Kat Stalls Post High Boost Run

[scotty-2-forty]

So I've been driving the ol' gal a little here and there even on the bald drag radials. I've noticed whenever the RPMs drop off from a high-boost run, it stalls. Immediately after a hard run, the RPMs drop down dead forcing me to restart while driving still (put in neutral, feather gas pedal), or keep the revs up while sitting (idling). Otherwise, the engine runs fine. For those who don't know, I use the EMS 4860 stand alone engine management system, GReddy T67 and 96lb injectors. I was thinking it could be too much fuel programmed in when accomodating the higher boost gain. Looking for input, especially those with (or with experience with) stand-alone engine management ... any thoughts?

[scotty-2-forty]

.

[WDRacing]

I don't have any stand lone tuning experience except with the SDS and that was many moons ago, but tuning is tuning. We should be able to figure this out even if you're using something I have zero experience with.

BTW, while I'm thinking about it, you don't post in here enough. IIRC you have build thread(s) NOT in the KAT forum, where's the love?

Back on topic

BOV vented to the atmosphere?
What are the AFR's when at full boost?
Does the ECU trigger the IACV to open upon throttle closure? Is it a timed sequence kind of thing? Are you even using the IACV?
Does it back fire on decel?
What system are we using? Haltech, AEM?

I can go look at some tuning options

[scotty-2-forty]

... you don't post in here enough. IIRC you have build thread(s) NOT in the KAT forum, where's the love?

Bah, sorry. I find myself so addicted to one particular forum that I tend to forget about all the others.

... BOV vented to the atmosphere?
What are the AFR's when at full boost?
Does the ECU trigger the IACV to open upon throttle closure? Is it a timed sequence kind of thing? Are you even using the IACV?
Does it back fire on decel?
What system are we using? Haltech, AEM?

I use the AEM/EMS 4860 ... http://www.enginemanagement.com.au/prod ... cts_id=129

I run two BOVs, one on the hot side, one on the cold. The HS recirculates; the CS vents. It is just the way the system was designed from the getgo about 8-9 years ago. It's worked fine that way for a long time. I've been considering closing off the vented one for some time. I also do not run a MAF, as the EMS accomodates this.

I'll look into the AFR at full boost and the ECU triggering teh IACV, as I don't know that right now. It has backfired on deceleration a few times, yes.

[biggie]

Most common is the IACV being dirty.

[scotty-2-forty]

Most common is the IACV being dirty.

I was going to look into that when I got home yesterday, but my girlfriend's stooooopid 16 year old daughter was stone cold drunk ... took her to the police station for a breathalizer ... now proves she'll have to be "babysat" for the whole summer - eeesh! It's off to grandma's house she goes!

Anyway, thanks for a tip Biggie. What's more important to mention now is that the car did the same thing yesterday driving home, without any high boosting; just normal driving. Didn't stall until about 20 minutes into stop-n-go city driving. Sooooo, I'm still planning on getting into that IACV tonight.

Any other ideas???

[WDRacing]

Seafoam the intake homie.

[scotty-2-forty]

Hmm, will do. What do you think; do the gas tank, crankcase and intake mani? Anything outside of this link that I should be aware of?
how-to-seafoam-your-engine-the-right-wa ... 26583.html

[WDRacing]

I didn't read all of that thread, but I have used Seafoam before on I think every vehicle I've owned. Don't drive your car around with Seafoam in the oil. That's just a bad idea, aside from thinning the oil it's circulating all the crap that it's helped dissolve.

Change the fuel filter and plugs after you foam it, basically when the fuel level comes close to E it should have done it's job and that's when I changed the plugs and filter.

As far as the intake goes...when people say it smokes...it seriously smokes...lol. I actually leave the neighborhood when I do it.

[scotty-2-forty]

.. As far as the intake goes...when people say it smokes...it seriously smokes...lol. I actually leave the neighborhood when I do it.

Yeah, that's what I'm afraid of. I'm in pretty close proximity to my neighbors.

[trackslut240]

run a pipe to the bathroom exhaust...lol... no dont do that...
it does smoke a lot, but advantage is it will get rid of all the bugs and flies in the neighborhood.
hello good neighbor, are you mosquito free now?? What? you are not, let me start that sprayer again. lol..

[WDRacing]

.. As far as the intake goes...when people say it smokes...it seriously smokes...lol. I actually leave the neighborhood when I do it.

Yeah, that's what I'm afraid of. I'm in pretty close proximity to my neighbors.

http://www.youtube.com/watch?v=ACHibS1KIaA

[C-Kwik]

Make sure all connections are tight. Its possible that during high boost, you created a boost leak. Keep in mind the connector can still be in place and still leak air, so it may not be apparent on first inspection.

[scotty-2-forty]

Make sure all connections are tight. Its possible that during high boost, you created a boost leak. Keep in mind the connector can still be in place and still leak air, so it may not be apparent on first inspection.

Hmm, this gets me thinking ... maybe one of the BOV's is not operating properly and causing a surge when pushed to a certain limit?

[WDRacing]

Just plug them real quick, blast up the highway for a test and you'll know right away.

[scotty-2-forty]

Just plug them real quick, blast up the highway for a test and you'll know right away.

Plug them???

[C-Kwik]

Hmm, this gets me thinking ... maybe one of the BOV's is not operating properly and causing a surge when pushed to a certain limit?

Surge compressor surge isn't going to cause stalling. BOV open to avert surge. Failure to open would induce surge, but isn't going to stall the motor out. The only way a BOV could fail that would cause this issue is if it leaked air. In which case, surge likely isn't going to occur.

[WDRacing]

Just plug them real quick, blast up the highway for a test and you'll know right away.

Plug them???

Cap them off, plug the openings, disconnect them, remove them from the equation

[scotty-2-forty]

Gotcha ... not thinkin' straight! ... Thanks.

[WDRacing]

Gotcha ... not thinkin' straight! ... Thanks.

Happens to the best of us...we're not getting any younger either...lol.