What dictates when a revlimiter will engage?
10-26-2007, 03:56 AM
#1
Honda-Tech Member
Thread Starter
What dictates when a revlimiter will engage?
Some of you guys might remember my thread a while back (https://honda-tech.com/zerothread?id=2105929)...
Well, my VTEC engages at the proper RPM of 5.5K, but my CEL shift light hits at about 7.4K and the rev limiter hits at 7.5K (set to engage at 7.8K and 8.2K)
What dictates when the rev limiter should kick in? Obviously the ECU, but what else?
I haven't ruled out the idea of a bad gauge cluster because my gas gauge crapped out for some unknown reason, but I just took a shot at the new distributor and bought a new one, so I'll be short on money for a bit.
No CEL's or anything like that, the car pulls hard and idles great now with the new distributor, but the shift light/revlimiter problem still exists
Well, my VTEC engages at the proper RPM of 5.5K, but my CEL shift light hits at about 7.4K and the rev limiter hits at 7.5K (set to engage at 7.8K and 8.2K)
What dictates when the rev limiter should kick in? Obviously the ECU, but what else?
I haven't ruled out the idea of a bad gauge cluster because my gas gauge crapped out for some unknown reason, but I just took a shot at the new distributor and bought a new one, so I'll be short on money for a bit.
No CEL's or anything like that, the car pulls hard and idles great now with the new distributor, but the shift light/revlimiter problem still exists
10-26-2007, 07:49 AM
#2
Darth ModerVader
Re: What dictates when a revlimiter will engage? (JKov240)
I'm a bit confused about your problem. First, how are you setting the shift light and rev limiter? Hondata or something similar, I assume?
It's possible that your stock tach is simply inaccurate in the upper rev range (which is a known issue - many ITR's will show an indicated 9000+ RPM fuel cut), and that your setup is otherwise functioning correctly. Have you tried using an external tach?
It's possible that your stock tach is simply inaccurate in the upper rev range (which is a known issue - many ITR's will show an indicated 9000+ RPM fuel cut), and that your setup is otherwise functioning correctly. Have you tried using an external tach?
10-26-2007, 07:51 AM
#3
10-26-2007, 08:04 AM
#4
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Thread Starter
Re: What dictates when a revlimiter will engage? (Padawan)
Read the older thread and you'll see in detail what I'm talking about...but a quick overview.
I was at the track and I was accelerating and ~7K it seemed like my car didn't want to pull anymore (and made a god awful noise...almost like you pushed the clutch in and stayed on the gas at 7K). I figured it was a bad ECU because the wrecked car that I got the GS-R out of was half-assed beyond belief, so I got the P28 from phearable.
When the car WAS running right with the phearable P28, I would end 2nd gear at 80mph...now I end at 75mph.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Padawan »</TD></TR><TR><TD CLASS="quote">I'm a bit confused about your problem. First, how are you setting the shift light and rev limiter? Hondata or something similar, I assume?
It's possible that your stock tach is simply inaccurate in the upper rev range (which is a known issue - many ITR's will show an indicated 9000+ RPM fuel cut), and that your setup is otherwise functioning correctly. Have you tried using an external tach?
</TD></TR></TABLE>
I'm running a chipped P28 that was tuned by phearable.net for my set-up.
I've yet to get my hands on an external tach, but it's on my list now.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by B serious »</TD></TR><TR><TD CLASS="quote">The ECU is the only thing that controls rev limit under acceleration. </TD></TR></TABLE>
Is it possible that the ECU is sensing not enough spark/fuel and engaging everything early?
I'm trying to look at the issue from every possible angle...and there's alot of angles
I was at the track and I was accelerating and ~7K it seemed like my car didn't want to pull anymore (and made a god awful noise...almost like you pushed the clutch in and stayed on the gas at 7K). I figured it was a bad ECU because the wrecked car that I got the GS-R out of was half-assed beyond belief, so I got the P28 from phearable.
When the car WAS running right with the phearable P28, I would end 2nd gear at 80mph...now I end at 75mph.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Padawan »</TD></TR><TR><TD CLASS="quote">I'm a bit confused about your problem. First, how are you setting the shift light and rev limiter? Hondata or something similar, I assume?
It's possible that your stock tach is simply inaccurate in the upper rev range (which is a known issue - many ITR's will show an indicated 9000+ RPM fuel cut), and that your setup is otherwise functioning correctly. Have you tried using an external tach?
</TD></TR></TABLE>
I'm running a chipped P28 that was tuned by phearable.net for my set-up.
I've yet to get my hands on an external tach, but it's on my list now.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by B serious »</TD></TR><TR><TD CLASS="quote">The ECU is the only thing that controls rev limit under acceleration. </TD></TR></TABLE>
Is it possible that the ECU is sensing not enough spark/fuel and engaging everything early?
I'm trying to look at the issue from every possible angle...and there's alot of angles
10-26-2007, 08:16 AM
#5
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there are actually very few angles to look at it in.
either the tach signal is messed up, the ECU is messed up, or the chip is messed up.
my thought process...
Since you said that the VTEC point is still right then it's highly unlikely that the chip is messed up. (they tend to be either good or bad)
Since the car does not exibit any other problems it's unlikely that its the ECU.
the tach signal could be three things, coil, ignitor or wiring.
since your tach doesn't jump or surge the wiring shouldn't be the problem.
coil and ignitor (when starting to go bad) will cut out at higher RPMs.
pull open the distributor and check them out, a black mark on the side of the coil is a dead give away thats the issue, but it's not always present.
either the tach signal is messed up, the ECU is messed up, or the chip is messed up.
my thought process...
Since you said that the VTEC point is still right then it's highly unlikely that the chip is messed up. (they tend to be either good or bad)
Since the car does not exibit any other problems it's unlikely that its the ECU.
the tach signal could be three things, coil, ignitor or wiring.
since your tach doesn't jump or surge the wiring shouldn't be the problem.
coil and ignitor (when starting to go bad) will cut out at higher RPMs.
pull open the distributor and check them out, a black mark on the side of the coil is a dead give away thats the issue, but it's not always present.
10-26-2007, 08:27 AM
#6
Honda-Tech Member
Thread Starter
Re: (Relic1)
Brand new distributor installed yesterday...the problem's still occuring.
This morning i had to get down on it when getting on the highway and VTEC engaged at what appeared to be 5.3K-5.4K.
I'm going to get my hands on an external tach and go from there.
This morning i had to get down on it when getting on the highway and VTEC engaged at what appeared to be 5.3K-5.4K.
I'm going to get my hands on an external tach and go from there.
10-26-2007, 08:57 AM
#7
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Re: (JKov240)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JKov240 »</TD></TR><TR><TD CLASS="quote">Brand new distributor installed yesterday...the problem's still occuring.</TD></TR></TABLE>
brand new from where?
Through the process of working on other cars, I've pulled four in a row from Autozone that were bad right out of the box.
Same with Napa, but I only got through two before we stumbled on a good one.
Since then I started ordering from this guy... https://honda-tech.com/zerothread?id=1302312 ... not a single bad one in the four that I've purchased from them.
brand new from where?
Through the process of working on other cars, I've pulled four in a row from Autozone that were bad right out of the box.
Same with Napa, but I only got through two before we stumbled on a good one.
Since then I started ordering from this guy... https://honda-tech.com/zerothread?id=1302312 ... not a single bad one in the four that I've purchased from them.
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10-26-2007, 09:58 AM
#8
Re: What dictates when a revlimiter will engage? (JKov240)
Stock cut off on a p28 IS 7200-7300 so maybe he just never raised the redline limit in the ECU?
Correct me if I'm wrong also but I thought that the VSS signal was taken into account for redline as well? could be a conflict there... I might be wrong though, it's been a while since working on these cars.
Correct me if I'm wrong also but I thought that the VSS signal was taken into account for redline as well? could be a conflict there... I might be wrong though, it's been a while since working on these cars.
10-26-2007, 10:00 AM
#9
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Re: What dictates when a revlimiter will engage? (NonovUrbizniz)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by NonovUrbizniz »</TD></TR><TR><TD CLASS="quote">Stock cut off on a p28 IS 7200-7300 so maybe he just never raised the redline limit in the ECU?
Correct me if I'm wrong also but I thought that the VSS signal was taken into account for redline as well? could be a conflict there... I might be wrong though, it's been a while since working on these cars.</TD></TR></TABLE>
No the VSS does not have to be there for rev limit.
Correct me if I'm wrong also but I thought that the VSS signal was taken into account for redline as well? could be a conflict there... I might be wrong though, it's been a while since working on these cars.</TD></TR></TABLE>
No the VSS does not have to be there for rev limit.
10-26-2007, 10:19 AM
#10
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Re: (Relic1)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Relic1 »</TD></TR><TR><TD CLASS="quote">brand new from where?
Through the process of working on other cars, I've pulled four in a row from Autozone that were bad right out of the box.
Same with Napa, but I only got through two before we stumbled on a good one.
Since then I started ordering from this guy... https://honda-tech.com/zerothread?id=1302312 ... not a single bad one in the four that I've purchased from them.
</TD></TR></TABLE>
The shop I work at goes through a company called WorldPac...they sell OE quality parts made in Japan.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by NonovUrbizniz »</TD></TR><TR><TD CLASS="quote">Stock cut off on a p28 IS 7200-7300 so maybe he just never raised the redline limit in the ECU?
Correct me if I'm wrong also but I thought that the VSS signal was taken into account for redline as well? could be a conflict there... I might be wrong though, it's been a while since working on these cars.
</TD></TR></TABLE>
The rev limiter's been raised...it's hitting at 7.5K which is above stock.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by B serious »</TD></TR><TR><TD CLASS="quote">No the VSS does not have to be there for rev limit.
</TD></TR></TABLE>
It's been disabled if I'm not mistaken.
And the ECU's already been sent back once...phearable.net examined it, but didn't see a problem...but just to make sure they sent me a new ECU with a new chip.
Through the process of working on other cars, I've pulled four in a row from Autozone that were bad right out of the box.
Same with Napa, but I only got through two before we stumbled on a good one.
Since then I started ordering from this guy... https://honda-tech.com/zerothread?id=1302312 ... not a single bad one in the four that I've purchased from them.
</TD></TR></TABLE>
The shop I work at goes through a company called WorldPac...they sell OE quality parts made in Japan.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by NonovUrbizniz »</TD></TR><TR><TD CLASS="quote">Stock cut off on a p28 IS 7200-7300 so maybe he just never raised the redline limit in the ECU?
Correct me if I'm wrong also but I thought that the VSS signal was taken into account for redline as well? could be a conflict there... I might be wrong though, it's been a while since working on these cars.
</TD></TR></TABLE>
The rev limiter's been raised...it's hitting at 7.5K which is above stock.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by B serious »</TD></TR><TR><TD CLASS="quote">No the VSS does not have to be there for rev limit.
</TD></TR></TABLE>
It's been disabled if I'm not mistaken.
And the ECU's already been sent back once...phearable.net examined it, but didn't see a problem...but just to make sure they sent me a new ECU with a new chip.
10-26-2007, 10:21 AM
#11
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Re: What dictates when a revlimiter will engage? (B serious)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by B serious »</TD></TR><TR><TD CLASS="quote">
No the VSS does not have to be there for rev limit. </TD></TR></TABLE>
sort of... no VSS = no VTEC, no VTEC = no power at higher RPM.
technically the rev limiter will be at the same RPM, but it will crawl to it.
No the VSS does not have to be there for rev limit. </TD></TR></TABLE>
sort of... no VSS = no VTEC, no VTEC = no power at higher RPM.
technically the rev limiter will be at the same RPM, but it will crawl to it.
10-26-2007, 10:53 AM
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Re: What dictates when a revlimiter will engage? (JKov240)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JKov240 »</TD></TR><TR><TD CLASS="quote">So what items dictate the rev limiter?</TD></TR></TABLE>
First, the p28 will show around a 7500rpm rev limit. People say tachs are off. So im saying it will SHOW that amount.
The ECU gets its RPM signal from the distributor. The ECU limits FUEL at whatever MAX RPM the ECU is set at.
First, the p28 will show around a 7500rpm rev limit. People say tachs are off. So im saying it will SHOW that amount.
The ECU gets its RPM signal from the distributor. The ECU limits FUEL at whatever MAX RPM the ECU is set at.
10-26-2007, 02:54 PM
#14
Honda-Tech Member
Thread Starter
Re: What dictates when a revlimiter will engage? (B serious)
Before I dive into it too deep, I'm gonna get an external tach and check it in the higher RPM range to see if it's accurate and then go from there
10-30-2007, 07:06 AM
#15
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Thread Starter
Re: What dictates when a revlimiter will engage? (JKov240)
What inside the distributor sends that signal? I'm assuming some kind of sensor.
Anybody else have any issues like this?
Anybody else have any issues like this?
10-30-2007, 02:48 PM
#16
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Re: (Relic1)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Relic1 »</TD></TR><TR><TD CLASS="quote">the tach signal could be three things, coil, ignitor or wiring.
since your tach doesn't jump or surge the wiring shouldn't be the problem.
coil and ignitor (when starting to go bad) will cut out at higher RPMs.</TD></TR></TABLE>
Every now and then the idle on the car won't be too smooth, and I've also noticed before that when cruising on the highway at say 75mph it will read 3.5K...then another time I'll be at 75mph and it'll read 3.3K
since your tach doesn't jump or surge the wiring shouldn't be the problem.
coil and ignitor (when starting to go bad) will cut out at higher RPMs.</TD></TR></TABLE>
Every now and then the idle on the car won't be too smooth, and I've also noticed before that when cruising on the highway at say 75mph it will read 3.5K...then another time I'll be at 75mph and it'll read 3.3K
11-02-2007, 03:20 PM
#17
Honda-Tech Member
Thread Starter
Re: (JKov240)
PROBLEM FOUND!!!
Something's gone bad/wrong in the ecu I bought from phearable for some unknown reason (first time it's happened to them too). I swapped P28's with a friend of mine who has a GS-R swap (but with no forged internals), my car ran perfect with his ECU, but kept hitting the revlimiter early with my ecu.
Time to see if phearable will do anything about it though
Something's gone bad/wrong in the ecu I bought from phearable for some unknown reason (first time it's happened to them too). I swapped P28's with a friend of mine who has a GS-R swap (but with no forged internals), my car ran perfect with his ECU, but kept hitting the revlimiter early with my ecu.
Time to see if phearable will do anything about it though
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