SR High Idle & Other Issues

[jscherf92]

I've found about as much information as I can and I still can't track down the problem with my engine. Its an s13 blacktop SR, all stock internals, ecu shows code 55. fuel pressure is 43 psi, followed guides on setup.

Now my main problem is a high idle, around 1500, even when its nice and warm. I've adjusted the IVAC all the way down and it doesn't get below 1450-1500. I haven't touched the TPS sensor position or anything on the throttle body. The ONLY change I got was when I re-ran the vacuum lines to the wastegate. Originally I had it set up according to the FSM with the boost control solenoid, I ran the wastegate straight off the hot pipe and the idle dropped to about 1200.

Timing shows about 15 degrees but with the high idle I know its not where it should be. Cam timing is spot on but I still feel like ignition timing is off.

Secondary problems are less power from the engine, and the transmission tunnel gets much hotter than it should in my opinion.

I am working on getting a wideband air fuel gauge to get more information, as well as a ECU Talk Consult cable, but the car budget is pretty tight so it might be a few weeks.

If there is anything else I can check or test to narrow down the problem please let me know. I'm just looking for some input, I've searched this and other sites and I will continue searching until I figure it out. My plan is to somehow lower the idle, then set the ignition timing and everything should be solved.

Tomorrow i'm getting some starter fluid/brake cleaner to check for leaks around the intake manifold. problems came up after new head gasket, new intake manifold, new fpr, bov and IC piping.

[Kingtal0n]

engine rpm is related to airflow. you have an enormous vacuum leak.

note that this may be inside your airpath, such as a bent throttle valve, or broken IACV.


Start by removing or plugging your IACV hose so as to eliminate the IACV as a source of problem. Without the IACV feeding air, the engine should nearly shut off.
The throttle body itself should be water-tight, the only other place for air to enter is from the valvecover (crankcase->intake). Or from emission equipment (if you car has "air" or EGR valves this can cause similar problems) I am not familiar with KA24 emissions control.

[jr_ss]

I'd clean the IACV. They are known to get dirty, and/or buildup inside causing issues.

[ultimateirving]

I'd clean the IACV. They are known to get dirty, and/or buildup inside causing issues.

This is true.

Also codyace had posted a method on how to set timing by revving and watching the timing marks as the Rpms drop.
Lastly since this is a new build, perform a boost leak test because turbo.
It's cheap and easy.


Once you get consult hooked up you can verify the car is in timing mode and set the timing that way. You can also review all sensors such as tps to make sure it's showing closed throttle at idle.

[jscherf92]

awesome, thanks for all the info everyone. looks like ill take my time and get the consult hooked up, and hunt down that leak. I'm thinking its probably the intake manifold gasket because I just had that off recently, could also be IC piping from swapping in new T-bolt clamps...

[jscherf92]

checking back in, I went through half a can of starter fluid and the engine didnt react any differently so Im assuming no leaks but like Kingtal0n said it could be internal. I did the test pulling each injector and they all reacted the same, so they're all good and fuel pressure is still at 43psi on the gauge.

I manged to get the idle back down to ~1100 by removing the IACV air hose from my coldpipe and then putting it back in place. When plugging the hose the engine completely died.

I will also need to re-stab the CAS because I cant quite get it back to 15 degrees now that the idle is lower.

Any other tests or info you guys can give me would be appreciated.

[steve shadows]

Can you force the idle down with the throttle plate screw just for the purpose of checking the timing right? The TPS just needs to be unplugged and try to get the idle down to within 750-950 rpms.

Then get an old spark plug wire from a KA and jame it into the inside tunnel of the no. 1 coil pack and the other end onto the spark plug on number one. Then hook up your timing light to this spark plug wire.

This will give you the best reading for setting base timing. Then once you're 100% sure this is right (which from the sounds of it your base timing is def off) then you can reconnect the TPS. turn off the car and get out a volt meter.

Now check the TPS and adjust with a volt meter. .400 v closed and 4.00 v full open is a good range. Make sure as you turn the throttle plate up and down with your hand this voltage out also changes on the voltmeter screen to validate that the TPS is actually working right. You just need the key in the ON position to do this. don't have the car on.

I would start with these two steps.

Then readjust your throttle screw and the IACV together to aim to get the best possible idle.

Then turn the car off and go back and re-calibrate the TPS one more time.

This is how I would start off. Thanks :l101: