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-   -   Noobness - first fire: poor response off idle with no load. (https://www.miataturbo.net/megasquirt-18/noobness-first-fire-poor-response-off-idle-no-load-88769/)

Turbonic77 04-26-2016 04:01 PM

Noobness - first fire: poor response off idle with no load.
 
,

have been an avid lurker for a while now and have just started my '92 1.6 turbo setup, ExtraEFi PNP, T3 turbo, with external wastegate, 425CC RX8 injector setup.

Running a MAP sensor and boost temperature sensor setup and an old techedge wideband.

Have it idling after a minor hicup: injectors 1 and 3 hosed enough fuel for it to drip out the exhaust joints (grounded wiring) It did however start on first crank and promptly gassed the street.






So after greeenpeace came round to advise me of the error of my ways: Injoector Prob Sorted, and the car idles. I am running tuner studio and have a base timing map and VE table to start from. Reinstalled 420cc injectors, and they pin out fine re resistance post hosing incident.

Base engine timing set at 10deg at appix 900RPM
Static injections at 360dec
2 x squirts per cycle.
Car runs at a high idle - during start up. Ignition advance after multipliers ~35Deg. Physica idle screw all the way in, idle can be brought undercontrol with less advance.


The Initial Problem (after teh exhaust/sump of fuel one)
All warmed up, and ANY throttle opening off of the high idle results in a very high AFR, plus popping In the turbo or manifold, and a drop in torque (basically farts an dies

So Activities:
Messed a little with ve maps - slight improvement actually moved off idle.
So: Frigged the required fuel to give a higher duration (about 8ms) and I can move off of the high idle with a poor transient response to the throttle opening/blip
Idle is also v rich.

Synopsis:
I am running v v v lean off idle using the calculated fuel settings from TunerStudio (calc'd 425cc, 14.7 afr target, 1600cc = 3.2ms duration)

Questions:
Soooo. I have read that the required fuel calibrateable is basically a scaling factor for the VE map, I believe that adding duration effectively richened it up, fine with that but:
  • What are others running with the RX8 yellow injectors?
  • If I am the odd one out, why would that be?
  • How are others dealing with transients (in my case I'm stuck at the blipping the throttle stage) have seen that there is an accel enrichment option
Caveats:
I actually don't know what fuel pressure I have - though believe the car was a stock '92 which I have bolted a turbo, EFI and a downpipe that took precisely 1 million times on/off the car to get to fit (though I got good with a grinder and TIG by the end)

Yes the car is real, and yes I no nowt as concerns Gasoline Cal, but I am getting there, any suggestions welcome.

Matt Cramer 04-26-2016 04:19 PM

Please post a data log of the issues and a copy of your tune file.

Turbonic77 04-27-2016 08:03 AM

Shall do this evening, cheers.

Braineack 04-27-2016 08:29 AM

if no vTPS, make sure youre using MAPdot for accel enrichments, and that it's actually tuned...

Turbonic77 04-27-2016 03:18 PM

5 Attachment(s)
So - a bit of playing this evening before neighbours lynched me.

Added Acceleration enrichment based off of MAPDot - was already "on" and soley based upon MAP
https://www.miataturbo.net/attachmen...ine=1461784721

Stuck with the "base" timing map

https://www.miataturbo.net/attachmen...ine=1461784721


and added sh1t loads of fuel rather arbitrarily, however have got it to respond to throttle blips.

https://www.miataturbo.net/attachmen...ine=1461784721

The extra fuel has obviously helped (as it did before when I altered the REQ_Fuel but I am still puzzled by the large numbers I have to use.

Next step: log files to back up my insane ramblings.

PS: for a standard MS2 - what is the transfer function for the MAP sensor? I assume I have a standard sensor in the ExtraEFI setup.

I have to date used an MPX4250 default.

Toon attached - feel free to point and laugh.

Turbonic77 05-01-2016 04:05 AM

So. Added fuel pressure gauge. ax pressure from pump 67psi ish, leak down also OK.

Tee'd off supply, bridged pump, 40ish psi, decreasing with added vacuum to regulator.

Started car: no pressure reading, but it runs. Bridged pump in diag connector, runs, but lots richer.

More messing today, however looks as though I've an issue with pump switching whilst running.

Today will prove/disprove the above with bridged pump, then look for the reason it isn't in the PnP setup/how I've broken it.


Super

Turbonic77 05-01-2016 04:06 AM


Originally Posted by Turbonic77 (Post 1328093)
So. Added fuel pressure gauge. ax pressure from pump 67psi ish, leak down also OK.

Tee'd off supply, bridged pump, 40ish psi, decreasing with added vacuum to regulator.

Started car: no pressure reading, but it runs. Bridged pump in diag connector, runs, but lots richer.

More messing today, however looks as though I've an issue with pump switching whilst running.

Today will prove/disprove the above with bridged pump, then look for the reason it isn't in the PnP setup/how I've broken it.


Super

Clarification: bridge pump, and engine running, pressure back circa 40psi.

ryansmoneypit 05-01-2016 08:02 AM

What the hell? Why is your system so complicated? It's less than 15 psi. Boost. I have one pump (190 hp) stock return regulator, and 20 psi boost.

Turbonic77 05-01-2016 02:41 PM

I think that in my effort to describe things I have made them sound more complicated than they are:

Its pretty much a standard install of a T3 from an RS Escort, ExtraEFI PnP, and 425CC Rx8 injectors.

Concerning fuel supply it is a standard pump and stock regulator, with the readings above generated when following prescribed tests according to the manual I have. At present - the pressure readings seem to be in spec, but the pump behaviour is not.

Have spent morning tidying up wiring, the car has had its fair share of additional items in its life, including a thatcham approved alarm installed by a certified prize tool (and not me). I shall pin out the PnP and see if the issue is there, and its not grounding the fuel pump when running. (which would be done normally by the MAF flap according to the circuit diags)

I am resigned to the fact that there shall be more faff tomorrow.

Super.

Turbonic77 08-17-2016 02:17 PM

Update......

The answer was: the transistor controlling the fuel pump has popped again, traced to a wiring fault on the vehicle. ECU sorted by Phil at ExtraEFI and all running very well.

So what happened was: it started as there was some fuel pressure cresated by a very slow running pump (not visible using the guage I had) and wouldn't run off idle because there wasn't enough pressure except to idle, unless the massive values were used on the VE table.

Has been running 0.3bar wastegate pressure for a couple of weeks whilst I sorted out the niggles, rattles, fuel leaks, alignment, wheels, tyres, and other such stuff....... then turned it up to .5bar at which point it is starting to get very interesting. Have used a manual controller for this, however can hear the wastegate flutter at lower RPM part load lift offs.

Much fiddleage still required with the current tune flashed, as it smells richer at idle than the wideband would suggest, and closed loop idle is proving to be a problem - but this will form the basis for a few other posts.

Ta.


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