I've only had my car on the road for a couple of months now since building it and having some trouble getting the engine to run properly. It's basically a standard RB25DET, standard turbo, ECU, injectors etc, but with uprated head gasket, oil pump etc. Just trying to get it to run reliably before I go for big power.
Engine seems to idle pretty well but when driving there's always a hesitation when opening the throttle. It backs off as if it's run out of fuel then goes again, but there's always a mis-fire when the engine is under load, and it seems to run out of puff about 5k rpm.
So far I've checked and gapped the plugs (these were new last year, NGK decent plugs which have done about 200 miles max), adjusted the TPS so it reads 0.45v when throttle closed, checked the coilpacks for any obvious signs of the them breaking down etc. Have still to clean the MAF but looks clean and in good condition.
My AEM wideband gauge reads between 14-17 when cruising which seems a bit high - am I right in saying that means it's running lean? The car destroys fuel at a horrendous rate. I'm barely driving on boost and it's managing 80-90 miles on 30 litres, which I'm putting down to the misfire. Fuel is 97 RON and any old petrol will have been flushed out by now. I've put about 70 litres in it since it went on the road, which has lasted no more than about 150 miles.
I previously had a 400LPH pump fitted and the fuel pressure was so high that it was chucking petrol into the engine and filling up the sump with petrol, plus the exhaust was sending clouds of petrol smoke into the unit - was really stinking. Have had a Walbro 255 fitted for about a year now and seems to run fine if a bit rich smelling. Also worth mentioning before I built the car I "refurbished" the injectors with new seals, nozzle caps etc before I got the engine running. Could I have ruining some or all of the injectors? Does seem like a stupid idea now! Running standard RB25 injectors, fuel rail with built in FPR etc.
Think the engine is pretty much boost-leak free, although haven't gotten round to doing a smoke test yet. Any other ideas?