Need fuel injection experts for Subaru problem

[pacem]

1998 Subaru Legacy, 2.2L auto, 150K miles.

I am stumped with this problem. Here are the symptoms:

When it's cold, you hit the gas pedal and it's not moving at all, just not effect.

It quickly gets better as it warms up. Warm up the engine for a few minutes and it will drive.

I get codes P301-P304 which translates to Cylinder 1 - 4 misfire. It's actively flashing in real time. Reset it many times and always comes back to it.

I get really bad MPG, maybe 15 so it's running incredibly rich. Lacking power during acceleration though if you really hit it, it will go.

I changed spark plugs and wires and O2 sensor.

My next thing is the coil. I already replaced the coil once, got a used one from a good car but I still suspect it's part of the problem although it doesn't explain the problem of not moving when the car is cold.

 

[demarpaint]

I'm not a FI expert but try taking a coil from one of the other cylinders and switch it, see if the misfire code moves to that cylinder. At least you'll know if the coil is out to lunch or not.

 

[Trav]

I know it maybe a pain but if you can stop driving the car until this is squared away.The cats can get damaged with all that raw fuel,maybe they already are.Did you check if the affected coils have 12v?

 

[chrome]

Have you checked fuel pressure or a clogged filter? Sounds like the motor isn't getting enough fuel during a cold start and cold operation. You mentioned poor acceleration when warm, this could point to a fuel delivery problem.

 

[mechtech2]

People often came in with problems and said. "it's the carburetor".

Why do you think it is fuel injection?
You have a code that says otherwise!
Plugs, wires, or coils are first to check, therefore.
A coolant sensor may be out of whack, and there is not enough fuel until it warms up.

 

[punisher]

Lots of assumptions on my part: waste spark, distributorless etc:

If 1 and 4 share a coil, then you know where to start...........ignition. The fact it isnt a P0300 would rule out common (common referring to all cylinders) fuel, sensor, MAF, MAP vac leak etc.

 

[mechanicx]

Check that fuel pressure is in spec. Also check that the fuel pressure regulator isn't leaking gas into the vaccuum tube.

 

[Gary Allan]

Quote:
When it's cold, you hit the gas pedal and it's not moving at all, just not effect.


Is this throttle by wire? Otherwise ..no bog ..no asthmatic gulping of air ..no buck ...backfire..or response of any kind whatsoever? No "running out of gas" sensation? Just idles along as though you didn't do anything?

 

[rcy]

Did you try asking at a Subaru specific forum?

www.nasioc.com
www.legacygt.com

etc. etc.

even www.subaruoutback.org has good info.

 

[pacem]

Thanks for the replies, quick comment --

I get misfire on all 4 cylinders, not just 1 and 4.

At this point my plan is to replace:

1. Coolant sensor
2. Fuel filter

 

[pacem]

Originally Posted By: chrome
Have you checked fuel pressure or a clogged filter? Sounds like the motor isn't getting enough fuel during a cold start and cold operation. You mentioned poor acceleration when warm, this could point to a fuel delivery problem.


That sounds very plausible, doesn't it. I will start with the fuel filter. I had a similar problem on an older Subaru Loyale.

When I find out how to check fuel pressure, I will do that too.

 

[pacem]

Originally Posted By: Gary Allan
Quote:
When it's cold, you hit the gas pedal and it's not moving at all, just not effect.


Is this throttle by wire? Otherwise ..no bog ..no asthmatic gulping of air ..no buck ...backfire..or response of any kind whatsoever? No "running out of gas" sensation? Just idles along as though you didn't do anything?



No drive by wire in '98. None of the above, idles just fine.

 

[pacem]

Originally Posted By: Trav
I know it maybe a pain but if you can stop driving the car until this is squared away.The cats can get damaged with all that raw fuel,maybe they already are.Did you check if the affected coils have 12v?


You are right, I realized this also. It has some serious fuel delivery or maybe ignition problem.

 

[stroked93]

EGR problem? to much Exhaust gas will not fire. Seems odd it gets better as the engine warms up. could also be a problem with ecm and cold start fuel trim but unlikely unless its been fiddled with.

 

[pacem]

Just swapped the fuel filter to no avail, I thought it would fix it.

A search of the subaru forums reveals that the Engine Coolant Temperature Sensor is a fairly common problem, resulting in exactly the symptoms I have. I will attempt this CTS swap tomorrow.

This seems to be a nicely written procedure:

http://www.lovehorsepower.com/SubaruDocs/CoolantTempSensor.html

If that doesn't fix it, the next item is Fuel Pressure Regulator check or swap, although I have just a general idea where it is and no idea how to measure the fuel pressure, maybe just swap it.

 

[pacem]

Changed the Coolant Temperature Sensor to no avail.

I will the swapping the coil next.

 

[mechanicx]

I really think you should check the fuel pressure and inspect the vaccuum hose to the fuel pressure regulator for a leak. I'm not a Subaru expert, but that's where I would look first or next. You spent a lot of time and money replacing parts already.

 

[mechanicx]

I wanted to add also you can check the coil with a voltmeter without having to replace it. Also you can look near where the coil and wires are for any spark arcing to ground. when it's dark it makes it easier to see arcings. Also you could have clogged up injectors and running a big bottle (treats 20 gals) of Techron fuel system cleaner may show an improvement.

My suggestion is to check fuel pressure first and the coil resistance.

 

[pacem]

What tool do I use to check the fuel pressure? Where do I get one.

I checked the vaccuum hose to the fuel pressure regulator - it's dry, not leaks.


I have a voltmeter, how do I check the coil resistance, where do I put the leads and what would be the specs?

 

[dhise]

What plugs and wires did you use? These motors can be fussy with aftermarket plug wires if you didn't use oem.