TEC3r issue. EFI gurus; help!-Solved, air leak
 

I have been using the TEC3r for 7 years now, and I am quite happy with the product.

It was initially used on a 3.2 carrera engine, now it is used on the same engine, but with PMO and enlarged to 3.4 w/twinspark. The TEC3r is running sequential injectors and dual waste spark.

Since I installed the EFI unit on the 3.4 in 2013, I have got it running pretty good. It pulled a dyno run with 280Hp at the crank. (Happy with that)
The driveability is pretty good too. I have been tinkering on the mapping on/off for the time since 2013 and feel that I have got a good grasp on the workings of the unit.

The problem I'm having is this: It is very driveable 50% of the times that I start it up.
I can start it up, and immidiately feel if it is going to be "a good one" or "a bad one". If it is good, the pedal action is immidiate, revving the engine quite happily. If it is a bad one, the engine hesitates when stepping rapidly on the accellerator pedal. (running lean when rapidly opening throttle)

To me it seems that the accelleration enrichments are turned off 50% of the times I start her up. How could that be?

Any other ideas as to what is going on here?

Thatns,
Otto

I would turn on logging, and take a look at what the TEC3r is receiving from the throttle position, temperature, and MAP sensors. Likely an intermittent sensor or connection in your harness. Also, if you have a fuel pressure sensor, take a look at that as well. Lean condition could be a pump that is on it's way out.

Tom

Thank you for your input.

I have not seen any fault messages, nor seen any strange things with the sensors from logging. Fuel pressure may be an issue, of course. But since it pulls well under high load and revs, and O2 is good, I doubt it.
Fortuneately I can check the fuel pressure meter with the fixed meter in the engine bay to see if it dips when throttling up quickly. So I'll be sure to check it out.

Any other inputs are greatly appreciated! :)

I've gone through similar things with MegaSquirt too. The problem is, is I always tuned when the engine was heat saturated. Then, when it was "luke warm", it would run not so good.

So last week, I ran a 30 minute data log starting once the engine got "luke warm" up to full hot. Then, I let the auto tuning software generate a,new fuel map. It has worked great so far in different varying temp ranges.

If you really have transient issues from one power cycle to the next, this won't fix it. But if it's due to large temp swings an air-cooled engine endures, this may help....

Sorry if I missed this detail, but is the issue only occurring during the warm-up cycle, or does it persist even when the engine is warmed up?

Since it's intermittent, one would think logging should pick up some difference between the "good" and "bad" runs ...

Thanks for yor input guys!
The issue happens regardless of temperature.

My fear is that this issue is a glitch, or bug if you will, in the software. After all, I am pretty much maxing out the units capability since it's twin spark and sequential injection. If anybody has any such experiences let me know... (hope not) ;)

I hope there is some "obscure" setting that affects the operation of the enrichment program. But I can't imagine what this could be...

Otto, have you got an AFR gauge (such as PLX) on the dash? It was my savior in getting the tec3r to run really smoothly. BTW, I run a 3.4 twin plug turbo conversion.
Cheers,
Johan

Yup, the gauge is invaluable for tuning and for troubleshooting if needed. Unfortunatly, I haven't had an oppurtunity to investigate further yet. Hopefully I can get around to it this week....

Double-check all of your ground connections....

+1. Can't have too many ground connections.....
I can't believe that your tec3r is near its limit. I've seen it handle air cooled motors far more hot rodded than mine.
Seeing that you are running twin plug, are you set up to turn off each bank of triple coils independently? I have a switch for each bank on the dash so I can instantly determine if I have a bad plug, plug lead or bad ground on that bank.
Cheers,
Johan

Thanks again for your input. :)

I think I would have seen any bad ground on the sensors by looking at the logs I have done. But I think this may need another look now, just to double check.

I guess that the ignition is also something I need to check. I can just unplug the connector at the DFU's, one at a time, and I should see any problem easily. I have tested this in the past, however, but I feel I need to be thourough now to finally get to the bottom of this annoyance once and for all.

I get best results when testing each bank under load not just stationary. I'm no expert on the data logger, but can only say that it's been of limited use to me. The AFR/boost/vacuum/temperature gauge plus my son in the passenger seat with the portable on his lap for two hour on country roads turned out to be my best tuning investment. Have been running the same settings for street and track since 2000, I think. Only fine tuning has been warmup-took patience due to the varying temperatures here in Canada.
Hope you solve your issue.
Cheers,
Johan

Check all the pins for tightness, I forget what the size is but I had a loose pin. They can be adjusted back into spec. There is an Electromotive forum you can find the procedure there.

Well, I finally got a chance to troubleshoot this issue.

The ignition is fine, runs good on either coil bank.
The sensors are fine, good ground, and stable read-outs on the logging runs. No fault conditions either. All seems to be in order.

A little repetition is in order to explain the issue:
In about 50% of the times I start her up, I can immediatly feel that it will not rev as happily as it should from idle. It runs lean in a split second after pressing the pedal rapidly, causing it to hesitate. This phenomenon will stay this way until I shut it off, and try starting it again. Then, if I'm lucky, the engine may run normally from the start. -Revving happily, and does not go lean when pressing the pedal rapidly. Then it will keep running normally like that until I stop the engine and try starting again.

EDIT;
I just realized that I may have misunderstood the staging function of the unit. I have tried to add fuel using this function, but that may have been a mistake.

So the search will continue once I correct the settings.

I use tecGT - are you using the Wintec software? Version?
I may be able to give you some places to look at settings.
But, it makes no sense that the engine behaves differently in random fashion.
If it is not the environment changing (temp), and it is not fuel supply or voltage/ground changes, then it seems to point to sensors.

In my case, I have had issues with the TPS. If it is not actually going back to "zero" then other settings do not get activated and it messes up operation. Anyway, I may be able to give you some areas to look at after I understand what software you are using to manage the engine with.

Also recommend the online forum Electromotive has - has been somewhat helpful to me a few times...

Does TPS do your transient enrichment? Sure it's reading fine?

Once again, thanks for your input.

Yes, the TPS is the main instigator for accelleration enrichments. It reads out fine. However, the potensiometer is maybe not quite 100% accurate. At idle I get a readout of 0.90-0.94V. It is not fluctuating or anything, it just settles a little randomly in between that gap. I put that Down to the potensiometer tolerance.
I have played around with the idle voltage setting, but this does not affect the issue. I think that only will affect IAC operation. I set it to 0.84V.

I am using the latest Wintec software for my (older) unit. (V3.5.6)

Your setting needs to be at or above the highest reading. This will definately cause an issue. Set it at .94 and tune from there. I have had my electromotive units for 25 years. Issues are usually programming error or mechanical fault.

Well, I have now tried that setting. (0.94V) -No difference.
I also removed the staging that I set by mistake. -again no difference.

I'm starting to think there is something wrong with the ecu...
I put up a question on the electromotive forum now. Hopefully somebody there can recognize this fault.

Thanks again for your input.

When's the last time you upgraded the firmware? MegaSquirt rolls out new ones very frequently.

Might be a FW bug.

I got the latest firmware for the older generation tec3r. It is from 2010 I believe.
Yes, I too have a suspicion that it is a bug in the FW.
Electromotive can upgrade the unit and prepare it for wintec4. But it requires me to ship it to them. Looks like that is something I need to do this winter.
Alternatively replace it for a more modern system.

I thought it would be a good idea to upload some print screens from two logging events. One with OK revs, one with bad. (Done while revving with a stationary car.)

So here goes:

First, the good one:
http://i132.photobucket.com/albums/q...psq1niro9l.png



The the bad one:
http://i132.photobucket.com/albums/q...pspylgmiey.png


I can't make sense of it. It looks very similar, only the bad one shows the slight hesitation in the RPM, and that the AFR goes really lean...
Hope someone else can figure it out?

I'm a Megasquirt guy, but here is something to check....

Sometimes things like accel enrichment and idle control are turned on/off by TPS set points. I found that occasionally that my TPS didn't always return to 0 (zero) due to linkage, etc. When I changed the TPS set point in a few of the setup screens a little further from true 0 ,mystery/illogical things started to go away.

Anyway, just something for you to consider.

Good luck!

Otto, I'd like to see your bin file before possibly commenting on you data log.
Johan

My major mystery with this system on my 2.8L race motor was due to the TPS. If it started at, say, 1V, on depressing the pedal it would drop, say to 0.5V. This was most pronounced driving the car, where there was a load. Needless to say it was hard to get it going, but when I coaxed it out onto the track, where the RPMs never fell below 3,000, it worked OK.

Why the potentiometer behaved that way was a mystery, but the solution was to make, say 1.25V be the nominal "closed" position, with what WOT measured as the WOT position, and let it draw the line between those two points.

In fact, with advice I hogged out the mounting screw holes in the TPS so it could be rotated away from what seemed a bad area. In the fullness of time I spent a lot of $ (for the TWR TBs it is some slightly rare German Ford part) for a new one. It had much the same characteristics, but at least I was looking for something like this.

Yours probably is fine, but one more thing to check - if the throttle or the sensor does not always return to the exact same place, that might cause your hesitation?

Thanks again guys!

Well, as I mentioned earlier, the TPS is pretty solid, always landing between 0.90 - 0.94V.
I can't imagine that this would make a huge difference. I am a technichian in electronics, so I know that making a voltage divider like the TPS is using a resistor and potensiometer is never going to be 100% accurate. So I can't imagine the Electromotive guys designed the system so that it cant handle some "tolerance" deviation from the potensiometer itself and the battery voltage...
Anyway, I have played around with the setting of the Idle voltage, and it looks like it does nothing. I suspect all it is ment to do, is start the "idle programme", wich I am not using. I am using PMO ITB's so no such controls apply.

I could send you the .bin file if I knew your mail adress. Send me a PM...

If there's a new FW and you're confident the TPS is good to go, I'd try the new FW. Of course, I work hard stuff to easy. ;)

In my tecGT with the older software, Electromotive had built in a .08 buffer on the TPS that they do not really clarify. So, in effect you need to add this to your TPS zero point to ensure the EXU considers the throttle closed. So, for example, if your TPS zero's at .94, you would need to set your TPS zero to be 1.02 (.94+.08) to ensure the ECU recognizes the TPS is at idle. You may want to try changing this value. You can always change it back later...

Looking at your graphs I see your EGO corrections seem to be quite high in both directions in good and in bad graph sets. You may need to keep tuning your AFR map and/or your fueling map. In the good set of graphs the AFR seems to bounce around within what you would think are good values (between 11 and ~15?).

When I look at the bad graphs, it looks like the AFR's are out of whack and it looks like the EGO correction is much more in play. Is it possible your O2 sensor or your EGO functions are not working consistently?

If you trust your fuel map enough, you might try turning of EGO correction. This would force the ECU to rely upon your fuel map without correcting it, and I think it would more or less also ignore the O2 sensor, I think. May be worth looking at your options here, as between the two graphs sets, it seems these graphs are quite different.

The corrections may look large, but they are only max 3% from map. So no real big difference is made by that. Its just enough to pull in some adjustment to the AFR when cruising. I have also tried turning i off. But no difference to the issue.

I tried that voltage when playing around with it earlier.

The second set seems to show the AFR's are off quite a bit compared to the first graphs.
I would look in that area - O2 sensor, fuel pressure or fuel regulator, fuel filter. The readings in the second set of graphs seem to show more lean conditions than the first set.

You need a good TPS reading all the time as it triggers your enrichments. The car does not have to be running. Pull up the main screen and watch the TPS voltage, it should be consistant all the time. It should never vary at closed throttle. If it does, it's bad. Replace it and data log again.

PM sent
Johan

your AFR is significantly leaner in the 'bad start" trace. At 1st glane, the other parameters seem to be consistent. Can you monitor your fuel pressure during these logs, to verify that the pressure is constant and in spec?

regards,
al

Great to have this much response in here. None so far from the electromotive forum...

I have monitored the fuel pressure gauge when activating the accellerator by hand in the engine bay. The fuel pressure needle is dead steady... always. So that looks to be OK.

Some thoughts to the Idle voltage theory:
If the Idle voltage really is supposed to be dead accurate down to the precise second decimal every time it goes back to idle, then I can't imagine I'm ever going to find a TPS good enough. You can't expect the potensiometer resistance be 100% accurate from one movement to the next, can you? I mean, there will always be some discrepancy...
If my memory serves me, I observed the same thing when I used the previous TPS on the 3.2 engine. It "lands" at random between for instance 0.86 and 0.82 each time the pedal is released. In my case now it is between 0.90 and 0.94. But it does not vary once it has landed. Then it is steady.

In an effort to solve this issue I have now made a complete rewrite of the entire map, using different UAP and TOG. Aditionally I tweaked the MAP figures in the left coloumns, so the map now effectively has a more detailed "image" of the area that is used for normal operation of the engine. (if that made any sense? ;) )
I also turned off the closed loop and tweaked the accell enrichments.
Anyway, I took some more logs, and it looks like you can now see the difference even more from a good one to the bad one:


Good one:
http://i132.photobucket.com/albums/q...ps2ccrdo1e.png



Bad one:
http://i132.photobucket.com/albums/q...psxlsdxe3o.png

Looks like they both activate the injectors equally from the PWON figure, yet it still runs lean. THAT is probably the real key to this issue. But what can cause that? I mean, it looks like the ECU is activating the injectors correctly. (but are they really activated like the log says??)
-Very strange indeed...

I am guessing you are using batch injection and you may have two injector wiring leads - one for each bank of cylinders. You may want to trace the injector leads back from the injectors to the ECU to make sure one is not crimped, cut, or in some other way "bad". Are both injector harnesses (assuming there are two) connected into the harness solidly? Both getting good voltage? Not sure how those are pulsed by the ECU, but perhaps there is an issue in the signal for one of the injector banks. Hope you find the issue soon.

Vacuum leaks can cause different running. Lawd knows I learned that the hard way!

Sorry, I haven't closely read all of the messages in this thread. What jumps out at me: sequential injection, and 50% of the time it runs well. Are you using a crank trigger or cam trigger for injection timing? If crank, there is a 50/50 chance your injection timing is using tdc versus bdc to start the timing sequence. A very noticeable effect in my old megasquirt days. Spraying while air is rushing past the intake valve versus 180 degrees out and the fuel ends up wetting the cylinder walls. Same injection times, different afr's. Something to think about. Good luck!

All good points, I'll need to investigate some of that a little closer. :)
A little explenation to your comments;
I'm using sequential injection, and they are syncronized by a cam sensor. It is working fine, I know this because I was thinking the same thing as you, nicd. :) Belive it or not, but I have the same issue even if the cam sync sensor is disconnected. -Wait, maybe this is what the "bug" is!? (In the ECU?) Maybe it appears to sync up, but the reality is different?

A vakuum leak is tricky sometimes, but I can't see anything wrong on the MAP though. I imagine I could see something there. Besides, there is really only one place a PMO ITB can leak; the brake booster connection from runner no. 2. (Or to the MAP sensor, but it seems to be solid)

So I am going to check out the possible leak anyway, along with the power supply to the injectors, checking the resistance in the wires all the way from the ECU.

Most screens look consistant, but there is quite the difference in pulse width at idle. There id also a difference in battery voltage, this will change your pulse width. Go into the file and get rid of the battery voltage compensation and see if you see a change.

Post a copy of your accell enrichments.