kadz

Hi Guys

I have a 1992 FD efini type r manual, mods on the car are :
Blitz twin air intake
Full exhaust
Blitz Bov
Ecu which I thought was Redom was actually stock with the redom cover only(perks of purchasing the car from an auction thousands of kms away)

Problems that came with the car:
Inside of the Fuel tank had rust, that was sorted and the fuel pump and fuel filter was changed.
Alternator was not charging, that too was repaired

The problem I am experiencing is something that comes and goes. It idles perfectly fine, revs up and boost free. When you rev and let go slowly, it will start to miss and give out some black smoke ,the idle will slowly correct itself and the smoke disappears. Even when driving if I keep it in the low rpm range it will jerk and miss but if I give it a little more gas or even WOT it will go perfect. Cruising will cause it to stall for split second , decel makes it jerk back and fourth as well sound like it has a miss. Where the car beats me is that in the morning, I will experience the above. When I pull over, switch it off and after ten mins get in, the car goes perfect until I have to stop .

I cleaned all existing grounds and added a HKS grounding kit from those grounding points to the battery.
Battery is new
Spark plugs are changed but i am using all 9's as no one had 7's
I check for boost leaks, intake leaks nothing.
I search through the forum for similar problems and possible solutions but nothing.
Some threads says TPS, or O2 sensor
Please help
thanks

Anderson Chen

1.) Are you experiencing this a problem only below 3k RPM?
2.) You sure the ECU is stock?

I'm leaning towards it being a problem running open loop, which is why I'm asking about the RPMs. If it's an open loop problem, it there are only a handful of components that can be a problem there - one of which is the O2 sensor.

GL

kadz

Yes i am 50% sure it is stock(ran against a gtr r35 , rs7 audi, carrera 4s, m3 e92 my lead was between 3-5 car lengths), it occurs below 3500rpm when letting off gas, but it idle fines.
I took it to an electrician to get the alternator tested and the tps
Both are in spec at closed and open throttle.
This evening i went under the car to check on suspension bolts due the jerking there were alot of rattling, whilst tighten the bolts i noticed a sensor that i think goes into the cat was cable tied and tucked aside and upon further inspection the sensor head is missing(broke off), so i left it as is.
I checked vacuum hoses once more and found that the hose that connect to the charge relief had a tear so i replaced it, also the EGR is disable (car came like that)sprayed Q20 on the accelerator springs, double throttle springs and the spring by the tps and left it to remove the access dirt.
I put everything back started the car waited for half an hour then i switch the stereo on idle remain normal, i switch the lights idle remain normal, and finally the a/c and it idle normal. Revved it a few times with my foot slowly releasing throttle no signs of missing nor hestitating. In the morning i will take it out for the day and will update from there.
One more thing , My boost gauge is connected to a tee peice that connects to the boost sensor is that okay, as the car came like that, because from the vacuum diagrams it normally runs from the manifold

kadz

Today I installed the new o2 sensor, the old one was rusted and covered in black dirt. It took me 5 hours because I decided to intall the efini y pipe (a good tip for those for have rhd fd3s and cannot get to the rear turbo bolts on the y pipe, after removing the two size 10 nuts on the front half of the y pipe that fits on the turbo do not remove the y pipe but place 2 size 12 nuts on those bolts and tac it with a welding gun, you can now unbolt the 2 bolts that hold the y pipe and front turbo together and slide the y pipe out with out any yanking, and after the efini y pipe is installed you can use the same bolt and screw it in ), when removing the air pump the hose that connect the air pump to the engine was split so I replace that. Put everything together went for a drive put all electricals (lights aircon radio) on no problems for the first 20 mins then it happen again hesitating, missing, so put the lights off still problem, ac off still and finally radio but I mistakely touch the button that released the radios face, I pulled off and after 5 mins started and drove, no problem whatsoever used lights nothing after 20 mins used ac still ran fine, after an hour used the radio and it started, switch radio off still problem was there when I removed the radio face it stopped . So for all those who did vacuum checks, the grounding kits, tps, alternator, new battery, fuel pump, filter, spark plugs, ecu and problem still occurred , sometimes the problem is in the cabin itself. Hope this helps others