Intermittent Jerking Issues

shiroitenshi

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I think most owners with a honda will have suffered this by now due to the age of our cars.
(noticed that inbox I never checked for so long is full.. and one of the interesting questions that came up is jerking issue.

Even I suffered this problem a few times, with different cars.

Normally, people will check fuel relay first. Which is right.
If it's not problem with the fuel system, they'll suggest to change the distributor.. then after chang distributor also problem, then that's where most workshops are stuck at troubleshooting.

So here's a question you need to answer first to identify the problem (after you confirm that it's not the fuel pump/distributor issue!)

*Does the jerking happen at low throttle positions (at 10-20% throttle?)
If yes, check the TPS voltage. This is easy if you have datalogging systems like hondata. Show me the graph of the TPS when the jerk happens and the problem is easily identified. Also check if the TPS does not have blank spots where it shows 0 Volts, if got, time to replace. if not, just set it to 0.5-0.6V fully closed. Don't use the ohm method to set TPS, this doesn't work for old TPS, only for NEW

The reason this happens is due to the DFCO function in all modern ecus.. detect 0% TPS, cut off injectors. In our case, the above is based on finding out that the DFCO kicks in by detecting 0% throttle. That's why look for 0% throttle in the datalog.

*DFCO - Deceleration Fuel Cut Off.

Does the jerking happen randomly? sometimes low, sometimes high?
*Check the main relay. Either fix or replace. This is not so common, but can cause intermmittent power to be sent to the ECU.. this one I spent almost 2 months to troubleshoot for my car, because never suspected the main relay, and the problem happens like once or twice a week. (Took the main relay, replaced, ambik kereta gelek2 that relay sampai hancur untuk puaskan hati.. lol.. ) <- not suggested, main relay problems is mostly fixable ok? :P

Another would be misfiring/knock retard, but that doesn't happen very commonly, as it is caused usually by improper tune/distributor problem/sensor issue.. This also easily identifiable if you datalog the jerk. This is rare though.

*note that this assumes all wiring connetions are OKAY..The above problems can also be caused my loose/spoilt wiring for the related sensors.
 
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rakyat

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My case should be due to the faulty TPS (always suspected it was some bump sensors)
The intermittent jerking happens around 3k to 3.5k rpm. Does it mean I need to change the TPS? How can I adjust the TPS voltage?
 

arrowhead

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i'd like to share mine as well, which was not the tps as initially thought. mine was due to faulty chip (re-chip) and also, crappy wiring job from previous workshop while transplanting.

both contributed to my 3 months troubleshooting problems, and after being sorted out properly by my current foremen, everything is back to normal.

thank god.
 

shiroitenshi

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here's a tip to check malfunctioning injectors.. use screwdriver, put on body and listen.. the solenoid in the injectors will vibrate when it's working, and you can hear it through the screwdriver. If the vibration is not the same as the other 3, then you've spotted the malfunctioning one.

The feel of losing 1 injector is different from having all four injectors cut out fuel at the same time. Losing 1 injector, you will feel immediate power loss, but jerking is minimal.
If four injectors cut out fuel, you will feel like the throttle is not working.. jerking is harder, and usually hard to explain the feel.
 
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SA6YEuro

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Mine was a overheated then melted 30amp fuse. In the indash fuse box tt regulates the fuel pump. Bad wiring...
 

shiroitenshi

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Mine was a overheated then melted 30amp fuse. In the indash fuse box tt regulates the fuel pump. Bad wiring...
hmm.. so bad wiring to pump, or relay?

But if like that, should be straightaway cannot start? if fuse burn't shouldn't the pump not run?
Just wondering how it happens to appear as jerking.
 

SA6YEuro

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Its actually the wiring to the relay. Jerking for me happens when tt fuse starts to run out of shape due to overheating. Jerks first then eventually engines dies. Diagnosed and found out tt the wiring for the aircon and fuel pump was wired to tt particular 1 fuse. Common mistake by a wireman in our case. Rewire back to the same relay thinking that the bigger fuel pump draws the same power.

The other common jerking i suffered before was a KOed distributor. Din notice the signs till it was 2 late. Car died otw back to KL.
 

shiroitenshi

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Its actually the wiring to the relay. Jerking for me happens when tt fuse starts to run out of shape due to overheating. Jerks first then eventually engines dies. Diagnosed and found out tt the wiring for the aircon and fuel pump was wired to tt particular 1 fuse. Common mistake by a wireman in our case. Rewire back to the same relay thinking that the bigger fuel pump draws the same power.

The other common jerking i suffered before was a KOed distributor. Din notice the signs till it was 2 late. Car died otw back to KL.
The distributor is common.. two years ago, drove my friends car down to KL, no warning, suddenly engine just died lol... stuck in the middle of nowhere along krai-gua musang route. Had to call his son to drive down with a spare distributor from Kota Bharu.

Went back, straightaway buy new distributor for my own car.. lol.. I still have my old working one, but don't want to take the risk.

Common issue usually kena for jerking for me is usually TPS.. usually just have to reset the TPS to 0.5V. the main relay issue really make me pening because it's uncommon, changed almost everything on my car before tracing it down to the main relay.. lol... seriously WTF moment for me.
 

SA6YEuro

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Learned my lesson. Fitted an external aftermarket coil. Hopefully would last longer.
 

g4i8y0t

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Very good info.. I think my car also has this jerking problem when I drive with the air-cond on. Its stronger than the jerk cause by the air-cond magnetic clutch.

May I know where is the main relay located?
 

shiroitenshi

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My FD2 jerking ...sometimes like the engine going to shut off....

Guess wat?

hih hih hih The battery kaput!!!
Very strange... usually for cars, upon startup, power comes from the alternator.. I'm curious how come it can cause jerking... would be interesting to know how that causes the jerking problem. Is the FD2 using a different type of charging system?
 

Sil80-13

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I have the jerking problem as well. Bought a TPS sensor from half cut shop. Just wondering when we replace the TPS sensor, do we need to do anything? Any setting will run off?

This is my 1st step of trouble shooting. If still happen will go to distributor & so on....:bawling: