I'm having quite the problem, I'm pretty tech savvy and mechanically inclined as I own a repair/autobody shop, however this has gotten me a bit stumped.

My personal Evo IX's problem:

First the car:
TBE exhaust including 02 housing
Tubular manifold
Intercooler hard pipes
Intake
BC 272 Cams
Walbro 255
Stock Boost
Stock everything else
Just performed the 60k maintenance at the same time the cams were put in. (63k miles), now has 64,xxx on it

What happened:
Drove the car around on a daily basis, the other night lightly got on it for a second pulling away from a stop sign, easily shifted into 2nd gear, and then worked my way up the ladder into 4th, completely off load, just regularly driving. About 1/3 of a mile down the road, all of the sudden a random consistent misfire started to take place. Basically misfiring on every stroke at the same time. Limped it over to my shop and hooked it up to my computer to see what was going on.

Got a Misfire in cylinder #4.

OK basic process of elimination now starts, checked compression, checked spark and checked fuel in cylinder 4. Good spark, good compression, not so good fuel. Tested each injector while the car was running, shutting one off at a time, and each made a drastic difference to the way the car ran except #4. So therefore I thought right there it must be an injector.

Went ahead and ordered some DW 880cc's, installed them and started the car up after some minor scaling and latency adjustments with ECU flash, car ran alright, lots of sputtering and seemed like it still was misfiring on cylinder #4....

Researched a little more, figured I'd try replacing the plugs as #4 looked a bit fouled compared to the other 3 at this point.

Swapped all 4 plugs, and now it doesn't run!?

Car tries to start very hard, lots of backfiring, and hic-uping but can't get it to stay running for the life of me.
I'm starting to think the timing belt jumped?

Idea's / opinions?

Never had an issue with this car up until this day.

Also forgot to add that I'm the original owner of the car.

 

Just pulled all the plugs again, performed another compression test and confirmed that every cylinder has spark, every cylinder gets fuel except for #4

150 across the board compression. What would cause this thing not to run all of the sudden.

 

Ya you are going to find it hard to get good info here. I have been having some strange voltage issues at my injectors, and I have not gotten anything. All I can suggest is to verify that you are getting voltage at your injector, test the resistance between the injector and the ECU.

Check all your grounds, check your injector resistor pack. You will need to test the voltage there also.

Best of luck to you.

 

Its crazy that the Evo board doesn't respond considering the car in question is an Evo, I've gotten more of a response on my MR2 forum. This is sad.

 

Just in case anyone else has this problem and its not the injector, check the resistance for each injector, my #4 was totally different than the other 3, replaced the injector resistor box and its golden.

 

My car is stock and I had a lot of P0300 code last months. But it turned to a P0304 for the last two weeks. I switched my coil pack and i still get P0304. sparks plugs are new and well gapped.

Yesterday I switched injector 3 and 4 and I am now waiting for my next CEL . Car still have a weird idle, like it is always missfiring a little bit.

What is the resistance injector box ? I am a bit confuse ...

 

im in the same boat now.. can anyone confirm that its the resistor box? if so it should be pretty easy to swap right?

 

bumping a old thread for some answers

 

Would love to see an answer here, I have a code for injector circuit malfunction in #2

 

im having same problem car is sputtering very bad, runs lean etc... i did the same injector test and injector #1 not working.. code is po201.. on monday ill go to the dealer and get it ordered.. hopefully itll fix the problem, getting tired of this car

 

is it intermittent for you guys? like for me it happen on and off but it is becoming more and more frequently. Like it just sputters if i try to give it gas, sometime the car will just die, or it'll just goes back to normal and i can drive and then it comes back.

hope u guys solved it and it was the resistor??!

 

i think its a injector drivers that go out... because my injector 1 went out i took the harness apart and replaced the whole wire and still not working ... so i just the injector 1 from injector 4 and it works now .... still got the code tho but deff stopped miss firing now

 

It's the injector resistor box guys. On the fire wall you'll see the metal casing plug going into the bottom with 4 white wires out the top.

I had the issue P0201. Replaced the resistor pack and problem solved

 

the thing is i dont have any CEL =\

 

any more comments? I'm having similar issues with no CEL