vitara running weird

[idontbeleiveiboughtit]

Hi

I've got a 95 2dr Vitara (TBI model), which is running odd. starts and ticks over just fine, when driving along it seems ok on full throttle, but part throttle or low revs it seems to stutter a little.
It does seem better when the air is cold, but that could just be my imagination. I've changed all the usual things, distributor cap, rotor arm, leads, plugs, air filter etc but it hasn't helped.
also the temp gauge doesnt really work, it barely gets above the C. Ive changed the sensor but it hasnt made any difference. If i ground the wire the gauge shoots straight up to hot.
I put a voltmeter on the wire at the sensor end and it only reads 5.59v. How can that be right??
the fuel gauge is also temperamental, although ive not managed to get the tank off yet (nuts all well rusted on!) its got to come off anyway since it leaks from the top when full.....
Ive had the clocks out and checked all the wires on the back and they are ok.

Sorry for the long post but this car is driving me mad... all replies are really appreciated!

[jtgh]

short post for bog problem and good too.
I looked at PL and see only 1 water temp sensor.
on the front of manifold. unlike the old cars.
it measure water temp and ECU waits for proper temp before going out open loop to closed loop.
THe obvious, does engine feel hot when gage is cold.?

then the ECU just mimics water temp via the Clocks in the form of simple voltmeters.
my point. the meter is telling the truth and the Sensor is busted and the engine never enters closed loop.
and stays rich and retarded timing.

here is my WTC (cts) curve ,
try it in a pan of hot water and use ohm meter.
or just swap it .
see next photo.

[jtgh]

as you can see hot = low ohms
and cold = high

so when you short sensor , gage goes HOT.

with this curve you can test ice, room and boiling.
well 176 deg F = about 300 ohms

get a $2.81 dig. multi meter had harbor freight.
such a deal.

[idontbeleiveiboughtit]

Hi, thanks for your reply. The new sensor acts exactly same as the old one, hence my suspicion the fault lies elsewhere.
I will definitely have the new one out and run the multi meter on it.

[jtgh]

we need to measure the actual coolant temperature.
I could just feel the upper RAD hose and say, its fully hot.
There is a way to do it expensive or cheap.
expensive , go to garage and have them shoot the IR gun at it.
$50 ( write down the readings)
cheap:
cold car !!!
in drive way.
pull rad cap. ( NEVER PULL CAP on a HOT CAR , PLEASE !!!))
find an accurate thermometor and insert it in to the neck of rad.
make sure rad is topped off. Therm scale most go to 200 F or 100C
(be aware as the water warms the water will spill over , so just let it.)
you could catch it in a pan if you want. "Being Green and all that"

now ,just idle the car until it gets good and warm.
you will see the therm rise fast and then the cars thermostat will open and the temp will stablize. may be 180-190 degress or about.
then stop engine. put cap back on. put overfill tank to 1/2 full mix.

Since your gage is broken we need to know if your car comes up to full temperature.
knowing that we can proceed.

WE MUST find out if car is really STUCK at C or not.
if it is, the thermostat may be missing or stuck open.

any car stuck at cold will use lots of gasoline and the CAT will overheat.

[idontbeleiveiboughtit]

Hi,
Thanks for the info, I had a play it this weekend, the sensor seems to be working okay. The engine gets good and hot, but the gauge is still not working properly.
in boiling water the sensor resistance is about 100ohms, cold is about 800. The new sensor reads exactly the same as the old one. Hmmm... a box of matches should cure it..........

[jtgh]

no,no ,not the torch !

the gage must be bad, a red herring. sorry you had to replace CTS!!!

100 ohms, hot tells ECU to go to full closed loop. So all is well.
ITs good. There.


this is a throttle body, so we wont have injectors 1-4 fighting each other.
Techron in the tank and drive 1 week.? < try this.
TWO:
if that dont work you can check the fuel pump pressure. at the same time replace FUEL filter.

I take it your CEL lamp never glows , except when at KEYON(nostart) it glows for a test ! ( ok there?)


-----------FP data -----------------------------------
At the input to the fuel filter the pressure must be:
34.2 to 39.8 PSI (key on) [ lasts on 3 seconds]
after 1 minute of key off , the pressure should be above 21.3 Psi .
While running the pressure should be while at idle , 24.2 to 29.9 PSI.
need T-fitting to do last tast.

History 1.6L vitara, TBI , with full tune up (minus fuel filter) and new CTS.(ECT).

when you get time , explain better your hot driveability problem.
explain what it does bad, does it back fire thru TBI , "POP"
does it get horrible gas mileage , 20mpg or less?
tell us a little more. Does it foul plugs, (they should look white to tan or cream but never gray , dark black sooty or black oil)
all the best to you and happy trails.

[idontbeleiveiboughtit]

Hi, been running a fuel additive cleaner in it for a while, fuel filter was changed this week too, all made no difference.

MPG is about 25, no back fires at all, plugs are good colour, just a juddery throttle response, not severe, just annoying. Like an old 2 stroke when you take the choke off too early.....

[jtgh]

back to square one:
95 VITARA?/ not in the USA, that started in 1999.
so you are in a NON USA country. (oops) ? Are you In the USA?
if not then we must guess which of the 28 variant Vitara's world wide , you may have.

worst case: ( like someone moved a car from Russia to Germany ,etc)
your smog sticker? (white under hood) has one of these numbers. what is your code?
E01, E03, E22,E24,E28,E33,E60,E63 ( i think that means target country Emission code)



my guess:
there you go, it is lean. ( at least on transistions)
I take it , you can cruise down the freeway at 60mph all day and not issues.! just a Throttle tansition issue, correct?

NO MAF sensor. ( scratch that) "Speed Density System."
here is a list , by order of cost:

* vacuum leak ( this engine races with any air leak , scratch that !)
* Oxygen sensor ( over 100k miles replace i,t on suspesion)
* TPS ( easy to test on car or off)
* Weak Fuel PUMP (low pressure all the time) ( possible)
* MAP sensor. < I dont think this is it.



TPS: ( un plug TPS, and check against this list with ohm meter)

http://hodson.myftp.org/TPS-data.GIF

when turning throttle the TAP or wiper armoutput; it must not JUMP, it must be smooth and proportional. It's just a very expensive Variable resistor.
when I test it I do:
end to end resistance. 3.5-6.5 k ohms 3500-6500.
Note the idle stop must be defeated with vacuum.

I have read that the TPS is the primary ,off idle detection device for the ECU (not the MAP) , it is said to give you a boost of gas , until better map readings are obtained. ( in the software)


I say all this on the presumption that You DO NOT HAVE A CEL lamp glowing during IDLE or DRIVING! <<<< ??
AND that the lamp glows at KEY ON, no start ??

if the LAMP never glows, (after checking for bad lamp) then the ECU is bad.

ECU

I hope this nfo proves helpful.


PS: if everone would fill out there profile. that would greatly help.
country, year, model, engine size # of cylinders, tranny type, 4wd/2wd, number of doors.
eg: USA 1.6L x4 8Vlave, Sidekick, 5sp, 4wd,2door