1997 Impreza, 2.2, automatic:

Sporadically will crank but not start.

Put accelerator to the floor and it will start.

Erratic idle speed at times. Will feel like it's on cruise control with tach at 1500-2000 and foot off accelerator.

Local shop cleaned throttle body and IACV with Seafoam. No improvement at all.

Runs fine on highway.

 

Diagnosis ? IACV ? Buy new (expensive...$350 ????) or used ? Where to buy ?

What else needs to be considered first ?

Is IACV  "likely" the problem ? almost surely ?

 

Thanks ofr any help/suggestions !!!

Probably the Engine coolant temp sensor is bad.

There are two separate sensors, one for the computer hat has two wires, one for the guage that has one wire.

It's the two wire one you need. The ECTS is telling the computer that the engine is significantly colder than it really is, so its giving it way more fuel than it needs which floods the engine.

Thanks for the insight  Fairfax...sounds very reasonable to me and worth a shot. Hopefully it's not $350.00 ...

I've seen them for about $20 -$25. Check advance auto and use discount codes from retailmenot.com and you can save some $$.

Junkyard isn't a great option for this since its a fairly common failure.

would a bad sensor show a code?

Pretty sure I have a couple of these laying around. If you want a cheap used one shipped your way, let me know.

 

otherwise, you could probably find one at a junkyard pretty cheap.

would a bad sensor show a code?

 

pretty rare for the coolant temp sensor to actually throw a code on its own, and also a very common failure.

 

Advance auto is a good source for the sensor, as Fairtax said - place the order online using the coupon codes to get the discount, then do a store pickup.

don't have AA nearby but I have an O'reilly's gift card so guess I will be finally using it.

so where is this little gem located?

Left side of the engine behind the number 3 intake runner. Look straight down under the IAC, there is a big wire harness that runs under the intake, and the two temp sensors are hidden under that harness.

thanks!

Left side of the engine (as you are looking at it from the front) behind the number 3 intake runner. Look straight down under the IAC, there is a big wire harness that runs under the intake, and the two temp sensors are hidden under that harness.

 

The 2 sensors are side by side in the coolant crossover pipe, under the intake.

 

You will lose a little coolant when you take the old one out, so have a rag underneath to catch it, and have the new one ready to stuff in as quickly as you can to avoid losing a lot (keep the cooling system closed up tight to minimize the loss, too)

unplug the engine harness, remove the gorund bolt, and get all tose wires out of the way. use a deep socket if you can you wont lose much coolant at all unless you can't find the hole putting in the new one.

Well, replaced the sensor and so far so good, Started up right away...now let's see if it starts up when it is colder.