out of ides....

SON240sx Automotive
1

ok here whats up. just getting my car going after the build.

here is whats wrong: starts well, idles, holds a vacuum of 35 or so cm/hg. has a high idle though. motor skips every second or so. after it runs for 5 mins or so its idle drops to like 500rpm and loses vacuum. stalls out. if i try giving it throttle it boggs like crazy, it back fires through exhaust. shakes like crazy. wide band reads 14s the whole time its doing this and the plugs come out BLACK. not wet from running rich or anything either. lots of carbon…

things ive done to try and fix this

new plugs gap to .028
new fuel filter
checked my cam timing all is good. lines up everywhere inc cam pos sens.
checked for boost / vac leaks with carb cleaner method.
checked grounds
dan came to put a base tune on the car for my setup.
checked to see if i was getting spark on all cyl.
checked compression 150 psi on all cyl

running a power fc with map sensor…

ill take some vids in a bit.

any help or advice would be greatly appreaciated

thanks!

nate

2

oh yea cleaned the iacv too. new oil.

3

sr? tps. have you done a boost leak test. is the idle changing when the thermostat opens

4

i did not even read past the first paragraph. 35 inches of vacuum is A LOT! I’ve never ever seen it come up on a gauge ever.

5

yea its a s13 blacktop. it could possibly be changing when the thermostat opens… like i said it usually takes 5 mins or so of idling before it does it. how do i check for that.

6

Not inches…

7

My bad

Now that I have read it all how ever.

Is the MAP system taking over the MAF system? (you have no MAF)?

If so, be sure the MAP has a clean manifold vacuum. Test the MAP sensor.

8

The map sensor is good I’m getting a signal for both map and iat through power fc. The iat is in the cold pipe. And yea the map replaces the maf. Mind you I still have the maf installed just unpluged. I can’t for the life of me figure this one out.

9

The map sensor is on the same vac line as my bov. I believe it is also tied into fpr. Should still be good no? As long as it getting vacuum

10

Should be fine. Try running a manifold vacuum to the MAP only. see what happens?

FPR bad?
Injectors working properly?

11

i know inj are good as they are brand new tomei inj. not sure aqbout fpr and tps. how do you go about checking these?

12

Unplug the tps , or test voltage.

13

check with a fuel pressure gauge.

a volt meter for tps

14

gotta get a fuel pres guage. gunna go check tps in a min… thanks man

15

http://www.youtube.com/watch?v=u2q4evFENr0

i took a quick vod of it…was running ok… wasnt stalling out and shaking like mad…hopefully thats over with… but bogging bad and backfireing. its like when i open the throttle it just cuts out completely. car gets off the charts lean… you will see if you watch vid. what i dont get is its backfiring like a beast but says its lean. anytrhing above 14.7 is lean correct?

16

What’s the ignition timing like?

17

Not sure. Going to pick up a timing light tonight. Do I need a certain one for the coil packs?

18

No, regular one works fine but you have to connect the sensor to a wire loop in the coil pack harness at the back of the motor. You’ll see it.

19

No, do not time SR motors with the loop.

What you need to do is pull coilpack #1 and use a jumper to jump to the plug. An old plug wire will work, or better and ignition strength tester. You can get on from NAPA for $15.

But with all that said, nothing seems really wrong with the car. That dead spot you are seeing is likely just the cold start map and/or some tip-in calibration issue. On the commander, make sure the coolant temp is above 80 degrees C and check to see if the dead spot get’s less noticable.

Take the car around the block, I bet you, other than pulling away in first gear or just stabbing the gas when the car is idleing, you will not feel that dead spot.

20

Ok awesome. Thanks man. Dyno tues sound good?