Final (?) Haltech tuning issues relating to OEM sensors??

davekmoore · Postby **davekmoore** » Wed Dec 10, 2014 12:11 am

Many people will have read between the lines about the challenges there have been in my tuner being able to get my 04 SE turbo to run correctly on the Haltech PS1000 ECU. It looks as if we're nearly there, after a lot of feedback from me (including with a lot of advice from people on this forum), and a lot of time spent going backwards and forwards to him.

The major remaining issue is the hair-trigger throttle response at light throttle openings. For example, 70 in 6th on a level road without changing the throttle position will see the car accelerate for a split second as if it's been given 10% throttle, then back off for a split second, then cycle through the whole thing again. Getting very gently on the throttle going into a corner is not possible as 1% throttle seems to produce a 10% increase in power, and coming 1% off the throttle feels like a 20% drop in power. All in all, it makes the car unpleasant to drive on the road and less than reassuring part-corner on the track.

The tuner is now saying there may be a fault in the OEM throttle position sensor or other sensors which are causing this hair-triggerness, and that they may not be down to the Haltech. He also says these faults may be original design faults, or due to the car now being 10 years old, or due to the sensors being expected to cope with probably 50% more power output than the car originally had.

To be fair to the guy, despite other forumites telling me to go to another tuner when the initial problems came up, the tuner has put $1,000s worth of extra work for free into getting the tune where it is now, so I'd like to have him finish the job.

So what advice is there about changing OEM sensors, throttle bodies etc to smooth out the throttle response? Or is the advice still to get another tuner as the Haltech, if correctly set up, should deal with all of this?

rascal · Postby **rascal** » Wed Dec 10, 2014 6:58 am

davekmoore wrote:
The tuner is now saying there may be a fault in the OEM throttle position sensor ....... due to the sensors being expected to cope with probably 50% more power output than the car originally had.

Wow, what a diagnosis. :roll:

A throttle position sensor simply measures the angle of the throttle and returns a corresponding voltage to suit which the ecu can use. It doesn't care whether the motor has 1 or 1000000 horsepower, makes zero difference.

So while a faulty tps could be causing this issue, it has nothing whatsoever to do with how much power the engine makes.

Get a new tuner!

sailaholic · Postby **sailaholic** » Wed Dec 10, 2014 7:22 am

Tps is easy to check for a tuner. He just has to look at the value reported and make sure it's linear through the range / increases in reported levels of throttle match how much the pedal is pushed.

As for other sensors I can't think of one that could be the issue. I still don't know if you are use a MAF or MAP tune.

The MAF sensor certainly does have a power limit as it can only read so much air passing through before it tops out. But this would only effect top end / high throttle unless it's been fiddled with to make work at the top end some how?

Timk probably knows the most on this as he found the power limit on his SE build.

The throttle body won't be an issue either.

Sent from my iPhone using Tapatalk

Magpie · Postby **Magpie** » Wed Dec 10, 2014 7:38 am

Whilst a long shot could it be the resolution of the TPS.

The American · Postby **The American** » Wed Dec 10, 2014 8:22 am

Dave, my '03 is running factory sensors, including TPS, with Haltech Ps1000, with no issues.

GT AutoGarage in QLD fitted the Haltech and tuned it to where it is now. They only had the car a few days. I would describe the throttle response as 'sensitive' but not anything like what you're describing. The car will go back for some fine tuning including a tweak to alternator control, but it's all working. It's using the internal MAP sensor in the ECU (no MAF).

It really is worth getting a second opinion.

hks_kansei · Postby **hks_kansei** » Wed Dec 10, 2014 9:15 am

Aren't the standard TPS fairly on/off in their signal? (not sure if NA/NB same here)

ie: it jsut says "throttle closed / throttle open"

I know pretty much every person who has turbo'd an NA6 has had to replace the TPS with one that offers a linear signal (ie: throttle 0%-5%-50%-etc)
From memory the common choice is a TPS as used on a VL commodore, or a BMW of some sort?

You'd need to look it up, I just remember a friend having to go through the hassle of swapping TPS when her turbo'd his car.

sailaholic · Postby **sailaholic** » Wed Dec 10, 2014 9:16 am

Only a na6 issue hks. Na8 on are 4 wire and linear.

Sent from my iPhone using Tapatalk

davekmoore · Postby **davekmoore** » Wed Dec 10, 2014 12:20 pm

Got him to adjust idle speeds today. They were previously high and random and would flare up and die down for no apparent reason. So idle is now more stable both with and without a/c.

And so far (touch wood) this seems to have solved the hair-trigger throttle issue too!

Why would this be?

Postby **NitroDann** » Wed Dec 10, 2014 1:29 pm

Mail the car to Newcastle please. This is beyond ridiculous.

Everything that Rascal said.

Dann

davekmoore · Postby **davekmoore** » Wed Dec 10, 2014 1:34 pm

Dann I'd love to send the car to you for all sorts of work when funds permit.

I'm starting a new thread now asking for Haltech tuners in Melbourne.

Magpie · Postby **Magpie** » Wed Dec 10, 2014 1:53 pm

http://www.haltech.com/dealer/dealers-australia/#vic

davekmoore · Postby **davekmoore** » Wed Dec 10, 2014 5:02 pm

Magpie wrote:http://www.haltech.com/dealer/dealers-australia/#vic

Thanks Magpie. The original tuner is on that list, so I'm looking for personal recommendations rather than a list of suppliers, and preferably of shops who are familiar with MX5s rather than V8s, and even better if they've successfully tuned an SE on E85 with a flex fuel sensor and ID1000s.

Magpie · Postby **Magpie** » Wed Dec 10, 2014 5:39 pm

If the Haltech dealer is on the list and not performing, maybe a call to Haltech head office and discuss what you have been trying to do and what is not happening. If you make the call in the way of looking for a solution and providing feedback you may find you could get additional help direct from the Head Office. I'm not trying to tell you how to suck eggs but you need to do it in a way that you don't 'bag' the hell out of the current tuner, rather you are trying to give feedback on one of their dealers and you are looking for the head office help...

davekmoore · Postby **davekmoore** » Wed Dec 10, 2014 6:07 pm

Yup, been there, done that in exactly the way you suggested. Even set it up so that the next time the car went in Haltech H.O. and I had had a long discussion and were fully briefed in advance for his phone call and gave him all the answers they thought he needed. He still blamed original parts on the car for not being compatible with the Haltech rather than making the Haltech work properly.