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No power when cold

Featured Replies

A couple days ago my 94 Leg developed a pretty annoying problem... after it's been sitting for a long time (overnight, or all day at work) it has absolutely no power on startup. I can put my foot to the floor and it doesn't rev above idle, and barely moves the car. In fact, my driveway is sloped, and in the morning it doesn't even have enough power to back out of the driveway- just rolls forward (it's an automatic). Above 2500rpm or so all the power returns, and if I drive it with enough throttle for about half a mile, everything returns to normal. Sitting in the driveway revving the engine does nothing- it only frees up when driven or allowed to idle for 15 minutes or so.

 

It still runs smooth as silk when bogging down. No smoke, rough running, or noises. Just NO power whatsoever. Gas mileage has dropped majorly, and I've also noticed a slight power loss on the interstate- I now have to downshift to climb hills I could usually handle in top gear.

 

Only recent thing out of the ordinary was I lost an alternator belt the other day. This problem started the morning after. I don't see how the two could be connected other than a voltage spike/undervolt condition. I'm leaving the battery unhooked tonight to reset the ECU just in case.

 

No check engine light or other trouble signs. I don't even know where to begin here. Any suggestions?

When was the last time you had your o2 semsor replaced. That would explain the drop in fuel mileage. No power when cold, if this was a carb i would say its a choke issue. So what acts like a choke when cold? Well the car needs to know its own temp. Another thing to look at is the tps sensor. See if the sensor has any response when the car is stone cold. you will have to take resistance readings off them before you start the car to see if they are dead or un responsive when cold.

 

Check all your wires and make sure the belt didnt break anything when it snapped.

 

How long does it take to be responsive?

 

nipper

hey steve, long time no see slick! where did you end up?

 

how old are the ignition wires and plugs?

 

do these things have an idle air controller of any sort? i'd check with those as well. on the XT6 you just have to clean the idle air control valve out.

 

no check engine lights (think - coolant temp sensor?)

I would think coolant temp sensor or possibly fuel filter. Temp sensor is more likely, though.

  • Author

Where is the coolant temp sensor located on this car?

Where is the coolant temp sensor located on this car?
Under the intake. It's the brown plug seen in this picture:

 

dscn2628rk4.th.jpg

  • Author

Installed a new coolant temp sensor this morning, and it made absolutely no difference. Any other ideas?

yes answer our questions above, then we can help you. Also i said to TEST the parts first, otherwise your just throwing money at it. Just throwing parts at things is NOT the easy way to fix somethng.

 

nipper

  • Author
When was the last time you had your o2 semsor replaced. That would explain the drop in fuel mileage. No power when cold, if this was a carb i would say its a choke issue. So what acts like a choke when cold? Well the car needs to know its own temp. Another thing to look at is the tps sensor. See if the sensor has any response when the car is stone cold. you will have to take resistance readings off them before you start the car to see if they are dead or un responsive when cold.

 

Check all your wires and make sure the belt didnt break anything when it snapped.

 

How long does it take to be responsive?

 

nipper

 

No clue on the o2 sensor. Nothing seems to have been damaged when the belt broke. Plugs and wires are 20k old. It takes about half a mile of in-town driving before the problem goes away, but even when warmed up I still have power loss on the interstate and crappy gas mileage.

 

How do you test the TPS?

No clue on the o2 sensor. Nothing seems to have been damaged when the belt broke. Plugs and wires are 20k old. It takes about half a mile of in-town driving before the problem goes away, but even when warmed up I still have power loss on the interstate and crappy gas mileage.

 

How do you test the TPS?

 

Get yourself a haynes manual to start off with, it will make life easier for everyone as we try to explain things. This will also tell you how to pull the codes off this car.

Since the o2 sensor is at the heart of the emissions system, i would put that on the list of things to replace, as that has a huge effect on your gas mileage.

There are a few things that this can be, it can be the Idle Air control motor is sticking (what happnes when you turn on the a/c), it can be a bad knock sensor, it can be the tps. Which temp sensor did you replace, hopefully the one for the computer.

 

nipper

No clue on the o2 sensor. Nothing seems to have been damaged when the belt broke. Plugs and wires are 20k old. It takes about half a mile of in-town driving before the problem goes away, but even when warmed up I still have power loss on the interstate and crappy gas mileage.

 

How do you test the TPS?

 

http://www.main.experiencetherave.com:8080/subaru_manual_scans/FSM_Scans/TPS_testing1.jpg

http://www.main.experiencetherave.com:8080/subaru_manual_scans/FSM_Scans/TPS_testing2.jpg

http://www.main.experiencetherave.com:8080/subaru_manual_scans/FSM_Scans/TPS_testing3.jpg

 

The last scan is really all you need to worry about to adjust it.

 

Did you replace the sensor with the brown plastic connector?

http://www.main.experiencetherave.com:8080/subaru/images/injectors/DCP_2477.JPG

  • Author

Yes, I replaced the one with the brown connector.

 

Hopefully will be able to try out these suggestions when I get back home. Coolant temp sensor was all I was able to replace today- I'm now posting from the bar at Pittsburgh Airport, waiting for a flight. I'll be reunited with the car Monday morning.

Yes, I replaced the one with the brown connector.

 

Hopefully will be able to try out these suggestions when I get back home. Coolant temp sensor was all I was able to replace today- I'm now posting from the bar at Pittsburgh Airport, waiting for a flight. I'll be reunited with the car Monday morning.

 

NONONONO No turkey for you untill its fixed. Now turn around go home and fix your car

 

 

 

hehehehehehehe

 

happy thanksgiving

 

nipper

  • 2 weeks later...
  • Author

Well, thanks to work and travel, I FINALLY got to check on the car again.

 

Legacy777, your links aren't working. Can you host them again? Or can anyone just explain to me where the TPS is and how to test it?

 

Bad o2 sensor would throw a check engine light, correct? I remember reading that the CEL will flash upon any problem that could potentially damage the cat converter.

Well, thanks to work and travel, I FINALLY got to check on the car again.

 

Legacy777, your links aren't working. Can you host them again? Or can anyone just explain to me where the TPS is and how to test it?

 

Bad o2 sensor would throw a check engine light, correct? I remember reading that the CEL will flash upon any problem that could potentially damage the cat converter.

 

If tis lazy it may or may not. The flashing CEL happens if there is a miss or backfire condition(or the cam can crank semsors are out of synch), not a bad o2 sensor.

  • Author

Per instructions in the Haynes manual, I tested the TPS and knock sensor. They both tested good.

 

Going to try to test the o2 sensor at work tomorrow if my boss will let me use the lift. I have no desire to get under my car on my current driveway, which is shaped more like a ski slope than a driveway.

For what it's worth Trogdor, I am experiencing the same thing on wicked cold days. I mean 0F, usually in the morning. I am guessing this is normal...wouldn't wicked cold air have a huge impact on driveability?

For what it's worth Trogdor, I am experiencing the same thing on wicked cold days. I mean 0F, usually in the morning. I am guessing this is normal...wouldn't wicked cold air have a huge impact on driveability?

 

 

It shouldnt. The only thing it will affect is when the tranny upshifts.

 

nipper

Oh. Then maybe we should take a look at the transmixer, eh?

Oh. Then maybe we should take a look at the transmixer, eh?

 

:confused:

 

nipper

Sorry, I mean to say that only part of getting the car down the road belongs to the engine. The transmission has to get it there, so what if we consider that the transmission is the issue.

  • Author

Considering the car acts exactly the same in neutral, it's most definitely an engine issue.

Considering the car acts exactly the same in neutral, it's most definitely an engine issue.

 

have we checked the engine temp sensor?

 

nipper

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