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in my auto gear honda fit gp1 hybrid car, (mileage 56 000 KM)

I had a engine tune up and changed my injectors (8 injectors) last month and after 2 weeks i started getting a slight knock (jerk or shaking). i remember i have had this once or twice in the last 6 month but it wasnt noticeable and looked like to be as a miss. anyway, now everyday morning when i start the car and drive for like half and hour or hour, it goes smooth and nice. and then in a while it gives the knock. (the time is not fixed, some days in 45 minutes, and some days in 30 minutes and sometimes in 20 minutes after first starting to drive it comes)

The knock is like, when i stop at a traffic light and accelerate it comes. it only comes after a break or a stop and accelerate so it comes in low speed. then when driving with the knock, it gets a bit worst and knock (jerk or shaking) goes up, when i drive a little more it becomes more worse. then when i stop for few hours and start back then knock (jerk or shaking) is less and smoothness is bad. so i figured out this is something to do with a heat. when one of vehcile's part becomes very hot it gives the knock.

so i went to a small mechanic and as advised changed my Gear box oil (ATF). it didnt fix the issue.

then i took it to Honda company by when i got a check engine light and they told to run without the EGR valve, then i did it that and noticed that knock (jerk or shaking) is 50% less but car is not at all smooth. (it takes too much power and was hard) i felt so when driving. then they told to clean it the EGR and drive as the Honda company diagnosed EGR valve is causing trouble. after cleaning it didnt work, so as they told i changed the EGR valve which costed around 500$.

And then my vehicle was super smooth and very very comfortable to drive. later after few hours of driving here comes the same knock (jerk or shaking). which confused me. apart from that the honda company told this is not a problem with gear box, (which means they told its not a judgger)

Then i took it back to my local bass as he suspected it can also sometimes cause with fault fuel pump. then i changed that too. still the issue is not fixed.

Now after having a small internet research i found this is a bit common issue, but only issue is finding the exact issue is difficult. Now i am confused what to do,

Company told they will need to remove the transmission and see in the worst case. some times if its a damaged flyweel it can happen. so before taking it to any place to repair i just want to get an experts advise here.

Should check in to these things to ?

  • Spark Plug Wires or Spark Plug
  • Starter clutch
  • ignition coil | coil packs
  • motor mount
  • flywheel
  • Catalytic Converter

I really really appreciate any feedback that will help me to sort out this issue.

UPDATE: The company also told me that not all issues will have an error code that can be read through obd 2, electrical issues will be displayed but not mechanical as they told. is that correct?

UPDATE 2

Yesterday i had a fuel pump change as well, but still the issue is there, please can somebody advise as what to do ? really appreciate. can this be a gear box issue with a burnt flywheel ?

Yesterday i had a test drive

When the car was started it went super smooth, after a while like 15 mins. the shaking came back when i stopped at a traffic and accelerated when green lit. (please note the shaking comes only when accelerating from a stop (when going from zero - 10/20 kmh). its not shaking when i am holding the break or its not shaking when the vehicle is idle.

then at almost every stop light, when i accelerated it came. and when i took of the leg from gas pedal and pressed again, it went but not smooth as early.

Then at 60 speed i noticed RPM at 3 and car was like going in gear 1 or 2.

Then at 80 speed also i noticed RPM at 3 and car was like going in gear 1 or 2.

after that vehicle was back to a drivable state but shake was there still after a stop or break when accelerating.

Can anybody provide some advice based on my latest information please?

UPDATE 3

Yesterday i had a injector clean at honda company and they told its all fine. when i started to drive the car today again the bucking or knocking came up and car wasnt smooth as before. when eco mode was on it started to knock or buck a little more. i think A/C also has a connection to this. when AC was off and ECO mode was off. knock was less. so i turned it off and drove but still its annoying to drive. its dancing like a horse when starting at a stop light. can this be related to eco system in gp1 and EGR valve? but today i noticed when the egr valve was disconnected just 1 hour ago, car wasnt smooth but knock or buck didnt come which came while i was driving and half a way i stopped and disconnected the EGR Valve and continued and found no problem. i know its not good to drive without egr valvue so i connected it back after checking.

can the problem be with EGR valve sockets ? because the EGR valve i have put is from a second hand vehicle but a less mileage and it looked almost new. i would say no carbon. so is there anything else connecting with EGR valve like the socket that connects EGR valve and the engine ? what is EGR Passage ? should i clean that too.

what problems will i have if i remove the EGR valve and drive, i got a engine check light once so didnt want to drive with that removed.

Update 4

I got it confirmed that its a problem with CVT Gear Box, a past automobile engineer at honda found the issue. he took a long drive with me and he changed parts with a another same running vehicle. in the start gear of CVT something is wrong and he suggested to get the gear box replaced. replacing is better than trying to fixing.

There was also a problem with a injector and coil, so he fixed it and vehicle is smooth now only the knock comes once in a while. (which will go away once the gear box is replaced)

  • Or can it be the Catalytic Converter ? – user9059 Jul 14 '15 at 10:29
  • Did you replace the fuel injectors with new units or reconditioned ones? Also, Are you sure there are 8 injectors on your Honda Fit? It seems unusual to have an engine with two injectors per cylinder. – Zaid Jul 14 '15 at 10:54
  • Are fuel injectors and spark plugs are same? what was replaced is spark plugs. all 8 spark plugs are there and they were replaces. GP1 base model. – user9059 Jul 14 '15 at 10:56
  • @Zaid As to my knowledge gp5 only comes with 4 spark plugs. – user9059 Jul 14 '15 at 10:57
  • @Zaid the spark plugs were brand new NGK. – user9059 Jul 14 '15 at 10:58
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+50

This answer is a bit hypothetical; please take it as one path to follow, that may be useful in this and other, similar, cases.

Perhaps the clue to the problem is not in the spark plug (or injector?) replacement, but rather in this part: "I had a engine tune up".

While we do not know if the OP had this performed at an official garage, if this was the case it is very possible that an ECU re-flash was undertaken, according to periodic instructions given by the manufacturer. ECU mappings go through a review process, as does software in general, going to version 1.1, 1.2, 1.3, etc. (One hopes not initial versions starting with zero: 0.1, 0.2, as these would be pre-release - though some have been seen to subsist in production models through error.) Successive versions fix bugs that have come up in previous ones, and are often applied by the official garages during standard maintenance as a matter of course.

However, newer versions of ECU software can also contain there own errors, newer bugs that were not present in the initial version loaded on the vehicle as it came out of the factory. This explanation would be consistent with the symptoms observed by the OP: injection mappings would be just a bit off for a certain combination of the parameters (temperature, pedal position, revs, etc.).

The solution in this case would be to have the car re-flashed, with a more recent version of the software - fixing the new bug, and hopefully not adding more bugs to further mix things up. Just having a quiet chat with the repair person (i.e. the guy/gal who really fixes your car, as opposed to just manning the front desk) can often confirm this supposition, without even needing to take anything apart.

I have recently come across a similar case of jerk/knock on 2014 Ford 1.6 TDCI, so this type of electronic hiccup is not limited to one particular manufacturer. The electronic guru in that shop went: "Oh yeah, we know about that one. Just bring it in and we'll have it 30 mins on the computer. No charge."

  • please check the updated part of the question with latest status. – user9059 Jul 18 '15 at 13:21
  • @dev1234 Interesting. It is clear that the ECU is not happy with what the EGR sensor is telling it. Perhaps a blocked valve? Or a sensor malfunction? In any case, you are progressing: you now know it is worth it to take a closer look at the valve. On the other hand, I do not think the aircon has anything to do with this. Simply, the aircon makes supplementary demands on engine output, so any symptoms of existing problems will get worse and/or appear more easily. – ALAN WARD Jul 18 '15 at 13:47
  • is it ok to drive without EGR valve? (disconnecting and driving) to find more about the problem – user9059 Jul 19 '15 at 17:16
  • @dev1234 On a simple engine (e.g. Land Rover Tdi), it can be done but you need to put a blanking plate in. On a modern engine, the ECU needs feedback from the valve to work correctly. Otherwise you will get endless error messages, and injection will be incorrect. Most engine management systems should actually end up in a "limp home mode". So you need to fix this ASAP. – ALAN WARD Jul 19 '15 at 17:23
  • I got it confirmed that its a problem with CVT Gear Box, a past automobile engineer at honda found the issue. he took a long drive with me and he changed parts with a another same running vehicle. in the start gear of CVT something is wrong and he suggested to get the gear box replaced. replacing is better than trying to fixing – user9059 Jul 23 '15 at 4:34
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I don't think you replaced the injectors. I think you replaced the spark plugs. Injectors are what spray gas into the combustion chamber, and those are usually replaced or cleaned on older cars.

You said it happened right after the spark plugs were replaced. Why not replace them again? They might be the wrong spark plugs, they might have the wrong spark plug gap, One or more if the coils might not be inserted all the way, or one or more of the coils may be bad.

  • Yesterday i had a injector clean at honda company and they told its all fine. when i started to drive the car today again the bucking or knocking came up and car wasnt smooth as before. when eco mode was on it started to knock or buck a little more. so i turned it off and drove but still its annoying to drive. its dancing like a horse when starting at a stop light. can this be related to eco system in gp1 and EGR valve? but today i noticed when the egr valve disconnected, car wasnt smooth but knock or buck didnt come. clubjazz.org/forum/index.php?topic=5345.105 – user9059 Jul 18 '15 at 13:14
  • I got it confirmed that its a problem with CVT Gear Box, a past automobile engineer at honda found the issue. he took a long drive with me and he changed parts with a another same running vehicle. in the start gear of CVT something is wrong and he suggested to get the gear box replaced. replacing is better than trying to fixing – user9059 Jul 23 '15 at 4:34
  • There was also a problem with a injector and coil, so he fixed it and vehicle is smooth now only the knock comes once in a while. – user9059 Jul 23 '15 at 4:37
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I suspect issues in two components of your car but since you have already mentioned that Honda people have had a look not 100% sure.

  • Clogged up Intake: I know it sounds very trivial but a clogged up intake is sometimes overlooked.
  • Faulty EGR system: Almost al of the symptoms you suggest are very much mimicking the symptoms for a faulty EGR valve here are the things you can do to verify it, take it to honda for further inspection.
  • Check for Open / Stuck EGR valve.
  • Check for carbon clogging on the valve, i would suggest double checking it , using some sort of probing material to do so.
  • Check the EVP sensor (EGR valve position sensor).
  • Also some cars have Differential pressure sensors which sort of are a mix or mechanical and electronic EGRs , I am not sure if your car uses this, but I would suggest having a look at it.

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  • Finally , replace the entire assembly.
  • Driving without the EGR connected will not be a problem and might slightly affect your fuel economy( many times not noticeable). Many performance modders remove this component thinking it improves performance but it does not since EGR is always 100% closed at 100% throttle.

Note: If i was in your place i would ask a honda service person to ride with me and escalate the issue , honda is 100% liable to provide you with a solution Do not go easy on them , since your are ready to pay for(and have already paid) the solution. I feel honda is being lazy.

  • I got it confirmed that its a problem with CVT Gear Box, a past automobile engineer at honda found the issue. he took a long drive with me and he changed parts with a another same running vehicle. in the start gear of CVT something is wrong and he suggested to get the gear box replaced. replacing is better than trying to fixing. – user9059 Jul 23 '15 at 4:33
  • There was also a problem with a injector and coil, so he fixed it and vehicle is smooth now only the knock comes once in a while. – user9059 Jul 23 '15 at 4:37

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