I had Shiv tune my Smart + Xede + XedeFlash in St. Louis recently; i have a bit of an issue with stalling under certain conditions though that I hope you guys can help me with.

Basically, when the engine is warmed up and I give it some gas and start to move; then quickly clutch-in and stop, the revs will drop too low - for example to 400 revs. In some cases it even stalls; particularly once it is fully warmed up.

I reduced the overlap of the cams a little to see if that helps; the same symptom persists. The car idles nicely otherwise particularly with the decreased overlap.

Here is a log of the AFRs where I did the sequence a cocuple of times in a row. The first time it just dipped too low, the second it eventually stalled. Note that the arrows I added are just "guesstimates" of where I did what - particularly the clutch in.

I turned up the idle screw to ~1000; that doesn't seem to cure it neither. I haven't changed the idle rev setting in the ECU yet though.

Mods are: Xede + Smart, XedeFlash, JDM MR DV, Jun 264 cams, TB exhaust + tubular o2, walbro 255. (So I am running the stock air intake + filter)

Could it be an issue with the LTFTs getting out of whack? (Is there a way to monitor those with the tactrix cable? Vacuum leak? Something else?

Thanks!

 

Check your BOV signal line. Make sure its not pinched. If it's not pinched, switch back to the stock BOV and see if that helps.

 

What mods do you have? A lightweight flywheel and clutch + cams will cause this problem. It can be helped with changing the idle parameters in the ecu. It will not go away completely however.

If you would like an example of what I do to keep the idle nice and steady just shoot me a pm.

I was having the same problems and have helped myself and 3-4 others now, no problems in over a month of daily driving.

 

Thanks, I'll try that. I have been wondering whether the DV migth be aggrevating it.

 

Thanks, I have cams, but I'm still on the stock clutch and flywheel (other mods are in the original post)

 

i have the same problem from time to time as well. i have the exact same setup as you with my cam gears at -2,-2. it only actually stalled once, but i had the lights on, wipers on full, and ac on one afternoon. i just keep an eye on it if i have those conditions and keep a short leash on the gas pedal to remedy it

 

Ok, first checked the DV signal line isn't pinched; looked fine but I loosened it a little more - didn't resolve it.

Then I increased the ECU idle settings a bit, added some more timing down low - didn't resolve it yet neither (might try to tweak this some more to see if it helps).

I then put the stock plastic DV back; I can still get it to go too low/stall though.

EvilBlueEvo8 - are you running HKS or JUN cams?

 

What is your Airflow signal Frequency(HZ) at idle and when this happens? Any way you can log the data with your Xede and send it to me? I've seen this before, but I want to see what the sensors are reporting before I suggest anything..

Some cars do this with the stock intake, but sometimes its surge from the turbo, other times its just venting from the DV into the intake confusing the sensor.. Another thing to check is all the connections on the intake pipe, airbox, etc.. make sure its not leaky, check your MAF sensor too, make sure its not dirty/grungy and the MAF Honeycomb isn't damaged..

You might be able to see if the problem goes away if you increase the tension on the DV so it doesnt vent at idle (partially open at idle)

 

hks 272s

 

Thanks Jack, I'll see what info I can get and will check the suggested items.

 

i would try raising the idle by screwing out the idle air-bleed screw. This screw's location is circled in the pic below. it's best to us a stubby standard or phillips screw driver.

Yeah, the ecu/i.a.c. will try to bring the idle down to its configured idle speed, but if you back this screw out, you'll be relying less on the iac to contrrol your idle, which may help you out.

give it a try, just remeber how much you back it out, so you can back to the way it was if necessary.

 

wot, how many turns per 100 rpm raised? is it better to raise idle the way you describe or by adjusting the throttle cable?

 

IMO it is better to simply raise the idle RPM targets in the ECU. Before I got ECUflash, I used to try to 'tune' my idle by adjusting the BISS, with very mixed results. Giving the ECU a higher RPM target to shoot for at idle has given me much better results.

l8r)

 

^ agreed. Wasnt certain that you could set the idle speed with the xede.

knowing that now, i would increase your idle speed set point to ~950 +/- 50 rpm, but based on the fact that the the ecu is hunting or trying to achieve your idle speed in the situation described in your original post, i would still open the idle air bleed screw up some.

I dont know if you can alter the gain for how the iac responds within the xede.

 

Sorry if my post is misleading ... you cannot adjust your idle speed with the XEDE, you have to use ECUflash and the tactrix cable (a whopping $89 investment. ) to adjust ECU parameters.

l8r)