Bog between 1st and 2nd gear

[unclgreggy]

this "bog" is a real problem.Happened a few times today - I also have been noticing something with the throttle too. after letting out the clutch it seems as though I'm giving a lot of gas but the engine is not pushing hard, then it comes on after a second - almost like the power is in two stages - it seems they are seperate issues.

 

[GR8_ASP]

Made some measurements last night using a GTech Comp Pro. Neat tool! Anyway I have 2 graphs below. Each graph is measuring vehicle acceleration during a normal part throttle, non-aggressive acceleration just before and just after the 1-2 shift. The graph in red is a normal acceleration without a bog condition. The second shows what I believe is the bog. It lasted about 0.2 seconds and effectively delayed the increase in acceleration soon after the shift. These (and other data) have been provided to PVO for analysis.

Additional Graph with a common x axis as indicated by post below. This was added 6/24 pm

 

[Vic]

Ron, once again, you provide concise, pointed evidence of the anomaly. I wish my customers were that adept at relating failure modes.

Anyway, one your first red graph, there is also a little wobble, right at about 6.5 seconds. I wonder if that is the same thing, just not as pronounced as the "bog" phenomenon? As small as it is, it may go un-noticed.

I wonder what the difference in the time/G-force increments in the graphs could tell us? Is there a way to get the G-Force to make graphs having the same scale of units? The second graph covers a shorter time period, which is almost like a "zoom", magnifying the uh, uhm, waveform, so that smaller perturbations appear more pronounced.

Regardless, it is still clear that something is happening there, regardless of differences in graph scale.

Hope I don't sound pedantic.

 

[GR8_ASP]

Vic, great comments. I added an additional graph with the same time scale. Your comment regarding the downward blip in the first curve is spot on.You will note a common blip in the 2nd graph at about 4.9 sec. It may be 2 completely separate issues.

What is strange is that the acceleration immediately following the 2 small blips is at a much higher rate of change than prior to it. I could speculate that it may be a transition from closed loop to open loop. In both graphs there is a similar blip just after a steady state accel in second gear is reached. Possibly going back to closed loop? If that were the case (closed to open and back to closed loop) it may be a side effect of the bog itself. You may note that even though no clear bog is present in the first graph, there is a shift in the rate of acceleration with almost identical relative timing to the bog. The timing of the start of the bog, or change in rate of acceleration, is right at 2400 rpm in both cases. That is coincident with the start of the torque hole in the overall torque curve. A possible connection. And maybe why it changes to open loop, if that is indeed true.

I had a co-pilot installed this evening and drove about 100 miles. Unfortunately I did not encounter the bog during the drive (even though I tried to match the conditions). Too bad as it was measuring all the engine operating parameters via the OBD port. Maybe tomorrow.

 

[Vic]

[******], Ron! I just had a big dinner, and I have to confess that don't have a shred of mental power left to concentrate on your post! Ha ha ha, I'm toast right now!

I'll re-read it later, I'm sure its great!

 

[Hans Christian]

Russ,

Thanks - I hope we soon hear something back

I also agree with you comments on PVO/Dodge/DC being top notch regarding the way they adress our technical issues.
NOW IF WE COULD JUST GET THEM TO ALSO LISTEN TO MY YELLOW OUTCRY FOR 04...
Though if I had to choose one over the other, I of course will go for their quick action on technical issues.

 

[Russ Oasis]

Ron,
Try accelerating a bit more aggressively prior to the shift point from 1-2. Perhaps something like 50%. Then keep it about the same pedal pressure (or a hair less) when you hit second gear. I think that you might find it more pronounced with a bit more acceleration. I'm going to send you some DC contact info to your private box so that you can get the graphs to the right person.

 

[Vic]

Ok, Ron. I see what you mean. Thats great information, now there is some real technical evidence of the problem. I think it won't be long now before the cause is identified.

What is a "co-pilot"? Is that like an OBD2 code reader?
I assume it performs what Dyno Dave calls "dcap", data capture. You are on the cutting edge of finding the problem, and I'm sure Dyno Dave can make use of what you send him. When something turns up on the issue, I trust you will post the details to this intriguing mystery.

 

[GR8_ASP]

Good news. Tonight I had the co-pilot installed and experienced the bog 3 times at the normal speed and load that I have noticed it. All three were recorded. But then, while just driving normally with the co-pilot still connected, I experienced the bog at a higher rpm (around 4000). I recorded that also. That is good news as having the condition occur at a higher rpm may help to determine the issue. I was not trying to capture the info via the Gtech so have only co-pilot info.

Now we can let the PVO guys go to work and isolate/resolve the issue. I am looking forward to some bog free driving.

I will be sending on the data once I download it tomorrow.

 

[Vic]

Cool! They should give you some floor mats for that!

 

[Twosnakes]

[******], I thought this was a problem that only you Guys had!
At 520 total miles I decided to "Off" the Neighbors '03 ZO-6 and almost (read almost) lost the race due to the stumble going to 2nd. Now at 600 miles it happens 50% of the time. Has there been any response from DC ????

 

[GR8_ASP]

Still taking measurements. Due to the holidays (and the desire to play with the car and not fill it up with electronics) I passed on making any more measurements. Due to poor weather forecasts it may not be until the end of the week until I have some. PVO claibration engineers are awaiting the data. Stay tuned.

 

[Smog Dog]

I have also experienced the bog, at least twice, maybe three times. Only when shifting from first to second under moderately aggressive acceleration and never at WOT. I tried to duplicate it after the second occurrence and couldn't. It definitely takes you by surprise when it happens. My car was built in early May (#1323)and has 1700 miles.I think driving style is a big factor in whether or not you experience the bog; if the conditions aren't just right, it's not there. I hope a fix is found. Thanks for all the effort.

Bill

 

[Skip White]

My car was built around May, I do have this problem, but the strange thing about it is it only happens when I'm really aggressive, When I'm just playing around, and not in an all out race, it does not seem to happen. It feels like an intermittent shutoff of the power. I really didn't realize it was what is referred to as a,"bog". I thought bogging of an engine would be something more pronounced.

Skip White

 

[Y2K5SRT]

I am experiencing this phenomena a little bit more as I have been out playing around with the car. It is only happening on 1-2 shifts (first to second) and I can duplicate it more often. It seems to occur when I lift off the gas when I change gears. Many have experienced a "normal" bog in our previous Vipers when you get a good launch at the dragstrip: The car will hesitate just a fraction of a second and then take off - almost like it is getting too little fuel. While it would not have surprised me on a launch, it is pretty disconcerting on a 1-2 shift.

Chris

 

[Hans Christian]

any word from PVO on this ???

 

[GR8_ASP]

Update. I have provided PVO with specific data for the bog condition that should provide a basis for understanding the root cause. As you know understanding the root cause is the first step. At this time I do not believe anyone would sign up for if and when any improvement would be forthcoming as the effect on emissions and other vehicle certifications are unknown.

Here are some acceleration graphs from the tests that data was provided.
Graph 1 - Medium rate of acceleration before 1-2 shift. Bog noted at 5.7 seconds.

Grph 2 - Light acceleration before 1-2 shift. Bog noted at 8.5 seconds.

Note that in experimenting and trying to make the bog (or sag as some refer to it) I have found that temperature plays a big part. The warmer and more soak time the car has after running, the more probability that it will occur.

Updates available as more info becomes available.

Note for the ah nevermind for whom: This was measured on a closed track on private property. All measurements made on DC property. The other data is proprietary and unavailable for the forum (taken with DC owned equipment). But rest assured that it is in the proper hands.

 

[Hans Christian]

Ron,

Many thanks for doing this and keeping us advised. Please let's us know if/when you hear anything back.

I am hopefully to soon receive my 04 and I must admit that above matter is the one thing that concerns me the most.

Thanks

 

[GR8_ASP]

Update - PVO has identified the probable cause for the bog. They are testing the solution currently to make certain that it corrects the condition and does not cause anything else to go wrong. So the good news is the bog was not a phantom condition. It was real and has a real explanation. I cannot provide too many details but the cause for the bog is essentially a retarding of the spark timing for a short period of time during tip-in at part throttle. The amount of retard was inappropriate and is being reduced to an appropriate level.

 

[Hans Christian]

Ron,

Great news and again thanks for doing so much leg work on this. Also thanks to Dodge/PVO for attending so well to your/our inputs.

Did you hear anything on when a fix would be forthcoming and what that might entail for current owners.

Again thank you for your great follow through on this !!!

Much appreciated

 

[riwracer]

When I first posted this "bog" I was really unhappy that my 03 SRT did not snap me back at partial and medium throttle between 1st and 2nd gear as I had expected.
I re-drove all my corvettes and clearly remember what my 2000 GTS felt like during shifting. The full power really shows consistantly at "red arrow" [5600 rpm], but not always at lower rpm.
I want to thank all of you guys for sticking with this problem, and especially Ron for his expert documentation.
I look forward to getting a letter and a fix from Dodge in the future.

riw
2003 SRT black
2000 GTS black - sold
2002 ZO6 yellow
1993 ZR1 anniv.
1967 427 yellow convert.
2003 AMG E55 - arrived and is fast and fantastic !!!!!!!!

 

[Newport Viper]

Thank you Ron. When I finally get an SRT. This will be fixed!

 

[Hans Christian]

Hi Ron,

Have you heard any further on above issue

Thanks

 

[Vic]

I hope this gets fixed before the Gen3 coupe comes out! Now that the Ford GT is looking like its gonna be a non-event, (too heavy from most reports), the Gen3 coupe will be the next goal to add to my garage.

 

[Viperfreak2]

So, when do we get a letter in the mail telling us to take the car to the dealer for "re-programming"? Looks like the problem was identified a month ago.....

 

[homesite]

Ever since I have removed the cats, I have not felt the bog.

 

[Russ Oasis]

Ron,
Any news on the bog? It will definitely be a computer programming issue. I'd love to get it straightened out.

 

[SylvanSRT]

Also curious here too, would like to remedy this annoying situation! Will someone from PVO or DC let current owners know how to get this corrected, thank you

 

[MiamiJeff]

So, when do we get a letter in the mail telling us to take the car to the dealer for "re-programming"? Looks like the problem was identified a month ago.....

Maybe DCX is working on a two-for-one fix: Get rid of the bog & fix the flickering headlights/dashlights all on one visit.

 

[Viperfreak2]

Isn't that considerate of them! ? My lights don't flicker, so I'd like my bog unbogged please. It's September. Will Sean Roes VEC2 fix the bog?