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View Full Version : Bogging s14 sr20 (lots of searching done)

jackal264
07-16-2009, 05:39 PM
ok so here is the deal. i spent like 5 hours doing research and came up with a list of likely things.

PROBLEM:

idle is fine.
car boggs and backfires really bad between ~2000-5000 rpm
must be under load
and car progressively gets worse from cold - 1 hour drive (like for the first 10 mins the car ran fine but was really really bad at one hour)

changed the plugs, fuel filter, knock sensor, and tps + recalibrated the tps checked compression and did leak down all perfect. oil and water temps are good.

still has the same issue

car runs on a tomei reytec ecu so i don't have a diagnostic port (can't pull or get codes). car runs on a map sensor so it's not a maf issue and makre plenty of boost(ie the 18psi it should)

i have a spare block which is where i'm getting all the sensors from. i was running the block before so they are all still good.

i'm going to change out the cas tonight to see if it make a difference.

any other ideas?
XenoVibe
07-16-2009, 06:04 PM
Are you sure you aren't running alittle lean? perhaps its the injector harness shorting out?
Dr.Baby
07-16-2009, 06:16 PM
where does the boost gauge read from? sounds like a boost leak to me.
jackal264
07-16-2009, 06:53 PM
Are you sure you aren't running alittle lean?


i run wideband and the ratios are fine. also checked the tune and it hasn't changed.
jackal264
07-16-2009, 06:54 PM
where does the boost gauge read from? sounds like a boost leak to me.


again i run a MAP sensor so a boost leak is irelevant as the sensor reads from the intake manifold.
jackal264
07-16-2009, 06:55 PM
perhaps its the injector harness shorting out?


i though about that to but couldn't figure out why the bogging would be so rpm/load specific. but i guess it wouldn't hurt to check.
Dr.Baby
07-16-2009, 09:30 PM
again i run a MAP sensor so a boost leak is irelevant as the sensor reads from the intake manifold.


it's irrelavant for idling, not under load if you have a leak after the map sensor it'll bog under load.

So if your intake manifold to motor gasket is leaking it'll run like shit under load.

Map sensors don't cure boost leaks, start at the basics you've done so much harder work already.
jackal264
07-20-2009, 10:11 PM
just incase anyone ever searches this thread. problem turned out to be the tune. i had switched intercoolers to a slightly larger one and it managed to throw the tune off just enough to foul the plug. i was able to foul a brand new set of plug in 5 mins.

so more new plugs and a retune and bang bogging gone.