[Sausager]

Hi guys. My g16b vitara is stuck on base timing, as if I had jumped the connecter under the bonnet to set dizzy timing. It won't advance timing throughout the rev range. I have checked the connector and confirmed that there is no jumper in there at the moment haha.

I am presuming that the ECU is what normally advances timing. Is there anything else that could influence the ECU's decision to not advance my timing? Is it likely a bad ECU? Anything else to check, or any other ideas?

[Jimny_No_Power]

check the fsm, do you have them? MIL/CEL?

I haven't done much on the G series diagnostics, though I think they had the six pin connector? check this

[Sausager]

Testing if this posts?

[Sausager]

Apologies for no response on here, I wasn't able to post responses.

My fault codes do silly things. When I check codes with ignition on (engine off) I get code 42. I noticed that when I am driving, though, I get code 12 (no codes) after a minute or so of driving. When I stop and turn the engine off, code 42 shows again. Maybe related, when I put the key to ON, I can hear the fuel pump priming, but it doesn't stop priming after a few seconds, it keeps pumping.

After doing some reading online about code 42, I saw a post in a forum somewhere and someone had a similar issue where the ECU thought the car was cranking, couldn't see a CAS signal, and so threw code 42. Similar thing?

Is it a bad ECU maybe?

Car is a g16b, AW4 with the neutral safety bypassed.

[fordem]

A code 42 is defined in the FSM as a CAS (Crank Angle Sensor) circuit problem, specifically, sensor signal not inputted for 3 seconds at engine cranking.

Normally you'll only see a code 42 when the engine doesn't start, when the ECU doesn't see the CAS signal (from the distributor) at the same time as it is seeing the start signal (from the starter circuit) - the only way to get a 42 on an engine that runs is, as you said, for the ECU to "think the car was cranking" when it's not - either a bad ECU or a problem with the wiring so it sees the start signal as high when it shouldn't be.

The start signal is generated by the very same wiring that would have been modified to bypass the neutral safety switch - if the connection to the ECU has been disconnected, it may "float" and confuse the ECU, which will, if it sees a "bogus" start signal, set a false code, and yes, run the fuel pump. I can't state for certain that this would also cause the ECU to lock the base timing, but, the last thing you want whilst cranking a gasoline engine is to have too much timing advance, so it's not unreasonable that the symptoms are all related.

I would start by getting the neutral switch replaced and returning that part of the wiring to it's original configuration.

[Sausager]

Thanks for this fordem. Great info.

I figured it was worth mentioning the NSS on the off chance it is related. When I say that it is bypassed, I mean that a new starter trigger wire was run straight from the ignition. The NSS and wiring are all still in place, but clearly not working as they should. I'll investigate reinstating it. I'll also test the dizzy wiring and CAS function again according to the fsm.

I vaguely recall reading somewhere that the NSS can be opened up and contacts tidied up. Was it Steve that said that?

How would I know if I have a bad ECU?

[fordem]

Sausager wrote:

When I say that it is bypassed, I mean that a new starter trigger wire was run straight from the ignition. The NSS and wiring are all still in place, but clearly not working as they should.

They may be still in place, but are they connected to anything?

Let's say, for the sake of discussion, that the original wire from the ignition switch to the NSS was cut at the ignition switch end, and likewise the original wire from the NSS to the starter solenoid was disconnected from the starter, and the "bypass" wire was run from point A to point B - that may or may not be how it was done, but if it is, then that would leave the "START" signal to the ECU not connected to anything, which, in computer terms is known as "floating", and which would normally cause the computer to interpret it as a active.

That is enough to cause the symptoms you have reported.

[Sausager]

Sounds like I'll have to hook out my wiring diagram and have a look at the wiring in my car.

If the NSS is roached (which I am sure it is. I don't have reverse lights), that would need to be reinstated along with the wiring corrections, right?

Thanks for your help mate

[Sausager]

I had a look at this on the weekend. Turns out, yes, the NSS bypass/trigger wire install had been done by cutting the main feed out of the ignition switch (black red) instead of splicing into it. Reinstated the black/red wire and was away laughing.

Thanks for your help on this one guys!