Megajolt not seeing Throttle Position Sensor Data

tomkidd · Post by **tomkidd** » Sun Aug 05, 2012 7:20 pm

How do folks

Just had a call from the man setting up my car and he has an issue with my megajolt. The car is running a TPS sensor and he said that the megajolt was set to run with a MAP sensor. He has now switched the megajolt to see and to run with a TPS sensor but the megajolt is only giving a 2d map and isn't using the TPS sensor properly.

He says it is running fine but at the moment the map is only 2d and thus only running like a distributor.

He says the TPS is wired up correctly but the megajolt is just not reading the data properly... which I think is weird as I bought the set up from another mini fan from his car that was running the exact same stuff.

He suggested that the car it came off would never have been making full use of the TPS sensor as the megajolt wasn't reading the data properly...?

The sensor is an original weber TPS seen here

Can anyone shed any light on the situation?

Cheers folks

cng1 · Post by **cng1** » Sun Aug 05, 2012 9:13 pm

There are two different types of ECU. If you have the MAP sensor version you can't simply wire in a TPS, you need to swap the ECU over to the TPS version.

fenderstrat536 · Post by **fenderstrat536** » Mon Aug 06, 2012 4:32 am

recalibrate the TPS?

tomkidd · Post by **tomkidd** » Mon Aug 06, 2012 7:58 am

Cheers guys. The ECU does not have a vacuum nipple on the body and has apparently been run with the TPS before.

Any other ideas? As the car is not with me and the tuner wanted me to leave it with him I can only relay what he has said...

cng1 · Post by **cng1** » Mon Aug 06, 2012 8:07 am

Check the voltage at the 5V supply pin. If you don't have 5V there then there is a hardware problem on the ECU.

Next check the signal coming back to the ECU. You should have a value swinging between 0 and 5V as you open and close the throttle. If you don't have a swing of at least a couple of volts you either have a faulty TPS or faulty wiring.

tomkidd · Post by **tomkidd** » Mon Aug 06, 2012 8:14 am

cng1 wrote:Check the voltage at the 5V supply pin. If you don't have 5V there then there is a hardware problem on the ECU.

Next check the signal coming back to the ECU. You should have a value swinging between 0 and 5V as you open and close the throttle. If you don't have a swing of at least a couple of volts you either have a faulty TPS or faulty wiring.

Cheers cng1, the guy who is tuning it said to me yesterday that he might give you a ring at some point today as you've helped him out before, his name is Paul Gardner.

tomkidd · Post by **tomkidd** » Mon Aug 06, 2012 1:08 pm

Right... just spoken to the guy again and he has checked that the ECU is seeing the TPS and the 5v feed is ok.

The ECU is a TPS version.

The analogue style dial on the screen of the megajolt software is moving and showing the TPS but it isn't feeding the data into the 3d map.

He is wondering if he can reset the firmware on the ECU?? He has another megajolt ECU in stock but it is a MAP version rather than a TPS version.

Thanks for your help folks

cng1 · Post by **cng1** » Mon Aug 06, 2012 2:40 pm

Has the load axis on the map been set to something off the top (or bottom) of the TPS calibration hasn't been carried out and saved to the ECU.

tomkidd · Post by **tomkidd** » Mon Aug 06, 2012 2:51 pm

cng1 wrote:Has the load axis on the map been set to something off the top (or bottom) of the TPS calibration hasn't been carried out and saved to the ECU.

Thanks again. I'll have to ring him and ask him, is there a better way of explaining it to him?

cng1 · Post by **cng1** » Mon Aug 06, 2012 3:00 pm

Go to the Edit menu and choose "Edit RPM and load bins" popup and make sure the numbers go from 0 to 100. One thing that occurs to me is where people have set the load bins "backwards". You might think that 100 goes at the top of the table and 10 at the bottom but actually it is the other way round, with 10 at the top and 100 at the bottom.

tomkidd · Post by **tomkidd** » Mon Aug 06, 2012 3:52 pm

I just rang him to talk through the suggestions and he said after reloading the firmware on the ECU it is now working...

So he is just going to run it up on the rolling road and get it something useable until its run in.

Thanks for your help folks

tomkidd · Post by **tomkidd** » Tue Aug 07, 2012 8:28 pm

Right... back to where we were...

Just had a call off the bloke who was ranting at me for how long it has taken him to get the car running etc etc.
He then suggested that I didn't tell him it had megajolt on it before I took it to him! He then started to explain to me that he had lost so many hours at his workshop with messing around with computers on engines and that I should just put a distributor on it and a set of point.

Anyway.

Can anyone think of any reason why it would be running fine one minute, and then going back to being a bag of rubbish the next?

He said that one minute it is seeing the TPS and the correct data and then the next it isn't seeing it anything and it is back to running really rough? He reset the firmware on the ECU itself and then ran it up, he then realised it had the basic map on it so then changed to the 1380 map which came on the ECU, he then said it was running crap again.

Is there anyway of checking to see if the ECU I have is faulty or can anyone else think of why one minute it would work fine and then the next minute it would be a pile of crap?

Any help great fully appreciated as I am pretty fed up about it.

tomkidd · Post by **tomkidd** » Fri Aug 17, 2012 10:54 am

So, after having the car back in my own possession last night we decided to try my mate's laptop with a serial port on.

After making a few mistakes by not 'committing to flash' when we had switched maps around etc it seemed to work fine.

We were getting a few errors in the software saying that it couldn't get global settings or something but when we clicked OK it seemed to then let us adjust the settings.

So it seems like it might have been a user error in the fact that they were writing the map to the ECU but then not committing it to flash.

I've uploaded a map for now to do some testing.

Thanks for your help folks.

Post by **brentp** » Sat Aug 18, 2012 2:48 am

Glad you have it working - and thanks for your persistence!