What's going on? T2 ecu

This section is dedicated to discussion of DTA engine control units such as the DTA E48 EXP, P8 Pro, DTA S40, S60, S80, and S100, as well as all things ECU related.
KeithS
Posts: 15
Joined: Sat May 28, 2022 4:29 am
ECU Model: No ECU
Distributor: Rawspeed Engine tuning

What's going on? T2 ecu

Post by KeithS »

Please bear with me - this is a long story but thought it better to tell all...

I have a Porsche 914 I use for hillclimbing which now runs a T2 ecu with wasted spark. Injectors are Bosch 440, crank sensor/trigger is Hall effect 36-1 set-up from Dubshop in the USA, with 48mm throttle bodies from CB Performance.

Car ran fine after set-up on Rawspeed rolling road in Plymouth (Graham Rawlings is the south west's DTA expert!), starting at the turn of a key without touching throttle etc. A few weeks ago on a Thursday I drove up to Dartmoor to meet a friend – the car ran faultlessly. I left it until the following Tuesday when I decided to check it over ahead of a hillclimb event the following weekend. It suddenly became reluctant to start, turning over and over. When it did start, it issued a belch of black smoke out of the exhaust. I went to drive the car up the road, but it could barely get out of its own way. I suspected a failed TPS as the only way it reacted was with wide-open throttle – I guessed the TPS was telling the ECU it was on wide-open throttle regardless of throttle potion, hence the over-fuelling. After some checking and rechecking, came to the conclusion the TPS was working and the car started... Too late for the hillclimb, but at least it started. Then a couple of days later it wouldn't start unless I jumped it off my Golf and kept turning it over for an eternity. However, once started, it would restart for the rest of the day, albeit a bit sluggish turning over.

Thinking the slow cranking speed might be a problem, a replaced the starter motor with a high-torque geared unit, and the old Optima red top battery with a new Odyssey. The engine spun over but wouldn't start.

The ECU wouldn't always connect with my laptop so it was difficult to see what was going on at times. When it did connect, I tried checking the crank oscilloscope readout but it wouldn't gather information (see video). I checked the sensor was working with a multimeter and manually turning the engine. It read 0 – 5v – 0 etc, suggesting all OK.



As it didn't even cough, I visually checked the injectors by opening the throttle wide and looking down the throttle bodies while my wife cranked the engine on the starter. Nothing from the injectors, but plenty of fuel pressure. Hmmm.

I sent the ECU back to Alex to check and it came back with a clean bill of health, other than a software adjustment to solve the comms problem with my laptop. I've now fitted a new TPS and wanted to try using the test function on the DTA software to check the injectors, but gather this is not possible with the Beta software.

What I don't get is how it went from running perfectly OK to reluctant to start and then on to won't start at all, without any warning or changes to settings. This is all new to me – I had a 911 running Jenvey ITBs with a Megasquirt system which ran fine and required very little fettling once dialled in. This car is driving me mad – and is now stuck immobile outside my house while I try to solve a problem I don't understand with the telephone help of Graham who is 30 miles away. :(
stevieturbo
Posts: 3577
Joined: Tue Aug 02, 2011 12:08 pm
ECU Model: No ECU
Location: Norn Iron

Re: What's going on? T2 ecu

Post by stevieturbo »

faults can happen at any time.

Changing parts at random is rarely helpful.

The fact it will not gather a cranking scope trace is the first issue you need to resolve.

Why will your laptop not always connect ? Is the laptop ok ? software installed ok ( try re-installing ), is the comms lead ok ?

Presumably when you are connected you can see if all sensors are giving sensible readings ? ( ie hence no need to change parts at random )
KeithS
Posts: 15
Joined: Sat May 28, 2022 4:29 am
ECU Model: No ECU
Distributor: Rawspeed Engine tuning

Re: What's going on? T2 ecu

Post by KeithS »

Laptop connects every time now. New comms lead. New laptop running Windows 11. New software download onto the new laptop. The only sensors other than TPS are inlet air and engine temps, which give readings consistent with ambient air temp and oil temperatures (when running). The TPS is the only part changed - the original wasn't new by a long chalk (the ITB set-up was used on Graham's dragster in the past, but everything else is new).
stevieturbo
Posts: 3577
Joined: Tue Aug 02, 2011 12:08 pm
ECU Model: No ECU
Location: Norn Iron

Re: What's going on? T2 ecu

Post by stevieturbo »

So with the new laptop can you get a crank scope ? Or was that with the new leads etc ?
KeithS
Posts: 15
Joined: Sat May 28, 2022 4:29 am
ECU Model: No ECU
Distributor: Rawspeed Engine tuning

Re: What's going on? T2 ecu

Post by KeithS »

Sadly, no. The change of laptop and leads made no difference other than it's a lot quicker and more user friendly (I'm a Mac user, so PCs feel weird!). I'd hoped to be able to run the new software, which requires Windows 10 or later, but it doesn't appear to be finished as yet.
KeithS
Posts: 15
Joined: Sat May 28, 2022 4:29 am
ECU Model: No ECU
Distributor: Rawspeed Engine tuning

Re: What's going on? T2 ecu

Post by KeithS »

Just checked permanent and ignition-controlled 12v feeds to ECU - both good. Also checked earths, which seem, well, earthed...
KeithS
Posts: 15
Joined: Sat May 28, 2022 4:29 am
ECU Model: No ECU
Distributor: Rawspeed Engine tuning

Re: What's going on? T2 ecu

Post by KeithS »

Also now checked 12v to each injector, continuity of earths back to ECU – and then the same for the coil pack. All good. I just pray it doesn't turn out to be a crank sensor failure as on this car it's an engine/gearbox out job, and more, to gain access to it...
stevieturbo
Posts: 3577
Joined: Tue Aug 02, 2011 12:08 pm
ECU Model: No ECU
Location: Norn Iron

Re: What's going on? T2 ecu

Post by stevieturbo »

Have you emailed Alex/DTA to enquire what would cause it to stop collecting data during cranking ?

When you crank, do you get an rpm reading ? In diagnostic screen or whatever does it indicate that it is seeing a good crank signal with no errors ?

Basics first before you need to start messing with wiring etc
KeithS
Posts: 15
Joined: Sat May 28, 2022 4:29 am
ECU Model: No ECU
Distributor: Rawspeed Engine tuning

Re: What's going on? T2 ecu

Post by KeithS »

This is a short video of cranking the engine this morning. The coil was disconnected at this point.

stevieturbo
Posts: 3577
Joined: Tue Aug 02, 2011 12:08 pm
ECU Model: No ECU
Location: Norn Iron

Re: What's going on? T2 ecu

Post by stevieturbo »

definitely looks like it's struggling with the crank signal for whatever reason.

I always prefer to disable injectors when cranking, that way you cannot flood the plugs. At the point where it said attempting to start it was probably injecting fuel.
But it should definitely sync up faster than that.

For testing a crank sensor. Not sure in lieu of the scope not working can you datalog the crank sensor raw input to try and get a visual of what's going on. I have not used any of the T series.

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