HESITATION STORY: Car running like a lawnmower.. PELASE HELP

[BoostAddict]

Hey,

I've been having a lot of problems with my 1991 Legacy Turbo recently. Over the last two months, I've had Code #22 appear from time to time and the car going into Limp-Home mode. When I pulled all the other codes from the computer, there have been LOTS of other codes, but none other than Code #22 has appeared during D-Check.

I put on a 3" cat-back exhaust on my Legacy and the car was running fine (for about 2 days). It would occasionally go into "Limp-Home-Mode", but overall it pulled hard and the only code triggering the check-engine light was still Code #22.

Then, on the 3rd day after installing the exhaust I had problems starting the car on my way to work. Still only Code #22 during D-check. At the end of the day, the car started running like a lawnmower and not having any guts during boost (as if the fuel was totally limited when it went into boost). Then the car stalled at an intersection. I nearly had to get it towed home... but somehow it started after like 15mins of playing around with it in the middle of an intersection

I drove the car home that night and it stalled... I could get it started again for like 2 days!!! Somehow I got the car started again and still only Code #22. I have never seen the car run worse since I got it, though. It didn't sound like a lawnmower anymore... It sounded worse.

Considering that Code #22 stands for a faulty Knock Sensor, I went out to the STEALership and bought a new knock sensor. I've installed it and reset the ECU (using the green&black connector method as well as leaving the battery disconnected for 2 days). All the other "stored" codes got cleared away, but Code #22 still shows up.

I have tested the O2 sensor using a multimeter and by checking the values from VRG's Laptop Scan Tool and they're fine... I have also replaced the Coolant Temperature Sensor, 'cause I've heard that they can also cause problems.

A friend of mine, who knows a little bit about Subbie's came by to help me figure out WTF is wrong with my car and said that he's seen problems like this on his 1991 Justy before. His verdict was that the probable cause of my grief is a "Pressure Sensor". Cool, at least now I knew what direction to look in... My only problem is that I've called nearly all auto-wreckers in Ontario and NONE of them have a 1990-1994 Subaru Legacy TURBO in stock... That means that I either have to go to the STEALership again and pay $500 (yes, five-hundred Canadian dollars!!!) for a new one, or figure something out.

Here comes the question... Will a pressure sensor off a N/A 1991 Legacy work on my Turbo? That's the only pressure sensor, which I could locate on a scrap-yard nearby.

Does anyone have a Turbo pressure sensor for sale?

Any other suggestions on what could be the probable cause of my car running like that?

Sorry for the super-long post.


Thanks in advance,
Peter
pcalak@uoguelph.ca

[vrg3]

Your friend's Justy used a pressure sensor to determine fueling, I believe -- it used speed density engine management. Your car's pressure sensor signal is not the primary variable in fueling calculations (the airflow meter signal plays that role) so I don't think that his experience with his Justy is relevant to yours.

(Incidentally, if you did need a new pressure sensor I'd suggest reading this page: http://www.graphics.cornell.edu/~v/chrysler_map/)

Maybe the ECU isn't resetting right? Did you press the brake pedal for 30 seconds during the 2 days that you left the battery disconnected?

When you installed the new knock sensor, did you do a good job of cleaning up the area on the block that it mounts to? Did the wiring harness that you plugged it into look like it was in good shape?

Your knock sensor code and your rough running may not necessarily be directly related... you should still look at other things that can cause the engine to run poorly. When did you last change the plugs? The ignition wires? The fuel filter? The air filter? Flush the coolant?

[evolutionmovement]

Your knock sensor's likely going off due to a misfire. Mine does this after pressure washing my engine (cover the elecronics? Pfft!) and the thing runs ragged for a few miles. How old are the plugs and wires? Did you run the other check? U-check I believe? It may give you something else.

Steve

[BoostAddict]

Hey,

Thanks for all the replies...

Come to think of it, I probably did a pretty s**tty job cleaning up the area that the knock sensor mounts to. I'll remove it and do it right this time.

I did press the brake when I disconnected the battery. The ECU reset itself correctly, because all of those other codes that were stored in it got cleared. Right now just Code #22 is showing up.

The plugs and wires are brank spankin' new. The plugs are NGK's and so are the wires. I had some problems with my previous (Subaru original) wires, but since I replaced them with the NGK's the car started running even better. No misfiring at all...

Untill the thing that I described in my last post happened...

Fuel filter is brand new too...

I've measured the O2 sensor and tried disconnecting it too... The car still runs the same. Seems like a fuel cut and realy bad hesitation as soon as the needle of my pressure gauge moves into positive boost. The car seems like it's about to die and it almost does...

No hesitation untill I press the gas though. The idle seems fine too (around 700RPMs).

Does anyone have ANY other ideas on WTF else could be causing this kind of behaviour? Any other suggestions on what other readings I could give you to better understand the situation?

Thanks a lot for your help,
Peter

[BoostAddict]

Oh yeah, the air filter and the coolant are fine... I even removed the whole intake piping and tried just running with an open throttle body, but the car was still running the same.

What other things could I check for an F-up?

[evolutionmovement]

Run the other check and see if there's something else - I've gotten stored codes with nothing showing up in D-check. Other than that, it sounds like you've replaced anything I could think of. How are all the vacuum lines?

Steve

[turbonator]

Hey,

Thanks for all the replies...

Come to think of it, I probably did a pretty s**tty job cleaning up the area that the knock sensor mounts to. I'll remove it and do it right this time.

I did press the brake when I disconnected the battery. The ECU reset itself correctly, because all of those other codes that were stored in it got cleared. Right now just Code #22 is showing up.

The plugs and wires are brank spankin' new. The plugs are NGK's and so are the wires. I had some problems with my previous (Subaru original) wires, but since I replaced them with the NGK's the car started running even better. No misfiring at all...

Untill the thing that I described in my last post happened...

Fuel filter is brand new too...

I've measured the O2 sensor and tried disconnecting it too... The car still runs the same. Seems like a fuel cut and realy bad hesitation as soon as the needle of my pressure gauge moves into positive boost. The car seems like it's about to die and it almost does...

No hesitation untill I press the gas though. The idle seems fine too (around 700RPMs).

Does anyone have ANY other ideas on WTF else could be causing this kind of behaviour? Any other suggestions on what other readings I could give you to better understand the situation?

Thanks a lot for your help,
Peter

Your getting fuel cut?? when in boost right??

At what rpm do you lose power??

My guess is that one of the hoses going in boost controler has come loose..

My buddy had this same problem it would idle fine but around 4 rpm the fuel would cut and it would feel like you hit a wall

Where in Ontario you from?? I am in Ottawa

[BoostAddict]

Ok... I'm starting to run out of options.......

1. Coil Pack - REPLACED (by a Diamond one)

2. Ignition Module - REPLACED (by a Mitsubishi one)

3. ECU - Reset AGAIN

4. Fuel Filter - REPLACED (there's normal fuel pressure in the lines, so the fuel pump is not fried for sure)

5. Spark Plug Wires - tried different ones (although the NGKs that I had on the car before it started acting now are vrand new)

...and Last, but not Least... The cars has HUGE problems now and when it does, it runs for like 5-10 sec... it's got like a -5 idle pressure...

I simply don't have any idea what to look at next. Any ideas would be highly appreciated.


P.

[elkaboom]

Have you looked at the injectors as a possible source for the problem?
It definitely sounds like a fuel problem, so in my mind, a thorugh inspection/shakedown of the fuel delivery system is in order.

[vrg3]

If the engine won't idle it's harder to do, but maybe you should look for vacuum leaks... inspect every portion of the intake tubing closely, and inspect every hose in this diagram: http://www.graphics.cornell.edu/~v/vacuum/

Did you clean the MAF sensor?

You might also want to pull the fuel pump out and inspect the "sock" filter attached to its inlet.

[madmonkey]

You know, my car kinda runs crappy too, feels like all four wheels are pulling at different speeds under hard acceleration, but rpms stay constant and steady. The car also idles high no matter what I do to adjust. But its still getting 28.5 mpg highway. 138,000mi 91 Legacy ej22 n/a

[BoostAddict]

Hey,

I just thought that I might update everyone on the status of my car.

The hesitation and weird running had nothing to do with any of the sensors. I've changed pretty much all of them and it didn't make any difference. The problem was a broken pin on the balancer shaft...

The pin which goes between the balancer shaft and the crank had fallen out (due to improper installation in the first place), the balancer shaft rotated a couple of degrees and needless to say, that screwed up the timing. After replacing the pin and re-installing the balancer shaft the car is running perfect.

Thanks for all your help along the way (especially vrg3).

P.

[petridish38]

Kinda like this?

http://bbs.legacycentral.org/viewtopic.php?t=15609

Andrew