Delayed throttle resp. causing multiple lurches
07-29-2009, 08:47 AM
#1
Thread Starter
Delayed throttle resp. causing multiple lurches
I've heard of others having similar problems before, but allow me to describe my symptoms.
VTEC:
When going WOT into VTEC, starting at the crossover, the car jerks and hesitates all the way to the 9k RPM redline. It's like the A/C drain, except it's worse and the bog isn't constant like when the A/C is on, but jerks not just once, but a few times along the way. It doesn't do this every time I pass the VTEC the car, but enough times that it's starting to irritate me.
NOT IN VTEC:
The car exhibits similar behavior below VTEC as well. When starting from a standstill, not in WOT, it almost feels like a stick shift novice is trying to take off from a stop from the multiple lurches/jerks lol. Also, when I'm cruising on the highway and not in WOT, I'm tapping the gas in 6th, the response is delayed by a second, then it finally "catches" and lurches from the "stored energy" if you know what I'm trying to say. The response is not only delayed, but it seems like the energy that would have been used to accelerate the car had there not been a delay, seems to come all at once. Again, this doesn't happen always, but enough times to bother me.
I do have nearly 130k miles, but I doubt it is general wear inside the engine as I assume the weakness in power would be constant if that were the case, and wouldn't cause jerks. The engine doesn't seem to have any other problems and there are no strange noises to speak of. Spark plugs can be ruled out as I just had them replaced with the new OEM ones. The car has been maintained with religious fervor and is still bone stock, powertrain-wise. What do you think is the problem? Does it sound like a moderately cheap fix or a multi-thousand dollar problem?
Thank you.
VTEC:
When going WOT into VTEC, starting at the crossover, the car jerks and hesitates all the way to the 9k RPM redline. It's like the A/C drain, except it's worse and the bog isn't constant like when the A/C is on, but jerks not just once, but a few times along the way. It doesn't do this every time I pass the VTEC the car, but enough times that it's starting to irritate me.
NOT IN VTEC:
The car exhibits similar behavior below VTEC as well. When starting from a standstill, not in WOT, it almost feels like a stick shift novice is trying to take off from a stop from the multiple lurches/jerks lol. Also, when I'm cruising on the highway and not in WOT, I'm tapping the gas in 6th, the response is delayed by a second, then it finally "catches" and lurches from the "stored energy" if you know what I'm trying to say. The response is not only delayed, but it seems like the energy that would have been used to accelerate the car had there not been a delay, seems to come all at once. Again, this doesn't happen always, but enough times to bother me.
I do have nearly 130k miles, but I doubt it is general wear inside the engine as I assume the weakness in power would be constant if that were the case, and wouldn't cause jerks. The engine doesn't seem to have any other problems and there are no strange noises to speak of. Spark plugs can be ruled out as I just had them replaced with the new OEM ones. The car has been maintained with religious fervor and is still bone stock, powertrain-wise. What do you think is the problem? Does it sound like a moderately cheap fix or a multi-thousand dollar problem?
Thank you.
07-29-2009, 10:41 AM
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I run a tad bit richer than a stock S2k (I'm boosted), and get lurching on partial throttle every 1500-2000 miles. I'm at 114k now, and I remove and clean the throttle body every oil change. Make sure to get an old toothbrush out to really get deep into the nooks and crannies around the flange.
I pop off the IACV every other oil change and clean it as well. This keeps my idle in check, and I can never, ever, pinpoint either as a possible source of a weird idle/dying problem.
If you're on the stock injectors, it's possible to send them in and have them cleaned and flow tested for $70. Injectors do foul up over time, and its possible a very small piece of build up could be robbing one or more cylinder(s) of fuel and could damage if left in that state. It is a $70 very well spent. I sent in my very slightly used 675cc injectors when I bought them to ensure they were 100% ready to go in this engine.
Also, grab a set of low mileage ignition plugs if you haven't already. They are a wear item, albeit slow to wear, and swapping them returned a few stolen HP, smoothed out my power band, and definitely increased throttle response. I picked up a set with 15k on them for $75 from someone on this forum. Practically a steal, IMO.
Last, but also very important, try to borrow a vacuum/boost gauge from a friend/fellow S2k owner and make sure your vacuum system has no leaks. You will not always be able to hear/see a leak, especially on a noisy motor like ours. One small leak can cause much hell on an otherwise well running car.
Hope this helps, and I hope you can get everything working well. If you were closer to me, or plan on being near Chicago one day, I'd offer to do everything for you! If it's worth your roadtrip down, I could put you up on my couch for a night or two while I look over your car
I pop off the IACV every other oil change and clean it as well. This keeps my idle in check, and I can never, ever, pinpoint either as a possible source of a weird idle/dying problem.
If you're on the stock injectors, it's possible to send them in and have them cleaned and flow tested for $70. Injectors do foul up over time, and its possible a very small piece of build up could be robbing one or more cylinder(s) of fuel and could damage if left in that state. It is a $70 very well spent. I sent in my very slightly used 675cc injectors when I bought them to ensure they were 100% ready to go in this engine.
Also, grab a set of low mileage ignition plugs if you haven't already. They are a wear item, albeit slow to wear, and swapping them returned a few stolen HP, smoothed out my power band, and definitely increased throttle response. I picked up a set with 15k on them for $75 from someone on this forum. Practically a steal, IMO.
Last, but also very important, try to borrow a vacuum/boost gauge from a friend/fellow S2k owner and make sure your vacuum system has no leaks. You will not always be able to hear/see a leak, especially on a noisy motor like ours. One small leak can cause much hell on an otherwise well running car.
Hope this helps, and I hope you can get everything working well. If you were closer to me, or plan on being near Chicago one day, I'd offer to do everything for you! If it's worth your roadtrip down, I could put you up on my couch for a night or two while I look over your car
07-29-2009, 10:52 AM
#5
Thread Starter
Originally Posted by JP Money,Jul 29 2009, 01:42 PM
Sounds like clogged injectors imho. Is the idle rough?
07-29-2009, 10:55 AM
#7
Thread Starter
Originally Posted by Ness2000,Jul 29 2009, 02:41 PM
I run a tad bit richer than a stock S2k (I'm boosted), and get lurching on partial throttle every 1500-2000 miles. I'm at 114k now, and I remove and clean the throttle body every oil change. Make sure to get an old toothbrush out to really get deep into the nooks and crannies around the flange.
I pop off the IACV every other oil change and clean it as well. This keeps my idle in check, and I can never, ever, pinpoint either as a possible source of a weird idle/dying problem.
If you're on the stock injectors, it's possible to send them in and have them cleaned and flow tested for $70. Injectors do foul up over time, and its possible a very small piece of build up could be robbing one or more cylinder(s) of fuel and could damage if left in that state. It is a $70 very well spent. I sent in my very slightly used 675cc injectors when I bought them to ensure they were 100% ready to go in this engine.
Also, grab a set of low mileage ignition plugs if you haven't already. They are a wear item, albeit slow to wear, and swapping them returned a few stolen HP, smoothed out my power band, and definitely increased throttle response. I picked up a set with 15k on them for $75 from someone on this forum. Practically a steal, IMO.
Last, but also very important, try to borrow a vacuum/boost gauge from a friend/fellow S2k owner and make sure your vacuum system has no leaks. You will not always be able to hear/see a leak, especially on a noisy motor like ours. One small leak can cause much hell on an otherwise well running car.
Hope this helps, and I hope you can get everything working well. If you were closer to me, or plan on being near Chicago one day, I'd offer to do everything for you! If it's worth your roadtrip down, I could put you up on my couch for a night or two while I look over your car
I pop off the IACV every other oil change and clean it as well. This keeps my idle in check, and I can never, ever, pinpoint either as a possible source of a weird idle/dying problem.
If you're on the stock injectors, it's possible to send them in and have them cleaned and flow tested for $70. Injectors do foul up over time, and its possible a very small piece of build up could be robbing one or more cylinder(s) of fuel and could damage if left in that state. It is a $70 very well spent. I sent in my very slightly used 675cc injectors when I bought them to ensure they were 100% ready to go in this engine.
Also, grab a set of low mileage ignition plugs if you haven't already. They are a wear item, albeit slow to wear, and swapping them returned a few stolen HP, smoothed out my power band, and definitely increased throttle response. I picked up a set with 15k on them for $75 from someone on this forum. Practically a steal, IMO.
Last, but also very important, try to borrow a vacuum/boost gauge from a friend/fellow S2k owner and make sure your vacuum system has no leaks. You will not always be able to hear/see a leak, especially on a noisy motor like ours. One small leak can cause much hell on an otherwise well running car.
Hope this helps, and I hope you can get everything working well. If you were closer to me, or plan on being near Chicago one day, I'd offer to do everything for you! If it's worth your roadtrip down, I could put you up on my couch for a night or two while I look over your car
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07-29-2009, 02:44 PM
#8
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You can do the "MAP whack" along with cleaning the electrical connector surfaces, or swap with someone who has a known good one to rule it out. Make sure to reset your ECU after the whack.
