Spark Only $OSE12 Tuning

[yoda69]

Been playing around with my spark only ford cleveland and decided to update from an old $5D bin to OSE12.
Engine is a 302 with 4 barrel intake, mild cam 204/214 @50, fitted with reluctor dizzy and camira ignition module & coil.
Sensors:
Engine Coolant
MAT fitted to airfilter box
MAP sensor
No TPS, O2 or VSS fitted.

Problem I'm having is that it doesn't want to leave closed loop idle spark control for sometime after being booted. Real slow of the line (10d spark) and then around 2500RPM engine check light comes on for high MAP, spark increases (~24d) and away it goes to nearly 5800rpm (nearly 100km/h in first!!). Have played around with a few settings but just doesn't want to play ball. Didn't appear to have this problem with the old 351 running the same setup on a $5D tune, altogh couldn't log much with $5D so it may have been.

When driving around also noted that it was dropping in/out of idle mode at ~2000rpm also causing havoc with spark.

yoda69

Note: bin is not actually matched to this log as I was modifying spark while out driving.

[VL400]

I think its caused by no VSS and TPS. To detect idle it uses both VSS or TPS - if there is a VSS fault it uses "IAC Params - Maximum MAP load limit". But having both TPS and VSS missing its having a very hard time With a TPS it will solve most of the issues, VSS you can get away without. You could maybe trick the ECU using 2 resistors setup as a voltage divider to get some voltage on the TPS wire so it always runs off the main spark table.

[delcowizzid]

yeah i reckon fit a TPS and it will be fine.there must be a setting thats not the same as $5d making it go nutta on 12p

F78: TPS - TPS default value vs RPM from $5d its the first value in the tables both different values for rpm based tps % when it uses a quessed tps %

[Mechcano]

yoda69

I had the same problem with my 360 Chrysler, spark only with $5d and it runs great, then changed to a Kalmaker and it would not advance untill about 1800rpm.

When i changed the table "Malf TPS - TPS default value vs RPM" from 0% at 1000rpm to 4.5% at 1000rpm this fixed the problem for me.

Regards

[yoda69]

I tried raising it to 10% and it improved but still had a stumble.
After reviewing logs I could see it thought it was idling fast so ECU was pulling out ~ 5 degrees of spark trying to reduce the idle speed.
Changed the idle spark parameters to increase spark if below desired idle rpm, but to do nothing if above, this made a big difference without upsetting idle stability.
What was happening is in normal driving would either run of normal spark map or idle spark map at low RPM (<2200RPM), depending what was happening it either was rather gutless or pinged.
Couldn't be bothered fabricating brackets for TPS so bought one of these http://www.holley.com/HolleyNews/article.asp?ID=196
Had to modify it a bit as mine has a Barry Grant which is just different enough from a Holley to stop everything just bolting up.

All hooked up, but haven't had a chance to play with tune or TPS setting, hopefully on the weekend.

yoda69

[Holden202T]

how does the TPS sensor connect to the shaft with that ? under the choke ?

[yoda69]

Here is a link to the fitting instructions http://www.holley.com/data/Products/Tec ... R10499.pdf
Part number even ends in 202.

Basically a modified rod that goes under the choke and then mounts in the outer housing to keep everything stable.
Feels OK by hand, but need to hook up the laptop to check voltages at idle and WOT. Apparently kit is used in the US for when people fit electronic autos behind a carby engine.

yoda69

[Holden202T]

yeah that was one thing that came to mind for me ..... when i first put a T700 behind my 202 without a delco computer it was dodgy at best to get TCC working!

[yoda69]

Rock on daylight savings.
Just took it out for a quick drive, what a difference with proper spark down low.
Set the TPS up at 0.78V closed throttle but was only getting around 3.2V at WOT which worked out to around 70% TPS, although I know it is WOT, as checked it all before putting back on.

Now just need to spend more time sorting out the spark table.
Couple of quick observations, is that I was getting a little pinging on the changes (3 speed auto), looking at the log I was getting around 88-90 MAP values at 4-6000 RPM and the spark was dropping off, then on the gearchange went to over 90 and into an area of higher spark advance, looks like I may target around 85-90 MAP as max spark and then ramp it off after that and see what happens.
Only tinkering at this stage, still want to inject it later.

yoda69

[delcowizzid]

i guess the carb is a bit small then since you dont see 100kpa at full throttle or the aircleaner is not flowing power to be had there