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.