Keeps cutting out and it's not the stepper - FIXED

[Rob Furniss]

Rowans car (my Son) keeps stalling when he comes to a stop (junctions, t lights etc).
I've swapped the stepper with the one from my car and it's still doing it.
No error codes.
I swapped coil packs with the ones from my car and it's still doing it, didn't swap ht leads though.

It will start up fine and idles but the revs dance around a little - not a lot.
Also sounds like a bit of an intermittant misfire when cold.

We did suspect head a while back as it overheated but compression is ok and no milkyness on the rad cap, swapped thermostat for new, new rad, new water pump and timing belt, it revs to 8K.
It wasn't doing this cutting out when we drove to the bonfire (just overheating).

So what am I missing?
Haven't checked the wiring to stepper, haven't tried swapping ecu's, could it be the fuel pump (we changed his fuel filter a couple of months ago)?
TPS? (but then wouldn't it throw an error?)
Injectors?
Spark Plugs? (they looked ok when we did compression test)
Re-do compression test?

[silverGPX]

Map sensor vacuum pipe or map sensor?

[Rob Furniss]

Cheers I'll give that a try, it's handy having another car to swap parts over to test for these things (I hardly drive mine)

[kiz]

My stepper motor was playing up really bad, tried 2 other stepper motors (didn't know the history on them though, so they may have been faulty) and it didn't help.

Then my alternator starting packing up and so I replaced it. My stepper motor has now sorted itself out. When was the alternator last done/checked?

[destinationtoby]

Could also be alternator dying.

[Rob Furniss]

Not sure about alternator he's only had the car a couple of months although the wiring to it has been hacked when he got it, looks like maybe a 2 pin had been fitted and the wiring altered to make it work and then later a 4 pin fitted, very dodgy spliced in wiring round the back but it does have a 4 pin on.

[Scorpionwally8]

I don't know that much about cars but sounds like a alt problem

[Rob Furniss]

Been trying all sorts with this car but it's still cutting out and hunting, swapped various parts over from my car and other spares that I had around and it's still doing it, sounds like a misfire too noticeable at the exhaust.

So far we've swapped stepper motor from mine, tps, coil packs and ht leads from mine, on the 3rd o2 sensor in the exhaust just in case it's that, swapped temp sensor previously but I guess it could have gone since, new spark plugs today, map sensor from mine.
I've done a test on his stepper motor and another one and all good - checked middle to outer pins - resistance quite low like 38 ohms or something, outer to outer ok - around 58ohms, getting 12 volts to the middle pins. I can make the stepper plunger twitch by putting 12v to it and touching wire with two opposite outers to ground but it doesn't wind in and out just twitches, i've stripped it down and can wind the core in and out but still not convinced that the ecu is sending signals telling it to do it.

The problems are only when the car has warmed up, revs settle to around 900 and then after another minute we start to see the dropping and rising of revs and almost cutting out.

Did a cambelt change on it a couple of months back - screwed up there with something?
He had a massive overheating problem previously when one of the coolant pipes broke and dumped all the coolant out, compression test seems ok and no milky oil cap and that's when we decided to do the cambelt change, also swapped crank sensor, cam sensor, det sensor (as the wiring was all melted off it).

Got no error codes.

What's next - ECU or temp sensor again?
Fuelling problem like fuel pump or FPR or injectors? (changed filter a few months back)

[kiz]

Did you end up checking the alternator?

[Rob Furniss]

No haven't touched the alternator, is there any test we can do on that like disconnect the data connector and see how the idle is then? I know it won't then mivec but might rule something out?
If it's stood for a few days the battery goes dead.

[Rob Furniss]

Fitted an afr gauge today and its running really rich (11:1) when its warmed up, swapped temp sensor - still rich, took cam covers off - rear bank exhaust cam is out one tooth ******* hell. So I need to sort this out. Is this going to fix the rich issue and hunting/bad idle?

[dstocks]

O2 sensor? Sorry if youve already done this. Havent read the rest of the thread.

[Rob Furniss]

O2 sensor? Sorry if youve already done this. Havent read the rest of the thread.

On the third 02 sensor at the moment but these were all 2nd hand what we had in the garage so don't know if bad or not.
Think I will sort out the rear cam first and then go from there, might put his original O2 sensor back in.

[PHIL069]

You will find that the rear cam will always be out by half a tooth.

[Rob Furniss]

Yeah it is more like 1/2 tooth than 1. Although I wasnt looking forward to redoing the cambelt I was hoping this was the reason for his stalling/hunting. Havent tried swapping the ecu yet and I havent tried the O2 sensor from my car which I know is good.

[Rob Furniss]

Swapped the following on this bloody car:

Knock sensor (this was broken, now isn't)
Crank sensor (this was broken, now isn't)
Stepper motor
Map sensor
O2 sensor (several times but the last one with my known working one)
Temp sensor
TPS sensor
IAT sensor
Injectors
PCV valve
ECU at the weekend and still issues

Checked the cam timing again and compared it to mine which was spot on, on Rowans the rear bank exhaust cam was actually 1 full tooth out, maybe 1 and a tiny bit (I said previously 1/2 a tooth - I was wrong).
Sorted this and the problem is now completely fixed, no more cutting out and no more need for left foot braking, fuelling is spot on, no more misfire and the engine feels smoother. (when I say feels smoother - if you put your hand on the intake plenum when he had the issue you could feel like a little thumping/roughness and now no more)

We've spent hours and hours on this, wish i'd properly checked the timing first when we hit these problems! (I did the cambelt change a couple of months back and thought it was spot on so it's my fault)
So pleased to have this sorted and the timing couldn't be better (excuse my pun) as we are moving house, Rowan has just this morning set off on an epic journey in the FTO, Melbourne to Port Hedland.
Adelaide first then Ceduna and over the Nullarbor to Norseman, then up to Kalgoorlie, Mount Magnet, Newman and finally Port Hedland 4600km after setting off.

I'm not doing that i'm flying as the little one didn't fancy 7 days on the road, the Landrover was picked up yesterday and my FTO will be going next week on a transporter.

[bjk]

Nice pun. good to hear the issue is sorted.

When will Rowan be in Adelaide?

[dstocks]

Congrats on finding the issue.

[PHIL069]

Well done Rob

[Vectose]

Good stuff. Glad to hear it's finally sorted.