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View Full Version : Red Top Bogging Issue


poormtnkid
01-02-2014, 10:50 PM
Im having a bogging/blowoff issue when at WOT at 4k RPM. I will explain everything in regards to the mods and what I have tested.

s13 red top in a Datsun 510. FMIC, Top Mount T25, 3 inch not cat exhaust, boost running 12-13 nistune dyno tune. The car had been running perfect until recently.

Things I have checked
-New spark plugs gapped to .32
-cleaned MAF with spray
-double checked all couplers are not ripped and are tightened down properly.
-Tested MAF with multimeter. Idle I got 1.53 volts, 3k RPM 2.1

So the FSM says that at idle it should be in between .8-1.5 and at 3k RPM it should be 1.4-2.0. It seems that Im right where it needs to be there. The numbers started a little higher and as the car got warmed up the lowered.

Fuel pump fairly new with less than 1500 miles. This is not a daily driven car . The weird thing is if Im driving with 50% throttle I can go past the 4k RPM. Its only happening when WOT. I did not change anything and this started to come up. It just happened one day while driving to a friends house.

I was thinking possibly my BOV can no longer hold the boost ? Never heard of a BOV failing but it seems to happen when boost is at its peak and its just dumping air out because when it happens my BOV goes crazy.

Any suggestions would help. Thanks

bmxer882x
01-03-2014, 12:53 AM
Bovs can leak. Rarely do they go bad all at once tho. My suggestion would be something in the fuel system. Have a wideband or anything to gauge afr's? Since its only at wot im thinking ur getting a fuel cut. Might try a fuel filter or check for a kinked fuel line

poormtnkid
01-03-2014, 08:08 AM
I do have a wideband but I have never hooked it up yet. I really have no where to mount the gauge right now but I guess I can just zip tie it somewhere to get some readings. What numbers would I be looking for if the fuel is dropping?

bmxer882x
01-03-2014, 02:14 PM
Its different for all rpm ranges. Idle im around 16, wot im around 11.5 but you pretty much want to be under 12 at wot in boost. Normal driving I fluctuate but when cruising im normally in the 14 range