In the numbers? Nailing down a hesitation problem.
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From: Longbeach, CA
In the numbers? Nailing down a hesitation problem. I'm doing several things at once to find out what's going on with my Ls1.
One of the easy things I can do is data logging with my autoCAL on EFILive.
I'm not terribly familiar with what I'm doing, but I've been going over the moments just before/after the hesitation to find out what's different in the system when it occured.
I punched the throttle right after for 2 reasons, 1 was to mark it on the log, the other was.. to get up to speed since it just interrupted me.
It's odd because the log doesn't show a dip in anything. I see a 400rpm drop, but I can't tell if that's 1-2 shift or if that's the actual dip. It only occurs for 2 frames, which makes sense because the hesitation is short, like a misfire or a skip, but there's no codes ever thrown when this occurs.
Happened at 40% throttle @ ~30/40mph, rpm was 2500, fell to 2100, then I punched it.. climbed obv.
I'm not entirely sure what I'm looking at.
Here's a screenshot of the frame the moment it appears to occur. Could be a shift again I'm no expert.
This problem is almost certainly being caused by a bad injector or a failing coil. I've put new plugs n wires in the car, new fuel filter, I'll be putting seafoam in the tank next fill up (which is tomorrow) to hopefully clean out the fuel system.
The only thing that looks "weird" to me is that the LT fuel trim is off by about 3% between bank 1 and 2, but I dunno if that's out of the ordinary.
One of the easy things I can do is data logging with my autoCAL on EFILive.
I'm not terribly familiar with what I'm doing, but I've been going over the moments just before/after the hesitation to find out what's different in the system when it occured.
I punched the throttle right after for 2 reasons, 1 was to mark it on the log, the other was.. to get up to speed since it just interrupted me.
It's odd because the log doesn't show a dip in anything. I see a 400rpm drop, but I can't tell if that's 1-2 shift or if that's the actual dip. It only occurs for 2 frames, which makes sense because the hesitation is short, like a misfire or a skip, but there's no codes ever thrown when this occurs.
Happened at 40% throttle @ ~30/40mph, rpm was 2500, fell to 2100, then I punched it.. climbed obv.
I'm not entirely sure what I'm looking at.
Here's a screenshot of the frame the moment it appears to occur. Could be a shift again I'm no expert.
This problem is almost certainly being caused by a bad injector or a failing coil. I've put new plugs n wires in the car, new fuel filter, I'll be putting seafoam in the tank next fill up (which is tomorrow) to hopefully clean out the fuel system.
The only thing that looks "weird" to me is that the LT fuel trim is off by about 3% between bank 1 and 2, but I dunno if that's out of the ordinary.
I'm no tuning expert but I think we would need to see the log itself instead of a screen shot. In HP Tuners there is a function that makes a graph which comes in handy for things like this and we can also share log files. I don't have EFI Live so I can't speak for it's functions but I know it is similar.
I had an intermittent hesitation that started after someone hit me which cut some wires in the process. I thought I fixed all the wires when I repaired the panels and didn't realize one power wire wasn't severed but the insulation had been stripped and that wire was arcing against a new bare spot on the body. Fixed the wire, no more hesitation. Mine showed up in the logs as a very quick .8 to 1.2 volt drop that lasted less than a second. I would have never noticed it on a grid type display like yours, but in a graph it stood out well.
If you look at the white line with the dip (partially obscured by the green line) above you will see what I'm talking about.
I had an intermittent hesitation that started after someone hit me which cut some wires in the process. I thought I fixed all the wires when I repaired the panels and didn't realize one power wire wasn't severed but the insulation had been stripped and that wire was arcing against a new bare spot on the body. Fixed the wire, no more hesitation. Mine showed up in the logs as a very quick .8 to 1.2 volt drop that lasted less than a second. I would have never noticed it on a grid type display like yours, but in a graph it stood out well.
If you look at the white line with the dip (partially obscured by the green line) above you will see what I'm talking about.
Last edited by gofastwclass; Nov 5, 2011 at 09:13 AM. Reason: Added graphic
Thread Starter
TECH Enthusiast
iTrader: (7)
Joined: Jan 2011
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From: Longbeach, CA
Thanks. I'm new to the whole logging thing and just used the autocal because it's what I have for scanning.
efilive does have a graph as well. I see a dip in mine too. "spark deg" famms from 29.5 to 20, then jumps to 31.5. RPM drops from 3156 to 2783, then falls to 2426, it sounds like I'm letting off the throttle there.. because the rpms continue to fall.
I may go out today and take a better non-traffic run. I'll go out to the country and do some hard pulls (within the speed limit of course. but it's pretty high out there.. like 65.) and some downshift/cruising to see what I can get it to do. It may not be a closed experiment tho because I was about to add seafoam to a fresh tank of gas.
i'd be happy to send someone this log. It's about 600k. I was also told by another member to check at the efilive forums. I'll do that as well.
efilive does have a graph as well. I see a dip in mine too. "spark deg" famms from 29.5 to 20, then jumps to 31.5. RPM drops from 3156 to 2783, then falls to 2426, it sounds like I'm letting off the throttle there.. because the rpms continue to fall.
I may go out today and take a better non-traffic run. I'll go out to the country and do some hard pulls (within the speed limit of course. but it's pretty high out there.. like 65.) and some downshift/cruising to see what I can get it to do. It may not be a closed experiment tho because I was about to add seafoam to a fresh tank of gas.
i'd be happy to send someone this log. It's about 600k. I was also told by another member to check at the efilive forums. I'll do that as well.
