Engine misfiring, jerking when accelerating - No Codes
#16
Moderator
After confirming with obdII that there are no codes, if you get hesitation/lack-of-power, investigate fuel delivery and proper operation of injectors.
Salim
Salim
#17
Driver School Candidate
Thread Starter
There are still no codes or pending codes. Will start working on fuel delivery system this weekend. Really appreciate the assistance, will update on what I find.
#18
Look, it won't cost you much labor and no money to take VVT solenoids and strainer filters out and spray clean them. For the year, it should be done anyway. See what happens. It's like 20 min per set, you have 2 of them in each engine head. Right next to each other. Just be very careful with strainers, their base is made out of some brittle plastic that crumbles easily after years of heat.
#20
Moderator
Desperation makes us think illogically.
OCV issues should trigger check engine light.
No spark should trigger CEL.
Wrong timing of spark should trigger CEL.
Unburnt fuel exiting the exhaust would also trigger a CEL.
When a misfire is happening without CEL, the logical conclusion is there is no fuel in the chamber.
So I suggest, check that the injectors are getting triggered and there is fuel coming in. Then trace it all the way back to the fuel pump in the tank as needed.
Granted there are times when you need to leave the logic, but one must follow logic to start with.
Salim
OCV issues should trigger check engine light.
No spark should trigger CEL.
Wrong timing of spark should trigger CEL.
Unburnt fuel exiting the exhaust would also trigger a CEL.
When a misfire is happening without CEL, the logical conclusion is there is no fuel in the chamber.
So I suggest, check that the injectors are getting triggered and there is fuel coming in. Then trace it all the way back to the fuel pump in the tank as needed.
Granted there are times when you need to leave the logic, but one must follow logic to start with.
Salim
#21
Lexus Test Driver
Before you throw more parts on it, please check fuel delivery.
It is very likely you have a low volume fuel delivery/pressure.
Possibly a weak fuel pump or a clogged Fuel Suction Filter - (fuel pump filter) sock as i call it.
Fuel pressure should be 44 − 50 psi at idle.
It is very likely you have a low volume fuel delivery/pressure.
Possibly a weak fuel pump or a clogged Fuel Suction Filter - (fuel pump filter) sock as i call it.
Fuel pressure should be 44 − 50 psi at idle.
#22
Intermediate
Replaced coils, plugs, filters, pvc valve, cleaned MAF and IAC units. All vacumn lines are connected, no leaks found. Engine idles fine, but when you accelerate the engine jerks and seems to misfire. Slow steady application of the throttle, then engine does better. No check engine indicator activity and no codes. Any ideas?
The job of the MAF is to determine the amount of air entering the throttle body. It does this but heating a wire, the ECU determines the amount of current needed to maintain the temperature of the wire. As more airflow over the wire more current is needed to main the temperature. You can see in my photo when I snapped the throttle at 61 g/s.
#23
#24
Driver School Candidate
Thread Starter
Installed fuel pump, filter, regulator and strainer assembly. The problem is resolved; runs strong and smooth through all rpm ranges. Transmission shifts well. Thanks everyone for all your help with this.
#25
Lexus Test Driver
#26
Actually I am going to do mine I have pulled my engine down changed my plugs coils and knock sensors three times now. I am not getting too many misfires but still getting them. I know air fuel mix didnt feel right and bursts of power after lag. I even have the hollow point spark plugs now lambo style to get some bloody spark.
Last edited by Australian; 02-19-19 at 03:13 AM.
#27
Moderator
Actually I am going to do mine I have pulled my engine down changed my plugs coils and knock sensors three times now. I am not getting too many misfires but still getting them. I know air fuel mix didnt feel right and bursts of power after lag. I even have the hollow point spark plugs now lambo style to get some bloody spark.
Only OEM plugs for RX please.
Salim
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