Other 3.5 UTEC guys chime in
#1
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Other 3.5 UTEC guys chime in
So Aaron and I have been talking, and we have been having the exact same problem with our UTECs.
Any time the UTEC itself is cold (45 degrees or less), we get a random/occasional misfire that is just like pulling a coil plug then plugging it back in. This only happens at partial throttle and idle, haven't had it happen at WOT. As soon as the cabin of the car heats up (the UTEC gets warm), it stops completely and never comes back. Obviously, this problem doesn't happen whatsoever when it's above 50 degrees.
I'd like to hear from other UTEC guys. Include how you have your UTEC installed and whether you notice anything similar.
Please don't clutter this thread with random opinions and comments if you don't have anything constructive to add.
Any time the UTEC itself is cold (45 degrees or less), we get a random/occasional misfire that is just like pulling a coil plug then plugging it back in. This only happens at partial throttle and idle, haven't had it happen at WOT. As soon as the cabin of the car heats up (the UTEC gets warm), it stops completely and never comes back. Obviously, this problem doesn't happen whatsoever when it's above 50 degrees.
I'd like to hear from other UTEC guys. Include how you have your UTEC installed and whether you notice anything similar.
Please don't clutter this thread with random opinions and comments if you don't have anything constructive to add.
#5
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Why would we run a MAP sensor N/A? You can't get proper resolution for tuning that way. There are tons of threads on my350z that reinforce my opinion, if you want to dispute.
The reason I didn't post this on my350z is because they have a different ECU than us and do not have the same problems as us, it's as simple as that.
The reason I didn't post this on my350z is because they have a different ECU than us and do not have the same problems as us, it's as simple as that.
#7
I don't have UTEC but I notice the exact same thing when it's really cold out with a VAFC. This probably doesn't help your thread, but maybe it does. Sometimes my SES light will flash and that it just randomly stops.
#8
if you want to sit here and dispute , I can have my Standalone tech guy dispute with you all day on a fourm on on a phone call , im not here to go back and fourth with anyone.
I was merely asking a question as my tech guy that tunes ask the same question , weather your N/A or F/I.
I have ZERO issue on what your describing , but I guess your a bit on the touche side for my opinion.
Good luck
#9
+1 to NizMo.
The MAP/Baro could screw up cold operation if the signal isn't read properly. Maybe the TXS MAP sensor is a solution.
My buddy's stock RX8 had a bad MAP/Baro sensor and the first sub-45* day we had it would not start. Just cranked. Even though the car uses a MAF reference system.
The MAP/Baro could screw up cold operation if the signal isn't read properly. Maybe the TXS MAP sensor is a solution.
My buddy's stock RX8 had a bad MAP/Baro sensor and the first sub-45* day we had it would not start. Just cranked. Even though the car uses a MAF reference system.
#10
the UTEC uses temperature compensation info from the IAT and since its MAF, the baro reading wouldnt mean anything. However, it sounds like theyre describing issues which are present when the UTEC is not altering signals, cause he said not WOT
#11
What sparks described in the OP is EXACTLY what my car does. I do not have my UTEC hardwired in though like he does. I am using a custom plug and play harness.
The colder the ambient temp gets, the worse and more frequent my misfires are. My misfires start to happen when the temp is below 60 degrees. This evening, I drove my car to the gas station real quick to fuel up for a meet tomorrow. It was 33 degrees outside. The coldest I've ever driven my car since getting the VQ35 engine and UTEC in my 92 Maxima. It was TERRIBLE. It not only happened more frequently, but it seemed to cut more cylinders at a time resulting in more of a stumble. The misfire only seems to happen during closed loop operation or whenever the UTEC does not take over (ie >70% throttle position). So the idle stumbles as well as very light partial throttle and cruising speeds (ie 55mph).
I talked to Jime via PM and he said he does not get any kind of misfire ever. Even when it's extremely cold up in Canada. His UTEC setup is hardwired. He should have used the exact same wires as you have Sparks.
I'm not. I believe I'm using the same or similar settings as sparks. Open Fuel MAF.
That could be useful since the misfire issue may not be a UTEC problem, but a wiring problem. My PNP harness is connected exactly like it would be from the factory. What I mean by that is that OEM ECU harness connectors were used along with the proper terminals that snap into place.
I believe Sparks setup is hardwired, but everything is soldered properly.
Yes. My Temp Correction tables have not been touched. Plus, as you mentioned, the problems seems to be happening when the UTEC should not be altering the signals. But I know for a fact that the UTEC does alter the signal, even on Map 0. Several 350z guys have confirmed this as well.
Also, one more thing to point out. I have never had my car misfire while at WOT. My timing and AFR is always spot on while making a WOT run. So at least the UTEC does it's job at WOT. That's all I really care about. But it would be really nice to be able to solve this misfire problem.
The colder the ambient temp gets, the worse and more frequent my misfires are. My misfires start to happen when the temp is below 60 degrees. This evening, I drove my car to the gas station real quick to fuel up for a meet tomorrow. It was 33 degrees outside. The coldest I've ever driven my car since getting the VQ35 engine and UTEC in my 92 Maxima. It was TERRIBLE. It not only happened more frequently, but it seemed to cut more cylinders at a time resulting in more of a stumble. The misfire only seems to happen during closed loop operation or whenever the UTEC does not take over (ie >70% throttle position). So the idle stumbles as well as very light partial throttle and cruising speeds (ie 55mph).
I talked to Jime via PM and he said he does not get any kind of misfire ever. Even when it's extremely cold up in Canada. His UTEC setup is hardwired. He should have used the exact same wires as you have Sparks.
I'm not. I believe I'm using the same or similar settings as sparks. Open Fuel MAF.
I believe Sparks setup is hardwired, but everything is soldered properly.
Also, one more thing to point out. I have never had my car misfire while at WOT. My timing and AFR is always spot on while making a WOT run. So at least the UTEC does it's job at WOT. That's all I really care about. But it would be really nice to be able to solve this misfire problem.
#12
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Again I will repeat myself. After the UTEC heats up with cabin heat (ITS STILL COLD OUTSIDE), the issue goes away and there is not a single hiccup. I can leave the car running for 2 hours without the heater on and it will keep doing it. The moment I turn the heater on and the UTEC unit gets warm, it stops. This is obviously related to the temperature of the UTEC itself, and not with my tuning method since it runs perfectly in cold weather as long as the UTEC is warm, and has ZERO issues at WOT (when the UTEC is acting as a standalone) even when the UTEC is cold.
I looked into running the map sensor N/A and was turned away from it by several of the "pro tuner" UTEC guys on my350z saying that the MAF had much better resolution and less problems tuning on a N/A vehicle. As a bonus you still get to use maf pulldown in open loop using MAF for load indication instead of having to fill in IPW for each load cell as you do with the MAP. It is much more simple to work with when self tuning and very precise. I'm not just pulling this out of my *** and I am not willing to argue on this thread about it. If you feel the need to keep cluttering the thread with it, you can PM me instead and tell me how horribly wrong I am.
I am not asking you guys to speculate on how it could be my IAT, or the fact that I'm not using a MAP sensor. This happens whether it's on map 0 or otherwise, and goes away when the UTEC unit warms up, which pretty much rules out this being tune related.
I am asking for other people who have spliced or patch harnessed a UTEC into their older (non 6th gen+) ECU to chime in on whether they experience anything similar. You guys can take it as me being an *** hole if you want, or you could just read what I'm saying and try to understand.
#13
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If I can get more information about others installation and whether they have this issue or not, it will be easier to track down. Thus why I said I don't want random comments... lol
#14
i dont THINK i have this problem, but my UTEC doesnt work 100% so it hasnt been in the car for a while. ill try to check it and confirm, sooner or later
you should try to log the ignition and the a/f when it is doing this to see if the UTEC will show what the problem is
you should try to log the ignition and the a/f when it is doing this to see if the UTEC will show what the problem is
Last edited by Gemner; 12-19-2009 at 05:41 PM.
#15
Yeah what I'm really trying to get at with this thread is that it's possibe that Darren has spliced(connected with patch harness) a wire or 2 that other hardwired/path harnessed UTEC users did not that is causing the issue without his/our knowledge.
If I can get more information about others installation and whether they have this issue or not, it will be easier to track down. Thus why I said I don't want random comments... lol
If I can get more information about others installation and whether they have this issue or not, it will be easier to track down. Thus why I said I don't want random comments... lol
Also, one other thing I'd like to note. On a nice cold morning (45 degrees), I decided to put a space heater in my car for 30 minutes to get the cabin nice and warm. When I cranked up the engine, no misfire. Nothing. And 45 degrees has always made my car misfire 100% of the time.
When I would reach down and feel the cover of the ECU and UTEC and they would be cold to the touch, that's when it will misfire. When the cabin gets warm enough that they do not misfire, the covers on the ECU and UTEC do not feel cold at all.
I feel the more information I provide in this thread, the better of a chance that someone will be able to help out.
#16
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Ok. Also list the wires you've spliced/patched if you have them handy. I'll get with darren (or he'll find this thread) to illuminate exactly which ones he's putting through our UTECs.
#17
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edit: And I'm not at all down on Darren's work. His wiring is extremely professional and down right perfect in my car, I wouldn't have picked anyone else for the job. I'm just saying wire choice could be a possibility with our problem, since it's perplexing that we're the only ones (that I know of) experiencing the EXACT same problem without any word of such a problem on my350z
Last edited by sparks03max; 12-19-2009 at 05:45 PM.
#18
Also, I do notice that when it misfires, my wideband gets a tad richer for a split second. It would go from about 14.5 to 13.5 all in that fraction of a second and right back to 14.5. But that is due to unburnt fuel most likely.
#19
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I did try logging for a little while in 50 degrees and couldn't see anything out of the ordinary when it would hiccup occasionally. But I'd like to datalog when it's misfiring often with temps in the 30s. When it's 30 something outside, at idle, the engine would stumble about every 3-5 seconds. When it's 50 degrees, it would only stumble at idle about every 15 seconds.
Also, I do notice that when it misfires, my wideband gets a tad richer for a split second. It would go from about 14.5 to 13.5 all in that fraction of a second and right back to 14.5. But that is due to unburnt fuel most likely.
Also, I do notice that when it misfires, my wideband gets a tad richer for a split second. It would go from about 14.5 to 13.5 all in that fraction of a second and right back to 14.5. But that is due to unburnt fuel most likely.
#23
yeah, or how its related to the difference between how we wire it and it being plug and play. i was tempted to say that its a problem with the wiring/resistors in the UTEC but then it would be causing a problem in plug and play apps too
#24
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I know for sure that I'm stumped as to the cause, and I'm very glad it's easily remedied with a little heater action. I almost want to hardwire a heat gun into my car and spend 30s heating up the UTEC before I start it in cold weather
#25
Yeah I'm really not sure what would cause the UTEC to misfire when cold in my car, but not in a G/Z, and not consistently like would be expected in the case of a wiring/resistor problem.
I know for sure that I'm stumped as to the cause, and I'm very glad it's easily remedied with a little heater action. I almost want to hardwire a heat gun into my car and spend 30s heating up the UTEC before I start it in cold weather
I know for sure that I'm stumped as to the cause, and I'm very glad it's easily remedied with a little heater action. I almost want to hardwire a heat gun into my car and spend 30s heating up the UTEC before I start it in cold weather
#27
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Their customer support is notoriously horrible since they outsource the production of the actual unit (somewhere in Australia maybe?). I'll try contacting them at some point anyway.
#30
yeah, but the customer service is handled in the US. Your experience will be completely based on luck. I have emailed them before where I exchanged 4+ emails in one day, and other times where I waited weeks for a response
#31
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That doesn't mean I won't give it a shot, but I'm not exactly hoping for too much.
#32
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Hmm that's a pretty good idea. Maybe aaron can take his UTEC inside with him one of these days and put it back in the car nice and warm when he starts it up. That would narrow it down between the UTEC unit itself and the wiring connections/stock ECU.
#33
I can do that. Easier than messing with a blow drier as I mentioned earlier.
#34
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I doubt we'd be tackling any missing issues with that beast in place
Oh well, I can wish. haha.
#35
This morning, it was 40 degrees outside when I wanted to start the car and run a quick errand. Instead of just starting the car, I unplugged my UTEC and brought it inside and set it front of the heater for about 10 minutes. I made sure the unit was up to room temperature and no more.
I plugged it up and started the car, NO MISFIRE! Not a single one as I drove the car for 7 miles. With 40 degree temps and the UTEC sitting in the car all night long (low of 30 last night), it would have misfired every 3 seconds while idling.
I plugged it up and started the car, NO MISFIRE! Not a single one as I drove the car for 7 miles. With 40 degree temps and the UTEC sitting in the car all night long (low of 30 last night), it would have misfired every 3 seconds while idling.
#36
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This morning, it was 40 degrees outside when I wanted to start the car and run a quick errand. Instead of just starting the car, I unplugged my UTEC and brought it inside and set it front of the heater for about 10 minutes. I made sure the unit was up to room temperature and no more.
I plugged it up and started the car, NO MISFIRE! Not a single one as I drove the car for 7 miles. With 40 degree temps and the UTEC sitting in the car all night long (low of 30 last night), it would have misfired every 3 seconds while idling.
I plugged it up and started the car, NO MISFIRE! Not a single one as I drove the car for 7 miles. With 40 degree temps and the UTEC sitting in the car all night long (low of 30 last night), it would have misfired every 3 seconds while idling.
#37
It still could be a combination of things. But the more info we have, the better. If it was strictly a UTEC issue and nothing else, then we'd see the 350z or 6th gen Maxima guys posting about this problem.
#38
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Well it could still be a problem with the UTEC that isn't apparent on the 350z or 6th gen ECU because of some difference in input/output voltage that is fine for them all the time, but isn't for us when the UTEC is cold.
#39
Yeah, that's what I was thinking. The way we wired up our Maximas may make things a tad more sensitive.