Maxima Man

My 89 vg se max is surging at idle then it will idle at like 500rpms then something kicks in to make the rpms quickley jump up to 1000rpms then back and forth and idling so low the lights dim.

I don't understand this car I think im doing everything right

heres whats new:

Fuel filter
vaccum hoses
air filter K/N
Cleaned IVAC
Cleaned throttle body
sealed up both with rtv silicone
(93 octane gas also)
Have run techron through the last tank

It was super cold and snowing today did this have something to do with it?


Thanks for any and all help guys!!!

MrSector9

iTrader: (4)

possibly check your coolant temperature sensor

Maxima Man

What are it symptoms how do i check it thanks!!!

MrSector9

iTrader: (4)

well depending what is wrong with it could be what you are saying. Basically when it is bad the engine will think it is constently cold OR OVERLY hot.. or inbetween, one minute it read hot the next cold and so on.

As for checking it is in the FSM that i dont have on this comp right now. You cehck it by the ohm reading i am pretty sure. Maybe try unplugging it all together and go for a short drive to see how ti acts.

Slamnasty

My 93 SE has done the same thing in the past, though it does it VERY infrequently...maybe a few times a year. My old 87 SE did this as well. Since my old 87 had the VG, it's probably the same issue.

But I never had my 87 checked out for that so uh, I have no idea what it is.

jewsonlot

I had similar problem at it,s worst car would run for a while then cut out and would not start untill engine cooled down, change coolant temp sensor she's been fine ever since

Maxima Man

What else should I look at

and

any one know exactly how to test coolant temp sensor?

MrSector9

iTrader: (4)

ok it is located at the top of the "water inlet housing"

as for testing there is a thermistor inside and as the engine warms up the resistance lowers. So you coudl take a DMM and check the resitance to ground. Better off to just replace it thoguh



for unstable idle it says to check in this order

EGR
perform balance power test (unplug each injector harness to see if ther eis a change in idle)
Check injectors
Ignition spark
spark plugs
02 sensor
intake air leak

Maxima Man

Ok I will check the above

how much will a coolant temp sensor set me back?

Where are possible places for a vaccum leak other than in the hoses (I already replaced them) Thanks .........

vansskaterfreek

iTrader: (14)

after you cleaned your IACV and stuff like that i bet you didnt out new gaskets on did ya??????? if not there may lie your problem

Maxima Man

I re sealed them with liquid gasket maker as mentioned in the original post!
So no thats not the problem! Thanks keep ideas coming

vansskaterfreek

iTrader: (14)

ohh ok didnt see that... did you try spraying air intake cleaner around the top of your motor.... where the upper manifold meets the lower manifold?????? (air intake monifold) if your RPM's jump then there is your leak!


just spray that stuff on all vaccum hoses and stuff then you should find it if it is a vacuum leak

wutsup

same my car has a rough idle if its cold outside

Alex_V

whens the last time it had a tune up?

~Alex

Maxima Man

Who Me or Wutsup?

Does anyone know how much a coolant temp sensor costs?

Thanks

Greeny

iTrader: (43)

About $20......

blackonblack

I remember my max doing that...

I would check: distributor cap, spark plug wires, alternator, mass air flow sensor... Your problem sounds to be electrical.

Maxima Man

Vans will the rpms jump up or down when I happen to spray a leaky hose?

and how much will they jump 10rpm or 100rpm?

Thanks

To blackonblack I have alredy replaced distriburter cap and wires and plugs fairly new alt. I have no idea about the mass air flow meter it has never been changed I sure

I don't want to spray electroics cleaner in there unless it broken because then I could not hurt anything (I hear they are super sensitive)

Thanks

vansskaterfreek

iTrader: (14)

with that air intake cleaner when you spray a hose or around the motor(where gaskets go)...when you spray there the RPM's will jump about 500-1000 PRM... so oyu will notice when you hit the spot

Maxima Man

Thanks Vansskaterfreek

vansskaterfreek

iTrader: (14)

no problem if u have any more questions ask