Atom - GTIR SR20 Intermittent Spark

[DMC]

HI,

 

I have a Nissan SR20 From a GTIR pulsar that has a distributor.  I set timing to Opt0 360 and have successfully completed the ECCS test and got a result of 9 degrees with all both triggers showing YES.  Now when trying to check base timing I get no spark at the plugs but there is spark at the coil lead.  When I put a timing light on the coil lead the spark appears to be intermittent, or not regular, I was expecting to see evenly spaced pulses.  Instead I seem to get roughly 1,2 miss a few, 3, miss a few 4,1.

The coil, leads rotor and power transistor (igniter) are all new and I have a 0.25uF condenser from a carburettored car wired between the coil + and ground.

Also, other sensors appear to be working correctly (engine and IAT temps, TPS, engine speed....)

Can anyone suggest where I might be going wrong or missing something?  Or what I should be testing/checking?

 

Thanks

[Adamw]

I suspect the reason for no spark coming out of the plug leads will just be because your trigger offset is wrong so the spark is going into the distributor when the rotor is not lined up with a post.  Unfortunately I dont have any sample maps from a GTiR to look at so I dont know what the offset is on one of these.  I would try adding 30deg increments to the offset and keep trying until a spark comes out of a plug lead, 

You are right that the spark from the coil however should be relatively regular so that seems odd, is ignition mode set to distributor?  I would try adjusting the offset as above until we get a spark at the plug then we will look closer at the intermittent spark then if we need to.

[Adamw]

Hi DMC,

Thanks to user @Ducie54, he messaged me some settings from his old GTiR map.  His trigger offset was -107° so try it around there. 

[DMC]

Hi, thanks for the info.  A recheck of everything discovered a plug wire not seated correctly so I not have intermittent spark at the plug.  I have set base timing using an offset of -94 and when the timing light triggers, although it is not a regular pattern it is always on the same timing mark on the pulley.

So it would seem that I am not getting the spark triggered at the coil every time, I get single sparks or small groups of 2 or 3 in a row.  

There is not a lot of wiring involved at the coil and igniter and I have rechecked it.  The igniter has three pins, the centre being ground/earth, the others being ecu signal and the wire going to the negative pin on the coil. Could these last two be the wrong way around?  I guess the signal would not get amplified? The service manual shows the plug wiring but it is hard to tell whether you are looking at the front or back of the plug, so the outside pins could be reversed....

The only other thing I can think of is that the 0.25 uF condenser from a points vehicle that I have used is not quite right? Would that cause this behavior?

The ignition mode is set to distributor too...

[Ducie54]

Black goes to ground

White goes to ECU

Green/yellow goes to coil

Gti-r Igniters are renound for causing issues when hot, A common mod is to removed it from the head bracket and add a PC heat sink to it. Plus the normal dissy cap and rotor button wear

[DMC]

Hi,

Thanks again.  That is the diagram I am working off too.  I had no loom and bought a new plug for the igniter so I did not have the wire colours to work with.  

I am assuming that when looking into the front of the igniter where I can see the pins that the green/yellow wire is on the left. This theory would seem to work looking at some old coil plugs that I have been given with bits of wire still attached.  So I am feeling that it is wired correctly, does that sound right to you?  

I have not used the factory resistor and condenser shown in the diagram and do not have them, but used a (new) condenser off a vehicle with points as suggested in the Link wiring info and it is wired between the positive coil wire and ground.  It is only a 0.25 uF condenser though so I am not sure if this is too small and causing issues?

The Rotor, Distributor Cap, Coil, Igniter, Coil and Spark Plug leads and spark plugs are all new items and appear to be identical to the old ones, so hopefully that should eliminate any issues caused by worn or aging components.

The spark is intermittent coming out of the coil so that would also eliminate the dist cap and rotor.  Seems to be something in the coil/igniter/ecu setup?  But after checking and rechecking I am not seeing what I am missing......

 

 

[Adamw]

What happens if you set ign 1 driver to test mode?  (coil lead hanging off coil and grounded somewhere)  Do you get consistent, regular spark then?

[Rossobianconero]

On 15/11/2017 at 5:14 AM, Adamw said:

What happens if you set ign 1 driver to test mode?  (coil lead hanging off coil and grounded somewhere)  Do you get consistent, regular spark then?

That test will rule out that everything (igniter, coil, etc is correct) but I remember that one time something like this happen to us with a race engine, it fire in a odd way, but when we take the spark plugs out (engine running with less resistance) the spark was OK and as it should but we put the spark plugs on and the engine didnt start. It was cause for a faulty started, that consume too much energy and the engine simple didnt turn fast enought for the triggers to work properly, this was on a motec that run that engine for years without problems. You can make this test to... on that engine I remember that we test every ignition output with the test mode on the ECU and they where OK.

[DMC]

Hi Guys, I have tried the ignition test and it does give a consistent spark.  And using the timing light on the coil lead the timing light is flashing consistently so it doesn't look like an issue with the timing light.

You have got me thinking now, I am using a small sealed lead acid battery and I am wondering if is not providing enough power for the starter and the electronics... I will go and raid a full size battery from another car and see if that makes a difference.  I guess I could isolate the starter from the rest of the system and run if off a second battery as a test....  Will let you know how I get on.

[DMC]

Hi.  After adding some more battery power the spark is now consistent and timing is correct.  I have turned the fuel on and the engine started on the first attempt. 

Thanks for all the help :-)

 

[Rossobianconero]

On 20/11/2017 at 9:15 PM, DMC said:

Hi.  After adding some more battery power the spark is now consistent and timing is correct.  I have turned the fuel on and the engine started on the first attempt. 

Thanks for all the help :-)

 

Great to know man... happened to us on a race weekend when I wasnt with the team, it wasnt funny but we sort it out on time.