E40 Idle Speed/Throttle %

[hrthsv]

Hoping someone can help me, I have mafless tuned a number of VZ HSV Ls2's with E40 controller running stock cam with intake and exhaust, some as long ago as 2007 with no problems ever.

I tuned a VZ Maloo in the last couple of weeks mafless with usual things intake and exhaust, it's goes great but it has this problem where if you put the clutch in whilst driving the revs spike lets say from 1200rpm to 1500rpm then they slow go down to 1100rpm where it'll fluctuate up and down 100rpm. If you actually stop it'll rev at 800 (commanded) sometimes or sometimes 1200rpm then slowly come down. At when it's idling at 1200rpm the throttle % on the log shows around 11% then over about 20 seconds slowly drops to 800rpm and and about 5- 6% throttle which is normal. Tried 4 different TB's same result. No DTC's.

Yesterday I put the maf back and did a full reload of the stock tune, drive the car, say 1500rpm put the clutch in to change up a gear the rpm jumps to nearly 2000rpm, push the clutch in at say 60km/h rolling and rpm will spike from say 1500rpm to 1800rpm, start to drop get to 1200rpm then jump again then settle to 800rpm, remember this is all with the clutch in and stock tune. With the stock MAF tune it will however idle at 800rpm when you stop, but the throttle % stays up longer than normal before falling to 5- 6%, idle timing is correct MAP is right, fuelling is right, no DTC's.

I did a full reload of the Mafless tune, looked at the TPS fault airflow table and progressively pulled air from that table and the car began to behave, got it spot on drove it for 30 mins and it was fine. Only issue was put the clutch in and hold whilst rolling and the rpm would drop to 1000rpm and fluctuate 100rpm other than that it was perfect. Owner drove it home all fixed.

Then this morning back to it's old tricks.

I had progressively pulled everything from the tune to the point where it's just mafless with patches, set VE table running 02's, less than stock airflow now in both Desired and TPS fault tables, I have always used stock airflow in these without issue on stock cams, set High Octance table. No changes to fuel pump (this Maloo has a variable one some Maloo's don't), throttle settings all stock.

Owner did tell me he had a speed sensor fault (he's not sure exactly) with light on a couple of months back which Holden cleared (not fixed) but that's it. Everything scans normal all engine sensors are fine.

Any ideas.

I'm thinking pedal but there is no DTC.

[rally1]

Have you got to the bottom of this yet?

[hrthsv]

I've got it bascially right I just had to keep pulling air from the TPS fault table and pulled a little bit from the normal airflow table. It still plays up out of the blue ocassionally though. It's weird, I'd rather tune a cammed one than this one.

[rally1]

Just as a note I have had similar issues with a VZ 5.7L and it was a dirty throttle body causing the learns to be very high which are then added to decel air. it only had 75k on it and was not overly dirty but caused all sorts off random issues.

[Jester]

I had this problem with an E38 ecm, haven't looked at E40 before but the tables I used to sort it was min idle airflow & max idle area. My TP was hanging at 10% 1200rpm then slowly coming back to 6%. I lowered the max idle area and TP comes straight back to 6% and 750rpm, although this does work in conjunction with min idle airflow which I have set at 8 g/s. This is cammed though.