Help with first wasted spark project

[Tonyorlo]

That was an easy fix. Thanks!

Now more problems,

The fuel pump does not shut off as long as they key is in the ON postion.

I have no spark.

I data logged cranking if that will be any help?

[rickb794]

Battery voltage drops pretty low 9.2v
TPS changes over 10% NEGATIVE!
CLT is spiking
IAT is spiking

Are pins 15-19 ran directly to the motor?
Is the battery negative cable clean and connected to the motor?
Is the sensor ground isolated from chassis ground? See section 3.2 of the manual
Is the MS powered through a relay from the battery? See wiring diagram on page 14
Fully charged battery? I prefer overnight on a float charger. Jump with a running car rather than use a charger when cranking.

The fuel pump not shutting off is critical, this should be addressed first. May be internal or external.

[Tonyorlo]

The battery has sat diconnected all winter. It sat on charge at 10 amp for about 20 min before trying to crank. I guess I need to let it sit on trickle charge over night. It showed good voltage at the dash gauge. That could mean there is a problem with the Power or ground to the MS.

I need to flop wires on the TPS. I also have a throttle cable issue I need to addresss.

CLT and IAC spikes are a mystery to me? Both are new sensors and plugs.

Pins 15-19 are all ran to the rear of the drivers side cyl head. Chassis grounds are in different locations.

Everything is new in the truck. Bed mounted battery, 1/0 copper cables with crimped and soldered copper lugs.

The MS is powered from the factory ECM fuse. Is that a bad idea?

The fuel pump relay wire showed to be a good ground. I got 13v when checked to a positive location.

I should have stated, when I have tried to crank I have always had the fuel pump disconnected. I am only trying to verify everything works.

For now I will look at the obvious problems like voltage, and the sensors. Something may come to light when I am doing that. The fuel pump not shutting off seems to be a internal problem. I'm bafffled by it.

[rickb794]

Does the fuel pump run with the MS unplugged?

If no it is likely internal.

Run it on a stim to verify.

Again I want to stress fixing obvious safety problems first.

A trickle charger is not a float charger and may damage your battery if left on overnight.

http://www.batterychargers.com/faqs/

RE the sensor reading spikes, if not caused by low input voltage, suggest a ground loop.

I don't see a factory ECM fuse in the recommended wiring diagram on page 14. :^)
The idea is to have a power source with no voltage drop and minimize noise.

[slow_hemi6]

The MS fuel pump circuit should only be providing a ground when it is priming or you have a rpm signal. If those conditions are not met it should not be grounding. Check Q2 for a solder bridge.
http://www.msextra.com/doc/pdf/html/MS2 ... 4-171.html

[Tonyorlo]

I am going to wire a new relay to power the MS. I am questioning a decision I made when wiring everything up in. I am using pin 26 to supply voltage to the TPS and to the Hall Effect crank sensor. I don't remember where, but I read that it was ok to use the TPS V reference to the crank sensor. Was that a bad idea? The diagram in the manual shows the sensor being powered by the MS relay.

All the sensors are grounded through pin 7.

The fuel pump only runs when the megasquirt is powered up.

Slow_Hemi6, the component diagram you posted looks to be for V3.0, mine is 3.57. I need to go through the back of the 3.57 manual and run through the fuel pump circuit. I am still learning so this is taking me awhile to completely understand.


I think the first thing I need to do is get the correct voltage to the MS, it may solve many of my other problems. Thanks for the help so far!

[Tonyorlo]

Well on the jimstim the fuel pump shuts off. I'm lost now.

Am I able to see if the coils are are firing through the jimstim? I'm not really able to pull the coils out of the truck easily. Can I use a multimeter or something to check that they are firing?

[Tonyorlo]

The fuel pump relay wire shows 12v to ground anytime the megasquirt is powered up in the truck. It should be showing 0v right?

I am still not getting any spark. Is there a reputable shop I can send my ecm to , to have it modified?

[rickb794]

You can use the Stim LED's to view the coils firing. You will need to turn the RPM down to see the LED blink, high RPM the LED will not appear to blink.

[Tonyorlo]

When I had it on the stim I saw the LEDs blinking which is why I was confused.

I discovered this,

With the Key off, fuel pump relay wire has 12v +
Key on, fuel pump relay wire voltage drops to 0v for 3 sec then back to 12v
During cranking the fuel pump relay goes to 0v

I switched the wires to the fuses from the 87 to the 87a on the relay. So now everything works fine.

I have the coil relay powered by the fuel pump relay wire per the megamanual, so that explains why they were not firing. There was no voltage during cranking. Now there is and they spark great.

I don't think I should leave it that way should I?

This is my first crank trigger install, since it is show RPMs during cranking does that mean it's working ok?

[Tonyorlo]

I got all the bugs worked out and attempted to start the engine. When it was cranking everything seemed normal but it did not start. I am lost on where to go from here, should I play with the timing during cranking?

[hybrid]

Check your timing with a timing light while cranking.

It's OK for your coils to have no power when the fuel pump is not running.

[Tonyorlo]

Well I gave it a try with the tune as is and the timing was way retarded. I don't know if this is the correct route to take, but I did and got results.

I changed the timing from Use Table to Fixed Timing. I gradually increased the Timing for Fixed Advance, and the Cranking Advance until I got to 12 deg BTDC with the light. I increased both because I assumed they would effect each other. I ended up at 51 deg to get the #1 cyl to fire at 12 Deg BTDC.

What did I screw up to have to do that to get the timing in the ball park? Is the trigger wheel that far off?

I also may of done something I should not have. When checking the timing with a light I had the fuel pump disconnected, and after I got the timing close I attempted to start the engine with fuel. It cranked fine but did not start, and nothing bad happened. I think my Cranking pulse and IAC steps need tweaked. I want to e conservative because I do not want to flood the engine. Any recommendations on adjustments to them? I am using a GM stepper IAC.

[rickb794]

Set timing to fixed 15°, then adjust tooth one angle to make the timing light show 15°¿

[Tonyorlo]

So what I came across was normal? I couldn't open the trigger wizard in my tunerstudio, but that's where I adjust the angle right?

[rickb794]

It is normal to adjust to correct the commanded timing. I don't think you need the trigger wizard to adjust that. Look for tooth one angle or trigger offset to adjust.

[Tonyorlo]

Ok, I tried to play with the timing and Im lost by the results. No matter where I set Tooth #1 Angle BTDC, the timing did not change while cranking. As well as timing for fixed advance, I could set it anywhere and the timing did not change. Only setting cranking advance would I see a change.

It stayed at a steady 12 BTDC while cranking so I gave it a try with the fuel pump. It spit and sputtered for a second and shut off.

After typing this I have another question. The cranking advance was set and #1 was firing at 12 deg, after it stops cranking does it go to the fixed timing #? If so is that why it would not run?

I am including a data log of the few start attempts.

[Tonyorlo]

When I installed the crank trigger the cyl heads were removed, so I could verify #1 at TDC. I placed the sensor 5 teeth ahead of the sensor per the instructions on diyautotune. Does that mean I need to set #1 tooth to 60 deg?

[rickb794]

You adjust tooth one angle until the timing light shows the number you have set for fixed timing.

So you set the fixed timing to 15° and then adjust the tooth one angle to bring the spark timing to 15° BTDC with a standard timing light or an adjustable light set to zero.

You can do this while cranking with fuel disabled if you wish (cranking spark set to 15°).

STOP! Should your ignition capture be set to falling edge????

What ignition pickup are you using?
What does the manual say to set the capture to?
You must get this setting correct prior to attempting to set the spark timing.

I think you need to look at a tooth log and see if the gap shows high or low.
I believe you need to adjust the rising / falling setting to get a low gap in the tooth log.
Perhaps someone can clarify?

[Tonyorlo]

I am using a diyautotune threaded Hall effect sensor,
https://www.diyautotune.com/product/hal ... on-sensor/

I followed their instructions for the settings
Set Spark Mode to “Toothed Wheel.”
Set the trigger angle / offset to 0.
Set Ignition Input Capture to “Falling Edge.”
Set Spark Output to “Going High

It later says set 8cyl tooth angle to 40deg.

In 6.9.6.1 of the megamanual it says trigger angle offset not used in tooth wheel mode.



I guess I am confused. When I change the tooth angle I see no change in the timing with the light. I have not tried to use the tooth log yet. I assumed that was all ok because it always says it's in sync.