Cold Start Tuning Help

[muttley383]

try this tune and see if it makes any difference to the hunting....

thanks, I will try it out tomorrow evening.
I hate having to wait till the weekend due to insufficient time through the week due to work commitments and neighbours complaining if I have the engine running to late in the evening.

[Holden202T]

lol im hearing ya, wish i was a a million acres well away from anyone!

[muttley383]

try this tune and see if it makes any difference to the hunting....

I tried this .bin this afternoon, very little difference. See attached log.
I adjusted the "IAC - Idle spark Adjustment params - Idle spark correction limit" scaler to zero to see if it was the timing shifting causing the hunt.

During the log the timing stays steady but the hunt is still present until it is warmed up. The issue has to be tuned related as it settles down once at full operation temperature. I may change out the spark plugs to NGK as I have Bosch units at the moment that were installed 2 weeks ago.

The MAP sensor seems to be ok as the log shows 100kpa @ 91% throttle.
I will probably leave the idle problem at the moment and move onto working out why the wideband O2 sensor does not read 14.7:1 when the narrow band sensor is switching back and forth. I will make sure all of the 0v reference points are the same for both sensors. I need to get this right so I can fine tune the VE table.

[Holden202T]

try increasing the afr's for cold start a bit and see if any makes any difference

[Jayme]

ive found most hunting that bad is caused by it being lean.

[vn5000]

Your running to rich on the 30 kpa side if idle and your running to lean on the 50kpa+ side of idle.But when i look at your bin i can see where youve tried to compensate with ve in this area.
I think your wide band is reading a lot richer than the actual a/f and that is whats causing the confusion .
Try tuning it the old way with blm values.Take it for a good drive and get some logs especially at very low engine rpm and low and high map values.

[muttley383]

I have been having a bit of play over the weekend and it looks like things are improving.
I have got rid of most of the error in the wideband O2 sensor by strapping all of the 0v for the ECU, narrowband and wideband together with a large cable and attaching this to the chassis. I changed the wideband setup parameters back to original, ie: 7.35 - 22.39:1 = 0 - 5v.

Attached are logs for a cold start and a hot run. The cold start seemed to be not that bad.

There is an issue in the hot run log at 22.41m - 23.10m where I stop at a set of traffic lights and the engine is still reving @ approx 1700rpm. It feels like a stuck throttle but the throttle tps is 0.47v, indicating a closed throttle. This sets the VSS fault as it is reving with no speed signal. This clears as I blip the throttle a couple of times once I start to move again.

BLM's dont seem that bad.

[VL400]

It still looks like you dont have enough counts at that point, 26 IAC steps and 1600RPM means even at 0 zero it will prob struggle to hold a reasonable idle. But later on its got 26 steps and is happy at 975RPM. So maybe its not working or there is a vacuum leak somewhere?

The knock retard is prob also making it drive a little average, and making the max 20 deg is a fair bit! At one point near that high idle it drops to 5 deg advance from 25.

[muttley383]

I put a heap of knock retard for safety as I have been concentrating on the fuel ve tables and paying not much attention to spark.

I was looking at my knock filter (snef) board last night and I think it is a V6 type. This will be a problem. I do have what I think is a VR V8 knock filter board (1F4160) that I will try and fit today and see if this makes any difference.
This engine has always been sensitive to excessive timing.