S40 Ingnition starting problems

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.
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s40pro
Posts: 19
Joined: Tue Jan 29, 2013 4:37 am
ECU Model: S40 Pro
Distributor: XAP
Firmware Version: 63

S40 Ingnition starting problems

Post by s40pro »

Hi,

I have a S40 ignition management in a car with a K-Jetronic injection ( all in perfect condition, tuned and controled )

All was perfect running before stop the car to rebuild the engine...

Once I finished the project, start ok, but if you stop the engine, you never know if it will starts again... not have a fail sequence, perfect in cold starting, but if 10 seconds after starts, engine is turn off, and you want restart again, may be yes, may be not.. usually not.

With the OEM ignition system have the car, starts perfect the 100% times you try, cold, hot, etc.. 100%.

I changed the crank sensor, and the problem it's the same...

The system it's working with:

Crank
MAP
Air temperature
Water temperature

Could you tell me, if we know we are sure, the crank sensor it's ok, if the MAP could be the problem? or more a temperature sensor ?
Not started with the laptop to see if something looks be over... but, I do the stroboscope test with the engine running and the timing it's perfect as I noted in the map, the only problem it's why if the engine is stop 5 seconds, 5 minutes, or 30 minutes, not want starts again.... In cold for the first start at the morning always start perfect as always.

May be the ECU have a problem ? It's frustrating because, I stop the car in perfect ignition condition, I made this conversion with the DTA 5 years ago and perfect since the first day...

Thanks for your coments
s40pro
Posts: 19
Joined: Tue Jan 29, 2013 4:37 am
ECU Model: S40 Pro
Distributor: XAP
Firmware Version: 63

Re: S40 Ingnition starting problems

Post by s40pro »

Hi Again,

Yesterday, I tested all the voltages in the temperature sensors and the volts variation in the map in vacum, 0, and pressure and all it's working fine... but not restart if I turn off the engine.

I will try to test the voltages also in the moment is not starting to see.

But, if the voltages are ok, crank sensor ok, map input voltage and volts variation working fine... looks like the sensors and loom it's OK, correct ?

Also the trigger wheel and crank position because with the engine running, tested with a stroboscope lamp...

I will post if I found the problem, I hope not the ECU damaged.

All theories or ideas accepted if you have an idea...:) thanks
s40pro
Posts: 19
Joined: Tue Jan 29, 2013 4:37 am
ECU Model: S40 Pro
Distributor: XAP
Firmware Version: 63

Re: S40 Ingnition starting problems

Post by s40pro »

Well,

Laptop in and first tests, and as expected, all it's working fine.

When the car not want's to start, the oscilo/crank it's ok, and all sensors, map, temps... working ok.

Only one thing looks not normal, when I start the first time, the power batterie was 12-12.3v, but when not start, the gauge in the live panel turns to the left blocked to minimum, red gauge and marks between 8.5 and 9.8v

May be it's not enough to works fine?

I will try to start in trouble moment with an external power supply to be sure have the 12v power.
PhillipM
Posts: 177
Joined: Tue May 13, 2014 5:30 am
ECU Model: S80 Pro
Distributor: DTA UK
Firmware Version: 73

Re: S40 Ingnition starting problems

Post by PhillipM »

Probably need to put voltage compensation in for the dwell if it's pulling down that far.
s40pro
Posts: 19
Joined: Tue Jan 29, 2013 4:37 am
ECU Model: S40 Pro
Distributor: XAP
Firmware Version: 63

Re: S40 Ingnition starting problems

Post by s40pro »

Thanks Phillip,

I will check if I can put voltage compensation to help the dwell after test with this external power supply to power the ECU, like that, not voltage failure in the start phase.

Long time ago I was worked in, I hope I will find the battery compensation in the settings :)
SMR
Posts: 137
Joined: Tue Jan 16, 2018 9:38 am
ECU Model: S100 Pro
Distributor: DTA
Location: Aberdeen

Re: S40 Ingnition starting problems

Post by SMR »

Check the engine earth straps - if the battery is good, it shouldn't be dragging down the battery voltage so much. Also check the large terminals onto the starter motor.
Alex DTA
Posts: 1622
Joined: Fri Feb 28, 2014 1:03 pm
ECU Model: S40 Pro
Distributor: DTA
Firmware Version: 79

Re: S40 Ingnition starting problems

Post by Alex DTA »

We've communicated via email as well.
Turned out to be reversed crank sensor wires.
Should be sorted tonight.
s40pro
Posts: 19
Joined: Tue Jan 29, 2013 4:37 am
ECU Model: S40 Pro
Distributor: XAP
Firmware Version: 63

Re: S40 Ingnition starting problems

Post by s40pro »

Hi,

After talk with Alex, I switch the wires in the crank sensor and now starts much better !
Oscilo read better also in test mode.
I am searching if any power supply problem to be down as that in volts.

As soon as I see if the power failure it's something with the car loom, I will check again starts and map timing map with the lamp to control timing it's correct as in the map or needs compensate a little calibration.

Thanks a lot to Alex and the DTA team, very quick answer and great by phone ( and my English is not my hard... sorry again ) fantastic job, in personal attention and technical support, not easy to see today.

I will post the final conclusions and if someone need this info, will be here for you.
s40pro
Posts: 19
Joined: Tue Jan 29, 2013 4:37 am
ECU Model: S40 Pro
Distributor: XAP
Firmware Version: 63

Re: S40 Ingnition starting problems

Post by s40pro »

Hi,

After a lot of tests, the solution was a wrong way in the crankshaft sensor...

It was working perfect since 5 years ago, but, now sometimes, not syncro.

Also I modified the power bat compensation for the dwell and all it's working perfect.

It's crazy, with the wires way changed, the timing it's exactly as I have in the map, and the same I was before the change in the wires way, in other cars I use this crank sensor, if you change the way, the timing map it's advanced 2/3º more or less, but in this case not.

Thanks a lot to the DTA team specially to Alex and the forum people interested in.

See you in other projects!

Kind regards
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