Help with backfiring/jolting issues
 

Hey guys,

I noticed some problems with my fd when i drive the car at a steady pace (barely pushing on gas pedal) I notice the whole car keeps jolting/choking and starts backfiring. This usually occurs when the car is warmed up. My mods are hks downpipe, stock cat(pretty old), blitz cat back exhaust, Rx7.com aftermarket O2 sensor, and intakes. I recently changed the plug wires to ngk. Any help will be much appreciated.

Thanks,

Charlie

Start here:

https://www.rx7club.com/3rd-generation-specific-1993-2002-16/fixed-my-idle-problems-backfiring-bucking-more-170731/

Does the TPS usually go bad out of nowhere? I was thinking my probelm would be bad sparkplug wire change or fuel filter related

Anything is possible, however you'll need to get dirty to get the problem narrowed down. Instead of asking questions, do some routine maintenance and see if the problem still exist:

* Spark plugs
* Check plug wires
* Fuel filter if it hasn't been changed in a while
* O2 sensor
etc..

If those are all in good shape and the problem still exist, the next easy thing to check is the TPS. After that, you need to look into a possible fuel issue (injectors) or ignition issue.

OK so i brought my car to my mechanic and the tps is ok, and spark plugs are ok. He says that it's the O2 sensor. The O2 sensor i changed it myself and had to solder it with the stock 02 sensor wire. The O2 sensor was bougth from rx7.com. My mechanic wants to order me a stock O2 sensor. My question is is there a difference in the jdm and usdm O2 sensors

same sensor, you can pick 1 up at local parts store direct bolt/plug in

My car does that too, only for the first initial 3-5 minutes AFTER it has already restarted from warmup.

Like if i start it dead cold, i can drive around for hours and not have a problem.

But once i've driven, then shut it off, then restart it, whether its 10 minutes later, 1 hour later, as long as its still warmed up from the previous run, it will buck and jolt at the beginning of the drive.

Someone told me its the coolant thermosensor? Like it thinks the car is cold because you have shut it off and its feeding more fuel into the car. Even though technically my car is wamed up, that sensor is probably getting faulty and sending it more fuel.

Yah well its something that started happening randomly when i was driving on the high way. I thought i'd have my problem fixed from getting it back from my mechanic i ended it up paying 1500$ and the problem wasn't even fixed.

well if your "mechanic" is not familiar with rx-7's then you are in for a headache. if you are unable to repair yourself, spend the money to have a known rotary shop fix it imo

Whoa whoa what??

What did he fix then??

I hope you wont ever go back to that guy ever again.

He adjusted the tps, changed the o2 sensor and also change the wheel bearings since they were due. but he stated that the car doesn't hesitate anymore, although he helped the problem since it doesn't start bucking till later he didn't fix it. That's why i was hopping to get help from this forum. I've searched every thread on, tps, o2 sensor, fuel filter, and everything with my problem and nothing.

Wow man, hate to say it but you got jerked big time.

To adjust the TPS and change the o2 sensor and a couple of wheel bearings is 1500 bucks?

Your problems actually sound like TPS issues so its highly unlikely he did the right thing.

I know i've been jerked but i'm going to bring the car back to him and complain the problem isn't fixed and should be able to get my car running right at 1500$ atleast. Could it be my ECU it's been tunned in 1998, i have a power fc just sitting in my room would that help fix or find the problem?

Try mazdees (RX-7 specialists) in Pickering.

Mazdees is too far from especially driving the car the way it is or getting it towed. It's weird the symptoms my car has it's fine when its running cold but when it warms up it start running like shit on light throttle. It started happening randomly when i was driving my car on the highway with a 1/4 tank of gas

you said it does this while driving at a steady pace or when you step on it? do you have a check engine light?

Let me tell ya - I had this problem and it drove me crazy until I read through this site's archives.... and it was the simplest of fixes.

Check out the ground strap that connects the Upper Intake Manifold to the firewall. It has a flimsy spade connector that becomes loose over time and no longer makes a good ground. The ECU seems to deem this ground critical to the ignition, injectors and solenoids and if there is additional current demand through the strap like AC compressor or AIR pump the ground strap cannot handle it. On mine the plastic spade connector insulator was melted. Get rid of this and install a good 6 gauge strap. Fixed all of my bucking and cruise jerking problems.

Maybe you already have done all of the grounding updates.... But a thought.

Hi there, this may be a stupid question....but your not driving at too lower RPM are you?
What happens when you change to a lower gear when the bucking starts?

Ok,,you are in Ontario I take it..most likely GTA.
Try www.rotarydynamic.ca
or www.rpmperformance.ca
They are located in Mississauga Brampton area.and Breslau I believe.
.Try getting a hold of RD_TURBO on forum or RPM,that is who those guys are.respectively.