Finally got my MP62 from Moss installed and the Powercard replaced (see other thread for the whole story and how great Moss has been). Now I have some other issues I'm hoping someone is familiar with since I can't talk to Keith until Monday. Car is a 94 R package.
I'm getting an intermittent TPS CEL - doesn't stay lit, just flickers, pulled the codes and it's a 12. However, I also have a fueling problem at tip in to boost where it just goes pig rich until I floor it. If I go from a normal throttle position to full throttle, everything is fine but if I ease into boost, it stumbles all over the place, like it's getting a full fueling request from the Powercard instead of tying it to the level of boost. The CEL flickers whether I go slowly into boost or floor it. The Powercard intercepts the TPS signal at the ECU to put the car into open loop mode during boost (I think) so I don't know if that's causing the CEL or not.
I can adjust almost all the stumble out of the car by leaning out the fuel added during boost (going from a 5 on the PC to position 2) but am afraid I'm only correcting it at tip in and then going lean at top end. I haven't put it on the dyno yet, that won't happen until the end of next week so don't know the AFR's yet.
Is it possible that the TPS can be so far out of adjustment that it is calling for more fuel than necessary for a given throttle position and then coupled with the PC signal, just overloads the engine? It ran/idled fine prior to the install, never got a TPS CEL and were no stored codes before the install.
Oh, last thing - I didn't use the wiring to extend the TPS harness that Moss provides, used some heavier gauge that I had and wrapped that in wire loom. Could there be enough resistance/voltage changes in the heavier wire to cause the TPS signals (it's also about a foot longer than what Moss supplies). As I recall, I used a couple of different gauges of wiring so that I would have different colors so as not to confuse myself so I may have some 16 and 18 gauge carrying the signals.
Anything I can putz around with over the weekend will be helpful and sorry for the long post, wanted to be as detailed as possible.
Here is Tom's (FFS) write up on how the PC-Pro works.
/are a lot of posts on the TPS (search throttle position sensor), not sure which suit your needs best.
The wire gage will not make a difference (20AWG is 0.01 ohm per foot, 17AWG is half that, the potentiometer in the TPS is much higher).
Well, not sure this is an answer or a bandaid but decided to disconnect the TPS side of the Powercard so that the R/B wire from the TPS was fed back into the ECU as it was stock and the wires from the PC just left blank. The results are a perfectly running car, no CEL, no ping, 7lbs of boost, no stutter.
I had checked the TPS settings at the TB, exactly to spec. The only thing I can surmise is that the bridge through the Powercard for the TPS was sending a WOT signal whether it was or not. Hopefully I'll know more when I talk to Moss Motors on Monday and getting it off the dyno. I don't want to be running quot;perfectlyquot; at the expense of running lean .
Not that I think it matters, but the PC came in a packaged marked quot;1996 Miataquot;. I suspect they are all the same but since the 96 is an OBD-II car, something else I'll bring up.
I believe the TPS for 94-97 cars is the same. The TPS may be the most challenging thing to set in the car, at least what I've found. I got a fair number of TPS issues, generally brought on by full throttle runs that were followed by periods of coasting (like on a dyno). What spec did you come up with on your TPS? I've read that, at least on the FFS kit, a recommended setting is approx. .010quot; - .020quot;.
That makes me wonder how the car would drive if the TPS signal were not manipulated at all... hmmm...
I take it you don't have a wideband? Though the car will be safe after set properly, it's useful in the initial tuning stages and if you run into any issues down the road.
Looks like your powercard isn't turned ON or your injector wires are not wired correctly. My car did the something when my powercard got disconnected. Pull the cover off ur powercard.
First, let me stress that the PowerCard provided by FFS is *NOT* the same as the one provided by Moss. May look the same, but the programming is different. Don't rely on FFS documenation for programming the Moss Motors PC Pro.
Some troubleshooting pointers: Did you let the engine run continuously for 5-10 minutes before hitting boost? Maybe take another look at your wiring connections and ensure that they're all tight. Lastly, check whether the PC Pro is correctly sensing vacuum/boost.
Originally Posted by CRYPTiC
First, let me stress that the PowerCard provided by FFS is *NOT* the same as the one provided by Moss. May look the same, but the programming is different. Don't rely on FFS documenation for programming the Moss Motors PC Pro.
Some troubleshooting pointers: Did you let the engine run continuously for 5-10 minutes before hitting boost? Maybe take another look at your wiring connections and ensure that they're all tight. Lastly, check whether the PC Pro is correctly sensing vacuum/boost.
The engine was running for about an hour with the over rich issues, to the point where the tailpipes were black with soot. I've gone over the wiring a couple dozen times, even had a neighbor take the installation manual and look at it with no prior idea of how it should be wired and it was correct. Also, all the wiring is cut and soldered, no vampire clamps or butt connectors.
Here's my theory on why I disconnected the TPS circuit - the older powercards didn't have that feature. It's supposed to make the system operate more seamlessly but if the old PC could handle fueling requests w/o the TPS feature, then perhaps the current version could do the same thing. I'm not quite sure how to measure the voltage output for that particular wire, so see if it's within spec, hopefully Moss can walk me through it. The TPS test given in the FSM, which my car passed exactly to spec, is only testing the quot;startingquot; position of the sensor, you then need to read voltage as the throttle is advanced and of course the FSM calls for a special service tool to accomplish that task.
Originally Posted by tom4416
Here's my theory on why I disconnected the TPS circuit - the older powercards didn't have that feature. It's supposed to make the system operate more seamlessly but if the old PC could handle fueling requests w/o the TPS feature, then perhaps the current version could do the same thing. I'm not quite sure how to measure the voltage output for that particular wire, so see if it's within spec, hopefully Moss can walk me through it. The TPS test given in the FSM, which my car passed exactly to spec, is only testing the quot;startingquot; position of the sensor, you then need to read voltage as the throttle is advanced and of course the FSM calls for a special service tool to accomplish that task.
I'm not familiar with the Powercard, but I had the same symptoms on a Link ECU that was installed with my turbo kit. Make sure the Powercard is setup to accept the 94+ ranged TPS (0-5VDC?) vs. the 1.6 motor TPS which is ranged in the opposite direction (5-0 VDC). There was a big dead spot off idle and the previous owner had attempted to compensate by dumping in more fuel. Once the backward ranged TPS problem was corrected everything tuned just fine and drivability was greatly enhanced. Just a suggestion - Good Luck!
Originally Posted by TimM
I'm not familiar with the Powercard, but I had the same symptoms on a Link ECU that was installed with my turbo kit. Make sure the Powercard is setup to accept the 94+ ranged TPS (0-5VDC?) vs. the 1.6 motor TPS which is ranged in the opposite direction (5-0 VDC). There was a big dead spot off idle and the previous owner had attempted to compensate by dumping in more fuel. Once the backward ranged TPS problem was corrected everything tuned just fine and drivability was greatly enhanced. Just a suggestion - Good Luck!
Thanks for the suggestion but had already checked the TPS function. It ranges .5 to 3.82 volts at closed/open throttle, respectively. When I add the TPS circuit of the Powercard to the equation, it goes to 3.62 (WOT) regardless of throttle position as soon as it losses vacuum at tip-in. Theoretically, that puts the ECU in open loop mode and it doesn't try to pull fueling so that it and PC aren't fighting each other. Unfortunately, because the potentiometer in the TPS at TB says quot;wow, I'm only open 60%quot; and the ECU says quot;nah, you're open 100%quot; there is some kind of conflict and the ECU won't turn loose of it's desire to fuel at 100% and sets the CEL for the TPS error (12). Don't know if it's some kind of limp home mode built into the ECU for a TPS failure (better too rich than too lean?) or the programming in the PC itself.
Fortunately, Jason from Moss has been very responsive and helpful and is going to program yet another PC himself and send it out to me as he believes it may be in the firmware of the card versus the ECU of the car. That TPS circuit in the Powercard is a relatively new innovation and obviously requires another layer of programming that maybe can't be generic for 94-97 cars.
Worse case, I can always have Moss send me an older PC without the TPS circuit and the fueling maps from the bygone days. Theoretically, it doesn't produce as much power as using the newer one but I can live with that if need be.
I do know that this is probably going to lead me to purchase and install a wideband O2 sensor for tuning and monitoring. Good thing this was on sale at the 15% off because I'm going to easily exceed the original price with all the add-ons .
Where are you checking TPS voltage? It comes into the PCM at 3M.
You are giving way too much credit to the TPS. It's a really dumb device. 3 wires
-5V input
-Ground
-Signal Out
The 5V and ground leads are shared with the other sensors.
The signal out is a simple variable resistor between power and ground. This is the only TPS feedback received by the PCM. There is no quot;conflictquot; possible.
If you are getting an error code, there are only 2 possible causes
-Wiring fault
-Incorrectly programmed power card
Frankly, I don't understand why the TPS clamp is even necessary. The TPS is mainly useful to tell the stock computer to shut off accessories at WOT. Do you really want the a/c compressor to shut off on a 100° day every time you pull away from a stop sign?
An o2 clamp is a good thing. TPS clamp in this basic car, I'm not sold.
I think the TPS clamp is to force the ECU into open loop when the car goes into boost. There is also a contact in the TPS that, when set properly, closes when the car just comes off idle. This tells the ECU to start adding fuel to drive the car. I've noticed when the TPS is set to too low of a value, the throttle will have a dead area when you touch the pedal slightly, then the car will lurch forward as the ECU sees the contact close.
Modifying the TPS signal is an alternate way to keep the fuel trims stable to fight idle droop. That can also be done using a modified O2 signal, as that is what we do on 1.6 JRSC kits. However, modifying the TPS signal is more CARB EO-friendly than altering the O2 sensor signal, especially with the tighter emissions requirements of later cars. We use the same configuration on CARB and non-CARB MP62s, so things have carried over. Those of you with standalones or aftermarket O2-clamps can obviously wire in whatever you like, as the cards included in the non-CARB MP62 kits are tuneable.
I suppose that if you got into boost every time you pull away from the light, the A/C will go off and then come back on once you are up to speed and ease up on the throttle. However, since you are in boost, you are accelerating at or above the rate you would be with an naturally aspirated car at full throttle. So, to accelerate at that rate in a non-boosted car, you'd have to be at full throttle anyway and the A/C would also turn off. Luckily, with the extra torque of the boosted car, you would reach your desired speed quicker and the A/C would turn back on sooner. The evaporator doesn't go back to being ambient temperature instantaneously, so it hasn't been an issue an A/C vent air outlet temperature standpoint.
Originally Posted by Jason@Moss
the cards included in the non-CARB MP62 kits are tuneable.
Are you saying that it can be programmed to pass through o2 signal then clamp it at 0 volts when the manifold is over atmo pressure?
BTW, how does the PC determine baro pressure? Sample at power on only? Real time while driving? No sample?
On the current 1.6 JRSC kits we create an O2 waveform that has a sweep that looks quot;stoichquot; to the ECU. Otherwise we pass the unmodified original signal through. We never actually clamp the O2 signal to a set voltage.
Both methods work, but since cross-counts were important on many non-Miata applications (PT Cruiser S/C kits, for instance) we added the processing horsepower to do it, so we might as well use it. Besides, I just like it better...
Fine, you don't do it. Can the thing be programmed to do it in place of this TPS clamp?
I doubt very much that Tom cares if his PC is cross compatible with a PT Cruiser.
:
For boosted applications, PowerCard measures relative pressure, resampling atmospheric (zero boost) pressure at each startup.
I'm not sure if you're asking if the PC Pro can apply an O2 and TPS clamp. It can.
Since the PC Pro sends the ECU goes into open loop when pressure exceeds 0.5 psi, there's no need to clamp the O2 voltage at that point.
Originally Posted by Ben91
Where are you checking TPS voltage? It comes into the PCM at 3M.
You are giving way too much credit to the TPS. It's a really dumb device. 3 wires
-5V input
-Ground
-Signal Out
The 5V and ground leads are shared with the other sensors.
The signal out is a simple variable resistor between power and ground. This is the only TPS feedback received by the PCM. There is no quot;conflictquot; possible.
If you are getting an error code, there are only 2 possible causes
-Wiring fault
-Incorrectly programmed power card
Frankly, I don't understand why the TPS clamp is even necessary. The TPS is mainly useful to tell the stock computer to shut off accessories at WOT. Do you really want the a/c compressor to shut off on a 100° day every time you pull away from a stop sign?
An o2 clamp is a good thing. TPS clamp in this basic car, I'm not sold.
Ben,
The FSM stipulates that voltage must rise proportional to the throttle position so it has to have data on both the throttle position opening and the voltage sent to the ECU. The TPS ECU signal is 2M on the 1.8 cars, four wires to the TPS with one of them obviously being the 2M position (3F on later cars). Maybe I'm way over complicating the system but it sure sounds like somewhere the computer is making a comparison between the physical throttle opening and the signal being received by the ECU which is what trips a TPS failure code in the OBD-I car.
But hey, it's all pretty much greek to me. I know without the TPS it runs properly (don't know AFR), with it, running pig rich. I also know that you're responsible for talking me into buying and permanently installing an LC-1 so I got that going for me.
beatle,
Not exactly. I am asking if it has the ability to clamp o2.
Clamping o2 instead of TPS would produce much better results.
Tom,
Sorry I pulled the pin out from memory, without actually looking it up. I don't own a shop manual for your year car, as I've never owned a 94 or 95. If it has a 4th wire, it would be for throttle closed. I've installed various band aid type engine management solutions into a number of cars and usually remember those things correctly.
There is no way for the PCM to know the physical location of the throttle off idle other than 2M. That is the entire purpose of the variable signal on 2M. There is no way of cross checking it. I imagine the only complication would be if the idle signal was given at the same time the WOT signal was given. Without a shop manual, I can not advise how to check. I assume that the idle pin grounds when the throttle is closed, but that is a guess and the shop manual and multimeter won't tell lies. Open the manual and verify it's an idle switch too. It could also be a WOT switch.
I still recommend ditching the throttle position clamp and going with an o2 clamp. I mean, it only works for thousands of other similar set ups.
Congrats on the LC1. It's the best wb controller on the consumer market. Make sure you wire it exactly per instructions and it will serve you extremely well.
What does whether I can program a PC-Pro to do an O2 clamp (I can) have to do with anything? The kit isn't sold that way. Period. If you want a custom card, go talk to Tom @ FFS or get over it.
How do you know whether a PC-Pro capable of outputting an O2-waveform with cross-counts is an important feature to Tom @ FFS? Do you think he's sitting still working on nothing?
Yes, yes, quot;much better resultsquot;. Let's just take a look at those results, shall we? Which vendors have CARB-legal Miata MP62 kits? Who doesn't? Which method do the CARB-legal MP62 kits use, O2 or TPS? Which method do the non-CARB compliant MP62 kits use? Better results? Good gracious.
Whatever. Congratulations for stepping into yet another help thread to disseminate anti-PowerCard FUD. Or are you actually interested in purchasing a PC-Pro with O2-clamp for your BEGi S4, Ben91? I got the impression that you were running a DIY PNP, sponsor...
Ben, if the TPS is not clamped, the ECU will remain in closed loop longer unless you actually go WOT. Is this not actually a problem? Won't fuel trims be affected?
Originally Posted by Jason@Moss
What does whether I can program a PC-Pro to do an O2 clamp (I can) have to do with anything? The kit isn't sold that way. Period. If you want a custom card, go talk to Tom @ FFS or get over it.
This is a very simple, polite question and deserves nothing less than a simple, polite answer. I don't need a PC programmed as such, but perhaps your customer does. You know, the one that's having repeated problems related to PowerCards.
How do you know whether a PC-Pro capable of outputting an O2-waveform with cross-counts is an important feature to Tom @ FFS? Do you think he's sitting still working on nothing?
Talk about left field. Don't know. Don't care. How does this help Tom?
Yes, yes, quot;much better resultsquot;. Let's just take a look at those results, shall we? Which vendors have CARB-legal Miata MP62 kits? Who doesn't? Which method do the CARB-legal MP62 kits use, O2 or TPS? Which method do the non-CARB compliant MP62 kits use? Better results? Good gracious.
Features of various MP62 kits are irrelevant, unnecessary, and unimportant to the topic. I'm happy that you have a CARB legal kit, and I'm sure it suits the needs of many customers. But just because something was done to be CARB-legal does not mean it is done in the best way. We're still not helping Tom.
Whatever. Congratulations for stepping into yet another help thread to disseminate your anti-PowerCard FUD. Or are you actually interested in purchasing a PC-Pro with O2-clamp for your BEGi S4, Ben91? What a joke. How's your DIYPNP competing product running, sponsor?
My goal here is to help out Tom. Let me remind you, since it was so easy to forget, that your customer who has a problem is named Tom. I said nothing negative about the PC product here, and probably haven't in at least a year.
And yes, I am running a fresh DIYPNP. So what? I didn't mention it in this thread, and only do so now because you made it an issue. I bought it, I built it, I installed it. I am not a vendor of the product. I have no financial interests in the product in any way shape or form. That has nothing to do with making Tom's car run correctly.
And no, I'm not interested in a PC, which also has nothing to do with helping Tom.
Jason, you need to get a grip man. Maybe start by helping Tom.
Originally Posted by beatle
Ben, if the TPS is not clamped, the ECU will remain in closed loop longer unless you actually go WOT. Is this not actually a problem? Won't fuel trims be affected?
No, you don't have to clamp the TPS. People have been adding forced induction to the 94 miata for 15 years now. I don't know why suddenly they need a TPS clamp.
Send a false lean signal to the PCM when under boost via an o2 clamp. It doesn't technically go open loop at low throttle position and rpm, but will go to max fuel in that part of its map. It will then go to open loop once throttle and/or rpm conditions are met--if you keep your foot in it. This will provide more consistent fueling to the vehicle and not cause the odd stumbling Tom was getting due to overfueling.
This is what people have been doing for 15 years. It works.
It seems that the PC is being standardized to be cross compatible with other vehicles which have other needs. I again ask if the end user cares if his miata PC is cross compatible with a PT Cruiser. I bet they don't. I further bet that the end user is more interested in it working correctly for their application than if it works in other applications.
CARB compliance or cross compatibility be damned.
Ben, perhaps cross compatible means that it is capable of working with other cars. Whether those features are used is up to the tuner. As mentioned, even among kits for the Miata, the programming can, and is, different.
Which is fine and good. Manufacturing a single product in higher volume may lead to lower costs to the vendor and ultimately the end user.
What Jason is saying though, pertaining to CARB, has deeper implications.
Please be sure to post up what fixed the issue when this gets back on topic. I am having similar issues with the Kit I just bought last month for my 1.6. I'm not technical like you guys are but I know a stumble on tip in when I feel one.
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