First RT Tuning Experience - OSE 12P BCLF based Camaro

[redcamaro]

The surging is still happening...

Drive normal and it surges gently apply throttle, and suddenly comes good and takes off.

What would that be? Not enough fuel pressure (injector volume), tip-in fuel, or timing?

[Holden202T]

sounds to me like at that certain map point its too lean, either that or lean cruise is enabled.

[redcamaro]

sounds to me like at that certain map point its too lean, either that or lean cruise is enabled.

Yep, right on - that makes sense! It seems like all over - at all points - while driving. Here's why I say that...


The relevant tune is redcamaro_tune delcowizzid_2-fixed.bin https://pcmhacking.net/forums/download ... hp?id=4322 except for, changed injector displacement value from 0.121 to 0.112

Same issue as described in my earlier posts...


I checked the Fuel Pressure and done the Ultimate Kinjiflow again - the result was 0.112 - Stock Psi is between 40.5psi and 47psi so I used 43.8psi as stock, when ignition on pressure is about 53psi and idling it's 50psi so I used 50psi in the spreadsheet.

In the spreadsheet I put 43.8psi as stock and 50psi as the current setting and I get 0.112


What I did first notice was that it tends to be richer at lower RPM and leaner at higher RPM - so I guess the VE needs more of a hump at higher RPM, (and maybe more AE - for a tiny flat spot at commence acceleration).

Having said that it also leans out upon deceleeration, too...

I dunno?

[Holden202T]

its supposed to lean out when decelerating.

it sounds to me like you just need to massage your VE more and it should be right. i'd be getting it right before playing too much with the AE.

[Jayme]

I think you are overthinking it mate, injector flow rate doesnt have to be set at one magical number as per the spreadsheet, thats just a guideline and a guess, it just needs to be wherever it needs to be to keep your VE table at sane numbers. being lean in a lot of places, I would be trying out delcowizzids tune with out touching a single thing, leave the injector rate where he had it, it will make it richer all over and will prob run better. if its still got lean spots then change the VE table only. you dont need to go finding every obscure setting and buggering round with it, you will end up chasing your tail..... you will be able to get it running pretty sweet by just touching hte VE table. if you get to 99 in your VE table and its still lean, then you go and raise the injector rate some more and start again.

[redcamaro]

I think you are overthinking it mate, injector flow rate doesnt have to be set at one magical number as per the spreadsheet, thats just a guideline and a guess, it just needs to be wherever it needs to be to keep your VE table at sane numbers. being lean in a lot of places, I would be trying out delcowizzids tune with out touching a single thing, leave the injector rate where he had it, it will make it richer all over and will prob run better. if its still got lean spots then change the VE table only. you dont need to go finding every obscure setting and buggering round with it, you will end up chasing your tail..... you will be able to get it running pretty sweet by just touching hte VE table. if you get to 99 in your VE table and its still lean, then you go and raise the injector rate some more and start again.

Thanks Jayme, that's a good explanation - straight to the point...

This is the delcowizzid tune that I'm trying to fix - i.e. to make drivable. He had it very close except for the surge/flat spot issue. All I have done is overthinked the injector rate and lowered it by 0.009 - it didn't really do much - same issue exists.

It was just to check the fuel pressure at the engine really, and in doing so I increased it as high as the stock pump will give me through the adjustable regulator - that's 52psi.

I might get an hour on a Dyno later this morning - I'll be quickly checking the timing advance and then focussing on the VE tables/injector rate and massaging them.

Thanks to Holden202 as well...

[charlay86]

It was just to check the fuel pressure at the engine really, and in doing so I increased it as high as the stock pump will give me through the adjustable regulator - that's 52psi.

You aren't going to leave the pressure set that high are you?
The fuel pump will not be able to maintain the max pressure you are seeing at idle/key on once the flow rate through the injectors increases.
That's why the stock pressure is set much lower than what the pump can supply in order to maintain a constant fuel pressure with respect to the manifold pressure under a wide range of operating conditions.
If you find that you can't get your fueling rich enough under high load conditions in spite of your injector rate and VE adjustments, it may be that your pump is on its way out.

[Holden202T]

if 52psi is at idle then its only going to increase as you get closer to WOT vacuum - assuming the fuel pump can handle that much!

i agree with charlay86, i'd be dropping the fuel pressure, maybe set it so you have max of 50psi at zero vacuum, but then if your injectors arn't maxed out then i don't see any reason to increase pressure at all, your only un-necessarily increasing the load on everything for nothing.

[redcamaro]

On the Dyno so respond soon

What is the Alternative sTEP?

mORE IMPORTANT HOW IS SWITCHING BETWEEN OPEN AND CLOSED LOOP CARRIED OUT.

OR THE OPEN LOOP CROSSOVER POINT.

What variales am I after to know when, where to change the switch over point between open and closed loop fuelling?

[Jayme]

I have no idea what you mean by alternative step.


as for open / closed loop theres a few things that can turn it on and off. the main one is:
Map A: A/F Ratio - 20-100kPa Air Fuel ratio vs RPM and MAP - when the cell = 14.70 then its closed loop. if the cell is anyhting else its open loop and it strives to acheive the AF ratio in that cell. (by using the VE table and air temp / map sensor to calculate air mass and apply a formula.)

also your engine needs to be up to temp - "Closed Loop Params - Closed Loop minimum coolant temperature"