Hi folks, I have a real brain teaser.. At least for me.. I had some little issues with the XT since I got it 4 years ago..but I still love it.. Long story short.. A few days ago I started getting really bad throttle response at low RPMS (1st Gear). Since it had been a while I got a new filter.. Not much help.. I checked the basics.. Fuel, conpression, spark. Very weak spark and the coil wouldnt jump 1/2 in to the wire.. SO I got a new coil... ( I think the old one was original.. HAHA).. Still wont start....

 

I pulled the plugs and turned it over and they spark fine.. I looked in the plug hole and noticed a some gas and a strong smell of gas.. Another forum member Jerry has been a great help but I hate to lean on him for everything so Id like some suggestions so I can solve this myself..

 

When I turn it over it cranks fine and starts to catch but will not... Im not sure what Im over looking here.. I dont see/hear and vacuum leaks, sparks good, batterys OK..

 

Im sure all the SUBI fans out here can understand I want to get my XT back on the road..... I hate the BUS!!!!!!!!! HA HA

 

PS for the last 2 years Ive had a code 21 check engine light.. Coolent temp sensor.. but the car always ran expecially when it was somewhat warm... ??? Thanks Chris

granted yours is MPFI and mine is SPFI, but I had a similar situation when my coolant sensor got unplugged by accident - given the fact you have been getting an error code for it - I think it is HIGHLY likely

definitely your contacts are corroded, dirty or loose or all of the above. this is one of the most annoying problems i've had with XT/XT6's. if you clean the contacts (really annoying), it will go away...for awhile, and then come back. if you buy a new sensor, it will go away...for awhile and then come back. so, i came up with a permanent solution:

http://xt6.net/forum/viewtopic.php?t=1767&highlight=fix

doesn't take long and saves you lots of issues down the road. i highly recommend doing the permanent fix or buying a new wiring harness connector (if you can locate one). cleaning or buying a new sensor is a temporary fix, i wouldn't recommend doing that.

Thanks for all the info guys... Jerry and I pulled the plugs and it eventually started but that code 21 Coolent temp sensor has to be replaced or it will drive me nuts keeping my foot slightly on the gas for a min or two each time I start it..

 

I think it was a combo of a weak coil and me flooding it... Yeah Im a bonehead...

 

I looked in the manuals and it looks its a total BEAR to get to that sensor... Intake manifold has to come off... ect.. ect.. Is there any other way to get to it??

I suspect the spark problem may be your ignition amplifier

 

This devise is just a power transistor mounted on the coil bracket

 

It is directly below the coil.

 

Bone yard model would be my choice.

be careful about coolant temp sensor...there can be multiple ones (or similar devices/similar named sensors) on the car. i have some electrical connection under my intake manifold as well (XT6), it's about the only part on the entire car that i don't have a clue what it's for. anyway, the coolant temp sensor on an XT6 is up front by the thermostat on top the motor. this is the one that gives the ECU code you're seeing. i think there's also one in the radiator for the cooling fans...which is sometimes referred to as a coolant temp sensor. just be careful which one you mess with, there's only one that you're looking for.

The FSM shows the FI "coolant thermosensor" is

located in the lower water passage manifold under the intake manifold.

 

It is beside the pipe for the heater hose, and is threaded in almost horizontal with it's leads facing the rear of the vehicle?

 

The one GG is speaking of is called the "thermometer"

it is for the dash gauge not the FI system.

 

There is one in the rad called the "thermoswitch"

 

The FI thermosensor can be tested

 

I'd check/replace the ig amp first

If getting spark and now running the amplifier should be OK. The coolant sensor(code 21) Is indeed on the block behind/under the intake manifold. There should be two sensors around the same area. A knock sensor and the temp sensor. The knock sensor is the one closest to the bell housing.

 

I have seen all sorts of symptoms caused and cured by the temp sensor. Surging, misfires, high/low idles, etc. I understand Gary's frustration about dirty and corroded contacts. But to say not to replace cause it will come back is sort of like saying if you add gas you'll have to add more later. Depending on your location corrosion and such are just a part of life. You deal with it and move on.

Good luck.

if you have trouble locating a coolant temp sensor for a subaru, you can cross reference with a nissan 240 sx, its the brown one, not the blue one