extremely confusing SR problem

[srpowered240sx]

background- red top sr20det in a 90 240sx. fmic, gt exhaust, blitz boost control, walboro fuel pump, stock everything else, has been running good for well over a year. here it goes...(6 months ago) kill first injector(stuck open, flood cylinder) on cyl no. 3(counting from front), replace injector, fixed problem(4 months ago) burn up coil and harness of cyl. 4 due to ground coming off firewall, replace coilpack harness and a coil, fixed problem, started race season, car ran great, mid 13s in quarter.(2 weeks ago) drop another injector, in cyl. 2 also stuck open. put in new injector, fixed problem, ran great again.(5 days ago) car would barely start after running great the day before. she would start but run on 3 cylinders, no. 2 injector was full open again. swap injectors to make sure problem follows the injector, but it doesnt this time. swap with another, same cyl is flooding and fouling the plug. now i start to scratch my head....so i call a buddy with an sr and we start to trouble shoot. i grab his ecu and plugged it in, and the car ran great. drove it around, ran tits again. so i plug mine in again to double check, and again, three cylinders, so im convinced. i order an ecu and overnight it, and plug it in (also to be sure i change spark plugs and reset battery) still three cylinders. WHAT!!??!!?!?!? same cylinder not firing.............im getting spark and fuel (seemingly too much) i need the SR20DET gods on this one. ive searched, and searched, and tried a lot of ideas found, but none have succeeded. any ideas would be appreciated, i need my car back, thank you in advance.

[Dori Dori]

Most of these injector problems are not the injectors themselves or the ecu but bad wiring in the harness. KISS theory always. Wire the injector(s) in question directly to the ecu and see what happens. If all's well, rewire and sell that extra ecu on ebay. I had the same problem and this fixed it. Good luck.

[srpowered240sx]

i did a compression test for the hell of it today and got 120-110-125-120 on a cold engine. i didnt want to warm it up because its only running on 3 cylinders. the cylinder is getting spark, fuel, and compression.......everything i know says there should be fire there....but no. im gonna borrow friends ecu again and see if maybe i got a fubar ecu by chance before i rewire, but thats next.

[Dori Dori]

Its easy to run the wires from outside the car real quick just to be sure it's not a stupid wiring issue. Also try grounding the crap out of your motor (like with jumper cables) to be sure it's not a grounding issure either. Good luck!

[srpowered240sx]

i think i found what was killing injectors. i ran wires outside the car idividually to each injector and still ran on three cylinders. so i started swapping parts again. coils, injectors, plugs, just moved one and started it again, until the problem followed one of them, and sure enough, #3 inj, dead again. i replaced and its been fine for a week. i think my original ecu was killing injectors. is that possible.....too many volts, overlapping signals, im still confused, but happy to be boosting again...

[xsublimefrekx]

i would say if it happens again and you have an extra injector see how your ecu runs on your buddys SR. That way you can rule out if it is for sure the ecu.

[srpowered240sx]

i tried to a few weeks ago while troubleshooting, he wasnt having it. i cant say i blame him, i wouldnt want people trying faulty parts on my car either.

[dsm007]

Might be the capacitors in your ECU are worn out from all the years of cycling,they begin to leak a sort of acid like goo onto the board and can cause shorts/cause all kinds of havoc on the daughterboard....ya always see this alot on ECU's 7 years old and older(also keeps the ECU repair shops busy,oh and television repairs shops in buisness too lol)...its very common on dsm ECU's which causes the goo to attack the fuel control drivers on the daughterboard....it wouldnt hurt to change them(desolder the old ones,clean up the goo with electrical parts cleaning alcohol and a soft brisle tooth brush and solder in new ones),make sure they are 105 degree celcius rated capacitors and the right rated micrafared (ie.22uf,45uf,16uf,ect.)and the same voltage or higher rated too....I have seen it before with a few cars and taken them to TV/VCR repair shops to have them fixed....its just a thought of something to try and wouldnt hurt,heck you might be surprised to find whats under the capacitor when its removed.