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05-16-2007, 11:26 AM | #1 |
Scooby Guru
Member#: 9960
Join Date: Sep 2001
Location: in bed...
Vehicle:2002 Impreza WRX WRBlue Perl |
Random stumbling with Hydra while approaching 0psi... ideas?
I finally got my car back on the road after a month of being out of action for my engine and ecu upgrades. Engine is running fine, but am having some issues with the Hydra unfortunately.
I had my tuner do a startup map on the car which worked successfully, and then had him tune the car up to 4500rpm for break-in. We noticed that at random spots and different throttle positions while comming up to 0psi, there was a stumble or hesitation in the car, but always while in vacuum as I am approaching 0psi of boost according to the OEM boost guage and the boost guage on my Eboost 2. Occurs randomly in all gears and different throttle positions as the boost guage is approaching 0psi of boost, we experience a single stumble/jerk as the revs are climbing. The Hydra was originally running an AEM external map sensor, and thinking that this was the cause, I had my mechanic switch back to the Hydra's internal map sensor, but the problem persists. At random areas and different throttle positions, as the car is accelerating, we get this split second hesitation. Feels like fuel cut jerk or something. Now, my tuner says that it is a very dangerous condition that needs to be fixed before the car can be tuned further, but I am out of ideas as to what the problem could be. We tried installing a ground wire on the engine, but no dice. We were thinking that it could be the alternator interfering with the signal from the external map sensor to the hydra, but that is not the problem either since the problem persists even on the internal map sensor for the hydra. My tuner is convinced that there isn't a tuning issue as it was occurring at random areas of the map in a random fashion that run fine the next time the ecu goes through those load areas. Sometimes it occurs, and other times it doesn't. He believes that there is a hardware issue somewhere, but not sure where else to look really. One other thing that happened also was that twice now, while cruising on the highway at a steady 60mph, the hesitation would show itself repeatedly and continuously out of the blue, leaving the car unable to maintain its set speed as it jerks. As soon as I disengage the cruis control and disengage the clutch and try to give a little bit of gas to free rev the engine (all the while staying out of boost here and below 4K), I was met with more of the same stumbling. When I clutched in to downshift, the revs dropped and the engine went out. When the engine went this time, the dash was lit up, so we know that the Hydra was receiving power. As soon as I rolled to a stop on the hard shoulder, I immediately tried restarting, but no dice. engine just cranked. It was not until I sat on the side of the road for a couple of minutes that the car fired up like normal and I continued on my way like nothing happened. Rather wierd. Any ideas as to where the problem could lie? The hydra is mounted in the location of the stock ecu underneath the kick panel on the passenger side of the car. Sorry for the long-winded post, but I wanted to get everything i experienced down just in case it might help diagnose the problem.
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05-17-2007, 02:42 AM | #2 |
Top Scoob 002
Member#: 32771
Join Date: Feb 2003
Chapter/Region:
BAIC
Location: Danville, CA
Vehicle:03 Black WRX 04 White M3 |
Doesn't sound like a tuning issue if it happens at random areas of the map sometimes and then other times it doesn't.
What kind of voltage are you seeing when this issue is happening? Maybe check the wire on the alternator (one that is secured by a 12mm nut) I once had this come loose and my car would randomly start bucking while cruising and voltage would get low. Also is your fuel pump ground secure on your intake manifold? My friend once had his ground loose and the car would sometimes not start and also buck. I would just go over all the grounds first to make sure they are connected. |
05-17-2007, 12:56 PM | #3 |
Scooby Guru
Member#: 9960
Join Date: Sep 2001
Location: in bed...
Vehicle:2002 Impreza WRX WRBlue Perl |
hmm definitely things to check... thanks for the tips Dan.
My mechanic says that if worse comes to worse, he will change out the Hydra box for a new one, but if there is a simple solution to the problem then that's always better right? I have the oem volt meter on the car, and don't notice the voltage dropping or anything when it occurs... just happens out of the blue, then the two occasions when the car just stumbled itself to a halt on the highway... no fun |
05-17-2007, 03:04 PM | #4 |
Scooby Newbie
Member#: 61371
Join Date: May 2004
Vehicle:2002 BMW 330ci Alpine White |
had the same sort of problem on my 03 with Hydra. At around 3300rpms, when i was coming into boost the car would hesitate REALLY bad, then hit boost and take off. very annoying and made driveability miserable, part of the reason i parted the car out and sold it.
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05-17-2007, 04:44 PM | #5 | |
Top Scoob 002
Member#: 32771
Join Date: Feb 2003
Chapter/Region:
BAIC
Location: Danville, CA
Vehicle:03 Black WRX 04 White M3 |
Quote:
Did you ever tune the car or just run it off the base map? I mean my base map had some hesitations when going into boost but thats because not all setups are the same. My car needed a good amount of fuel added during the spool up area and once that fuel was added the car became very smooth. Seems like you gave up instead of trying to work out the kinks. |
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06-01-2007, 10:39 AM | #6 |
Former Vendor
Member#: 54918
Join Date: Feb 2004
Chapter/Region:
MAIC
Location: Gaithersburg, MD
Vehicle:673 WHP Element Tuning Pro Comp Engine |
Sounds like a tuning issue to me. So often I see this when maps are emailed to me and they are not smooth at all. If your fuel map is not smooth then the car will not drive smoothly. Also hesitations are usually a sign of the fuel map being too lean. This appears to be the case due to your hard starting which is also a sign of the fuel map being too lean.
There could also be mechanical problems causing the lean condition so dont overlook that. You can email me the map for review on Monday when I am back in the country. Thanks, Phil www.elementtuning.com |
06-01-2007, 07:20 PM | #7 |
Scooby Guru
Member#: 9960
Join Date: Sep 2001
Location: in bed...
Vehicle:2002 Impreza WRX WRBlue Perl |
Hi Phil,
I *think* we may have the issue... It was the injectors having the wrong settings keyed into them on the Hydra. My tuner was given the wrong settings for the UR injectors that i am running on the car. I believe they were 2 ohm or something, and he was told 5ohm. It seems that the wrong settings would cause the injectors not to open at all at random times or something to that effect, causing the stumble . Here is the story that led us to the discovery on the injectors: The unit again left me stranded again on the highway last week. Cruising with CC set at 60mph, then all of a sudden, stutter stutter stutter stutter stutter...continuously, and the car can't maintain speed anymore. I disconnected cruis control and tried to give gas, but the revs just would not climb at all. I pulled over to the side of the road where the engine just sputtered itself out. No black smoke or anything coming out of the rear at all. After 10 -15mins on the side of the road, it fired back up again like there was nothing wrong, and would continue like normal. A few miles later, the sputtering returned and again I had to get off to the hard shoulder of the highway. When I pulled the hydra out to see if anything was disconnected, i noticed that it was pretty darn hot! as in hot enough that one would think a computer fan should be included to keep the unit cool or something. Thinking that the problem was a short circuit caused by the box of the hydra touching metal in the car. I laid it on the carpet, and waited for the unit to cool again. After another 10-15mins, it started up again and I was on my way. After getting to my mechanic's shop the next day, we were discussing with Andrew from Hydra what could have been causing it. They had a look at the map and thought that the injectors did not match the fuel map i was running, and had my mechanic run a multimeter across the terminals of the injectors. It was then we found that the wrong Ohm settings were given to us by UR (an honest mistake by their supplier i later found) for the injectors. Aparently, the settings were causing the hydra's injector drivers grief and in some instances not allowing the injectors to open, causing the hesitation. After changing the ohm setting on the hydra, the random hesitation seems to have gone, and the fuel map had to be retuned by my mechanic (who works with Hydra's but isn't a tuner by trade... although he does minor stuff like drivability and the like). Unfortunately now, at anything under about 10***37; TPS, the car hesitates. Give it more gas, and its like normal.. I know this is a tuning issue also, but at least the main problem I had in the first place with the hesitation in random areas of the map and the sputtering to a stop on the highway *might* be solved. Not sure...more testing is needed with this new map (which isn't perfect either, but is enough to get me around to continue breaking in my engine). This is pretty much how things are right now with the car. The hesitation seems to have gone, but now at less than about 7% TPS, there is a hesitation... but i don't notice my egts rising either at that TPS, just hickuping in the power delivery. As i said, I am sure that this is a tuning issue, and i can drive around it until i get a proper tune for the car. I will have to do more long distance driving to see if the car decides again on the new injector settings to stutter itself to a stop again on the highway after 2 hours of driving like it did last time. |
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