I am absolutely stumped
Thread Starter
Melting Slicks
Joined: Aug 2007
Posts: 2,583
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From: Erwin, NC
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? 
the cars revs all the way through 1st-3rd no problem.
the video is processing on youtube. i should have it up in a little bit.
Last edited by 99FRC Newb; Apr 25, 2008 at 08:26 PM.
Safety Car
Joined: Aug 2000
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From: San Rafael CA
i did have the column lock recall done sometime in october
That won't affect you .... the engine would shut off completely if, by some weird quirk, the column lock fuel shutoff was invoked at 120 instead of 2 MPH ..... that's not your problem.
ofcourse its at the track
i THINK the car has 3.73's. not completely sure.
Again ... not your problem ......
the cars revs all the way through 1st-3rd no problem.
the video is processing on youtube. i should have it up in a little bit.
That won't affect you .... the engine would shut off completely if, by some weird quirk, the column lock fuel shutoff was invoked at 120 instead of 2 MPH ..... that's not your problem.
ofcourse its at the track
i THINK the car has 3.73's. not completely sure.
Again ... not your problem ......
the cars revs all the way through 1st-3rd no problem.
the video is processing on youtube. i should have it up in a little bit.
I'll check the video as soon as it's up ... but it sure sounds like someone altered your MAX SPEED setting for 4th gear, as I said in the earlier post.
Thread Starter
Melting Slicks
Joined: Aug 2007
Posts: 2,583
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From: Erwin, NC
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.
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)
OK, that's important ... now if you can do it, as I asked in post #10 .... if you're in 4th and hit 120 and it won't go faster ... what happens if you select 5th ????
I'll check the video as soon as it's up ... but it sure sounds like someone altered your MAX SPEED setting for 4th gear, as I said in the earlier post.
I'll check the video as soon as it's up ... but it sure sounds like someone altered your MAX SPEED setting for 4th gear, as I said in the earlier post.
Thread Starter
Melting Slicks
Joined: Aug 2007
Posts: 2,583
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From: Erwin, NC
http://youtube.com/watch?v=gu48q2fW2Ns
and i was wrong earlier. at the end of the run, it throws 2 codes.
P0137 HO2S Circuit Low Voltage Bank 1 Sensor 2
P0157 HO2S Circuit Low Voltage Bank 2 Sensor 2
but they go away after a minute or so.
and keep in mind i no longer have cats.
*edit* because of the angle, it looks like i was at redline, but i wasn't. getting close, but not at 6k
and i was wrong earlier. at the end of the run, it throws 2 codes.
P0137 HO2S Circuit Low Voltage Bank 1 Sensor 2
P0157 HO2S Circuit Low Voltage Bank 2 Sensor 2
but they go away after a minute or so.
and keep in mind i no longer have cats.
*edit* because of the angle, it looks like i was at redline, but i wasn't. getting close, but not at 6k
Safety Car
Joined: Aug 2000
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From: San Rafael CA
Sure sounds like someone either intentionally or unintentionally has speed limited your car. I know that products like EFILive and HPTuners would allow you to quickly get in and see what is going on .... I don't think a dealer could help with a Tech2, other than to re-load a whole new set of software into the PCM.
Any idea if the car was taken to a "tuner" in the past ??
If you can redline 1,2, and 3 ...... and you can't redline 4th ... it has to be the PCM ..... the engine itself doesn't know or care about gear selected, but the PCM can calculate the selected gear (RPM and road speed) so it has to be the PCM ....
Any idea if the car was taken to a "tuner" in the past ??
If you can redline 1,2, and 3 ...... and you can't redline 4th ... it has to be the PCM ..... the engine itself doesn't know or care about gear selected, but the PCM can calculate the selected gear (RPM and road speed) so it has to be the PCM ....
Thread Starter
Melting Slicks
Joined: Aug 2007
Posts: 2,583
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From: Erwin, NC
Sure sounds like someone either intentionally or unintentionally has speed limited your car. I know that products like EFILive and HPTuners would allow you to quickly get in and see what is going on .... I don't think a dealer could help with a Tech2, other than to re-load a whole new set of software into the PCM.
Any idea if the car was taken to a "tuner" in the past ??
If you can redline 1,2, and 3 ...... and you can't redline 4th ... it has to be the PCM ..... the engine itself doesn't know or care about gear selected, but the PCM can calculate the selected gear (RPM and road speed) so it has to be the PCM ....
Any idea if the car was taken to a "tuner" in the past ??
If you can redline 1,2, and 3 ...... and you can't redline 4th ... it has to be the PCM ..... the engine itself doesn't know or care about gear selected, but the PCM can calculate the selected gear (RPM and road speed) so it has to be the PCM ....
when i first bought the car, it was fine. i got it almost to 170.
it had the trans overhauled in november, didn't really mess around much in the winter, but now it doesn't want to go past 120.
unless the place that did the trans tuned my PCM, it should have the stock tune
*edit* with no load on the wheels, it will redline 4th and 5th no problem
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Safety Car
Joined: Aug 2000
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From: San Rafael CA
when i first bought the car, it was fine. i got it almost to 170.
it had the trans overhauled in november, didn't really mess around much in the winter, but now it doesn't want to go past 120.
unless the place that did the trans tuned my PCM, it should have the stock tune
*edit* with no load on the wheels, it will redline 4th and 5th no problem
it had the trans overhauled in november, didn't really mess around much in the winter, but now it doesn't want to go past 120.
unless the place that did the trans tuned my PCM, it should have the stock tune
*edit* with no load on the wheels, it will redline 4th and 5th no problem
Dude,
Your profile says you are a "Benz Service Writer" .... how do you feel when a customer brings in a car, gives you ...
a) partial information .....
b) incorrect information .....
and expects you to figure out the problem ....
You said in your original post "it does not throw any codes." ... yet your CHECK ENGINE light is glowing brighter than the sun (and your seatbelt warning is ON also ... I'm gonna assume you havve other codes besides engine codes .... NOBODY would do a run to 120 without their belt on .... right ???) .... and now you throw out "and keep in mind i no longer have cats." .....
What else aren't you telling us ???
The P0137 and 0157 are most likely the issue ..... the PCM sees the Heated O2 sensors reporting a VERY lean condition and is running the engine very rich. You are way down on horsepower. You don't notice it in the lower gears, there is enough HP to get the car to redline .... but you don't have the HP to reach redline in 4th, 5th, or obviously 6th.
You need to fix the O2 sensors, you may have melted wiring on your exhaust and they are shorted, or they have been damaged and are not reporting the correct O2 content ....
Let us know if you want to fix it before you take off ....
Tech Contributor
Joined: Apr 2007
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From: Forney Texas
I'm going to have to go with door #2. I got a feeling like you have some left over restriction in your exhaust. A piece of cat material maybe??? Not enough restriction to keep it from running properly until you go WOT. Since it doesn't take too long, pull the exhaust and check it from end to end.
Tech Contributor
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From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Steve
Yep,,,,,,,,,,,,,you nailed that one down to the footer!!! As soon as I saw the U Tube video I saw the CEL and said the SAME THING! WTF???
There's a code in there some where!
CODES TELL ALL!
BC
Yep,,,,,,,,,,,,,you nailed that one down to the footer!!! As soon as I saw the U Tube video I saw the CEL and said the SAME THING! WTF???
There's a code in there some where!
CODES TELL ALL! BC
Tech Contributor
Joined: Dec 1999
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From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Safety Car
Joined: Aug 2000
Posts: 4,933
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From: San Rafael CA
I'm going to have to go with door #2. I got a feeling like you have some left over restriction in your exhaust. A piece of cat material maybe??? Not enough restriction to keep it from running properly until you go WOT. Since it doesn't take too long, pull the exhaust and check it from end to end.
I'm trying really hard to start the weekend as a "nice" guy .... but man you two are pushing my limits .....
Fouled plugs ????????? Mis-fire (code P0300) ....... and he'd have the problem in all gears ..... and he'd be complaining of a rough idle .... What (name just one) "symptom" led you to diagnose the problem as "fouled plugs" ???
Restricted exhaust ???? Again, please name (just one) symptom that led you to that conclusion ????
And if it helps, guys, his PCM has already given us the answer .... P0137 and P0157 .........
BOTH of his O2 sensors are DEAD or something is causing him to run incredibly lean. The PCM expects to see the O2 sensors reporting in a range of anywhere from 10 mV (Way Way LEAN) to 1,000 mV (super RICH) and to set the DTC the two O2 sensors have to be reporting consistently (for over 6 minutes) at less than 80 mV.
Until these codes are fixed (and I suspect there may be others) playing with other stuff in the engine is pointless. The PCM is unable to "manage" the engine properly .... as I said earlier .... he is way down on Horse Power with these codes.
Thread Starter
Melting Slicks
Joined: Aug 2007
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From: Erwin, NC
I'm trying really hard to start the weekend as a "nice" guy .... but man you two are pushing my limits .....
Fouled plugs ????????? Mis-fire (code P0300) ....... and he'd have the problem in all gears ..... and he'd be complaining of a rough idle .... What (name just one) "symptom" led you to diagnose the problem as "fouled plugs" ???
Restricted exhaust ???? Again, please name (just one) symptom that led you to that conclusion ????
And if it helps, guys, his PCM has already given us the answer .... P0137 and P0157 .........
BOTH of his O2 sensors are DEAD or something is causing him to run incredibly lean. The PCM expects to see the O2 sensors reporting in a range of anywhere from 10 mV (Way Way LEAN) to 1,000 mV (super RICH) and to set the DTC the two O2 sensors have to be reporting consistently (for over 6 minutes) at less than 80 mV.
Until these codes are fixed (and I suspect there may be others) playing with other stuff in the engine is pointless. The PCM is unable to "manage" the engine properly .... as I said earlier .... he is way down on Horse Power with these codes.
The check engine light is because i just installed an Off Road X Pipe. p0420 and p0430 are setting the check engine light. those have nothing to do with my problem. ignore the light
Thread Starter
Melting Slicks
Joined: Aug 2007
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From: Erwin, NC
Instructor
Joined: Mar 2008
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Sorry I'm not meeting up to your standards. I suggested fouled plugs as sometimes something simple is overlooked in these situations.... I'm not diagnosing anything but I thought the point of this forum is to get help and ideas from other forum members.
As for symptoms, I had a similar situation with a past vehicle where the top speed was limited well below normal. No rough idle, no rev problems in any other gears. After weeks of trying to figure out the problem, it turned out to be the plugs which were not even that old.
Thought sharing my nearly identical experience may help someone else.
As for symptoms, I had a similar situation with a past vehicle where the top speed was limited well below normal. No rough idle, no rev problems in any other gears. After weeks of trying to figure out the problem, it turned out to be the plugs which were not even that old.
Thought sharing my nearly identical experience may help someone else.
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Sorry I'm not meeting up to your standards. I suggested fouled plugs as sometimes something simple is overlooked in these situations.... I'm not diagnosing anything but I thought the point of this forum is to get help and ideas from other forum members.
As for symptoms, I had a similar situation with a past vehicle where the top speed was limited well below normal. No rough idle, no rev problems in any other gears. After weeks of trying to figure out the problem, it turned out to be the plugs which were not even that old.
Thought sharing my nearly identical experience may help someone else.
As for symptoms, I had a similar situation with a past vehicle where the top speed was limited well below normal. No rough idle, no rev problems in any other gears. After weeks of trying to figure out the problem, it turned out to be the plugs which were not even that old.
Thought sharing my nearly identical experience may help someone else.
His car is supercharged and in the upper RPMs under power would start misfiring and limiting power. Turned out to be that his plugs were gapped WAY too large and his spark would blow out. Simple regap of the plugs and PROBLEM SOLVED! So, sometimes its best to listen to all the recommendations and suggestions and run it through the check process.
I agree with BLACKZO6 in that is not plugs because it runs OK in the lower gear range but dies under really heavy loads.
Check those O2 sensors and get rid of those damn codes.
BC
Le Mans Master
Joined: Aug 2005
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From: CA.
St. Jude Donor '13-'14-'15
Bill--Hi----hey just a thought--Guessing that the problem happens while he's at WOT--Won't the 02 sensor codes have nothing to do with a WOT run ?? The car should be in PE mode and in "open loop drive" meaning that it's not running off the 02's in closed loop anyway ---It still may be lean in closed loop--that's whay he's getting the codes-AND it is probably lean in PE open loop as well if the problem is a general fueling issue that affects it in both closed and open loop modes-
I don't think you would get a lean 02 code on PE open loop mode----
What do you think ???----maybe it is NOT going into PE open loop--could be they got the O2 wires crossed from front to back ??
I don't think you would get a lean 02 code on PE open loop mode----
What do you think ???----maybe it is NOT going into PE open loop--could be they got the O2 wires crossed from front to back ??