ScWift92

Hey CL,

I Have An Sc300 and it backfires on idle like Badly with a rough idle but it is NOT A MISFIRE!

I Can Rev The Engine And It Revs Normal Right Now im just running an obx open midpipe

and I HAVE NO CHECK ENGINE LIGHTS.

i have already changed cap, wires , ecu ,maf , before the problem the car just got running correctly

it was in my old sc300

PLEASE ANY HELP I NEED THE BEST OF THE BEST.

ScWift92

Heres Video

SC400slide

iTrader: (11)

Could be MAF, TPS, Coils, dirty TB, clogged cats, missing or cracked vacuum hoses. With and idle that bad there should be a CEL. GL!

ScWift92

i Swapped Out MAF Havent Checked The Tps My car Doesnt Have Coils TB Might Be A Source Car Is Catless With Straight pipe And I Have Replaced Vacuum Lines .

SC400slide

iTrader: (11)

Just watched the video again and it seems like it isn't getting the correct fuel to air ratio. I would think that it could be one of the 2 master ECU's. (Main ECU or fuel pump control ECU). You mentioned that you replaced the ECU but which one? The fuel control or main?

I know you probably already did but quickly reset the ECU...since you replaced it.

Candela

iTrader: (1)

If you plugged in whatever that connector was, and had an exhaust on the car, it would sound much better

ScWift92

my car never had a fuel pump ecu but had the connector so i replaced that and i replaced my ecu with my other sc's ecu

ScWift92

my car never had a fuel pump ecu but had the connector so i replaced that and i replaced my ecu with my other sc's ecu

ScWift92

gonna bolt up the exhaust this week

SC400slide

iTrader: (11)

Could be something caused by your swap you did a couple months ago then...??

ScWift92

like? any ideas?

SC400slide

iTrader: (11)

Go through everything:
MAF-you replaced it
TPS-unknown
Coils-none
Fuel pump ECU-none
ECU-replaced with working one
Dirty TB/IACV/components-unknown
Vacuum hoses-replaced ALL
Cats-none
spark plugs & wires-new
-dirty fuel...?
-clogged/ malfunctioning injectors...?
A q for you, how does the SC work without the fuel pump ecu?

ScWift92

but the car revs normal but backfires on idle

Ali SC3

iTrader: (10)

not sure thats backfiring but its definitely not running healthy, probably a vacuum leak or something routed wrong. If you capped anything double check its supossed to be capped, also did you remember the vac line under the distributor that goes to the intake pipe, it comes from a metal hardline from the drivers side power steering idle up switch. also don't spray the maf, I have had similar symptoms after trying to clean one, the odb1 maf's are not hotwire maf's you cannot clean them with regular maf cleaner. a better picture of the engine bay would help.

ScWift92

i found out my car has the 12v mod and had no fuel pump ecu but i installed one before i got it running good can that be interference to the mod? it is only breaking up at idle also i changed back to a regular manifold instead of a TRAC manifold just to make sure it wasnt the IAC. Also i changed all the O-rings on injectors so there good and they All Read 14.7-15.0 ohms