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Discussion Starter #1
Hi All, welcome to the IMA TPS Mod, currently testing results.
Below is a message in part I’d sent in regard to city driving assist and how it induces almost constant hidden charging that most of us never see or feel without a vacuum or boost gauge. If you have an OBD you may see it thru you MAP signal if you don’t run into anything while you’re doing so. This mod may improve mpg especially when in Insight specific lean burn/purge mode:

Yes, I agree. Better to make one plug and play kit. It's what I would do
after developing the turbo kit, whew... And of course make what will work
best for the most. Without MIMA if I could only do one thing to improve the
insight, with or without a turbo, I would limit or better, stop IMA when
under normal acceleration. I always wished for this for the life of Baby's
predecessor, my '00 insight 5 spd. Proved this many times by driving with
IMA switched off. With the boost gauge I now see how extremely prevalent
hidden charging is and wish for this even more. That's the "why"; I need
the "how". Is there a way for a non-engineer to do this? If anyone would
know it would be you. Thanks, Jack
PS: Willie and I agree the 5 spd is over geared. The hidden charging is
almost always there and causes the little engine to struggle even more. We
do not use the turbo as an advancement; we use it as a cure. Still, the hidden
charging even holds the turbo back from utilizing its full potential. IMA
under normal acceleration is the primary cause of hidden charging and is
near useless as payback is immediate and prolonged.

Any doubt? Switch off the IMA battery and drive city. You’ll find little or no change in mpg. Go ahead, prove it yourself. Like most of you, I am drooling for one of Mikes MIMA’s. Till then I’m probly doing what Willie or Kip would, do something. A number of items control IMA, one prevalent one is the TPS. By controlling the signal that comes off its pin 2 to the ECM we can effect change to reduce IMA, we’ll see.
Some references to the Throttle Position Sensor can be found at:
Service Manual, pages 11-10 (not TPS specific, correlates relation of ECM to abnormality), 11-25 and 11-53.
Electrical Troubleshooting Manual, pages 23-3 (circuit), 201-1-9 and 202-19-94.
Basically, the TPS is a 5k ohms potentiometer (variable resistor) that is mounted to the passenger side of the throttle body and is trimmed by same. It has three wires, pin 1 ground, 2 is the .5 to 4.5 vdc signal to ECM and 3 is the 5 vdc reference. By cutting the wire to pin 2 (it’s the one in the middle) you can crimp on insulated male and female snap connectors so you can reconnect them if you decide this mod sucks and I’m nuts. Using same connectors you can hook two wires to them, run the wires into the cabin (drill hole in firewall aprox. 1 inch above where throttle cable goes thru, this is also a good spot to run your vac line thru for your vac gauge). Then hook the wires in cabin to the gizmo I made. You could also hook in a volt/ohm meter to see the signal changes you’re effecting. OBD will indicate throttle position changes.
The gizmo, for now, is just a 1 megohm linear taper potentiometer rated for .5 watts mounted in a box with a knob on it. The products were purchased at Radio Shack. Here’s what was bought:
Potentiometer………….part number 271-211 (may switch to higher megohm)
Project Enclosure……………………270-1801
Insulated Snap Connectors………….64-3085
Insulated test/jumper leads………….278-1157 (to quick connect volt/ohm meter)
Control Knob………………………..274-402
18 Gauge Speaker Wire……………..278-567 (copper, low ohm’s)
Photos at: http://community.webshots.com/user/jackmpg , our squirrel’s name is “half”.
Added a second 1 megohm pot in series so the first pot can be set for the threshold chosen, kinda like Ron Popeil’s “set it and forget it” at Ronco, of course. Current threshold is 3% throttle. Median voltages for each percentile: 9%=.498 vdc, 8=.448, 7=.400, 6=.351, 5=.302, 4=.254, 3=.205, 2=.156 and bottoms at .120 before 1% is reached. A DTC is generated as 2% is approached. “Throttle position voltage less than expected”, I guess… It is possible DTC’s may not be generated if adjustments beyond the threshold for DTC’s are made after engine start and returned to begin position before restart. See SM, page 11-10. Testing is currently under way, will be posting results/changes. If it works I could put these things together for those who would like them plug and play. If it doesn’t, it was fun learning a little more about the most fun vehicle I’ve ever known. Baby’s a little nervous though… Jack
 

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Re: IMA TPS Mod, less assist

What concerns me most is that you are also forcing the fuel management system to bias fuel delivery according to its TPS algorithm.

While I've not investigated myself, the ABS busy signal to the MCM is a "known" IMA defeat signal. Possible a simple fixed voltage of 5 or 12v. (ETM pg. 44) I have the need to cross the Smoky Mountains a couple of times a year. And I don't like draining the IMA pack for little or no MPG benefit when climbing these mountains.

Since necessity is the mother of invention when the next trip arrives I'll be ready to try an IMA defeat. MIMA would work, but I'm looking for something simpler.
 

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In the last few weeks of commuting, I've been watching the actual IMA current (as indicated by the hall effect sensor voltage) during most driving conditions, both with the MIMA on and off. The forced charge (with MIMA off) doesn't seem to engage when the indicated SoC is > 85%. However, with headlights or other accessories on, it can draw up to 7 amps at various times when the indicated SoC drops below approx. 85%. At much lower SoC levels, charging can occur regardless of accessories use.

If the goal is to temporarily disable the forced charge, it shouldn't be necessary to have the complete MIMA modification. However, with the MIMA modification, I have the ability to maintain a > 85% indicated (and perhaps actual - soon to be determined) SoC while sustaining consistent 80+ mpg fuel economy.

If it's necessary to drive in the mountains (such as those in eastern Tennesee and western North Carolina) maintaining an 85% SoC with or without the MIMA modification would probably be "mission impossible". However, in Florida, with the MIMA modification, it shouldn't be so much of a challenge.
 

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Jack, you just joined the wild man club!

You cracked me up with that comment "baby's a little nervous". Now don't do anything Mom wouldn't approve of. :wink:

Seriously, thanks for taking the initiative. The concept is interesting regardless of the means of implementation. It sounds like John has an interesting idea for a really simple switch. Take care. Keep us posted.

Kip
 

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Discussion Starter #5
IMA TPS

Jack here,
Yeah, did an ECM reset on Baby last night with mod left at 3% to see what the car would think of it. First drive will be this morning. Thanks Kip, yes I'll be checking John's idea in the ETM first so I have a jump start on pondering his idea and the reply from Nemystic. There is a difference to me in forced and hidden charge. I can initiate forced by shifting a low gear, i.e. 2nd at 3800rpm, and top the soc off. Hidden I can't tell without Willie's idea to check the vac gauge. Map on the obd is not stable enough. Have hooked vac to same source as map to check this. Well, I'm off to the ETM, Jack
 

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my brain hurts
 

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With the exception of the NOx "re-burn" condition, where the temporary surge in power can be felt, in the normal IMA mode of operation, I can't detect the presence or absence of the "hidden charge". That's not to say it doesn't have a significant effect, but that it seems to be gradually ramped on and off, so as not to be easily detectable.
However, when the hidden charge is in effect, and I switch from normal IMA to MIMA (joystick neutral, no assist or regen), the sensation is very similar to that of the NOx "re-burn". Similarly, going from MIMA to normal IMA with hidden charge, the "drag" is very noticable. In both cases there is virtually no ramping.

Jack, for the time being, perhaps you might wish to consider an IMA current indicator, which is much easier to install than the MIMA, and is a sub-set of that installation you'll presumably be doing in the future. 'Don't know if you had a chance to see it at the Tour, but I'm using a small digital volt meter that cost only $10.
'Sorry I don't have photos of the connection points in the back. Sputnik is all back together now. However, Mike may be able to provide a photo, as I assume his Insight has all the covers off these days.

We'll look forward to hearing your test results, and hopefully, in the not-too-distant future, your reports about Turbo + MIMA!
 

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Discussion Starter #8
IMA TPS

Nemystic,
I think I see what you mean, the MCM & BCM seem to have test points for meter serial comm's. If so there appears to be another TP at con C507 which is located behind seats, middle of floor. Looks like pins 7 & 17 are waiting for my meter probes, is this so? ETM page 32, photo 201-14-87, view 202-38-159. Also, what current level, at $10 your volt/ohm probly reads to 10amp? In the mean time I'll go tear up the carpet and see what's there, got to replace one of the blurry photo's too. Jack

ps How's project coming, I could be in MA in a week. Another device, Baby's starting to be a bit cluttered. Oh, did get a DTC for low signal with mod set to 5% but did not get one yet at 3%, should be interesting. Also, when this happened IMA assist stopped but car ran just fine, maybe good for John's mountains? Auto-X-Ray sells refirbed OBD's, same as Willie's, for $75 with cable and adaptor. Will do the job for little bucks.
 

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Jack
The battery current signal does not pass through the harness that goes through the shift console or to the front of the car at all. It is just three short wires from the current sensor through the harness going to the BCM and MCM within the electronics bay behind the seats. It is easy to tap into the current signal, but if you do it incorrectly, or use a low impedance volt meter, it can cause the IMA light to come on, and all IMA functions will shut down.
As Brian indicated, the real forced charging of 10-15A is a load on the engine, that can be felt in the speed of the car, and depending on the 12V loads that are on and drawing current, the DC/DC needs to draw current to keep the 12V battery charged up, which means if the background charging is disabled, by any means, the 144V battery will be drained by the DC/DC as it supplies the needed charging to the small battery/accessories, and will continously discharge. If you had the forced regen brake mod, you could selectively charge when going down hills, but that would not work if the IMA was disabled.
If I were you, I would just hold off till MIMA is ready, or explore Johns suggestion about the ABS disable.
I ran the car yesterday with MIMA_C in place of MIMA_L, and it is looking pretty good. I had a couple of small issues, mostly to do with setting codes and disabling the IMA when the MIMA_C program was stopped for debugging, but after making a couple of hardware changes and code changes, that issue is resolved as long as the system is put back in IMA mode before stopping the program. None of this will effect the normal non programming use of MIMA_C.
Still a lot to do, I have not connected the MAP and TPS signals yet but will be doing that this afternoon.
I have all the instalation photos and data ready for assembly into my webpage, the boards are still being layed out, the code will need some more work and lots of testing before I will be comfortable sending it out, so you guys will have to be patient with me, I am putting in all the time I can spare.I do have other things to do.
 

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Discussion Starter #10
IMA TPS

Hi Mike,
Don't worry, I only use low (Oops, high) impedance meters. Forced charging is not an issue for me either as I can top off the soc at will with engine under load and I have my own version of the forced regen brake mod too that adds one less thing to the cabin. Not really interested in completely disabling IMA, only reducing or stopping it where I do not consider it necessary. Sounds like your really moving along even with all you have to do. Yes, can't wait till your mod is complete. Right now I'm having allot of fun and seeing some unexpected eye opening results from this mod whether it does what I'd like or not. Yes, there is reduced assist. They weren't expecting us when they made the window for P1121's. Have noticed a difference in lean burn/purge as well but need more time on highway, will do this weekend. Other data on obd all seems to be in line. Insanity; To hope for betterment in ones life, station or business without the willingness to initiate change. No pain/No gain, Jack
 

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Jack,

I'd thought perhaps you might find the ability to watch the IMA current to be helpful, both in testing your modification and otherwise.
Since installing the MIMA mod., I've been watching the current indicator as much as the fuel consumption indicator.
It's also enabled me to unlock some of the mysteries associated with the "hidden charge".
I hear what you are saying about having too many "accessories" though. My dashboard is beginning to look like a science project.

In this case, the IMA current is actually measured as a proportional voltage (20mV/Amp) from a hall effect sensor. The indicated value needs to be divided by 2. The measurement is between the sensor signal (from the MCM area) and logic ground (in my case, convenient from the MIMA module). 'No need to repeat the precautions about impedence. (I'm hoping in my case that a curious passenger won't switch the DVM to the wrong setting and cause an IMA fault condition.)

HTH

Brian
 

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Jackmpg wrote:

"Hi Mike,
Don't worry, I only use low impedance meters."

Hi Jack,

I'm guessing you meant to say "high impedence meters". Most digital volt meters should be OK. Analog meters could cause an error, or worst case, an IMA fault condition.

I don't want to mislead you or anyone else, so, not having access to the Insight service manual at this time, I can't confirm the connector pin and wire color information, and I don't trust my memory. Unfortunately, I didn't take a photo, and as mentioned previously, the control system on Sputnik has been closed (for now). I'll take photos and share info (on request) the next time it's open.

The logic ground is on one of the 4 MCM harness connectors. The hall effect voltage signal (proportional to IMA current), if I remember correctly, is on a 3 socket connector in the front/center region of the control complex behind the seats. That particular branch of the wire harness had almost no slack, making the connections very difficult. (I didn't forget that!)

I'd suggest the safest way to confirm that you have the correct wire would be if the adjacent pins/sockets are shown as + and - 12V respectively. Otherwise, caution is highly recommended.

Further discussion about the specifics may be best by PM.

HTH

-Brian
 

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Discussion Starter #15
IMA TPS

Hi All,
Took Baby on a 100 plus mile run on I-75 this weekend, here's what we have so far. Reduced assist is less than hoped for, but, we didn't know what to expect anyway. Fooling with pot while under way we generated a P1121, "TPS reading lower than expected". This turned off IMA assist and regen. Before reseting the code with obd drove for awhile for the experience. If you didn't look at dash you couldn't tell there was no assist, it was a dream to drive. Remember the turbo? Remember the exhaust? JoeCVT is on the right track, the free flowing exhaust definately improves performance, mileage and lean burn/purge. Then, Oh well, time to reset the code.
Factory setting for throttle at idle is 10%. By running at 6 or 8% we had some reduction in assist, no change in regen. At 6% we almost couldn't keep the car out of lean burn/purge. Observed obd, everything else was in order. Since TPS is only one of a number of items the ECM uses for input we didn't expect much change. With obd observing LB/P is easy. Induce LB/P by purging first cat. Do this by easing throttle for a second or two. O2 sensor 1 goes from .6XX (normal) to .2XX (lean burn) for aprox 15 sec. Then goes to .7XX for 6 sec as purge occurs with a cycle of aprox 21 sec. Purge is an asset as it gives the over geared car a little surge that assists in maintaining or increasing LB/P vehicle speed. Modified exhaust and/or turbo will noticably improve this further. What's the answer? Why, Mike's MIMA, of course. In the meantime, more testing today... Jack
 

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Discussion Starter #16
TPS Mod EDIT w/Momentary sw

TPS Update, well, where to begin…
Was getting some erratic results from tests. Turns out with the improved turbo Baby wants to be in lean burn/purge mode just about all the time. So I took time to learn to drive her all over again. How’s lean burn/purge with the AC on sound? Anyway, here goes…
This may interest Mike; OBD Load Value is down 10-12% when hidden charging stops. With hidden charging off you can accelerate (very softly) without assist, even in second. With hidden charging on you get assist to compensate for the hidden charging, and yes we know they don’t do both at the same time.
Next, tried John’s voltage to the wire for the ABS busy signal. It’s 5.0vdc, SM, page 12-9, pin 14. Used a micro switch so I could do a momentary application too. Didn’t separate wire, it has a low signal when not busy for the MCM, SM, page 12-45. Sorry John, no luck there. Was the best idea so far for a simple solution.
Now, tried the momentary idea on the TPS Mod, it works. Radio Shack didn’t have a single pole double throw momentary but they did have a roller micro cherry sw which works just fine. Setting the pot for approximate .300vdc we could stop assist by pressing the switch while accelerating in each gear. Tried various settings, didn’t receive any trouble codes above .265vdc. This also just about stops hidden charging since we are noticeably reducing the parasitic assist during normal acceleration. Now Baby really wants to lean burn/purge. Testing ongoing, still want a MIMA. Still, this looks like a simple, inexpensive way to reduce assist and noticably improve mpg. Jack http://community.webshots.com/user/jackmpg
Additional Parts:
Project Box pn 2700288, on package 270-288
SMini Switch 2750017, 275-017A
Screw 6403010, 64-3010
Nut 6403017, 64-3017
 

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Jackmpg said:
<snip>
Next, tried John’s voltage to the wire for the ABS busy signal. It’s 5.0vdc, SM, page 12-9, pin 14. Used a micro switch so I could do a momentary application too. Didn’t separate wire, it has a low signal when not busy for the MCM, SM, page 12-45. Sorry John, no luck there. Was the best idea so far for a simple solution.

<snip>

This also just about stops hidden charging since we are noticeably reducing the parasitic assist during normal acceleration. <snip>
Thanks Jack for trying. However, without hidden charging the 12v system will be stressed or dead (12v battery) in 10-20 miles depending on 12v load. Sorry, still looks like MIMA will be the only way...:?:

HTH! :)
 

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Discussion Starter #18
DC/DC Converter

Hi John,
Good news, we are not disabling IMA system, only reducing assist. Therefore there is no effect on 12v regen. Hidden charging is for the IMA batt, DC/DC does the 12v. Been checking the 12v anyway and theres no effect, have also driven 120+ miles and it isn't dead yet. That's not to say I'm not trying though...
Better news, hot down here, with AC on you get allot of assist. Lowering the voltage down increases the assist reduction. We lowered the voltage to .280vdc (takes 10 seconds at a stop sign or light) and that took care of the increased AC assist. None of your mountains here, but we also did some highway driving. At over passes, hit the switch with a little gas, over we went, no assist.
As long as you don't generate a DTC, IMA system remains online. This may be your ticket accross your mountains, nothings for sure, allot more testing to do, but looks real good so far. Data from OBD looks good too. A note of caution to all, mod or NO mod. If you drive a MT with your hand resting on the shifter you can wear out any tranny. Even a lite pressure may engage the syncro's, a no/no. Thanks, Jack
 
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