PDA

View Full Version : 3rd cylinder keeps misfiring


aaron.nueva
10-06-2015, 11:42 PM
Hey so we just got my sr20det running and 3rd injector keeps sticking or stopping. So at first it was running the 3rd cylinder started to misfire. I swapped it out with another injector then everything was fine. 20 minutes later 3rd cylinder misfires again and after testing again found the problem to be the injector again. So i swap it out again then everything is fine. then the next morning when i drive it to my friends house to help me look at it it starts to misfire again. so at this point i was like "Fuck It!" so we take 3rd injector and 2nd injector and swap them then start the car and what do you know, runs fine. Then after a couple of minutes it starts to misfire again then we swap 2nd and 3rd again so now the injector that was originally on 3rd is back on 3rd cylinder. start the car and runs fine. get back to my house and starts to misfire again so we switch 3rd and 4th injector then start the car and everything is fine again. then it starts to misfire again. so we take out the injector to see if something in the rail is clogged or causing the injector to stick and everything looks good. we check the pigtail thast connects to the injector to see if it was getting power while the car was misfiring and it was, we checked with a test light. what i didnt do was check to see if it was giving the right amount of voltage cause i ran out of time which ill do tomorrow. so yesterday i ledft the car alone after it was misfiring on 3rd cylinder. today i start the car and its running good. so right now we think that when its misfiring it could be either the ecu, or making the injector give way less fuel. cant be too much fuel cause i dont smell any gas as if it was running too rich. so we tried to pull codes from the ecu and put it into diagnostic mode and turn the key "on" and no light. open the cover to the ecu only to find the tiny bulb thats supposed to blink, missing. it looks almost as if the ecu never had it. just my luck... and the other problem we are having is the car is a off on ignition timing. right now the cas is advanced all the way and needs, lets say anothe 2-5 degrees to be where it should. i know that when you install the cas its centered and that should already be damn near close to where ignitikon timing should be set. ive had 4 friends other than me check my timing marks and everything is on point. 9 links between the mark or 11 if you count the one that the mark is on. 5 teeth from the top of the head to the dot on the intake cam, 9 teeth from the dot on the exhaust cam to the top of the head, while on tdc and the crank pulley is aligned to the 2nd tic mark on the needle. and the dow pins are at 10 and 12 o'clock. and the cas was aligned to the second dot then when slipped onto the exhaust cam rotated to align with the first dot. so everything is on point. so right now its not advanced enpugh to where we need so we advanced the cas one tooth and now it wont retard enough so we put it back to its correct position but its still advanced all the way. someone please help me. tomorrow im gonna continue trouble shooting. im gonna wait for the car to misfire then shut it off and remove the fuel rail and disconnect the coil pack harness and crank the motor to see if gas is even being squirted out of 3rd injector. but as of now we're thinking its the ecu:picardfp:

kruked
10-07-2015, 03:22 AM
Get a set of noid light tester. Drive the car until it starts misfiring again. Stop driving the car, (do not shut the car off) and disconnect the cylinder 3 injector. Plug in the noid light and see if it's responding.

Seems like you either have a short in the wiring or a faulty ECU. I'm leaning towards a short because very seldom do we have problematic ECUs.

aaron.nueva
10-07-2015, 11:10 AM
I was going to do that to! And if it was a short you think it would be a ground short? And I've never done this test before but if it doesn't respond it's either gonna be a short or the ecu? And thanks for the help I appreciate it!


Sent from my iPhone using Tapatalk