early bronco megasquirt pnp2 amortization thread

banditbronco

New Member
May 5, 2019
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AZ
Hey guys, first post alert.

I have an early bronco with a mustang harness in it. I recently swapped in a 351w and switched to a megasquirt pnp to control it since none of the dyno shops in town would touch the tweecer piggy back that was in it previously with the built 302.

I have everything hooked up, am running an LC-2 innovate wideband, I successfully connected for the first time today and tried to start it. It will crank but not start. I have verified spark and it smells like it is getting fuel. I have pressure on the rail, didn't check injectors though. It is popping every now and again like the timing is off. I set it to 10 degrees from TDC on the compression stroke and verified it again after it wouldn't start. I can't get my timing light to light up during cranking to see what the balancer is showing, could have a bad tool.

All I have changed in TS is the engine CC and injector CC since they are larger than the base map. I calibrated the TPS, and clicked on the map calibration but didn't change anything and it didn't seem like it did anything, not sure what I am looking for there.

I have attached a couple datalogs of two cranks to see if anyone can spot something out of the ordinary. I am too green to fully understand what to look for.

This seems like the most knowledgeable reliable up to date place on the interwebs to get help from what I have been reading. Keep up the great work those of you that put in the time to help.
 

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  • crank no start 1.msl
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  • crank no start 2.msl
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Got it fired off yesterday. We moved the dist. counter clockwise 2 teeth and that seemed to do the trick. It idles for 30 seconds at about 1200 rpm then dies, you can keep it running with the throttle. We attempted to set base timing but were having some weird issues, according to the timing light I am 60 degree's advanced, which seems impossible because it wouldn't crack right off or run at all with that much timing. We double checked TDC on the balancer multiple times and it is dead on. Messed with the trigger wizzard a little but nothing that did much good.

I am also getting some odd AFR's the gauge says it is idling at 7.5 or so, the computer says 17.5. This is the first time this motor has run since the build so it was nice to here it run even if it was rough and open headers. My first goal is to get it running good enough that it can get itself on the trailer and go to the exhaust shop.

I didn't get any datalogs as I had a few friends over helping me get it going. I plan on getting some today and will post them for more detail.
 
So the thing that is knocking my brain is, right now, where the dist. sits at TDC it is lined up perfect, pointing 10 degrees from #1 on the cap, Originally we have the rotation wrong so we were on the wrong side of #1 on the cap, so moving the Dist. which swapped the pointer to the correct side giving the engine the ballpark it needed to start. So moving it would push it too far to where it wouldn't start.
 
If you are reading 60* BTDC on the balancer from the #1 plug wire then something is very wrong. or you are taking your readings incorrectly/ balancer may not be marked correctly.
Remember that the PIP is getting its signal from a shutter wheel inside the distributor it is critical to get it lined up correctly.
 
From what I am thinking there are a few things that it could be. Timing chain was installed incorrectly, not sure how I would have done that but it is possible. Aftermarket distributor is no good, grabbed a napa one to swap and see. Aftermarket balancer is incorrect, also hard for me to believe if I set up TDC at 0 on the timing marks it should work correctly. Anything else I should take a look at?
 
with the timing set at 25* BTDC with the timing marks the rotor should be roughly centered on the #1 cylinder post. it is helpful if you have an old distributor cap you can cut a window in to check this with.
 
So I checked the rotor placement at 25* it is pretty close to the #1 cylinder post. Set the fixed timing to 15 degrees and then set the offset to 0 and worked my way up, it seemed to run okay around 10, any higher and it didn't like it, still dies within 15 seconds or so. Here are some datalogs of 3 starts
 

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  • start up 2 plus 5 trigger angle.msl
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The offset should be around 10* but the MS will allow anything in the range of 0-19* of offset value. The stock ECU had a programmed 10* offset value.

at 25* BTDC the rotor should be centered on the #1 post if it is not you should adjust the distributor until it is. Then check the timing and adjust the offset value as needed, if all goes correctly you should have an offset value of around 10* and the timing in the trigger wizard should match what you are getting on the balancer.
Use a value that is easy to read on the balancer, I like to use 20-26* as this will help force the engine to stay running.
 
I have an odd issue happening along with the rest of my issues I haven't completely worked out yet. The IAC sensor is clicking every 5 seconds or so when the key is on engine is off. I am running an explorer sensor as it is smaller and won't stick up too high and hit the hood, If you unplug it and try and start the engine you have to give it some gas for it to fire. If you plug it back in it starts a little easier but not much. I did have to solder the new connector on to match the sensor, the wire colors are the same from the explorer harness to the mustang harness for this particular sensor so I did just assume that they would be the same. It obviously works (not sure if it is correct). Also while running I see the correct rpm on TS but it is very low on my autometer gauge, I would think this wouldn't be any of my issue since what I see on the computer sounds correct.
 
yeah the aftermarket gauges can be a real pain.

you got it running i see, thats great. How far out was the timing after you got it centered?

There are a few different settings but you can check under the idle control settings 'run valve before start' if its on then the IAC will buzz or click when KOEO [key on engine off] turning this off will fix the issue.

Now you just need to get your feet under you to start tuning, I do offer classes to get guys up to speed quickly.. PM me for details if your interested.

I love me some datalogs, the tune file the log was taken with is also needed. If you want my advice on specifics

:nice:
 
The timing thing is still up in the air, If I set it up correctly as you stated it will only gurgle while cranking and not start. It has to be something out of the ordinary I just haven't pinned it down yet.
 
What is the best way to make sure timing marks are good? I made a piston stop yesterday but didn't go through the whole process of using it to find TDC. That is probably the best way to rule out the balancer right?
 
verified TDC with a piston stop this weekend, and it matches up with the balancer and the pointer which I figured since I fabed the pointer and set it all with the heads off during the build. So still a mystery why the timing is reading so high.
 
Timing light was on the correct wire, I checked it 10 times. Riddle me this, I swapped the A9L I ran in this rig previously that was tuned with a tweecer for the previous engine back in, it fired right up and will stay idling. Check timing with a light and it reads correctly at about 10 degrees. So with the megasquirt somehow it reads 60 ish and with the a9l it reads 10 like it should.