Intermittent poor performance @ WOT
#1
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Intermittent poor performance @ WOT
I've logged almost 150 miles so far and a couple of mechanical problems have surfaced. One of which is an intermittent lack of power at WOT. Here are some details:
Power seems fine starting from low speed roll-on. The tires usually start spinning. Begining at say 40mph or so, sometimes the car will put you in the back seat but more times than not, there is a decrease in power during WOT. It doesn't feel like one cylinder at fault. There is no stumbling or roughness in the motor. Boost gauge indicates between 7-8. It simply feels like I've let off of the throttle a small amount. I have not changed the fuel filter yet so it has been bumped to the top of the list. Also, the SES light has been coming on at low accelleration (only giving it enough fuel to maintain a steady speed). The only code pulled is a 13 (oxygen sensor open circuit).
Any other thoughts?
Power seems fine starting from low speed roll-on. The tires usually start spinning. Begining at say 40mph or so, sometimes the car will put you in the back seat but more times than not, there is a decrease in power during WOT. It doesn't feel like one cylinder at fault. There is no stumbling or roughness in the motor. Boost gauge indicates between 7-8. It simply feels like I've let off of the throttle a small amount. I have not changed the fuel filter yet so it has been bumped to the top of the list. Also, the SES light has been coming on at low accelleration (only giving it enough fuel to maintain a steady speed). The only code pulled is a 13 (oxygen sensor open circuit).
Any other thoughts?
#2
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Well the o2 sensor shouldn't have any effect on your WOT performance, its not listened to. I'd say look at the fuel as its fairly easy to check. Look for possible causes of KR. If you have a scantool that would help a LOT.
Also, was the engine fully rebuilt or just some parts? You really shouldn't be going WOT at only 150miles.
Also, was the engine fully rebuilt or just some parts? You really shouldn't be going WOT at only 150miles.
#3
I know at 40 MPH sometimes my car downshifts into 1st gear sometimes it does not. Try a roll from 25 and see if the performance is consitant or not. IF it downshifts into first I'm thrown back into my seat too, but if it does not the performance is definately dissapointing.
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40? wow, thats pretty high I bet that does throw you back!
My '93 has never downshifted higher than ooooh 31-32mph. Generally 28-29mph will always downshift and give a good jump. Not sure if mine is just a freak though
My '93 has never downshifted higher than ooooh 31-32mph. Generally 28-29mph will always downshift and give a good jump. Not sure if mine is just a freak though
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Mine tops out at 32mph in 1st.. and thats when the governor kicks in [tranny gov.], and it doesn't downshift into first.. hardly ever. Second gear is a really good gear, because at 45, giving full throttle, that'll push you back.. and 60 in 3rd will push you back too..
IMO its fuel delivery.. that sounds exactly like the issue at hand. However, i am no fuel system expert. doc is right, WOT with a freshly rebuilt engine is baaad.. but I think you are smart enough to know that.. rebuilt.. I say no.
-justin
IMO its fuel delivery.. that sounds exactly like the issue at hand. However, i am no fuel system expert. doc is right, WOT with a freshly rebuilt engine is baaad.. but I think you are smart enough to know that.. rebuilt.. I say no.
-justin
#6
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The engine was not recently rebuilt. As a mater of fact, very little was needed. Plugs, wires, 1 coil, TB removed & cleaned... that'* about it.
I know what you're saying, Custom but this is more of a "hold you back" situation. It can even be heard in the pitch of the engine. My first thoughts were fuel or timing but tranny related problems were in the back of my head. Although, it doesn't feel like it'* slipping.
I know what you're saying, Custom but this is more of a "hold you back" situation. It can even be heard in the pitch of the engine. My first thoughts were fuel or timing but tranny related problems were in the back of my head. Although, it doesn't feel like it'* slipping.
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Trust me, if your tanny was slipping, you'd know it. IMO its fuel related.. if your fuel filter looks anything like mine [rusty.. recall the pics I posted in my brake problems thread], then you really should replace it. My car doesn't pull very much above 4k.. and the more I think about it, and now that I know the fuel filter is shot.. then chances are that is the culprit. Because I think 81% of the torque peak is still at 5200rpm.. so I should still feel a pull.
-justin
-justin
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