Engine shutting down 3-5 seconds.

[SJR302]

Hi,

I have a Megasquirt PNP2 for 86-93 5.0 Mustangs, it comes with a base map.

My car is pretty basic cam/heads/intake etc, the base map was set up for 19Ib injectors, I have changed this for 24Ib to with this match mine. I started the car so I could follow the timing procedure, it starts fairly easily, but the fuel smell is a little odd, it then shuts down after after a few seconds, it doesn't splutter or anything, it just shuts off.

I have hopefully added the MSQ and a very short data log.

I'm desperate to get somewhere with this, as I would love to get the car out before the end of the small window that we call the British summer!

Thanks in advance,
Justin

[jsmcortina]

It's a bit difficult to tell with no meaningful AFR in the log, but I'm guessing that the bottom left corner of your VE table is too lean. Where you have 55, 56 etc. down there, try adding 10% to them (i.e. 65, 66 etc.) See if that makes any difference.

James

[SJR302]

Thanks for the reply James,

Would the low settings, lean conditions account for the "Clean" shut off? It shuts of so cleanly, no stutter/stumbling etc.

Cheers,

Justin

[jsmcortina]

I don't know. Try it and see.

James

[SJR302]

I have increased the fuel table numbers, the car didn't seem to like it?

My wideband only just heats up before the motor cuts out, but once the motor stops, the wideband says 42.03:1???

Any help would be much appreciated,

Justin

[billr]

You have a narrow-band O2 sensor? Ignore its readings, and turn off EGO control. Turn on "include AFR target". Give us current MSQ and MSL files.

[SJR302]

I have an Innovate LC-1 wideband with a XD-16? Gauge, it's not yet connected to the Megasquirt, I thought I should get the car running first, do you think I should connect the Innovate to the Megasquirt now?

Is the MSL file the data log?

Thanks,
Justin

[Blown88GT]

I have an Innovate LC-1 wideband with a XD-16? Gauge, it's not yet connected to the Megasquirt, I thought I should get the car running first, do you think I should connect the Innovate to the Megasquirt now?

Is the MSL file the data log?...

It should start & idle with the NB's. Just not easy to tune.
I think your current problem is timing. You have timing set Fixed at 10deg. Change to Use Table, which looks OK.
Trigger Offset Angle is 14deg. Change to 10deg.
Also,
ASE is much too high at higher temps. Tool Tip says: 50% (cold) 5% (warm)

Yes, MSL is data log.

[SJR302]

Thanks for the reply,

I have the timing set to fixed 10 degrees, as I have yet to do the base timing, but it still cuts out when using the table.

Sorry to ask, but what is the ASE?

Cheers,

Justin

[DaveEFI]

Thanks for the reply,

I have the timing set to fixed 10 degrees, as I have yet to do the base timing, but it still cuts out when using the table.

Sorry to ask, but what is the ASE?

Cheers,

Justin

Heat up your wideband before starting, and do a log. Might show what happens when the engine dies.

Are you sure your pump is still running while starting? The priming pulse might be enough to give fuel for a few seconds.

[billr]

The MSQ posted has the O2 set as NB, that should be corrected if WB is actually what is being used.

[Blown88GT]

...I have the timing set to fixed 10 degrees, as I have yet to do the base timing, but it still cuts out when using the table.
Sorry to ask, but what is the ASE?...

Your base timing is too far off to start the engine. The base map will start the engine. All you have to change is the Required Fuel.
http://sbftech.com/index.php/topic,7114 ... 114.0.html

ASE = After Start Enrichment

[billr]

I disagree...

If the engine fires and runs for those few seconds, the spark timing can't be all that far off. Regardless, check it with a strobe light, that is the only true test; and should be done before even trying to start the engine.

Do not change the "req_fuel" from what is calculated. It is not a tuning parameter, it defines the relationship between your engine displacement, the injector flow-rate, and the fuel stoic ratio.

[Blown88GT]

The Base Map is set for 19 lb injectors, he has 24's & has changed Required Fuel to match.
Do you still say do not change the "req_fuel" from what is calculated?

[billr]

Yes, do not change the "req_fuel" from what is correctly calculated! That is one of the prime benefits to not using "req_fuel" as a tuning parameter; when you change injectors (or fuel type, or bore/stroke) you just need to recalculate the "req_fuel" and most of the tune stays pretty close to the same. Now, if that "base" you are copying had a bogus "req_fuel", then all bets are off. If the OP posted the "base" that was started from, we could confirm if the "req_fuel" there was correct in the first place. And if it wasn't... I would be tempted to abandon that base and start from scratch.

OP, please note that how to handle the "req_fuel" is one of the more often-debated subjects here. Search for it some, read up, ask questions, then come to your own conclusions about what makes sense for you. I'm just offering my opinion.

[SJR302]

Test.

[SJR302]

I wonder if I should buy a carb?

As this is the PNP for 87-93 5.0 Mustangs, and my car is pretty basic H/C/I with bigger injectors, am I right to think I shouldn't be having these problems? I understand that it would need so extra tuning, but it should start and run reasonably well?

I think I will remove the distributor, and start from scratch making sure it is set correctly on TDC compression stroke, can I then set the timing with a strobe light just turning over the engine, with the fuel pump fuse removed, or does the engine need to be running? Then maybe reload the original Megasquirt base tune and see where I am, is that the consensus?

When the car was on its Ford A9L computer the car was starting fine, then running a bit lumpy (Engine shaking) at idle, and was running lean 18:1'ish, but it didn't cut out. I don't really have any shops to turn to here, and am concerned that I am going to end up leaving the car in the garage.

Any help much appreciated,
Justin

[jsmcortina]

I've helped setup a couple of PNP Mustangs and they both worked great.

James

[billr]

Yes, you should be able to check spark timing at cranking speed. It helps to do it in a dark environment, and make the marks white with paint, chalk, or similar.

Changing the injector flow-rate 26% is really a rather big change; it's no wonder to me that it isn't as "PNP" as you were expecting. It is also unlikely that the new injectors have the same dead-time, further complicating things if you haven't flowed them and input the correct DT.

[Blown88GT]

...
1. I wonder if I should buy a carb?
2. As this is the PNP for 87-93 5.0 Mustangs, and my car is pretty basic H/C/I with bigger injectors, am I right to think I shouldn't be having these problems?
3. I understand that it would need so extra tuning, but it should start and run reasonably well?
4. I think I will remove the distributor, and start from scratch making sure it is set correctly on TDC compression stroke, can I then set the timing with a strobe light just turning over the engine, with the fuel pump fuse removed, or does the engine need to be running? Then maybe reload the original Megasquirt base tune and see where I am, is that the consensus?
5. When the car was on its Ford A9L computer the car was starting fine, then running a bit lumpy (Engine shaking) at idle, and was running lean 18:1'ish, but it didn't cut out...

1. No.
2. Yes. You might want to check for a vacuum leak. Entire tune is based on proper MAP reading. I now use a combination of MAP & MAF.
3. Yes. Mine did with 30lb injectors & S/C on the base tune. Dead time settings are close enough; I used them for a couple years.
4. You can set the base timing at 10* BTDC with the A9L.
5. Could be the distributor is not "stabbed" properly. If you follow these, the strobe will verify.
http://www.fullsizebronco.com/forum/23- ... 351-a.html
http://sbftech.com/index.php/topic,7114 ... 114.0.html

BTW, your MSPNP2 is mostly the same as my DIYPNPF60, both are Microsquirt Module based. I started with the same base map as you did. Recalculated the required fuel for 30 lb injectors & that's all there is to starting & idling. Running under load requires further tuning as does a smooth idle under all conditions. That's when you need the wide band. There is someone on this forum that is keeping the narrow bands with a mostly stock engine, do it is not absolutely required under all conditions.

I've compared your tune with mine & see nothing that would prevent your engine from starting except for for those items which I stated earlier & you stated that you changed. Log file shows TPS at -5.9% throughout the entire log. Did you calibrate it in Tuner Studio (Tools---Calibrate TPS)? Also calibrate CLT & AFT.