I am absolutely stumped
Thread Starter
Melting Slicks
Joined: Aug 2007
Posts: 2,583
Likes: 415
From: Erwin, NC
I am absolutely stumped
so, i've been having ENDLESS problems with this car, but there is one that i can not figure out!
its a 99 FRC with just over 41k miles on it.
The car WILL NOT accelerate past 120.
1st-3rd gear it feels great. it blows the tires off in the 1-2 shift and it chirps 3rd pretty hard.
my cats were clogged, so i assumed that was it. put an ORX pipe on it yesterday, still nothing past 120.
it does not throw any codes.
car has a new fuel filter, so i know that isn't the problem.
what would cause me to have an issue at those speeds but still let the car act perfectly normal accelerating 1st-3rd?
only thing i can think of is to throw it on a dyno and put a load on it to see whats going on.
i'll get a speedometer video for you guys later so you can see exactly what it is doing
its a 99 FRC with just over 41k miles on it.
The car WILL NOT accelerate past 120.
1st-3rd gear it feels great. it blows the tires off in the 1-2 shift and it chirps 3rd pretty hard.
my cats were clogged, so i assumed that was it. put an ORX pipe on it yesterday, still nothing past 120.
it does not throw any codes.
car has a new fuel filter, so i know that isn't the problem.
what would cause me to have an issue at those speeds but still let the car act perfectly normal accelerating 1st-3rd?
only thing i can think of is to throw it on a dyno and put a load on it to see whats going on.
i'll get a speedometer video for you guys later so you can see exactly what it is doing
Thread Starter
Melting Slicks
Joined: Aug 2007
Posts: 2,583
Likes: 415
From: Erwin, NC
i wish i had time for that. i leave for the army on tuesday and i won't be able to get scheduled in that soon. Speed Inc is right down the street
Burning Brakes
Joined: Apr 2007
Posts: 966
Likes: 9
From: Phoenix AZ
Transmission problem? I thought I read somewhere of a forum member having a similar issue in his A4-equipped car...I'll see if I can find it.
EDIT: wait...it's an FRC, so it's a six speed, right?
EDIT: wait...it's an FRC, so it's a six speed, right?
Last edited by RoccoC5; Apr 24, 2008 at 11:36 PM.
Racer
Joined: Feb 2005
Posts: 288
Likes: 2
From: Winnipeg, MB, Canada
bring it up to the cutout at a variety of rates and see if you can collect any information. this may give you information as to what is dropping off. for example, during hard acceleration to its "maximum", does it harshly cutoff like a rev limiter or does it gradually lower in acceleration. harsh cutoff is indicative of electrical/PCM and gradual points to fuel/air/exhaust flow restriction... just a thought... good luck.
edit, don't rule out mechanical. listen for noises- might be collapsed lifters or floating valves... just a thought.
have you checked your air cleaner? or spark plugs for any hints?
edit, don't rule out mechanical. listen for noises- might be collapsed lifters or floating valves... just a thought.
have you checked your air cleaner? or spark plugs for any hints?
Last edited by Bloodvette; Apr 25, 2008 at 12:22 AM.
Le Mans Master
Joined: Feb 2006
Posts: 5,267
Likes: 40
From: Phoenix AZ
This will sound funny, but I once had a superbike I bought used that would not rev out in the taller gears. Checked EVERTYTHING, then said oh well so much for racing this weekend.....might as well change the oil. It holds 3 quarts and had 6 in it!!!!!!!!!!!!!!!!!!!!!!!!!
After that it ran like a raped ape.
After that it ran like a raped ape.
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Le Mans Master
Joined: Aug 2005
Posts: 5,375
Likes: 328
From: CA.
St. Jude Donor '13-'14-'15
Is it an automatic or a 6 speed ?? If it is a 6 speed and you are trying to run WOT in 6th gear--it probably won't pull it in 6th over 120and you are just running out of power--Try it in 5th at WOT--
Could also be a slipping clutch--
If it is an automatic--I would check the trans fluid--could be low on oil-
It really needs to have some data logging otherwise as it could be so many things--Check injector duty cycles---fuel pressure--Actual timing at WOT--Also could be bad fuel--try another station--If you are continually getting spark knock--it will eventually drop into the "low octane table" making it a total dog under a big load---(flat out @ WOT)
Could also be a slipping clutch--
If it is an automatic--I would check the trans fluid--could be low on oil-
It really needs to have some data logging otherwise as it could be so many things--Check injector duty cycles---fuel pressure--Actual timing at WOT--Also could be bad fuel--try another station--If you are continually getting spark knock--it will eventually drop into the "low octane table" making it a total dog under a big load---(flat out @ WOT)
Safety Car
Joined: Aug 2000
Posts: 4,933
Likes: 30
From: San Rafael CA
The engine will run to redline in lower gears (1, 2, or 3) ?????
Have you tried both 4th and 5th gear .....get to 120 in 4th ..... if you can't go faster .... try 5th .... is 120 MPH still the limit ??? If the answer is yes ..... then the PCM is limiting your speed.
The PCM does have some parameters that can limit the cars speed, it sounds like someone either intentionally or accidentally set a parameter to limit you to 120 .... IIRC it is possible that the limit may only affect 4th gear .... you can set the max speed by gear.
Have you tried both 4th and 5th gear .....get to 120 in 4th ..... if you can't go faster .... try 5th .... is 120 MPH still the limit ??? If the answer is yes ..... then the PCM is limiting your speed.
The PCM does have some parameters that can limit the cars speed, it sounds like someone either intentionally or accidentally set a parameter to limit you to 120 .... IIRC it is possible that the limit may only affect 4th gear .... you can set the max speed by gear.
Last edited by BlackZ06; Apr 25, 2008 at 06:20 PM.
Team Owner
Joined: May 2001
Posts: 36,836
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From: Dear Karma, I have a list of people you missed.
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15-'16
That seems to be an obvious point being missed by several people posting up here. A tuner can get it on a dyno and make a few passes while data-logging to see what's going on in real time.
Le Mans Master
Joined: Nov 2005
Posts: 5,451
Likes: 2
From: East Peoria Illinois
maybe somebody tuned it to stay like that. if all the other gears run up to 6500 RPM or so, theres no reason 4th shouldnt. Id get it to a tuner, somebody has some funky stuff in there i bet
Race Director
Joined: Apr 2001
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From: Saint Augustine, FL
Mid-TN Events Coordinator
St. Jude Donor '03-'04-'05-'06-'07-'08-'09-'10-'11-'12-'13-'14-'15-'16
Drifting
Joined: Oct 2006
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From: Heath Texas
St. Jude Donor '12-'13-'14-'15-'16-'17
Drifting
Joined: Dec 2005
Posts: 1,720
Likes: 3
From: East Hampton CT
Besides the obvious "rev" or "speed" limit by the PCM, one other factor might be kicking in here....Cat protection mode. If I recall, the pcm will go WAY rich if it thinks your cats are overheating. This will dump MASSIVE amounts of fuel in as well as cutting spark in an attempt to get exhaust (cat)temps down. A tuner would see this with a wideband on a dyno (as well as black smoke at WOT) . This could be putting a "speed" limit on long high speed pulls.....which I'm sure you're doing at a local track, RIGHT? 
Race Director
Joined: Mar 2007
Posts: 18,308
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From: Marlton. Increasing performance one speeding ticket at a time! NJ
Are you sure it doesn't have 4.56 gears.........
Very high gearing could affect your top speed, but I also doubt that it would stop a 5k, should go all the way to redline.
Let us know and thanks for your service
Very high gearing could affect your top speed, but I also doubt that it would stop a 5k, should go all the way to redline.
Let us know and thanks for your service