Sr20det redtop problem!!

[ll_EvOluTIoN]

So just did my swap and I'm having an idle problem. It seems to be idling around 1000rpm(tach nonop) then it seems to cut out for a sec. I was checking the injector pulse with test light and when the engine cuts out the injectors stop pulsing.

I checked tps adjustment an it's at .4v. I'm getting spark at all plugs. New spark plugs n gas. New stock injectors spray great. I switched between 3 ignitor chips n same prob. Switched in known good ecu. Same prob.

Any ideas of what it could be?

[92dagrey]

when you say "cut out" do u mean the engine fully dies or it almost dies n then barely comes back to life? There could be some kinda short thats happening. check ecu for codes

[ll_EvOluTIoN]

No. Its like a momentary drop in idle it doesn't cut out enough to die or almost die

[92dagrey]

do all the injectors cut out at the same time?

[ll_EvOluTIoN]

Not sure. Ran codes n got 55. Checked tps it's .48v-3.8v wot. Maf is .8v key on engine off.

[ll_EvOluTIoN]

Bump!!! Still need help

[anarchyperf]

I would try swapping out your maf first. Also sounds like you might have a loose/broken wire in the harness

[codyace]

How does the car drive?

[ll_EvOluTIoN]

I haven't driven it yet I'm afraid it will damage the engine.

[codyace]

Is the engine itself literally cutting out, or is it just sorta/kind stumbly at times?

EDIT: Can you take a video with your cell phone and post it to youtube for us?

[ll_EvOluTIoN]

It's cutting out and it's consistent. It doesn't die cuz it's idling high so when it cuts out momentarily. Even if I accelerate a little higher it will still cut out the same unless I hold it at wot

[ll_EvOluTIoN]

So the injectors are cutting out. I tried a new tps n it fixed the idle for 5 min n did the same. So put a new maf and the problem goes away untill I hit the throttle. Then idles bad again. Now today no matter what I do it idles bad. Here's what I got.

YouTube - Sr20det problem (http://www.youtube.com/watch?v=GXfN9IlsMQs&feature=youtube_gdata_player)

[codyace]

It sounds like you have a HUGE vacuum leak, or something wired incorrectly.

[slomar91]

It sounds like you have a HUGE vacuum leak, or something wired incorrectly.

+1 on the vacuum leak.

[Kingtal0n]

the computer has a method for controlling fuel when the tps is untouched.

if anyone with an SR20det raises the idle without moving the tps eventually the engine hits a cut off point for fueling, its called idle fuel cut rpm. For instance if the engine is getting extra air from a vacuum leak and the idle raises to 1200rpm or so, the fuel will cut if the tps is unmoved (no one is touching the gas pedal). this is because the ecu thinks the car is in a deceleration. You want the fuel to cut when you lift your foot from the gas pedal so the engine can brake to a lower rpm.

anyways, my point is that it sounds like you have a vacuum leak, and this raises the idle to the fuel-cut RPM which causes the engine to sudden "cut out" till the rpm drops back down.

find the air leak and create a stable idle, the sudden cutting out is an actual proper mechanism within the ECU nothing is wrong with it.

[DirtyLoud]

the computer has a method for controlling fuel when the tps is untouched.

if anyone with an SR20det raises the idle without moving the tps eventually the engine hits a cut off point for fueling, its called idle fuel cut rpm. For instance if the engine is getting extra air from a vacuum leak and the idle raises to 1200rpm or so, the fuel will cut if the tps is unmoved (no one is touching the gas pedal). this is because the ecu thinks the car is in a deceleration. You want the fuel to cut when you lift your foot from the gas pedal so the engine can brake to a lower rpm.

anyways, my point is that it sounds like you have a vacuum leak, and this raises the idle to the fuel-cut RPM which causes the engine to sudden "cut out" till the rpm drops back down.

find the air leak and create a stable idle, the sudden cutting out is an actual proper mechanism within the ECU nothing is wrong with it.

+1
I'm gonna have to go with what he said!

[ll_EvOluTIoN]

Thanks that was a pretty awesome explanation. I'm gonna make boost leak tester n see what's up. Thanks for the input!

[ll_EvOluTIoN]

So made my boost leak tester n sure enough. Intercooler is leaking hardcore!!! Thanks for the help everyone.

[codyace]

Nice stuff! Awesome troubleshooting by everyone!

[anarchyperf]

So made my boost leak tester n sure enough. Intercooler is leaking hardcore!!! Thanks for the help everyone.

Good find. Let me know if you plan on ordering a new intercooler. I'll hook you up.

[ll_EvOluTIoN]

Hey guys here's an update. I replaced my intercooler and checked for leaks got rid of most of them holds pressure for a min then it goes back to zero. I started it up still cutting out. Drove it just for kicks and when I was almost to my driveway it started revving on it's own so I shut it off before it went up to high. Since I tach wasn't working didn't want to permenently damage engine.

Now I put a decent tps and fresh harness. Same ecu already tried a different maf same prob. Got my rps working :) going forward atleast. Tach bounces off 1500 to 2000 rpm. I disconnected the iacv to see what happens wile running and nothing changed. Still cutting out

[Kemps]

So the engine harness has been replaced? Change the ecu and try again, could very well be a wiring problem.

[ll_EvOluTIoN]

Yea I have a brand new harness. I changed the ecu also to my Buddys ecu I know it fir sure works cuz it just came off his running car.

Should the car turn off when I disconnect the iacv?

[Kemps]

Did you clean the IAC? Spray carburetor cleaner into the IAC passages and see if that works, if not then replace it and see if the idle comes back.

[ll_EvOluTIoN]

Haven't done that yet. So just spray into where the 2 hose connect to right?

[Kemps]

ya just to clean out all the carbon build up in it

[ll_EvOluTIoN]

Thanks for the help.
You think that might have caused that random rev up as well?

[SR20Driftking4lyf]

I did this one time.....smelled like hell, I would do it outside and not in a garage

[Kemps]

it very well could be

[ll_EvOluTIoN]

So I took the iacv all the way off n super cleaned it. Same problem occurs idle bounces from 1500to 2000 n still have the injector cutt off.

Y is it that when I unplug my tps it revs up instead of getting regulated by ecu. Is the iacv used to reg the idle when tps is disconnected?

This same thing happens when I unplug coolant temp sensor.

I did a boost leak test n it holds pressure but looses it after 1min or so. I fill it to 10 psi. Does that leak seam big enough to keep causing injector cutt off?

[ll_EvOluTIoN]

This thing is driving me crazy!! I'm in the sacramento area. If there's any one that's good with srs let me know I'm willing to try anything at this point. Just want this thing to run right!!

[ll_EvOluTIoN]

Hey guys really needs some help. This things been nothing but a headache since I got it!!

Thanks!

[norcalslider]

someone help this man...very similar problems but my injectors arent cutting out.

[ll_EvOluTIoN]

Alright FINALLY!!! So found the throttle stop screw was set way too high I had to move it like half an inch. Finially idling smooth just a little high but I can fix that with iacv adjusting. My vacuum is at 15hgs so it's good. Waiting on a new 02 cuz the one on there was garbage and it will be ready to slide!!

It was so simple never though it be that.

Thanks for all the help!!

[didderson]

I had this problem when I swapped my sr in. Things that fixed it were:

Making sure the IACV cooling lines are hooked up.
Check your timing, my distro was off by a tooth.
The throttle plate was a little too open, adjusted the throttle return screw.
I think thats it.

Edit, awesome dude that's what I like to hear! You can eventually shoot for 18-20mmHg of vacuum but anything 15-20 will make it run nicely at idle!