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  #16  
Old 08-16-2002, 04:23 PM
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I haven't had this problem on either svx but I normally don't floor it going out of the driveway - I don't go over 4k until the engine reaches operating temperature.
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  #17  
Old 08-16-2002, 05:07 PM
rbalach rbalach is offline
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I never had this problem until about 5-10k miles ago. I've had the car since 38k, i'm at 110k now. The problem seems to be on light acceleration. Everytime my 94 does it, i give it more gas and then it seems to wake up.

RB
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  #18  
Old 08-16-2002, 05:18 PM
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ummm...who said they floored it out of the driveway? ANY use of the pedal when my car is cold gives a jerky acceleration. apparently you don't know what we're talking about, because i also let the engine get up to operating temp (mid-temp scale) before i "get on it". and we're all proud that you do the same.

Alan
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  #19  
Old 08-16-2002, 08:41 PM
ehyde111
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Originally posted by Landshark
ummm...who said they floored it out of the driveway? ANY use of the pedal when my car is cold gives a jerky acceleration. apparently you don't know what we're talking about, because i also let the engine get up to operating temp (mid-temp scale) before i "get on it". and we're all proud that you do the same.

Alan
I agree. It's not flooring it at all. It seems to be any type of acceleration above a crawl.

Chris
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  #20  
Old 08-17-2002, 11:37 AM
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Maybe one of you could try new plugs, cleaning the throttle body, new air filter, (other regular tune-up items) and see if the hesitation goes away.
Neither of my svx's do this, but I have done regular tune-ups on them both. My little red wagon used to start hesitating about every 30k and each time a new set of plugs, clean the throttle body, air filter, and the problem went away.

Your car should not hesitate like this if it is tuned up properly. I see alot of people get in, turn the key and have it in drive and the pedal to the floor the instant the engine fires - and then they wonder why it coughs and burps for a little while. If you are warming it up at each start you shouldn't have any hesitation.
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  #21  
Old 08-17-2002, 12:54 PM
CaptHowdMasta
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exactly

If you warm it up is what we said but if you get in and floor it no matter how well you have it tuned up it still is going to hesitate a little bit correct?
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  #22  
Old 08-17-2002, 03:17 PM
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I normally let my cars idle for about 30 sec to a minute before selecting drive. After this I try not to race the engine until it gets warm. On the rare occasion that I have to floor it right after idleing - warm up it still does not hesitate but I hate doing this and thinking of the cold oil and metal grinding going on in my nice shiny aluminum engine.
If I turn the key and immediately jump on the gas on a cold engine I'm not sure what it would do - I won't try it in my car, but my expectation from watching other people do it is that it is going to burp.
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92 Ebony LS-L. ecutune stage1v4, motorsport 1pc pulley. Garage Queen - sold to Dad in upstate NY 155,000 miles
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89 DL 4x4 little red wagon - a.k.a. The immortal suby. 275k R.I.P.
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  #23  
Old 08-17-2002, 03:19 PM
DavieGravy DavieGravy is offline
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I've done regular tune-ups on my car. Plugs have about 20k, new air filter, and throttle body is clean. This has not solved the problem. And I never have problems with rough idle either.

Looks like whe need to have two boards. One for the newbies and somewhat newbies and the other for senior members. I'm sure there's some of you out there that could answer this question, but prefer to watch us make idiots of ourselves while we contemplate what's going on.
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  #24  
Old 08-17-2002, 03:33 PM
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Beav - where are you?

Since you've done all that already I would get some rubbing alcohol and a q-tip and clean the wire in the MAF (be careful). Check to make sure you have no vacuum leaks also. Since yours is a 92 - have you done the noise suppressor mod yet?

Where is Beav when we need him?

How bad is your hesitation - is the car bucking or just a little bog when you pull out?
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2015 BRZ Limited 6MT
92 Ebony LS-L ECUtune Stage2av1, Z32 MAF, 370cc injectors, TomsSVX intake, BontragerWorks 22mm RSB #003, HID Hi and Lo beams, OT endlink and bushing mods, PWR Aluminum radiator, Harvey's QC shift kit, 2.5" flowmaster 80 exhaust, 17" Michelin Pilot Sport A/S, Poly sway bar bushings, Slotted Bradi rotors, AFBeefcake powdercoated calipers, 97 grill, and a huge set of air horns. 300,000 miles and counting
92 Ebony LS-L. ecutune stage1v4, motorsport 1pc pulley. Garage Queen - sold to Dad in upstate NY 155,000 miles
19 Subaru Ascent Premium - -Hers !.
89 DL 4x4 little red wagon - a.k.a. The immortal suby. 275k R.I.P.
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  #25  
Old 08-17-2002, 03:49 PM
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just a little bog for me the first time I accelerate
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  #26  
Old 08-17-2002, 07:16 PM
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Re: Beav - where are you?

Quote:
Originally posted by immortal_suby
Since you've done all that already I would get some rubbing alcohol and a q-tip and clean the wire in the MAF (be careful). Check to make sure you have no vacuum leaks also. Since yours is a 92 - have you done the noise suppressor mod yet?

Where is Beav when we need him?

How bad is your hesitation - is the car bucking or just a little bog when you pull out?
Mine is a 92 also. Actually, I was a little too chicken to crush something on my car's computer, so I swapped in another form an SVX with the noise suppressor and EPROM upgrade. As for the MAF, it's recently been cleaned along with the throttle body. Plugs are next. They have about 70k on them.

Oh, the svx doesn't buck, it bogs -- like my 1972 Buick Regal used to when I floored that.
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  #27  
Old 08-17-2002, 11:49 PM
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Whoa!

Patient: "Doc, it hurts when I do this."

Doctor: "So don't do it."

The computer's programming depends on the input of many sensors. However, before it begins to decipher their readings and base its responses on them it wants everything warmed up and functioning properly. When the engine is cold it operates in 'open' loop, in other words the computer runs from a fixed set of parameters. Once the temperature and oxygen sensors (typically, this can vary slightly from one OEM to another) it will go into 'closed' loop where it will use all incoming sensor info to determine its responses.

So, all that you're probably witnessing is a bit of sub-optimal response while the computer is still in open loop. The engine doesn't have to be fully warmed up to reach closed loop, just enough for the computer to realize what's going on and respond. Some cars have better open loop programming than others and won't exhibit any/many flaws, others aren't so lucky.

If your car is up to date with spark plugs, fuel and air filters, the throttle body and idle air controller is clean and the check engine light isn't on, you're probably good to go. Just expect the foible until it's warmed up a bit and be thankful your car isn't picking you to pieces....
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  #28  
Old 08-18-2002, 12:29 PM
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Agreed, I bought a used ECU out of a parted out SVX to do the crush mod, and saw absolutely no difference.

Couple things I noticed however, is mine does this on a fairly regular basis as well. However fuel seemed to be the biggest key for it to go away. I used to use nothing but 91+ octane, but after much research into the whole attitude per octane talk, I changed to regular. Within a week the hesitation started quite noticibly, even people I car pool with saw the difference. I changed to silver grade gas, and the problem went away.

On a side note however, I don't drive off right away either. The car will be sluggish if you just go for it after starting it up, but every car I've ever had worked the same way. Driving your car without letting it warm up a bit is a bad thing anyways, be patient. If you can't give it the minute to warm up, go buy a remote car starter.
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  #29  
Old 08-18-2002, 06:52 PM
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Quote:
Originally posted by DavieGravy
I've done regular tune-ups on my car. Plugs have about 20k, new air filter, and throttle body is clean. This has not solved the problem. And I never have problems with rough idle either.

Looks like whe need to have two boards. One for the newbies and somewhat newbies and the other for senior members. I'm sure there's some of you out there that could answer this question, but prefer to watch us make idiots of ourselves while we contemplate what's going on.
Hey Dave don't be like that, I'm sure that if somebody knew what the cause of the problem was, they would say.

I have not had the problem so it is hard to troubleshoot it.
What Beav has put up seems to be valid and I would accept it as the probable cause.
The open loop time, is a problem, hence the electrically heated O2 sensors and quick heat catalytic converters now used on later cars to speed up the event.
Harvey.
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  #30  
Old 08-18-2002, 06:55 PM
DavieGravy DavieGravy is offline
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Quote:
Originally posted by oab_au


Hey Dave don't be like that, I'm sure that if somebody knew what the cause of the problem was, they would say.

I have not had the problem so it is hard to troubleshoot it.
What Beav has put up seems to be valid and I would accept it as the probable cause.
The open loop time, is a problem, hence the electrically heated O2 sensors and quick heat catalytic converters now used on later cars to speed up the event.
Harvey.
I apologize.
Thanks.
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