Strange TPS problem

ianscrowston · Post by **ianscrowston** » Tue Jun 02, 2009 8:55 pm

Seem to have got on very well so far with sorting the megajolt out, but just come across a problem I can't seem to solve.

When the ignition is on and the engine not running the TPS shows zero to full scale on the laptop when operating the throttle all looks fine. As soon as I start the engine the TPS range never gets above about 10%, I'm completely stumped as to what the issue is, any assistance appreciated.

Thanks

NITROPIXIE · Post by **NITROPIXIE** » Tue Jun 02, 2009 9:19 pm

Double checked your wiring????

Post by **brentp** » Thu Jun 04, 2009 5:47 am

Agreed- that is a strange problem. Can you monitor the voltage going into the TPS input with and without the engine running?

ianscrowston · Post by **ianscrowston** » Fri Jun 05, 2009 12:00 pm

Thanks for the replies. Going to have another look the only thing I can think of is that that the voltage is collapsing for some reason when the engine is running.

Ian

NITROPIXIE · Post by **NITROPIXIE** » Fri Jun 05, 2009 7:26 pm

Do you have a voltmeter to hand?? As another thing you could try would be to test VREF output of the MJLJ with everything connected both whilst the ignition is turned on and whist the engine is running and see if there is a variation in voltage. It should be the same and stable all the time. If not then a replacement voltage stabiliser would be required. Although if this were happening i'm sure the rest of the hardware wouldn't function correctly.

What it sounds like is happening is that for some reason your getting a lower voltage when the engine is running at VREF, therefore this would reduce your Vin from the TPS.

Just an idea anyway

skippyjon · Post by **skippyjon** » Thu Jul 16, 2009 7:26 am

Hi, I was wondering whether you have resolved this issue. I have the exact same problem!!

Thank you,

Jonny

ianscrowston · Post by **ianscrowston** » Thu Jul 16, 2009 7:46 am

Problem turned out to be simple in that I was being a bit light with the right foot when pressing the accelerator when I took it to the rolling road the TPS read fine, although it is a bit coarse.

Ian