm the test would NOT work as dropping a cylinder at this low rev would reduce the tick over to less than 500 rpm which would not allow for a valid test.

 

 

Setting of base idle is simple when done correctly if badly advised or just incorrectly done it will be a pain in the ass driving with an uncertain tick over that will race one moment and cut out when braking the next.

 

Hope that helps

 

Jeff TT

 

Badly advised? PMSL Thats exactly what you've just done:

 

http://www.300zx.co.uk/cgi-bin/manual.cgi?list=efec&dir=&config=&refresh=&direction=forward&scale=0&cycle=off&slide=39&design=default&total=190

 

Don't try to make me look stupid :mad:

 

Is NOTbase idle is exactly that, the lowest idle speed the car should run at with no high load electrical bits switched on or air con on, the engine at normal operating temperature and the electronic idle at its smallest setting of 15% open.

 

 

 

 

base idle is setting of the idle speed without any ECU control. once set the ECU then controls the idle via the idle control valve. it has nothing to do with the "lowest" idle speed!

Quoted by andy duff

Badly advised? PMSL Thats exactly what you've just done:

 

Don't try to make me look stupid

 

 

Dont need to, you quite capable of that all by yourself.

 

Data you linked to relates to a brand new engine ( as does any workshop BASIC data) in the real world you have to know how to interpret it.

 

I appologise Jonce if you feel you thread has been hijacked by an insecure andy duff

 

Jeff TT

Dont need to, you quite capable of that all by yourself.

 

Data you linked to relates to a brand new engine ( as does any workshop BASIC data) in the real world you have to know how to interpret it.

 

I appologise Jonce if you feel you thread has been hijacked by an insecure andy duff

 

Jeff TT

LMAO ignore the service manual everyone, its not relevant to your car only a brand new one. FFS WTF have you been taking? You've just made yourself out to the person you really are...

Was going to set my t/over up-think I'll wait for this thread to go on a bit!........

Quoted by Paul C

base idle is setting of the idle speed without any ECU control. once set the ECU then controls the idle via the idle control valve. it has nothing to do with the "lowest" idle speed

Paul C

 

Yes exactly so when setting the base tick over via a Conzult is sets the idle control valve to its stated tickover setting ( 15% open) and makes no further adjustments whilst in this mode thus prevents it operating outside the correct setting whilst you adjust the base idle, once set this way both the idle control valve AND base setting will be correct set.

 

Jeff TT

How can you argue with the service manual ffs? The idle speed is controlled by the ECU! Or does yours have carburetors???

Quoted Andy duff

How can you argue with the service manual ffs? The idle speed is controlled by the ECU! Or does yours have carbeurettors???

 

Not arguing with the manual just your interpretation of it! yes the idle speed IS controlled by the auxiliary air valve VIA the ecu but base service settings are just that, guide lines, and do not always reflect what you find on every car whether it be a 300 zx or a Vauxhall Nova,

 

I know you have more than enough experience to understand that, experience in seeing what works in the real world on real zeds with 100k miles on them a daily basis is more realistic and leads to a higher understanding of getting the best from a car that sadly is no longer in its first flush of youth.

 

Jeff TT

WTF!?!?!? The ECU relies on the base setting being below its target setting in order to control the idle properly! Idle on a TT should be 750rpm - no more, no less! This is controlled by the ECU, end of story. If it wasn't then there wouldn't be an idle valve would there....

You are missing the point entirely! on a daily basis this set up has proved 100% successful in keeping the now older, worn ( average wear and tear) engines idling smoothly and with a very good level of stability, you can not use settings for items such as tick over from data designed for new engines to be relevant for older engines in its entirety, interpretation and fundamental knowledge of an engines weakness in older age are of primary importance, if not why not just give a YTS a book of settings and let him loose on your car.

 

Jeff TT

interpretation and fundamental knowledge of an engines weakness in older age are of primary importance, Jeff TT

 

Jeff

 

I do not think there is a single person on this board who could doubt the knowledge and hands on experience that Andy Duff brings to the 300zx forum and its members

 

Ryan

NO!!!! If the car is not idling correctly then there is a problem with the idle control circuit. Do you understand fuel injection systems at all??? You cannot just mask the problem, you need to fix it.

NO!!!! If the car is not idling correctly then there is a problem with the idle control circuit. Do you understand fuel injection systems at all??? You cannot just mask the problem, you need to fix it.

 

How true is that..!!FACT

Quoted by Ryan

I do not think there is a single person on this board who could doubt the knowledge and hands on experience that Andy Duff brings to the 300zx forum and its members

 

Have you posted on the right thread? Andy Duff / vast experience is NOT been wholly questioned

 

 

 

Quoted by MickeyB

Originally Posted by andyduff

NO!!!! If the car is not idling correctly then there is a problem with the idle control circuit. Do you understand fuel injection systems at all??? You cannot just mask the problem, you need to fix it.

 

MickeyB: How true is that..!!FACT

 

Mickeyb See below

 

Quoted by Andy Duff

NO!!!! If the car is not idling correctly then there is a problem with the idle control circuit. Do you understand fuel injection systems at all??? You cannot just mask the problem, you need to fix it.

 

 

No No No No to quote yourself, masking problems running or otherwise is not what is been discussed here, what is been discussed is simple ABC`s of idle setting, and to not make the common mistake of misunderstanding the set up, your own words here echo that very point

 

“This is controlled by the ECU, end of story. If it wasn't then there wouldn't be an idle valve would there”

 

Idle control valves do not just maintain a constant idle, as I previously stated and you well know the idle control valve is much more than this, it maintains a stabilised tick over after both quick and slow throttle openings which with out would cause stalling and / or sudden dips in rpm when sudden throttle closures occur, which is EXACTLY the case when the base idle is too low and the idle control valve cannot operate quickly enough to maintain a minimum tick over, this is very commonly seen and the procedure for correcting NOT masking this is the proven procedure I set out previously.

 

Commonly a very low base idle will result in a 50% or 60% opening of the idle control valve to just maintain a normal tick over! which means the idle control valve has a very large opening angle to move through and the delay of this is the problem.Equally this will mean that when the engine is colds the enriched tick over will be very unstable as it will be lower than required with the valve at almost 100% open.

 

Jeff TT

Quoted by Ryan

I do not think there is a single person on this board who could doubt the knowledge and hands on experience that Andy Duff brings to the 300zx forum and its members

 

Have you posted on the right thread? Andy Duff / vast experience is NOT been wholly questioned

 

 

 

Quoted by MickeyB

Originally Posted by andyduff

NO!!!! If the car is not idling correctly then there is a problem with the idle control circuit. Do you understand fuel injection systems at all??? You cannot just mask the problem, you need to fix it.

 

MickeyB: How true is that..!!FACT

 

Mickeyb See below

 

Quoted by Andy Duff

NO!!!! If the car is not idling correctly then there is a problem with the idle control circuit. Do you understand fuel injection systems at all??? You cannot just mask the problem, you need to fix it.

 

 

No No No No to quote yourself, masking problems running or otherwise is not what is been discussed here, what is been discussed is simple ABC`s of idle setting, and to not make the common mistake of misunderstanding the set up, your own words here echo that very point

 

“This is controlled by the ECU, end of story. If it wasn't then there wouldn't be an idle valve would there”

 

Idle control valves do not just maintain a constant idle, as I previously stated and you well know the idle control valve is much more than this, it maintains a stabilised tick over after both quick and slow throttle openings which with out would cause stalling and / or sudden dips in rpm when sudden throttle closures occur, which is EXACTLY the case when the base idle is too low and the idle control valve cannot operate quickly enough to maintain a minimum tick over, this is very commonly seen and the procedure for correcting NOT masking this is the proven procedure I set out previously.

 

Commonly a very low base idle will result in a 50% or 60% opening of the idle control valve to just maintain a normal tick over! which means the idle control valve has a very large opening angle to move through and the delay of this is the problem.Equally this will mean that when the engine is colds the enriched tick over will be very unstable as it will be lower than required with the valve at almost 100% open.

 

Jeff TT

 

Well you just proved you know **** all. What opening angle does the idle valve open to? It can't because its a plunger ffs. What does the manual say? 750rpm idle with ecu control. By falsely adjusting the base idle in order to mask some other problem isn't an option. In fact there's a lot of faults you *could* cure by upping the base idle :rolleyes: Yes increasing it might work, but thats not what FIXING cars is all about is it? Well not in my world it aint.....

Anyone for half time oranges?

Quoted by Ryan

I do not think there is a single person on this board who could doubt the knowledge and hands on experience that Andy Duff brings to the 300zx forum and its members

 

Have you posted on the right thread? Andy Duff / vast experience is NOT been wholly questioned

 

 

 

Quoted by MickeyB

Originally Posted by andyduff

NO!!!! If the car is not idling correctly then there is a problem with the idle control circuit. Do you understand fuel injection systems at all??? You cannot just mask the problem, you need to fix it.

 

MickeyB: How true is that..!!FACT

 

Mickeyb See below

 

Quoted by Andy Duff

NO!!!! If the car is not idling correctly then there is a problem with the idle control circuit. Do you understand fuel injection systems at all??? You cannot just mask the problem, you need to fix it.

 

 

No No No No to quote yourself, masking problems running or otherwise is not what is been discussed here, what is been discussed is simple ABC`s of idle setting, and to not make the common mistake of misunderstanding the set up, your own words here echo that very point

 

“This is controlled by the ECU, end of story. If it wasn't then there wouldn't be an idle valve would there”

 

Idle control valves do not just maintain a constant idle, as I previously stated and you well know the idle control valve is much more than this, it maintains a stabilised tick over after both quick and slow throttle openings which with out would cause stalling and / or sudden dips in rpm when sudden throttle closures occur, which is EXACTLY the case when the base idle is too low and the idle control valve cannot operate quickly enough to maintain a minimum tick over, this is very commonly seen and the procedure for correcting NOT masking this is the proven procedure I set out previously.

 

Commonly a very low base idle will result in a 50% or 60% opening of the idle control valve to just maintain a normal tick over! which means the idle control valve has a very large opening angle to move through and the delay of this is the problem.Equally this will mean that when the engine is colds the enriched tick over will be very unstable as it will be lower than required with the valve at almost 100% open.

 

Jeff TT

 

So if you alter the base idle then all the other components alter to compensate for the base setting that has been changed. Isn`t this factory set for a reason or did nissan guess and say that`ll do.... :rolleyes:

Anyone for half time oranges?

 

are they sweet or sour? ;)

Anyone for half time oranges?

lemons you mean :rofl:

Quoted by andy duff

Well you just proved you know **** all. What opening angle does the idle valve open to? It can't because its a plunger ffs.

 

Percentage angle !!!! you know READABLE degrees etc. remember at school?

 

Masking running faults???

 

why does getting an engine to run at its best become masking a fault ? lets assume all the circuits and valves, sensors etc. are in order so there are NO faults to mask setting up the base idle as I mentioned earlier will give both good stability and reliability to that stability no dipping of revs or stalling, base idle set at 650 is not correct for every zed in my view and experience which incidentally is over 20 years worth and at least 15 years of that been on fuel injection cars and the last 8 years on zeds

are they sweet or sour? ;)

Moist.