Bog And Hesitation Time .....
07-11-2004, 08:50 AM
#1
Former Moderator
Thread Starter
Bog And Hesitation Time .....
Interestingly enough... I replaced my MAP sensor a while back when I was having the hesitation problem where the car feels like it starves for a second for fuel and loses power then it just kicks back in. The problem could be powered through with more gas or just cluctched and re-engage then hit the gas again mostly. I replaced my MAP with one my friend had lying around from a 99-00 Si that was the same part # as the S2k one. My problem disappeared instantly .....until now.
It seems the ugly demon has pulled his head up again because last night I felt the problem again.
I am replacing my spark plugs next weekend. They have 30k on the ones that are in the car now (platinum) Car has 73k miles on it. Getting another MAP sensor and seeing if that fixes it is another option to do again. I just wonder if its something more to it than that, but it fixed it last time with a quickness.....
any other ideas ie (dirty air filter, dirty injectors etc)
It seems the ugly demon has pulled his head up again because last night I felt the problem again.
I am replacing my spark plugs next weekend. They have 30k on the ones that are in the car now (platinum) Car has 73k miles on it. Getting another MAP sensor and seeing if that fixes it is another option to do again. I just wonder if its something more to it than that, but it fixed it last time with a quickness.....
any other ideas ie (dirty air filter, dirty injectors etc)
07-11-2004, 03:07 PM
#2
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Here are my thoughts on the bogging issue. There's many threads on this subject and my solution may not be the ultimate solution, but it does minimize on the occurances.
I live in Hawaii, humid and hot all year around... or just raining like hell. Bogging or what I call the "kangaroo'ing effect" happens only when the car is sufficently warmed up, but I could never discover any patterns to the problem.
There's a very well written thread about the MAP sensor and the infamous "whack it with the back of a screwdriver" trick. I didn't believe for one second that this alone was the problem since many have replaced it with a new unit and continued to have problems. If it was indeed just the MAP sensor, then Honda seriously has a problem with that part.
My current theory of the suspects are the following:
1. Heat
2. Nature of the gearing of the S2000.
3. MAP sensor
4. Ignition timing value when the car is hot (warmed up).
Regarding 1. Heat is definitely a problem since our ECU is designed to pull away timing (retard timing) to prevent engine damage, this could contribute to the problem since retarding ignition timing (in an extreme case) would cause dieseling (how some cars continue to run after you turn off the ignition). It could also cause the occasional stumbling of the idle, easily noticed in stop and go traffic. Having the ignition timing too far advanced could cause overheating and detonation so Honda designed the ECU to be conservative (a little too much, but a wise choice). Controlling heat can be done by...
Installing a lower temp t-stat with a lower temp fan switch (which must be done together). A higher pressure rad cap IMHO isn't as imporatant since the low-temp stat opens up earlier, you won't see as much pressure in the system... but hey, the rad cap is a cheap mod and it comes with a neat Mugen sticker. Another mod which can be used is a Hondata insulator intake gasket, which is a much more involved install but worth it if it can prevent the ECU from pulling away excess timing.
Regarding 2. Normally you can't do much of this without messing with your diff with gear reduction so I won't go into it here.
Regarding 3. You can either replace or tap it with the back of a padded screwdriver, which may help, but for me it did nothing.
Regarding 4. You can't do much about the OEM ECU (even with a VAFC) to affect anything regarding timing (except replacing it with an aftermarket ECU). In general, advancing the timing increases low-end power and some throughout the entire rpms. It also raises the idle a bit, may generate a little more heat (and therefore a little more power) and will put you at higher risk of detonation. Once the ECU senses too much heat or knock, it will start to retard timing (to protect the car) but this IMHO contributes to bogging when you need power the most. So, the idea is to run as much ignition advance safely before knocking/detonation occurs. Since engine knock is caused by heat (from poor gas, too much ignition, high intake air temps), we need to focus on what we can do to lower the temps so that the likeliness of engine knock is reduced and allow the ECU to maintain more ignition timing advance.
What I've done is installed all of the above (Hondata gasket, Mugen t-stat, Mugen f-swtich, Mugen rad-cap) on a stock ECU and I don't get bogging issues anymore, something that happened quite easily when I got off a long freeway drive, right into stop-n-go street traffic.
I hope this helps.
I live in Hawaii, humid and hot all year around... or just raining like hell. Bogging or what I call the "kangaroo'ing effect" happens only when the car is sufficently warmed up, but I could never discover any patterns to the problem.
There's a very well written thread about the MAP sensor and the infamous "whack it with the back of a screwdriver" trick. I didn't believe for one second that this alone was the problem since many have replaced it with a new unit and continued to have problems. If it was indeed just the MAP sensor, then Honda seriously has a problem with that part.
My current theory of the suspects are the following:
1. Heat
2. Nature of the gearing of the S2000.
3. MAP sensor
4. Ignition timing value when the car is hot (warmed up).
Regarding 1. Heat is definitely a problem since our ECU is designed to pull away timing (retard timing) to prevent engine damage, this could contribute to the problem since retarding ignition timing (in an extreme case) would cause dieseling (how some cars continue to run after you turn off the ignition). It could also cause the occasional stumbling of the idle, easily noticed in stop and go traffic. Having the ignition timing too far advanced could cause overheating and detonation so Honda designed the ECU to be conservative (a little too much, but a wise choice). Controlling heat can be done by...
Installing a lower temp t-stat with a lower temp fan switch (which must be done together). A higher pressure rad cap IMHO isn't as imporatant since the low-temp stat opens up earlier, you won't see as much pressure in the system... but hey, the rad cap is a cheap mod and it comes with a neat Mugen sticker. Another mod which can be used is a Hondata insulator intake gasket, which is a much more involved install but worth it if it can prevent the ECU from pulling away excess timing.
Regarding 2. Normally you can't do much of this without messing with your diff with gear reduction so I won't go into it here.
Regarding 3. You can either replace or tap it with the back of a padded screwdriver, which may help, but for me it did nothing.
Regarding 4. You can't do much about the OEM ECU (even with a VAFC) to affect anything regarding timing (except replacing it with an aftermarket ECU). In general, advancing the timing increases low-end power and some throughout the entire rpms. It also raises the idle a bit, may generate a little more heat (and therefore a little more power) and will put you at higher risk of detonation. Once the ECU senses too much heat or knock, it will start to retard timing (to protect the car) but this IMHO contributes to bogging when you need power the most. So, the idea is to run as much ignition advance safely before knocking/detonation occurs. Since engine knock is caused by heat (from poor gas, too much ignition, high intake air temps), we need to focus on what we can do to lower the temps so that the likeliness of engine knock is reduced and allow the ECU to maintain more ignition timing advance.
What I've done is installed all of the above (Hondata gasket, Mugen t-stat, Mugen f-swtich, Mugen rad-cap) on a stock ECU and I don't get bogging issues anymore, something that happened quite easily when I got off a long freeway drive, right into stop-n-go street traffic.
I hope this helps.
07-11-2004, 05:23 PM
#3
Former Moderator
I'm a little hesitant to blame the MAP sensor for your problem. Given the PCM's ability to retard timing with high intake air temps, as well as knock sensor input, I'd be more apt to believe it's no more than heat soak. It would be worth pulling the backup fuse to clear the PCM memory to see if the problem goes away.
07-11-2004, 09:57 PM
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Dark Sub Rosa, check this thread out https://www.s2ki.com/forums/index.php?showtopic=57405
There's a conspiracy I tell you!
Good luck, let me know if you find resolution to your problem.
There's a conspiracy I tell you!
Good luck, let me know if you find resolution to your problem.
07-12-2004, 12:36 AM
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I know some of you won't share the same experiences as I, but here's the patterns I've discovered on my own car.
1. Never bucks when the car is cold (below 3 bars), and I mean never.
2. Low end power/response is best when cold (below 3 bars).
3. Doesn't make a difference day or night... symptoms arise when the car is warmed up.
4. Easy to duplicate bucking after a good highway/freeway run then driving up a steep parking ramp at a slow pace.
5. MAP sensor whack never worked, neither did the new replacement unit.
6. Removing the OEM airbox lid and driving it around in traffic made things worse (bucks almost all the time). I don't suggest you do this if you live in a climate similar to mine.
I believe that the issue is caused not from 1 single cause, but the sum of a lot of factors contributing to the symptoms known as bucking/bogging/kangaroo'ing.
#1 and #2 would seem to indicate that temps are involved to whatever degree. On any car that has a central ECU/ECM to control the engine, it's common to have it monitor and adjust to temperature changes, to include knock control and such. As the engine warms up, the manifolds/coolant/IAT's start heating up. It's not hard to understand that the ECU backs off ignition timing when conditions get too hot, or it is preprogrammed to deal with and/or anticipate knocking conditions (even before knocking occurs). If you've ever played with a mechanical (vacuum advance) distributor, you'd know that turning the advance from zero to 6 advance, may raise the idle of an older car. It would also increase low end power, and as a result of more power is more heat, however if the engine is prone to detonation easily, that fortells bad things for your car. The fact that our engines lack a lot of bottom end torque, weighs a bit more than a Miata, has a much taller 1st gear, runs a higher compression motor, and is capable of revving to 9000 rpms, it's understandable that Honda intended to tune on the safe side of things, to keep things reliable. Can you imagine the consequences of detonation at 8000rpms in a high compression engine versus 6000rpms in a lower compression car?
Advancing the ignition timing to gain power is an old school trick, however the old school rodders know that anytime you increase power, you increase heat output, so at the same time, you need to focus your attention to making the cooling system more effective, so you can use more aggressive ignition settings safely. The trick is to run as much ignition timing while controlling the extra heat, without detonation. The ECU on our car is adaptive and like my old cars, don't have a static ignition timing value. I'll be willing to bet that if there was a way to trick the ECU by altering the values of the IAT, coolant temps, and make the knock sensor a little less sensitive, the bogging issues will be minimized considerably because the ECU would be led to believe that it's okay to provide a more aggressive setting which improves low end performance.
For example, try to imagine a B16A CRX, run 11:1 compression with similar gear ratios for 1st and 2nd gear, with the same pwr/trq/weight ratios as the S2000. Now equip the car with a mechanical distributor-type ignition (having a volume knob-like device in the cockpit for ignition control). Run as much ignition timing advance as the engine will allow. It'd have great throttle response and good power down low, perhaps the entire powerband. Now imagine simulating a condition caused by knock/ping and a brief spike in temps... turn the knob quickly to retard the ignition timing (say 10-12 degrees to prevent damage to the engine, just as an ECU would) just as you clutch out in 1st gear... you will bog.
Just sharing 1 experience out of.....
1. Never bucks when the car is cold (below 3 bars), and I mean never.
2. Low end power/response is best when cold (below 3 bars).
3. Doesn't make a difference day or night... symptoms arise when the car is warmed up.
4. Easy to duplicate bucking after a good highway/freeway run then driving up a steep parking ramp at a slow pace.
5. MAP sensor whack never worked, neither did the new replacement unit.
6. Removing the OEM airbox lid and driving it around in traffic made things worse (bucks almost all the time). I don't suggest you do this if you live in a climate similar to mine.
I believe that the issue is caused not from 1 single cause, but the sum of a lot of factors contributing to the symptoms known as bucking/bogging/kangaroo'ing.
#1 and #2 would seem to indicate that temps are involved to whatever degree. On any car that has a central ECU/ECM to control the engine, it's common to have it monitor and adjust to temperature changes, to include knock control and such. As the engine warms up, the manifolds/coolant/IAT's start heating up. It's not hard to understand that the ECU backs off ignition timing when conditions get too hot, or it is preprogrammed to deal with and/or anticipate knocking conditions (even before knocking occurs). If you've ever played with a mechanical (vacuum advance) distributor, you'd know that turning the advance from zero to 6 advance, may raise the idle of an older car. It would also increase low end power, and as a result of more power is more heat, however if the engine is prone to detonation easily, that fortells bad things for your car. The fact that our engines lack a lot of bottom end torque, weighs a bit more than a Miata, has a much taller 1st gear, runs a higher compression motor, and is capable of revving to 9000 rpms, it's understandable that Honda intended to tune on the safe side of things, to keep things reliable. Can you imagine the consequences of detonation at 8000rpms in a high compression engine versus 6000rpms in a lower compression car?
Advancing the ignition timing to gain power is an old school trick, however the old school rodders know that anytime you increase power, you increase heat output, so at the same time, you need to focus your attention to making the cooling system more effective, so you can use more aggressive ignition settings safely. The trick is to run as much ignition timing while controlling the extra heat, without detonation. The ECU on our car is adaptive and like my old cars, don't have a static ignition timing value. I'll be willing to bet that if there was a way to trick the ECU by altering the values of the IAT, coolant temps, and make the knock sensor a little less sensitive, the bogging issues will be minimized considerably because the ECU would be led to believe that it's okay to provide a more aggressive setting which improves low end performance.
For example, try to imagine a B16A CRX, run 11:1 compression with similar gear ratios for 1st and 2nd gear, with the same pwr/trq/weight ratios as the S2000. Now equip the car with a mechanical distributor-type ignition (having a volume knob-like device in the cockpit for ignition control). Run as much ignition timing advance as the engine will allow. It'd have great throttle response and good power down low, perhaps the entire powerband. Now imagine simulating a condition caused by knock/ping and a brief spike in temps... turn the knob quickly to retard the ignition timing (say 10-12 degrees to prevent damage to the engine, just as an ECU would) just as you clutch out in 1st gear... you will bog.
Just sharing 1 experience out of.....
07-12-2004, 06:19 AM
#7
Former Moderator
Thread Starter
Mine happens at any given moment.. I can't seem to find a pattern, mine even does it when the car isn't up to temp. Maybe its after the car has been sitting for a while and the engine bay just soaks up lots of heat during that time or something. I hate that this keeps happening to everyone including myself.
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