I have a 99 Legacy L 2.2 auto. It starts and runs fine until you give it throttle. it starts to rev, then it falls on its face, bogs down, no power, acts like its not getting fuel. no check engine light. I change the fuel pressure regulator from a parts car but no change. I was playing around with pinching the fuel return line and it seemed to help slightly, is why I changed the regulator. any ideas?

Get yourslef a vacume gauage and tell us exactly what it does. This will give us some insight as to what is going on.

 

 

My first guess would be a completly clogged catalytic converter or exhaust system. Does it stall or seem like it is choking for air. Can you feel exhaust coming out of the tail pipe?

 

Check for a potato in the tailpipe, maybe you pissed someone off.

It doesn't stall, just bogs down, like a faulty accelerator pump on a carburetor. but never revs up higher than about 1500 rpms. I can hold the bog steady with half or full throttle. I got a little more rpm by pinching the fuel return line. but the problem is still there. It has power and runs well up to 1500 rpms. there is no potato in the tail pipe.

Hrmm fuel pressure regulator?

 

nipper

Ever change plugs and wires? 90% of all fuel problems are electrical.

 

I have a 99 Legacy L 2.2 auto. It starts and runs fine until you give it throttle. it starts to rev, then it falls on its face, bogs down, no power, acts like its not getting fuel. no check engine light. I change the fuel pressure regulator from a parts car but no change. I was playing around with pinching the fuel return line and it seemed to help slightly, is why I changed the regulator. any ideas?

Maybe we are missing the obvious. A 99 legacy. How many miles? When was the last time a full timing belt change (inculding idlers and tensioners) were done? And I am waiting for that vac gauge info.

 

 

nipper

i recently had a car like this.

 

turned out he had filled up from a dubious sorce [buddys got a farm gas tank out back that somehow got a bunch of water in it.]

 

well, i had to drain the tank, blow out all the lines, and replace all 4 injectors [i just put a new intake w/fuel rails on it]

 

try some gas drier first.

Its been running like this for awhile. several tanks of fuel. It runs very well at low throttle.

If it has not been done recently, replace the fuel filter. Maybe that's the problem. You probably need a new one anyway. And while you're at it replace the air filter. You probably need that also.

G.

Yes, the fuel filter and air filter are new. the timing belt was changed 10k ago. the car has 110k. Its a family members car so I only drove it once around the block. It ran great as long as I didn't give it to much gas. I'm told, sometimes it runs fine.

Were all the idlers replaced? Does the car let out any black smoke when it bogs down?

I checked the timing belt. It is a new gates belt. the marks are dead on. Idlers and tensioner look old. checked compression, 200 psi all cylinders. I drove it about 1 hour today. It pulls hard from standing start and revs to about 4000 rpm on flat or downhill, as long as throttle is not floored. I came out of a parking lot with a steep long driveway uphill, barely made it up. about 5 mph is all I could get. any throttle caused it to bog. at the top I turned down the road, it ran fine to 40 mph. I have to nurse the throttle, not to give it to much. Its like a switch, to much throttle and it shuts off. Briefly down the hiway it made 55 mph.

no check engine light.

starts and idles fine.

plugs are new and burning clean

wires look new

to me its acting like a fuel problem, I've got another fuel regulator on the way,

any ideas?

Edited February 8, 201016 yr by Tahoe Subaru

200 psi is too high, factory spec is 185 max. Old idler and tensioner should be replaced. Something is out of wack.

 

Do you have anything that can read the OBDII in real time. I want to see if this engine temp dependent (the dash gauge only tells you vague things).

 

What happens when you put the car in neutral when it wont move?

 

I dont think it is a fuel problem. I dont like the compression test, it tells me something is out of time. I know the knock sensor can hurt performance. I wonder if the timing being off, and the knock sensor trying to compensate, its killing performance.

 

nipper

Apologies for a newb question, but for my benefit as well... what would a real-time OBDII scan tell him vs. "regular" cheapy OBDII scanner?

Its a 99 phase II 2.2 with 10:1 compression ratio.

It bogs in the driveway in neutral. can hold the bog with half to full throttle.

Like I said before, I can hold the bog, no power, then pinch the fuel return line and it will rev up.

 

Weak fuel pump,plugged filter(new means nothing)

 

Try blowing thru the filter

 

If still no joy,do a fuel pressure test.

I dont have a 99 FSM but i have a 98 (9.5:1 CR and 137-176 PSI) and a 2000 ( 10:1 CR 156-185 psi MAX compression). Compression ratio in the FSM is 10:1, but that doesnt have any effect on compression depending upon when the valves start to open as the piston goes to TDC. COmpression ratio is a number purely derived from BDC to TDC.

 

 

A good OBDII scanner you can read sensors output in realtime, so it can sometimes help you connect the dots.

I'd love to have a scanner for the pc. Any recommendations? Funds are very tight right now. I may have to bite the bullet on this one and take to the shop. Heaven forbid

Afm.

"I'd love to have a scanner for the pc"

 

I have an OBDcom scanner for my PC and it does realtime, freezeframe etc.

I would check/clean MAF sensor. This is one of the symptoms of a defective/dirty MAF.

 

Another could be front O2 sensor. But that usually acts like fuel is cutting off after warmup and above a certain RPM.

I would check/clean MAF sensor. This is one of the symptoms of a defective/dirty MAF.

 

Another could be front O2 sensor. But that usually acts like fuel is cutting off after warmup and above a certain RPM.

 

That is what I come up with. Neither will give a cel until they die. I am guessing MAF.

Thanks for the suggestions. I'll check it out.

One other thing I forgot to mention.

with the key on but engine not running

I hear a buzzing sound, down by the transmission, when the throttle is applied. it quits buzzing back at idle position.