I just got my GTR and it is running quite rough and I was lloking for some help diagnosing the problem.
I picked up my GTR 3 days ago with a dead battery big suprise. After boosting the battery, is ran like **** on the way home, kinda a slight thumping sounding and feeling almost like a misfire, and I was getting only about 1/2 boost.
It came with a Brack Box A/M ECU and when i replaced it with a stock GTR ECU it ran very rough and rich( could smell and see the gas in the exhaust) so i guess I prob have A/M injectors. So I put the A/M ecu back in and it ran decent the entire night. It ran good the next morning as well, but after I took it for a wash it started running like **** again with the same characteristics that i had when i first picked it up.
any ideas would be awsome, the only things i can come up with so far are O2 sensors, of MAS sensors
forgot to say that I got the car with not gas, and filled it up with a tank of shell 91, andyes I did replace plugs with the proper NGK iridium’s, I also cleaned th MAF. I think 1 or 2 of the coil packs might be part of the problem. I had the car running and would disconect the coilpacks one at a time, and the idle would get slightly worse for 4 of the pack which i think indicates they work, but there was no change for the other 2 which would make them not working( cylinders 1 and 4). I am wondering though if this would account for the low boost that my car is receiving, since there would be 1 or 2 less cylinders feeding exhaust through the turbos?
everything you need to know to diagnose any problem with you car can be found in the GTR FSM. Id start off by checking the MAF’s, TPS, knock sensors, AAC in that order. Before that you should be checking for plugs, grounded out coils, and maby even your fuel filter if its running as shitty as you say and as inconsistant as your problem is. I would also check codes and the FSM will tell you exactly how to do that too.
Also I never use synthetis ois in a shitty old engine. Everytime I do I see blow by. I find that mineral oil in these old engines is best. I even use 10w40
um if you want, but i cut the wiring back so there is only about4-5 inches of wiring off the controler, and i threw the rest iin the garbage[/quote]
did you just cut alot of things out randomly just to make it “pretty”? Or did you spend some time and follow where everything went and take it from the source. You might have ruined the wiring to some good electrical units and made your task of solving this problem that much harder.
um if you want, but i cut the wiring back so there is only about4-5 inches of wiring off the controler, and i threw the rest iin the garbage[/quote]
did you just cut alot of things out randomly just to make it “pretty”? Or did you spend some time and follow where everything went and take it from the source. You might have ruined the wiring to some good electrical units and made your task of solving this problem that much harder.[/quote]
The Turbo timer was just sitting in the car, not pluged into anything. and the electric fan controler ran somewhere around the rad support but was not attached to anything so pulled that since i did not have any electric fans to control anyways.
So I finally replaced the coilpack for the number 4 cylinder, and the coilpack harness, and now the engine seems to be running fine, but full boost still comes and goes intermittantly. I have alot better pull now though when the car is running poorly, but only seem to get 2/3 to 3/4 of the i should be getting for stock. I guess I will look over the IC piping and stuff for a boost leak, but I’m not sure if that is what it would be since I will still sometimes get full boost before the seals and couplings get hot and expand.
i would suggest getting your car tuned and purchasing either different stock maf’s or going to z32 maf’s. because if its running rich and you can see gas out of the exhaust your def burning to much gas. tuning it will bring your gas mileage up and possibly solve some of your problems.
also try GTRcanada.com they might have some similar experences or give some good advice
Stock mafs are fine. No need to upgrade unless you have big power. RB26 MAF’s still max out at 5V. They are good to 500hp no problems.
I still sugest your ecu is crap. I have a factory one you can test aslong as your injectors are still factory it will be a good way to fix the problem!
sorry for not looking back on this thread earlier, I tried my friends spare stock gtr ecu and it ran the same, so i ran the ecu for codes, and it was throwing the knock sensor code, so i cleaned them up, and ran a few tanks with octane booster and everything seems to be working fine now with both the brack box ecu and stock ecu
