[1self]

Guys,

When operating fuel/ ignition via a piggyback ECU (obviously on a highly modified engine), are there any fault codes that the stock OEM ECU throws up & the 'check engine' lights up? If there are such codes, what do you do to quell them?

I would like an answer from experienced petrol-heads running a piggyback?

Thanks & regards,
Vivek.

[paras211]

Never had one except when it just died for no reason.

[pranavt]

What sensors are you going to modify? It would be wise to check their ranges and to make sure the piggyback doesn't exceed them. That would be a surefire way to get the check engine light on. Apart from that, depends on the car's ECU and how anal it is. You'd do better by checking on forums where Hyundai experts have already done something similar before.

[1self]

Originally Posted by pranavt

What sensors are you going to modify? It would be wise to check their ranges and to make sure the piggyback doesn't exceed them. That would be a surefire way to get the check engine light on. Apart from that, depends on the car's ECU and how anal it is. You'd do better by checking on forums where Hyundai experts have already done something similar before.

Thanks Pranav! 'How sensitive an ECU is' does make sense because in the Elantra, advancing spark timing via the Apexi gave no error codes at all & the car is working just fine, but in the Sonata, it immediately gave codes & would not rev above 5000 rpm!

Also, i wanted to ask/ confirm, do you have to 'intercept' the incoming crank spark signal or can you just 'tap' into it? Since i'm advancing spark timing. Does it even make sense? The manual says to intercept but i've read stuff on other forums that says to just tap?

I had taken the Apexi off the Sonata, but since i've installed the aluminium flywheel, i'm wanting to try again. Plus, i've installed LOTS of earth wires, so that will compensate for the battery relocation to the rear? (better signal earthing?)

There is something called 'near earth' & 'far earth' on the AEM ECU for example. Any idea why this system? There are saperate pin-outs for this.

[pranavt]

What piggyback are you going to use?

[Racedynamics]

Hello,

If the piggyback ecu is configured well, check lights shouldnt crop up. It depends on the vehicle too, for example if its an older generation suzuki like an esteem or baleno, they wouldnt throw checklights with piggybacks even if it was turbocharged, on the newer vehicles unless the piggyback can intelligently manipulate input signals or actuators outputs, check lights can be an issue.

As for some ecus needing different grounds placed a little away on the same ground wire is largely due to electronic architecture (near and far ground), ecus heavy on analog electronics usually are this type. Some of them split grounds for power, signal and/or digital electronics. Most newer piggyback ecus have eliminated that to a large extend needing just one single ground point.

AS for your hyundai, if using the crank signal, then you are better off running it through your ecu. if using a 'T' connection for ignition line, then you can retard by a few degrees depending on original ecu setup. Some hyundais go into a limp home and cut revs down if the original ecu does not read the ignition coil load or inductive spike from the coil, which might happen if the piggyback ecus isnt configured to handle these parameters. You are probably facing this issue. If you are running crank signal through your piggyback then you have to make sure signal out in in sync with stock crank sensor signals with respect to amplitude, shape, gaps, etc.


-RD

[1self]

Thanks RD, that was some awesome info & knowledge!

To be honest I was'nt expecting anyone to reply here. Glad to have you around!

I initially used a Apexi SITC (super ignition timing converter), a first generation piggyback. I got it ultra cheap on ebay. It was a gamble, but paid off BIGTIME when i used it on a 2006 Hyundai Elantra. I set the piggyback controls (all knobs) to an Mitsubishi EVO system & I've using it from that day on with NO PROBLEMS & no error codes! I simply cut & intercepted the crank & cam inputs & outputs (positives only) & voila...all good.

So, I brought another one of the same type (again cheap) & attempted the same on the 2003 Hyundai Sonata V6. I followed exactly the same procedure, except that the piggyback controls were set to Mitsubishi 6g72 engine. The car ECU immediately popped codes about crank & cam signals, but started & ran fine till 5000 rpm,(redline 7200 rpm) after which it shut off! It restarted fine & I continued to use it for some time till the 5000 rpm redline.

I tried other car system type settings & played with the negative sensor wires too, like Honda, Toyota, Subaru, but the car would'nt even start with these other settings. It only starts & runs on the Mitsu settings.

I will follow your suggestion about the ignition coil load & check if any other wires are feeding this info to the ECU.

[Racedynamics]

Glad to help .. If its only the crank and cam you are intercepting, then the 4g63 and 6g72 (if i remember correct) run a one tooth per cylinder tdc crank signal and for cam its non-uniform 2 teeth for 4g63 and 4 teeth for 6g72 per 720 deg of crank. Both 5v signals. Your 03 sonata v6 most likely uses either a 60-2 or 36-2/1 inductive crank signal and 5v signal for cam. You will be running on limp mode from the word go.

For your current setup dont bother with the coils.

[1self]

Originally Posted by Racedynamics

Glad to help .. If its only the crank and cam you are intercepting, then the 4g63 and 6g72 (if i remember correct) run a one tooth per cylinder tdc crank signal and for cam its non-uniform 2 teeth for 4g63 and 4 teeth for 6g72 per 720 deg of crank. Both 5v signals. Your 03 sonata v6 most likely uses either a 60-2 or 36-2/1 inductive crank signal and 5v signal for cam. You will be running on limp mode from the word go.

For your current setup dont bother with the coils.

You are correct, the Sonata & Elantra both run 60-2 missing teeth crank & a 5 volt cam. All sensors are Hall type.

However I feel that due to relatively poor earthing (battery relocation) on the Sonata, I was having problems. Now I plan to earth the Apexi very near the signal earth of the OEM ECU. I will check if that helps. I also suspect that some noise may be present in the crank signal.

Will attaching/wrapping a ferrite core around the crank/ cam signal wire help?

The 4g63 crank/ cam signals work fine on the Elantra because the engines are more or less similar.

[Racedynamics]

A snap on core over the cmp and ckp wires might help, focus on something that works at >13-20khz with an SRF of approx 30-50khz. Or you could use a decent low pass filter.

I do think problem with your package is more to do with signal mismatch rather than noise. Ideally look for a system that gives you direct control over ignition and injection system rather than those that modulate engine position and synchronization inputs to OE ECU.

[1self]

Originally Posted by Racedynamics

A snap on core over the cmp and ckp wires might help, focus on something that works at >13-20khz with an SRF of approx 30-50khz. Or you could use a decent low pass filter.

I do think problem with your package is more to do with signal mismatch rather than noise. Ideally look for a system that gives you direct control over ignition and injection system rather than those that modulate engine position and synchronization inputs to OE ECU.

Thanks RD! I too was thinking about a snap-on core. I'm just trying various configs to see which just might work.

I downloaded the service manuals of a 6g72 & the sonata v6.

The cam/crank positive signal wires of the 6g72 go straight to the ECU & the negatives to ground. However for the sonata, both wires of each sensor(positive & negative) go to the ECU. These are typical 3 wire hall sensors. The negatives have their own pinouts in the ECU.

The APEXi piggyback has no means to intercept the negative wire in this confguration. Do you think this could be a reason for the fault codes?