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今天准备先检查一下throttle旁边的情况，发现问题出在air intake hose, it's broken. $15 part.

Altair 写了： 2024年 5月 6日 13:02 今天准备先检查一下throttle旁边的情况，发现问题出在air intake hose, it's broken. $15 part.

WHF.

让我们大家抓狂许久，就这？

话说Intake hose破损不是应该给你个
Fuel trim

Lean code?

你们先别急，等我换好parts，再来汇报。不过基本上所有症状都对上了。裂缝很隐蔽，拆除intake hose才看到。多谢各位大佬的鼎力相助。

wolf_north_1234 写了： 2024年 5月 6日 19:49 WHF.

让我们大家抓狂许久，就这？

话说Intake hose破损不是应该给你个
Fuel trim

Lean code?

timing chain对不上我感觉主要疑点是只有车热起来停下来加速有问题。还有那个MAP信号跌落，好像一下没有气了。现在看来应该是引擎intake stroke的时候的问题, 车速度下来之后踩油门throttle打开了裂缝造成了真空丢失。idle 或者恒速throttle 打开很小所以真空问题不大。你们看看我这个分析有没有哪里不靠谱。

我做的比较傻的是vacuum leak test, 最后烟从air filter housing冒得到处都是已经看不到从这个裂缝出来的烟，看来这个smoke test 人必须一直盯着看烟先从哪里冒出来。明明这个测试理论上就可以找到这个裂缝。

qiuewex 写了： 2024年 5月 6日 19:51 你真是弃婴？

Altair 写了： 2024年 5月 6日 21:55 你们先别急，等我换好parts，再来汇报。不过基本上所有症状都对上了。裂缝很隐蔽，拆除intake hose才看到。多谢各位大佬的鼎力相助。

这个应该不是主要原因。
我一个旧车intake hose 也裂了，更换之前没任何症状。

Altair 写了： 2024年 5月 6日 22:02 timing chain对不上我感觉主要疑点是只有车热起来停下来加速有问题。还有那个MAP信号跌落，好像一下没有气了。现在看来应该是引擎intake stroke的时候的问题, 车速度下来之后踩油门throttle打开了裂缝造成了真空丢失。idle 或者恒速throttle 打开很小所以真空问题不大。你们看看我这个分析有没有哪里不靠谱。

我做的比较傻的是vacuum leak test, 最后烟从air filter housing冒得到处都是已经看不到从这个裂缝出来的烟，看来这个smoke test 人必须一直盯着看烟先从哪里冒出来。明明这个测试理论上就可以找到这个裂缝。

Most likely the intake leak has nothing to do with the hesitation. You have extra air coming in after the air filter. It would have set a code if you have a MAF. Since you do not have a MAF, the engine can not monitor unmetered air. Your engine will run dirtier. However, I do not think you will have a big problem with power due to an intake leak.

seymour 写了： 2024年 5月 6日 23:57 Most likely the intake leak has nothing to do with the hesitation. You have extra air coming in after the air filter. It would have set a code if you have a MAF. Since you do not have a MAF, the engine can not monitor unmetered air. Your engine will run dirtier. However, I do not think you will have a big problem with power due to an intake leak.

Exactly same opinion here. ( Intake plumbing wise ) MAP engine really doesn't care what's before TB. As long as no vacuum leak after TB( much noticeable idle hunting ). Infact many us 4AG guys whether ITBS or single TB, we love running the engine without air filter and intake plumbing. Yeah it's a lil dirty but the engine is much more powerful and responsive, noticeable immediately.

And I even run turbo engines with everything before TB detached( due to some mistakes FMIC stagnant water hydrolock, have to run as NA temporarily ), the car's cool happy with it. Yeah without turbo no boost, but otherwise healthy and no misfire etc.

Even diaphragm diff vacuum/BAP to intake plumbing usually OK with exposing to atmosphere, nothing changed, still same BAP, only less flow and slight hotter

Repair is done, pcm/ecm reset, hesitation is still there but much less severe. Here is a picture of recorded misfires after driving for 10 miles. Is 0101 the 3rd and 1st cylinder? What does that mean?

类似map 信号跌落还有，但是不像以前严重。如果加速踩的猛，会有misfire, engine stalling。

Altair 写了： 2024年 5月 8日 14:03 类似map 信号跌落还有，但是不像以前严重。如果加速踩的猛，会有misfire, engine stalling。

｛｝


早给你说了，timing chain拉长，导致intake valve(发动机前面那个)关闭延迟，
发动机进入压缩冲程的时候，intake还没关闭，这样当然会影响map读数

你把valve cover拆了，看看timing mark不就完了，看你啰啰嗦嗦折腾个没完，
浪费多少时间了

下一步检查Timing chain

弃婴千枝 写了： 2024年 5月 8日 14:38 ｛｝


早给你说了，timing chain拉长，导致intake valve(发动机前面那个)关闭延迟，
发动机进入压缩冲程的时候，intake还没关闭，这样当然会影响map读数

你把valve cover拆了，看看timing mark不就完了，看你啰啰嗦嗦折腾个没完，
浪费多少时间了

Altair 写了： 2024年 5月 8日 14:03 类似map 信号跌落还有，但是不像以前严重。如果加速踩的猛，会有misfire, engine stalling。

A few observations.
1. I will have to assume the TPS correctly reflects your gas pedal position, which is gradually increasing with a major press toward the end. I won't be able to tell if WOT goes all the way up as the graph scale is scanner dependent.
2. MAP measures the absolute pressure. Thus, I will have to assume you are at the sea level. A MAP of 100 kPa means zero pressure relative to air. If you are at Colorado, it makes a big difference.
3. The MAP should increase as RPM increases. A dip is possible when VTEC goes from one profile to the other. However, a VTEC profile change at 2500 looks too early. Do you know if you have VTEC or iVTEC? For VTEC, profile changes at 2500 is implausible. For iVTEC, I do not really know.
4. The dip in MAP you see looks different from the dip when VTEC changes, also the RPM should not drop if VTEC changes profile. So it definitely indicates a problem.
5. I somehow felt at higher RPM the vacuum is too high, you really should be approaching 100 kPa as engine speed increases to 3000 RPM. Valve train is indeed a possible reason for MAP reading to be unreasonable. When did you last do valve clearance adjustment? If you were to pop the cover to inspect timing, it is a good time to check valve clearance. It is fairly easy and straightforward to pop the cover on a small i4. Honda is one of very few major car manufacturer that still uses solid lifters until maybe 5 years ago. Per Honda manual, the valve clearance adjustment is needed once every 110k miles. You can have burnt valves if those go out of spec and not noticed in time.

seymour 写了： 2024年 5月 8日 18:56 5. I somehow felt at higher RPM the vacuum is too high, you really should be approaching 100 kPa as engine speed increases to 3000 RPM. Valve train is

I have to say this higher than expected vacuum when accelerating is bothering me. The MAP is pretty much a pressure sensor mounted at the TB.
If you turn on the car without starting the engine, it should read ambient pressure, which is about 100 kPa. If you idle the car, the intake valves are sucking in air, the TB is pretty much closed, you should see a fairly good vacuum. When you accelerate, the intake is sucking in more air, however, because your TB is pretty much fully open, you should see the pressure approach 100kPa. (Obviously this depends on where exactly this sensor is mounted.) If you suddenly let go the gas pedal, the TB closes, the engine RPM is still high, you should see a huge vacuum. This thing can go all the way to 20 kPa. (That is engine braking on a passenger car as there is usually nothing on the exhaust side to restrict the airflow. )

If you have a valve train malfunction, the intake valve is not fully open when it is supposed to, you should have a loss of vacuum. Thus the MAP reading will be higher not lower. I actually can not image a case where a valve train malfunction will give you a better vacuum. Note that a better vacuum means the engine has more suction power to breath in the air, which is a good thing.

I do not have much experience on the K24. (Although I did play with one once for some valve work.) Without a known good MAP graph, I won't know how much vacuum is normal when it accelerating since this depends on where the sensor is measuring. However, a high vacuum could actually mean the TB is not open enough, which should not really happen as you are trying to accelerate. Could this be a simple blocked engine air filter?

谢谢更新。。。看来老车一堆毛病要一个一个解决。。。版上看到千奇百怪的毛病，进入大家数据库后，下次看到类似的毛病就能马上联想到。这才是本版的好处。。。记得上次有位车子开动起来有奇怪的鸣响，原来是一片纸掉到进气道了。。。

Altair 写了： 2024年 5月 8日 14:03 类似map 信号跌落还有，但是不像以前严重。如果加速踩的猛，会有misfire, engine stalling。

卧槽，你这个情况极度非常严重。原来你一直都没松油门就rpm/mgp下掉（我问你log TPS参考，还以为下掉的时候你已经松了油门呢，只是想看看松油门和下掉有没有offset，一般正常发动机是严格同时的。但是没有想到你居然其实没松油门，而且还在加大踩的力度！！！暂时别开了，小心发动机开得打气门报废）

立即停用别再开了，别再瞎鼓捣ECU了 故障跟ECU又没关系，您不做机械诊断光瞪眼看ECU是诊断不了的。伤机的损失期望可是比瞎胡乱修修好的期望大得多。听人的先看机械情况，至少timing mark先肉眼看看啊又不费事儿，不要老玩没用的obd了。还有基本三件套的另外两个comp test，ign base timing（外加TPS可以先calib一下，应该没意义就是方便诊断。看这AFR多完美，严重异常掉rpm还保持AFR on target几乎跟闭循环似的。比如我一开始觉得EFI比如TB的嫌疑，这样基本消除。。。）

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Edit: as a yota guy I dunno honda vtec logic, also that depends on your exact engine head type, but it could set to activting when somewhere 2000-6000rpm range, could also be a culprit you really should check timing thingymajiks asap

compression (170, 160, 170, 170) 和timing chain均无问题。timing chain is very tout, no slack and perfect alignment.

Altair 写了： 2024年 5月 13日 20:05 compression (170, 160, 170, 170) 和timing chain均无问题。timing chain is very tout, no slack and perfect alignment.

I believe the book method is to check timing chain tensioner. If the tensioner travel is less than 13.5 mm, the chain is fine. Your timing looks good.
As I said, it not really conceivable that a timing issue will lead to the MAP reading too low. Did you check for intake restriction? Clogged air filter, foreign objects in intake. A loose bolt where the throttle cable goes into throttle body is not completely impossible. Other issues with the TB is a possibility. Also, you can take the intake hose from the TB and take your car for a spin. If the engine power is good, MAP reading is higher at open throttle, you have an intake restriction. Otherwise, something is physically wrong with the TB. Be careful when running the car without intake hose, anything fly in TB, your engine is ruined. Clean the area carefully and maybe make a make-shift wire screen for some protection. Maybe ziptie a large clean drain filter to the TB.

再说一遍，排气管非常可能堵了，一般在催化器那里

本田把自家车的发动机都改成turbo小排量算不算自毁长城？

wugrav 写了： 2024年 5月 15日 15:35 本田把自家车的发动机都改成turbo小排量算不算自毁长城？

涡轮增压发动机也可以做得很可靠，但是本田技术有限公司技术有限