Hesitation

[Mark Ward_]

Hi everyone,
I am still weeding out 1 last problem on the car. What is happening is that if I have been at part throttle or off throttle for more then 1 or 2 seconds and I go to full or alot more throttle, the car really hesitates for a few seconds (feels like forever). If I am doing a quick shift or when I first start off there really is no problem, the car accelerates smoothly. I have error code 45 currently and error code 24 and cant seem to get rid of them. I will pull off the IAC and give it a good clean with carb cleaner.
To me, the car is flooding when this happens then clears up, I dont understand why though...
Mark

[ciper_]

Id say try filling up with premium fuel and trying it again. Perhaps try to temporarily remove the knock sensor while still keeping it connected. One of the times that a large amount of knock is produced is sudden increases in throttle opening. I had a similar issue with my second legacy, and when filled with premium the issue went away. This lead me to believe there was a problem either causing excessive knock or a problem with the knock detection. I replaced spark plugs and ran some engine cleaner through. I did some other maintenance items as well and the issue went away.

[John D]

Is this for a turbo?
Automatic?

Have you done any regular maintains yet?.

…When I got my sport sedan I had the same problem….

I’ve replaced these parts:
PCV valve
Fuel Filter
Tune up (wires plugs)
Timing belt
Stock Pulley for a UR
02 sensor
clean fuel injectors
Bypass Boost solenoid.

Out of all of that Bypassing the Boost Solenoid with a MBC seemed to do the trick but sometimes when it gets really hot and humid I still get it.

Someone mentioned a while back that it could be the fuel pump going bad….

Also you might want to ask Josh what symptoms a bad MAF would cause as that might be the problem also.

The last thing that you might want to check is the Spark plug coil pack. Someone mentioned a while back that they had the same problem and finally noticed that it was cracked.

[Mark Ward_]

Yes it is a Turbo EJ20 5spd tranny from a JDM RS, New air filters, one new ignition coilpack (4 on car total I have 3 more spares), Clean air cleaner, unknow fuel pump (but I didnot have the problem with the old 2.2T) I can check some of the others you mentions, I will go and check the knock sensor (per ciper)
I always run 94 octaine (the best I can get).
Mark

[Ian Shastko]

You might check your TPS (throttle position senser). I have been fighting
hesitation off and on sence I bought the car and replaced everything senser
wise and things ran fine for a while untill I was getting a funny bogg like
symtom (hesitation) during acceteration. The ECU showed no errors so I took
it to the shop and had them check the TPS and it was no good. Put a new one
in and it was like a new car with power all the way to the floor. Apparently
the TPS has no error code in the ECU. At least that is what I was told by
the subaru dealer in Florida that suprisingly know what there talking about.
Hope that helps.

[John D]

Interesting.... can I ask what they charged for the sensor?

[Mark Ward_]

I have checked 2 different TP sensors. and neither seem to be within spec of
what the manual says. I tried the Knock sensor but didnt seem to help. If
you want to see excactly what it does, go to my media page and watch the
Pacific forest rally incar, about3 or so minutes in, you will here me
complain to my navigator about not having any power coming out of a sharp
turn.

I think I might change the tps depending on price. It couldnt be that
expensive... could it?
Mark

[smotocon_]

It cost me $320.00 + tax so aboy $350 just for the senser from subaru.

[John D]

You know what else I forgot in my list that actually did help. Was
adding more grounding points throughout the engine bay. It also got rid
of the dimming of the clock radio when I would push the brake pedal.

John Dolinga
www.SunnyGulf.com

[Todd Munson]

would you happen to know the part # for the TPS?

[Ian Shastko]

I'LL TRY AND GET IT FOR YOU IN THE MORNING. I HAVE THE BOX AT HOME.

[ciper_]

Before replacing it I would suggest heading down to radio shack and picking
up a bottle of "TUNER CONTROL" to clean and lubricate. Fixed an intermittent
connection in mine.

Also realize that the spec for adjustment of continuity between pin one and
pin two is 30-33 when fully tightened and the engine is cold. In order to
get this spec you will have to tighten and loosen many times. Don't try to
use some spark plug gappers or something as they arent as accurate, use a
real feeler gauge.

My intermittent contact caused hesitation somewhat similar to what you
explain and the tuner control was a cheap fix.

[Josh Colombo]

The TPS sensors are pretty much never what they're supposed to be....according to the manuals. HOWEVER.....the 90-94 subie motors had a 4 pin TPS. The fourth pin was the throttle stop switch. This is pretty much what you want to adjust the TPS to.....not necessarily to what the manual says it's range should be. I set it to the manual specs....and got a CEL. As long as the voltage increases/decreases smoothly it should be good.

[Josh Colombo]

here, read this info. It's scans from the FSM about how to test and adjust the TPS

http://www.main.experiencetherave.com:8 ... sting1.jpg
http://www.main.experiencetherave.com:8 ... sting2.jpg
http://www.main.experiencetherave.com:8 ... sting3.jpg

Do make sure you use a feeler gauge set, and use the bottom stop screw....not the top one. I did the cleaning thing.......can't say it helped tremendously....

[Douglas Hancock]

I tried this on my car. I had some noisy tappets (still have). The knock sensor was picking it up and throughing it in limp mode (back to 8psi) once and a while. I was told to place a piece of rubber under the knock sensor and see what happens. I have had the smoothest running engine for 7000 kms. I would try this first and then get to the more expensive parts later if this does not work.

[Andrew Mouser]

Would you mind explaining this piece of rubber setup
and how this assists the knock sensor? Thanks,
Andrew Mouser

[Josh Colombo]

The rubber setup muffles the engine noise. Other thing you could try is a fiber washer for an oil drain plug.