c20let still not sparking!!

[dearing5]

as you know i replaced my wastegate and its messed about since!

i have replaced

plugs
leads
rotor arm
dizzy cap
coil+amp
cts
removed and checked wiring loom
check every plug for voltage
fuel relay
cleaned crank sensor
checked timing
afm replaced

and it still won't start, its got fuel as it stinks and pressure is up but it can't be sparking! the eml is on with ignition so ecu has power.. it did start about 2 weeks ago but ran like ****.

need help bad as it needs to go!

[dag]

maybe you could check the crankshaft sensor,topbuzz explain a bit of how to test it,i had an astra mk3 gsi that leaked water through the bonnett vent onto the crank sensor conection which eventually killed the sensor took me ages to find that

[dearing5]

going to buy another one, its cheap so.

i know they can cause non starting etc so worth a shot, if its not that im lost.

[CorsaTurbo2008]

dont buy a crap aftermarket crank sensor if you do buy one.

[dearing5]

na mate gettin one off cemex.

[westyvan1]

temp sensor wiring ?

[dearing5]

yeah also replaced it, that wouldn't stop it starting though.

[tiff_lee]

I've had trouble starting an xe before when cts was unplugged, so much in fact it stank of fuel and flooded the plugs.

You say " but it can't be sparking", does that mean to say you have actually checked whether it is sparking or are you just assuming it isn't as not firing/smell of fuel?

[dearing5]

well i put a lead and plug on the coil and i couldn't see one.. maybe i should try it in the dark?? just to make sure..

[garymanc]

have you checked the leads are in the correct order, only suggesting as i have done the same myself

[dearing5]

yeah as it ran after i fitted new leads an plugs for about 2days then didn't start.

[MSG]

aah I can see the only thing you haven't mentioned is the dizzy hall effect sensor, it is notorious for not generating spark when its 3 pin connector is loose or with dodggy connections, so i would concentrate on this next.


The 3 plug that plugs on the dizzy should have square wave pulses coming out of the left pin and the middle pin being ground and the right pin is the supply volts from the ecu and can be anything between +5V to +7.5V so do not put 12v+ to it when trying to diagnose problems.

Use an LED with a series current limit resistor as a tester to see if you can get it to flash on/off as you crank the engine, there are various ways to get to the plug and socket to attach your tester wire to the left pin, easiest being strip back the wire which I do not like as it leaves the wire vulnerable to corrosion and shorts!


You could firstly check the plug itself when it is off the dizzy, see if you can get some voltage at its right pin?

then buzz (continuity test) the middle pin it should be almsot at ground potential, so if you measure ohms between this pin and the battery negative it should be pretty close to zero ohms

The left pin is the output so you won't get anything at this pin apart from you might get a pull up reading through the ecu internal pull ups, this may or may not be at 12V+ could be at a lower voltage that corresponds to the ecu chip supply voltage.

but what i do is get a very thin wire and use just a few strands from the wire, and try and fit this wire such that when you connect your plug to the socket it has made a contact for testing, the negative side of the LED should be grounded to any good earth, the positive side of the LED tester should be wired with a series resistor any value between say 220 ohms to 1k ohms.

[tiff_lee]

I thought if the hall sensor fails it just changes from sequential to batch firing

[dearing5]

i have checked that and the connection seemed fine.

[MSG]

did you really check it with an LED tester? Did the led flash as you spun the engine, you could spin it by hand when the dis is out, and have you confirmed its continuity back to ECU pins (on a 2,5 motronics the 3 pins are 15 being earthed, pin 8 and pin 31, not sure which of these two is the +volts and which is the pulses in. but either way you will see when you get to the loom connector, you can buzz for continuity in the least. using a long piece of wire insert one end in the pins at the dist hall connector and the other at the ecu plug and use a multimeter to determine that you are getting an almost zero ohm continuity. That would rule out this sensor wiring but not the catual sensor if it is faulty.


to check hall effect sensor, it is relatively easy, if you apply +5 volts or therebouts to the right hand pin on the DIS connector, having removed the 3pin wiring plug of course, then apply the -ve to the middle pin and hook an led on the left pin, with current limit a series resitor of about 220 ohms to anything up to about 1K and the LED should go on off as you spin the rotor. I think it is safe to use a 9volt pp3 battery but i wouldn't use full 12volts. Or you could hook up 3 to 4 AA cells and use that for testing the sensor.

[dearing5]

just checked for spark as its dark, defiantly not sparking!

gettin so lost with it now!

[MSG]

Unfortunately, you have tried everything, so logically this only means one thing, you have a possible break in a cable in one of the prime sensors, thats why I am trying to help you and you have not even replied to say you have checked the hall effect sensor with an LED.

Giving a visual look is different from measuring things with a multimeter, or an LEd tester.

[tiff_lee]

hall sensor won't effect spark

OP is it the same fault again you had in this thread?

c20let no spark.. coil??

[dearing5]

as said i have tested all the plugs, they all have voltage.

i tested this first.

tried my standard chips and it still wouldn't start.

ecu?

[daveybee]

Black cap on the back of the ignition barrell, ihad a problem just like this. Car would run fine but misfire while driven, then started cutting out. Then eventually just stopped sparking.

[MSG]

ya it can be the ecu itself, bad connections in the plug, or other possible faults on the pcb, blown transistors etc, so try a swapp if you can, what ecu is it? 2.5 motronics or another?

Or better still if you can't get hold of or borrow one from a mate, then just try and check that you are getting all the necessary +12v and grounds to the pins on the loom plug, and also I am assuming your FPR is good , have you checked the voltage on your FPR pin 9 or realy base marking 85b, it should be +12v when cranking. This feed back goes into the ecu on a 2.5Motronics it goes to pin 37 on the ecu.

[tiff_lee]

read the thread I linked to, all this stuff has already been mentioned

[MSG]

/\ yup, Vinci has given some very good checks to do, using an LED tester. This should be done as matter of course.

[dearing5]

i was going to look at this, what was yours?

i tried a spare coil etc and already read back through that thread.

cheers msg

[MSG]

only leaves you with the ECU now doesn't it. Give it ba visual inspection inside, look for any obvious damage/burnt tracks/burnt parts/ split transistors (cooked) etc etc, chips inserted incorrectly, or chip pins folded underneath the ics instead of being inserted into the socket, all can result from careless handling of any piece of electronic printed circuit boards. Particularly check for contacts inside the socket on the loom. these can easily be bent down and not making any contact with the ecu pins.

I think pin 1 is responsible for the spark signal to the ignition amp, so I would give it a good look around this pin and its associated tracks going inside the ECU and follow the tracks to its final output component, probably a driver or a power transistor.


The last time someone done a C20XE conversion and it wouldn't start (no spark) and it turned out to be a dodggy connection on the distributer hall effect sensor plug. as it was not sparking the engine was flooding with fuel!