1992 V6 idle idiocy

graham7773 · 30-11-2009, 07:30 PM

I am looking at a 1992 V6 telstar as I like them. Problem is that the car will idle fairly normal at 1000rpm then kicks up to 3000 rpm for no reason. Anybody have a clue as to what can cause this? All ideas welcome.

fixit again dan · 01-12-2009, 12:14 AM

Apart from the first question of when was the car serviced last?,
Simple new plugs, oil & filters may be the answer.
there comes to mind many possibilities. On my V6 there was an idle problem, I went the way of

a) replacing HT leads since they were arcing within the lines, they were cracked and damaged every where including the part that connects to the plug.

b)Broken or deteriorated coolant lines onto the throttle body, you won't see them all visually without removal of the air box, without proper flow of coolant in this area the car will use more fuel and idle strangely.

c)Distributor could be on the way out, search www.probetalk.com for the HEI ignitor replacement mod, for fix
d)Throttle Position Sensor adjustment, there is a simple way of setting the tps so that the car idles and revs better.

e)Need more info or to be there, to see if the car stutters before reving higher-alike its starving of something fuel or spark or otherwise

graham7773 · 04-12-2009, 09:37 AM

Hi fixit again dan. Got a couple of questions. I am a little curious. How can a poorly maintained ignition system or delayed oil change cause a motor to jump 2000rpm above normal idle speed and stay there for short periods of time without depressing the throttle? I also do not understand how a failing distributor can cause the same problem. This would normally cause a loss of revs rather than excess revs wouldn't it?

Peter B - CV8 · 04-12-2009, 10:20 AM

I'd suggest removing the throttle body & giving it a good clean (including the stepper motor/throttle position sensor.

Stocko · 16-12-2009, 07:09 PM

Quote:

Originally Posted by graham7773

I am looking at a 1992 V6 telstar as I like them. Problem is that the car will idle fairly normal at 1000rpm then kicks up to 3000 rpm for no reason. Anybody have a clue as to what can cause this? All ideas welcome.

Could be as simple as a battery or alternator problem. These cars are designed to idle up as a response to low volts, although 3,000rpm is a bit extreme. They also idle up for headlights on, HVAC fan speed, A/C and power steering load.

I recommend a battery test and a look at the alternator performance at your local auto electrician. This is a quick, easy and cheap way to at least eliminate a couple of common problems. Also a good idea to go around the car cleaning and tightening all the earths. It's amazing how many of these little 'gremlin' issues in EFI cars go away when the electrical system is put right.

fixit again dan · 31-01-2010, 09:02 PM

As 'stocko' wrote,
"It's amazing how many of these little 'gremlin' issues in EFI cars go away when the electrical system is put right.",
this is very true, as I have seen on my car after a starving of spark the car either through vacuum or from the ECU, increases revs so to not stall the car and yes up to and over 2000 rpm intermittently and for a few seconds. Sometimes instead of stalling the EFI car will compensate for a 'poorly maintained ignition system.
The oil change was an indication of how well the car is looked after, or when last the hood was opened before this problem emerged. So to eliminate say a blocked air filter so that then the car will be gasping or starving of air causing fluctuations in idle.
Yes you are correct the colour of the oil or when it was changed is not a major pivotal point in this collection of idea's around the fault on this forum.

Russ · 10-02-2010, 09:14 AM

I had a '93 V6 Telstar Ghia and I had all sorts of trouble due to a failing distributor (common problem) On these models the distributors have silicone sealed circuitry and over time due to heat the silicone dries out and cracks form which allows moisture to get into the circuit board. Mine use to just die, I had just overtaken a car one day @ around 110 - 120 kmh and when I pulled back in and slowed back down slightly, I hit the accelerator again to hold speed but the engine had cut out. I pulled off the road and tried to restart it but it just turned over and wouldn't fire, left it for about 10 mins and away it went. I found out about the cracked silicone a few months later when I was having a new clutch fitted to the car, at the time it cost me $500 for a reconditioned (exchange) distributor. Car was much improved after that.

graham7773 · 12-02-2010, 08:00 PM

put it in the too hard basket and bought a KH Laser. Thanks for all the info

Russ · 13-02-2010, 11:10 AM

Quote:

Originally Posted by graham7773

put it in the too hard basket and bought a KH Laser. Thanks for all the info

If you ever have a similar problem occur with the Laser with revs idling up and down, it will more than likely be to do with the Throttle Body sensor. I had the same issue on a KH Laser I owned a few years back, picked up a replacement from the wreckers for about $30 and problem was fixed. Other than replacing a few suspension bushes and fitting a new clutch, the only other repairs were all general maintenance things (muffler, brake pads etc.....) all in all a great little car, best of luck with it

crankyTX5 · 26-02-2010, 02:36 PM

I would be looking into the air flow sensor just along from the air filter. This allows the car to determine when you are slowing down for a stop or at cold start up and picks up the revs. The engine management system relys on it for for so many things. Only a couple of model telstars , 626's and the VL commodores have these sensors .This is a frightfully expensive part so I got a replacement from a mazda wreckers for $100.

A diagnostic mechanic will see any error codes and work out why the idle speed is fluctuating. Good luck