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Old 02-24-2006, 04:51 PM   #1
qhatherly
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Default Hydra Fuel/Ign Cut When Stopping

This is a problem that goes way back to when i first installed the hydra, i'm just getting around to looking into it in detail now.

I've seen this covered before so hopefully someone can give me at least an idea of what to look into.

Every once and a while (seems completely random) my car stalls when i depress the clutch coming to a stop. Sometimes it catches itself around 500rpm, sometimes it just dies outright.

I've logged this numerous times and the only difference between then and a normal stop (no stall) is the fuel and ignition cut out completely as soon as i take my foot off the throttle. At this time my vacuum is higher (600 rather than 300-360) but i'm not sure if its the chicken or the egg. All the other logged data appears to be completely unrelated. I've tried changed my max vacuum to 759 just incase that was the issue. I've also turned off pretty much everything related to any kind of fuel and ignition cut like launch control, decel cut, ect. and I changed all the other ignition maps to a flat 15. I left my alternate fuel maps what they came as b/c i just wanted to see if there'd be any change, unfortunately ignition continued to drop to zero in these instances.

I always contributed this to a bad tune on my part but what is confusing me is the immediate drop to 0 of both fuel pulse and ignition advance.

Problem numero 2 is that i recently swapped out my 5mt for a jdm 6 speed and now my vss jumps all the way up to 256 when im idling in place, or when im moving. My cluster doesn't though. Thats a little bit less of an issue for me but i wouldnt mind taking care of that too.

If anyone can help me im open to any and all ideas. Thanks.
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Old 02-24-2006, 05:13 PM   #2
qhatherly
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I should probably add this too, neither the fuel or ignition maps reach zero at any point.
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Old 02-24-2006, 05:15 PM   #3
bboy
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Raise your Moving Steps value. I think it's under Settings-->Injection (might be ISC). This will raise your idle slightly when the car is in motion. Try bumping it 10% of whatever the value is now and see if you still have stalling.

Another thing to do is under Settings-->ISC, with the car warmed up, raise the ISC PWM Min value until your idle RPM rises, then back off by one. This value has the ECU tell the engine "at least this much air" will be let in under idle. This value can contribute to stalling, and it's not a bad thing to tune on your car anyway.

Do the ISC PWM Min first, then the Moving Steps.

Leave max Vac at 610. I promise the two suggestions will fix your stalling problem.
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Old 02-24-2006, 05:19 PM   #4
qhatherly
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Already tried both, thanks anyway though.
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Old 02-24-2006, 05:38 PM   #5
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When and tried them again just incase and neither isc pwm duty settings seem to have any effect on idle, i can set the min as high as it'l go and idle won't budge. I seem to remember the PID's not having any effect either. Didn't think much of it at the time.
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Old 02-24-2006, 11:09 PM   #6
Warp3
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Hmmm...this topic caught my eye because my car does this as well (though I'm not sure I have any datalogs of it happening, so I don't know if the 0 fuel / 0 ignition thing is true on mine). It's also odd that mine is a 99RS as well and I, too, disabled decel cut and bumped the "moving steps up" setting without effect (haven't touched the ISC PWM settings, though). Actually, maybe this is related to why my car won't idle above about 900rpm or so even when it is cold (when it should be idling at more like 1500rpm according to my idle target map).

{subscribes to thread}

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Old 02-25-2006, 11:53 AM   #7
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RS guys,

The ISC Min and Max settings may not help you since some of these cars have stepper ISC valves.

I have never tuned an RS but the EVOs use a stepper ISC valve also so I can give you some tips:

I usually set the EVO PID settings to 200, 200, 35. If your idle is lower than your target then lower the integral and if it's too high increase the integral. Increasing your vehicle moving steps will help but it's a crutch since that's not the root of the problem. The bottom line is that your idle fuel tuning sucks

The best way to tune your idle fueling is to increase the idle to 1600 rpm, tune it to 14.2-14.5 AFR, turn AC on and tune the other load sites, lower the idle slightly and repeat until you are down to about 900 rpm. I've have my idle tuned all the way down to 400 rpm.

The next step is the most critical and is really the root of your problem. When clutching in fast under deceleration, the selected load cells are usually in the next lower load column. Turn your deceleration fuel cut off before tuning this. Blip the throttle while at idle and track the fuel cells used and tune these to match your idle AFR. When this is done correctly you will find when you clutch in the idle will catch at a much higher rpm and then slowly drop to your target. Having an AFR too rich or too lean will cause it to drop way below the target and sometimes even stall out as in these cases.

Also Iíve had best luck not using deceleration fuel cut at all and instead tune the deceleration portions of your fuel map instead.

Good luck!

Phil
www.elementtuning.com
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Old 02-25-2006, 12:11 PM   #8
qhatherly
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Thanks alot for your help, i'll definately give that a try today, but what's really troubling me is the seeming randomness of it, and more importantly the imidiate drop of fuel and ignition to 0 as soon as tps hits 0 (decel fuel cut is disabled) and it remains 0 until it either dies, or catches around 500 rpm or lower. This only happens mayb once a every half hour or so of driving, but it can be every 5 minutes or go a day or 2 without doing it.

This especially bothers be because nowhere on my map does fuel or ignition even approach zero, and all possible fuel/ign cuts are turned off.

What else could cause an immidiate drop of fuel and ign adv to 0?
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Old 02-25-2006, 06:33 PM   #9
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That sounds like you are loosing your crank/cam signal. I don't sell many RS units but haven't had any issues with any recent sales. You should either contact your dealer or Hydra EMS directly. I know on the older RS units this could happen so the circuit/software was updated to boost the signal.

Phil
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Old 02-25-2006, 07:22 PM   #10
qhatherly
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ahhhh, I was afraid it was a problem with the unit itself
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Old 02-26-2006, 08:30 PM   #11
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well turns out that isn't it, so the search goes on...
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Old 02-27-2006, 03:24 PM   #12
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If there is anyone out there with an RS that doesn't do this, could you shoot me a map to qhatherly (at) shaw.ca so i can take a look at what i'm doing wrong? I would appreciate it like you would't believe.
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Old 02-27-2006, 04:55 PM   #13
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Just to completely throw a wrench in the works, my car idled normally today for the first time in a long time...it didn't attempt to die at a stoplight even once this morning. (In fact, it is almost working *too* well, so I may have to move my "proportional" and "moving steps up" values back down a bit now.)

The only change I've made since my previous post was some interior work over the weekend (reinstalled cruise control stalk in dash (since I have a Momo steering wheel as of a week or so ago), connected horn on Momo hub/wheel setup, removed fog light switch (since I'd already removed the foglights a long while back), etc.). I couldn't imagine any of that affecting the ECU.

I had considered installing my grounding kit and ground wire upgrade kit this weekend, but I'm kinda glad I didn't now, or I would have assumed the grounding kit had made the difference.

Shane
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Old 02-27-2006, 06:39 PM   #14
qhatherly
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Good 2 hear, hope it keeps up.
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Old 02-28-2006, 11:03 AM   #15
Warp3
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Nope...this morning it was back to its normal low-idling self again (with no changes, that I'm aware of)...{sigh} I have enough fun with intermittent computer troubleshooting at my job, much less doing this for "fun"...

BTW, if it makes any difference: Unlike qhatherly, my car is naturally aspirated (though it does have Cobb spicy cams). Also my car has a lightweight flywheel (9lb SPEC aluminum flywheel), which I'm sure doesn't exactly help since the RPMs drop more quickly.

Shane
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Old 03-01-2006, 06:55 PM   #16
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The lightened flywheel is a hassle. I'm only about 20% lighter and I notice I "kill" the engine much more easily + I've had to up the PWM and Moving Steps to compensate.

You may want to consider a solution that is similar to the "idle adjustment screw" on a carburator to keep the throttle open just slightly and raise your idle speed. From what I've read so far here, it doesn't sound like the Hydra is controlling your idle much at all (no PID, no PWM control).

Phil's suggestion to fatten up the load sites below your idle RPM will help too.
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Old 03-14-2006, 12:44 PM   #17
Warp3
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FWIW, yesterday I tried importing an old spark map (a more aggressive one) from before I had begun taming the ignition timing to try and fend of a high knock voltage issue and the car idles FAR better with this spark map (and no other changes) and doesn't try to die at idle when I clutch in now. The ignition timing at the cell for warm idle (900rpm) is pretty close to what I already had, but the cell above it (1200rpm) is notably higher.

The problem was that a few of the times I lowered the ignition advance, I lowered all (or nearly all) of the map, so I was messing with areas that were perfectly fine. Too bad there isn't some sort of "reduce this section by x%" feature, so I could scale the map more easily instead of having to freehand it.

Any improvement with your issue, qhatherly?

Shane
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Old 03-15-2006, 09:54 AM   #18
qhatherly
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still the same, but i'm headin down to minnesota for a tune in april, so hopefully this all gets taken care of

good 2 hear ur idle problem's taken care of
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Old 03-15-2006, 04:02 PM   #19
Element Tuning
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Quote:
Originally Posted by Warp3
FWIW, yesterday I tried importing an old spark map (a more aggressive one) from before I had begun taming the ignition timing to try and fend of a high knock voltage issue and the car idles FAR better with this spark map (and no other changes) and doesn't try to die at idle when I clutch in now. The ignition timing at the cell for warm idle (900rpm) is pretty close to what I already had, but the cell above it (1200rpm) is notably higher.

The problem was that a few of the times I lowered the ignition advance, I lowered all (or nearly all) of the map, so I was messing with areas that were perfectly fine. Too bad there isn't some sort of "reduce this section by x%" feature, so I could scale the map more easily instead of having to freehand it.

Any improvement with your issue, qhatherly?

Shane
Glad you worked it out. It sounds like you are using software 2.12 since 2.14,2.16,2.17, and 2.5 all have multiple cell edit. All you do is hold the cntrl key and use your arrow keys to highlight multiple cells for edit.

Thanks,
Phil
www.elementtuning.com
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Old 03-15-2006, 04:13 PM   #20
Warp3
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Quote:
Originally Posted by Element Tuning
Glad you worked it out. It sounds like you are using software 2.12 since 2.14,2.16,2.17, and 2.5 all have multiple cell edit. All you do is hold the cntrl key and use your arrow keys to highlight multiple cells for edit.

Thanks,
Phil
www.elementtuning.com
No, I've got 2.14v11 and I use the multiple cell edit feature constantly, so I'm sure it is there...hehe What I'm referring to is the lack of ability to scale values. In other words you can drop the selected fields on the spark map by "2 degrees", but not by "10%". Considering how many of the maps are "curves" by nature, the ability to scale by a percentage would be very valuable.

Shane
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