Nissan87
02-10-2016, 12:25 AM
So here's the problem I've been having...
Symptoms when the problem is occurring:
loss of power under moderate load
odd thing is boost will keep rising normally but RPMs stay the same; usually happens when I'm trying to go from 10% throttle to a little more when going up a hill
OR when I'm going from maybe 20% throttle to 30/40% throttle on level elevation
exhaust sounds slightly quieter
sometimes, when starting engine, RPM doesn't go up to normal 800/900 RPM, and only struggles up to about 600 but holds steady and CEL comes on. If I blip the throttle, the RPM goes up to the usual 800/900 RPM and CEL turns off
Other times, the engine sounds and runs great and it sounds "punchier" when blipping the throttle. When those problem symptoms are occurring, the engine response feels like it lags a bit.
Current mods:
Stock blacktop S13 SR20DET (recently rebuilt with OEM parts)
HKS SSQV BOV (vented to atmosphere) (I know, I'm getting it recirc'd soon because I'm using a MAF, but not sure if this is the main cause of all these symptoms)
New Walbro 255lph pump
Stock 370cc injectors
Stock T25 turbo
Stock (and clean condition) MAF
Straight 3 inch exhaust with no resonator or cat
Reman ECU
I was going to wait until I get a fuel pressure gauge, and my wideband hooked up (soon), to further help diagnose this problem, but I wanted to post this to try to get some ideas to what it could be. I don't think it's a boost leak problem because the engine boosts normally without any sudden drops.
Cold starts in the morning or at the end of the work day don't show these symptoms (but noticed it's sometimes happening even at these times now). It used to only happen after a long drive and the engine sounds like it's being restricted a little.
I had my fuel pressure checked at a shop which checked out normal, but they only were able to check it while the car was only under light load or maybe when the symptoms weren't occurring.
I'm thinking it could maybe be a bent fuel line (was told by someone that the fuel pump gets more overworked when it gets hotter, so a bent fuel line could make these symptoms occur only when the fuel pump is hot).
I'm thinking it could also be a wiring or ECU problem. I don't know if this is normal, but ever since I got the car, there would be a tick sound every three seconds coming from somewhere near the front side of the driver side door or kicker panel fuse box. When it ticks, the RPM drops slightly during idle and the clock light on the gauge cluster fades slightly. When it ticks again, the RPM rises slightly and the clock light comes back a little brighter. This cycle would repeat, and it's always been occurring. Other than this and the once in a while "hesitant" engine starts, I don't have any idle issues.
I'm going to be checking the fuses and fuel lines soon, and setting up my Power FC (to rule out the Reman ECU as being the problem, though I'm not having any other problems with it) once I find a reputable tuner nearby. But the really odd thing is this only happens sometimes, and boost keeps rising when the problem happens but no power.
Any thoughts on this would be greatly appreciated.
Symptoms when the problem is occurring:
loss of power under moderate load
odd thing is boost will keep rising normally but RPMs stay the same; usually happens when I'm trying to go from 10% throttle to a little more when going up a hill
OR when I'm going from maybe 20% throttle to 30/40% throttle on level elevation
exhaust sounds slightly quieter
sometimes, when starting engine, RPM doesn't go up to normal 800/900 RPM, and only struggles up to about 600 but holds steady and CEL comes on. If I blip the throttle, the RPM goes up to the usual 800/900 RPM and CEL turns off
Other times, the engine sounds and runs great and it sounds "punchier" when blipping the throttle. When those problem symptoms are occurring, the engine response feels like it lags a bit.
Current mods:
Stock blacktop S13 SR20DET (recently rebuilt with OEM parts)
HKS SSQV BOV (vented to atmosphere) (I know, I'm getting it recirc'd soon because I'm using a MAF, but not sure if this is the main cause of all these symptoms)
New Walbro 255lph pump
Stock 370cc injectors
Stock T25 turbo
Stock (and clean condition) MAF
Straight 3 inch exhaust with no resonator or cat
Reman ECU
I was going to wait until I get a fuel pressure gauge, and my wideband hooked up (soon), to further help diagnose this problem, but I wanted to post this to try to get some ideas to what it could be. I don't think it's a boost leak problem because the engine boosts normally without any sudden drops.
Cold starts in the morning or at the end of the work day don't show these symptoms (but noticed it's sometimes happening even at these times now). It used to only happen after a long drive and the engine sounds like it's being restricted a little.
I had my fuel pressure checked at a shop which checked out normal, but they only were able to check it while the car was only under light load or maybe when the symptoms weren't occurring.
I'm thinking it could maybe be a bent fuel line (was told by someone that the fuel pump gets more overworked when it gets hotter, so a bent fuel line could make these symptoms occur only when the fuel pump is hot).
I'm thinking it could also be a wiring or ECU problem. I don't know if this is normal, but ever since I got the car, there would be a tick sound every three seconds coming from somewhere near the front side of the driver side door or kicker panel fuse box. When it ticks, the RPM drops slightly during idle and the clock light on the gauge cluster fades slightly. When it ticks again, the RPM rises slightly and the clock light comes back a little brighter. This cycle would repeat, and it's always been occurring. Other than this and the once in a while "hesitant" engine starts, I don't have any idle issues.
I'm going to be checking the fuses and fuel lines soon, and setting up my Power FC (to rule out the Reman ECU as being the problem, though I'm not having any other problems with it) once I find a reputable tuner nearby. But the really odd thing is this only happens sometimes, and boost keeps rising when the problem happens but no power.
Any thoughts on this would be greatly appreciated.