zozoka

Tried to order a water temperature sensor ( there are 2 , one wich goes to water temperature indicator, 1 wire, and the other wich is in connection with the cold start injector, i think it has 4 wires), but they asked me a part code for it.
My MPG is extremly high , and i think the problem is with the sensors, becouse the idle is high (1200-1500 rpm) even after 10-15 mins of running.
Or maybe the problem is with the thermostat.

Must to figure it out....(25 l /100 km = 9.4 MPG in city driving is killing me).

Thanks

Ganoid

Be REALLY careful with that cold start switch. It looks like a water sensor and its even located near the water sensor but it cost me $130+ when I broke it by accident. It takes a special socket to remove but I ended up cutting a regular socket to put it back in. If you can avoid it I would not mess with that water block area with all those sensors in it. Its hard to get a socket in there straight with out pulling the upper manifold and crooked socket = broken sensor.

Edit...You may want to replace the fuel filter and if you must go ahead and replace the water temp sensor ($17 at the local parts house). If you really think the thermo time switch is killing your fuel economy just unplug the cold start injector. I did that once to test the theory and the worst thing I had to deal with was 12-15 sec of cranking my engine to start when cold instead of the usual 5 sec.

MIKEMOKAS

i dont mean to hijack the thread, but thats all the cold start injector does? how could that actually hurt your gas mileage?

how does a cold start injector go "bad?"

ttyl

Matt16

When the engine is cold, more fuel is injected through the cold start injector (effectively choking the engine like on a chainsaw). If the water temperature sensor is broken, then it is interpretted as always being "cold" thus the cold start injectors pump more fuel than needed all the time which reduces your economy and causes you to burn rich (leading to carbon deposites as well). I have a 22RE that got 350km to a tank last time (read: horrible)

I think I may have this problem, is there any easy way to test the problem or will it throw a code?

MIKEMOKAS

my coolant temp sensor is good, but i think im going to unplug my cold start injector anyways... my truck idles all wired when its cold.

so i just unplug the connector going to the cold start injector at the back of the plenium by where the coolant temp sensor was?

thanks!

thook

Ganoid....
A plumber's basin wrench works really well to access those sensors back there.

Mike....
A cold start injector is just like a fuel injector. I forget the specs off hand, but it operates on a pulse from the ECU via the cold start time switch when the coolant is below a certain temp. The only way it goes bad is either it gets gummed up or there is a problem with the electrical connection. The time switch works on resistance/voltage. The resistance/voltage goes up or down depending on the coolant temp. The ECU reads that resistance/voltage to activate the cold start injector.

Uplugging the cold start injector won't fix your idle and it's a good way to wear out a starter. You more than likely have something else going on. If the temp switch tests good there may be a problem with the signal getting to the ECU. Or there is a problem with the air temp sensor or TPS. In other words, the cold start system would be the very last thing to look at.

Ya'll ought to look in the FSM and start testing these things. They're real simple tests with a good ohm meter. I mean with all the guessing that could be done, you could be testing and get conclusive answers real quick. It will save you a lot of money in the process. Maybe it's just me, but I always get a bit of a sick feeling when I just replaced something that didn't fix the problem.

Zozoka....
Your problem does sound the coolant temp sensor. But, test it first. If it were the thermo it would be apparent the temp gauge. Something to look at.