Possible free mod to reduce stock ultra rich mapping.

[InsanityInc]

Well, in my search to try and make my car run not so rich and kind of jerky at low throttle, I started playing with my TPS today. Since I was being lazy, I didn't feel like using my multimeter, and I knew it was already adjusted to "spec" anyway. Rotated all the way away from the front of the car, that made it run a lot worse, so I rotated it all the way towards the front of the car, and immediately the idle quality improved. Well, I figured that the idle just improved but it would run like crap, right? Wrong. It runs better than ever. No stuttering or jerkiness in sight. Haven't put it on a sniffer to see if it's running any less rich, but considering the richening of the KA fuel maps increses quite rapidly with an increase in throttle position, it's quite possible that this fools the computer into thinking you have less throttle than you do, thus utilizing a leaner part of the map.

Disclaimer: My engine hasn't blown up, but I dunno if this is safe or not yet, so don't try it if you can't afford for something to go wrong. I should have an idea of what it did to the A/F sometime in the not too distant near future.

[240crawler]

Excuse me, but I am a total noob and have no time to check FAQ as I am using the library computer and they will close soon. What does the TPS look like, and how do I rotate it backwards? When I check back in a couple of days, I want to be able to fix this, as my car is very jerky and the idle sucks.

[InsanityInc]

Well, you may want to check for other problems first. I've replaced basically every sensor on the car, so I figure there's nothing wrong with any of them.

[240crawler]

It ran perfect until I put bad gas in it, but every 240 I have ridden in (KA) is a little jerky @2-4k rpm. I am going to drain the gas on Thursday and refill with my usual, but I am very interested in the TPS mod.

[skatanic28]

the fuel map on my s14 is pretty solid. idle and cruise stays in the high 14's. they are a bit conservative at WOT, but from an oem standpoint its understandable.

[NateDogg]

You probably put the TPS into default mode and now it's running without the TPS since it's out of spec.

[240crawler]

Turned TPS almost all the way back. Car starts much easier, revs faster, and idles like a champ. Plugged EGR vacuum line at same time, so maybe not TPS at all, but I am not changing back.

[InsanityInc]

You probably put the TPS into default mode and now it's running without the TPS since it's out of spec.

Nope. It would have thrown a CEL if I had. And it definitely wouldn't have run better, as I've run with the TPS unplugged before to get my car to operating temp in order to set the timing and idle, and it definitely didn't run like this.

[InsanityInc]

Turned TPS almost all the way back. Car starts much easier, revs faster, and idles like a champ. Plugged EGR vacuum line at same time, so maybe not TPS at all, but I am not changing back.

The EGR blocking will have a positive effect for the most part. Did you rotate the top of the TPS towards or away from the front of the car?

[elgarvo616]

sounds like an interesting mod. what direction should i rotate the TPS?

edit::nevermind. i read the first post. but i am curious if this is damaging to do? is the A/F still in a safe zone?

[deviousKA]

You guys really need to start tuning your ecus, even the commonly-bashed groups of honda and dsm are way ahead. This isnt due to lack of information, its due to laziness

For ka24de, boards are going incredible cheap. $10 gets you an original biki daughterboard pcb, the parts to complete and install these boards is under $20.

I am selling boards as well, similar design. $20 for a board or 40 shipped for a kit. I would even assemble, install, and test in an ecu, with chips, for about $100.

Many others available.

Besides those, you are going to need a chip burner ($50 new on ebay) and a couple chips (.25cents to 7 bucks). You will need a pc but if you are reading this that shouldnt be a huge problem.

If thats not affordable, I dont know what is. You have access to every parameter exactly like a "standalone", your only limitation would still be the MAF (of which you can change to any that you would like thru ecu tune). You can keep an eye out for MAP conversion in the future.

There will soon be a better public NA tune for the DE (besides the jwt), similar to the stage 3 NA SOHC that i have given out. These are good place to start, but you can create your own tune as well (or fine tune).

Fully adjustable 16x16 fuel/timing maps (all of them, including closed loop)Fully adjustable X,Y map axis scales, increase RPM or Boost axis.Adjust for different size injectorsAdjust for different MAFDisable closed loop/knock functionadjust your rev/speed limiters to whatever you would like (as that seems to be a topic lately).

Those are only a few of the things you can do. I didnt even include the map switching capabilities or anything like that.

Sohc 89-90 MT stock (red) vs. deviousNA3

Dohc 91-94 MT stock (red) vs. JWT (early)

Those are the primary fuel maps that your car is running off of.

http://eccs.hybridka.com/ for more information.

[InsanityInc]

Yeah, yeah. I'd have a bikirom by now if the 240 didn't spontanously break once a week for the past month. Screwy EGR system to a flat tire to a dead starter. Blah.

[OneBitchin240]

Would an SAFC render all of this other stuff obsolete cuz my air/fuel is def. off but I plan on getting an SAFC and having her professionally tuned in the near future....

[240crawler]

The EGR blocking will have a positive effect for the most part. Did you rotate the top of the TPS towards or away from the front of the car?

Top went towards firewall. The little bolts holding it to the throttle body are a ***** to get to. I finally had to get my friend to undo the bottom one as my hand is quite large like the rest of me.

Idle is Lexus smooth now, car is much less jerky in 1-2 gears. Before, when I cranked when car was warm, it would have to spin over 8 or 9 times. Now, I just bump the key and it runs perfect. Don't know about air/fuel ratio, but I do not have a check engine light coming on.

I know that this is off-topic, but where is the temp coolant sensor. My uncle that works at Jones Nissan in shop told me that they need to be replaced every 24 months. He said when they go out, no light or code appears, but it will cut power and mileage by 15-30%. If he works on the car, he will want to get paid. Maybe Autozone can order a new sensor.

[InsanityInc]

Top went towards firewall. The little bolts holding it to the throttle body are a ***** to get to. I finally had to get my friend to undo the bottom one as my hand is quite large like the rest of me.

Idle is Lexus smooth now, car is much less jerky in 1-2 gears. Before, when I cranked when car was warm, it would have to spin over 8 or 9 times. Now, I just bump the key and it runs perfect. Don't know about air/fuel ratio, but I do not have a check engine light coming on.

Strange. That will richen your mixture, since you're basically telling the ECU that your load is higher than it actually is. I think. I'd have to open one up to make sure, but I'm pretty sure rotating the top to point away from the firewall will make it run leaner, and pointing it towards the firewall will make it run richer.

Quote »I know that this is off-topic, but where is the temp coolant sensor. My uncle that works at Jones Nissan in shop told me that they need to be replaced every 24 months. He said when they go out, no light or code appears, but it will cut power and mileage by 15-30%. If he works on the car, he will want to get paid. Maybe Autozone can order a new sensor.[/quote]The coolant temperature sensor is the larger of the two sensors that screws into the coolant passage in the front of the intake manifold.

[SilviaS14KA24DE]

TPS Stands for...?

[dickie]

throttle position sensor

[SSS]

This is an extremely poor method to lean out your fuel, i would not recommend rotating the TPS out of its recommended specs.

[NateDogg]

Not only does it affect the fuel map but most importantly it affects the timing map. Similar to using an s-afc with 50lb injectors and no ECU tuning.

[240crawler]

Strange. That will richen your mixture, since you're basically telling the ECU that your load is higher than it actually is. I think. I'd have to open one up to make sure, but I'm pretty sure rotating the top to point away from the firewall will make it run leaner, and pointing it towards the firewall will make it run richer.The coolant temperature sensor is the larger of the two sensors that screws into the coolant passage in the front of the intake manifold.

Do not know if it is richer or leaner, but do not really care. EGT is no more, cranks better, and has a little better bottom end. I tried your advice, and it worked fine. I tried last night to rotate it to the front. I just wanted to see if it was different. It still cranked better, so I think the EGR mod may have helped. With it turned to the front, it does not rev up as fast at a standstill. I may put it back where it was, just because I am bored today.Thank you for the coolant sensor answer. How hard are they to change; I mean are they stuck like an exhaust bolt, or do they come out easy? Also, how much coolant will I lose?

[DjPantsSpecR]

if you can get to it easily, which i'm almost positive you can (i dont have fan shrouds anymore, cant remember) it simply unscrews very easily, and if you have the other one right in hand you can immediately shove it in and you might lose like 3 tablespoons of coolant, just dont work on a hot car and relieve radiator pressure before you start

InsanityInc, you dont even have a narrowband o2 gauge? I might just have to give this a whirl myself and report back... but it would be much nicer if someone had a wideband...

[InsanityInc]

InsanityInc, you dont even have a narrowband o2 gauge? I might just have to give this a whirl myself and report back... but it would be much nicer if someone had a wideband...

Somewhere. I think I need to fiddle with some other things first. I know I'm running rich and I think the culprit has to be the fuel pump at this point. I'm running a 255lph walbro and have an adjustable FPR adjusted down to factory pressure so it theoretically should be fine, but the higher flow could very well be causing problems with putting more fuel in than the computer is trying to, and I've replaced or checked every sensor on the car that has anything to do with A/F, so I'm figuring that has to be the problem, especially since I got the car smogged initially with the factory pump in and wasn't running rich.

[DjPantsSpecR]

okay, i think i'll just have to do this myself, just cuz with 248/232 sometimes when you go to WOT at about 2000r's the car falls on its face a little and then starts to rip a little before 3000. Just a little hesitation, certainly nothing wrong with 248/232....

i know narrowband o2's are hardly accurate, but whenever i see WOT the gauge sits just on the edge of Stoich and Rich. Not pig rich by any means, just on the edge. However, from my old internship on the dyno, about 12 to 1 is the best for making power, but not necessarily in the factory safe range.

I'm definately going to try this to see if i can rid any of that hesitation, but more importantly to see if it makes any difference of the A/F when the ECU sees WOT

I'm all about blowing this motor up, cuz i already lost four of the trannys synchros and i got the 61,000 mile KA just waiting

[InsanityInc]

Hm. the timing map thing could be a definite problem. Does anyone have a picture of the KADE timing map?

[DjPantsSpecR]

thats a good point, if we can get a hold of that, and i know it shouldnt be THAT difficult to find, we can compensate for the timing issue by advancing or retarding the base timing

i got a gang of homework, and i'm sure you do too, but i know there is some rom editors and such with downloadable maps at http://www.phatg20.net or .com, i think its net though

either way, its really nice to have all the stuff you can get there even if you dont find what you are looking for

you have to register and everything, but then in the download section you will promptly be rewarded

[deviousKA]

1993 ka24de ignition map.

Stock in green, weak JWT in red as a comparison.

[InsanityInc]

Hm, so, looks like the ignition wouldn't be affected very much, as it seems the load has very little effect on timing at high RPMs, especially since it wouldn't throw off the top value by more than 10% or so. However, I fiddled with some stuff and gained some possibly interesting insight into what exactly it was that I did.

Well, I decided to rotate my TPS back to "spec" (more on "spec" later) this morning to see how the car would run. So I measured between the two terminals which go from low to high and set the closed throttle resistance to 2k ohms. Ran cruddy like it used to. Hmm. Ok, whatever. Thing is, in order to get my idea of 2kohms increasing with throttle position I had to fudge what the FSM said a bit. The FSM tells you to measure terminals 2&3 (if I recall), but measuring between 2 & 3 gives a reading that starts high and decreases with throttle position, so that seemed a little weird to me considering the FSM said 2k closed and 10k at wot. I seriously doubted the TPS was backwards, as the car would run like absolute **** (not just marginal ****, as it was), so out of curiousity I measured across terminals 1&2, and viola, a resistance that increased with throttle position. So I set it to 2k at no throttle across 1&2 and called it good even though it would only read about 9.2k at WOT. That is what I'm now considering to be "spec". Since I had to do a little interpretation from the FSM, obviously the method is suspect. Now, today I had an idea. What if I measured across the terminals that the FSM said, but instead of looking for 2k-10k, I looked for 10k-2k? Seems more reasonable anyway, since typoing two numbers by switching them seems more likely than screwing up a whole diagram. So I do it, and lo and behold in my "good but wrong" position, it reads exactly 10kohms closed, and about 2.3k at WOT.

So, what I figured I actually did was randomly stumbled across the correct setting for my well-aged TPS.

[dickie]

if you are correct than this is making a lot more sense than a sudden "magic" enhancement like some people say it is...

[guyaverage]

Insanity, as you now know the FSM is wrong (its wrong in many, MANY places). It has the TPS info backwards. You found out the hard way.

[InsanityInc]

Insanity, as you now know the FSM is wrong (its wrong in many, MANY places). It has the TPS info backwards. You found out the hard way.

So it's the numbers that are backwards and not the diagram?