First start issues

[alex240]

I attempted to start my Explorer 5.0l swap in my nissan 240sx today, and it did not want to go! To get everyone on the same page:



Explorer 5.0l, freshly rebuilt with hotter cam (Advertised Duration 276/280, Lift .544/.560) and a bunch of goodies
Ford Motorsport 24lb/hr injectors (High Impedance)
MS3 w/MS3X (running sequential fuel and wasted spark)
Quadspark amplifier between MS and ford coil packs
Stock explorer everything else- IACV, crank/cam sensors etc.

I imported the spark, VE and fuel maps from the 1993 mustang GT tune provided on DIYautotune's website as a starting point and I tested my injectors, verified fuel pressure, verified base timing while cranking, verified all spark outputs, verified sensors didn't fluctuate during cranking, verified the 36-1 and cam pulses in the tooth logger while cranking, and the only Issue I have noticed is the MAP sensor reading does not drop while cranking. I verified the map sensor operation by sucking on the vacuum line and it drops to 65~ish kpa from lung power and responds as it should. I had it tee'd off the FPR vacuum line so I tested sucking on different ends of the tee to ensure there were no leaks or blocked passages-all good. I then concluded I must have a massive vacuum leak so I tested the system with a halloween style fog machine and was unable to find any leaks (I even wrapped in air filter in cellophane to ensure it would build pressure) and when I pulled the MAP/FPR vacuum line off of the intake smoke came shooting out verifying that the vacuum port isn't clogged on the intake. I then thought that maybe the cam wasn't producing enough vacuum at cranking RPM (I was seeing 120rpm~) to close the plunger on the normally open ford IACV and that I should just try and see if I could get it to start and idle and see if it registered vacuum. This brings us to current day- I attempted to start three times and had the same result each time- the motor would crank for 2 or 3 second then catch up to around 250rpm and immediately the "cam fault" would light up and drop off and keep cranking and not catch again. I have attached the .msq, datalog, and composite logger from the first start attempt.

So questions-
1. What the heck could be going on with the MAP sensor? Is it pretty much guaranteed I have a vacuum leak or is it possible the cam isn't building enough vacuum at that rpm to close the IACV and show a reading on the MAP?
2. Why is my cam fault lighting up when everything looked good curing the crank test composite logger for crank and cam signals?
3. Are my settings in the .msq appropriate for this engine?

Thanks in advance for any help, this project has been very challenging for me (first time building motor, first time soldering/wiring) and really pushed my comfort zone....but it's so close!

[alex240]

And here are the datalog and composite logger files from another start attempt as well as my tooth logger from a few days before:

[Matt Cramer]

So questions-
1. What the heck could be going on with the MAP sensor? Is it pretty much guaranteed I have a vacuum leak or is it possible the cam isn't building enough vacuum at that rpm to close the IACV and show a reading on the MAP?

The amount of MAP sensor drop is pretty normal while cranking.

2. Why is my cam fault lighting up when everything looked good curing the crank test composite logger for crank and cam signals?

Because you are getting a cam signal EVERY revolution of the crank. If this is a VR type, try adjusting the MS3X trim pots for less sensitivity.

3. Are my settings in the .msq appropriate for this engine?

Not seeing anything blatantly wrong, at least.

[billr]

Since you have a 36-1 crank wheel and wasted-spark, simply disconnect the cam sensor and ignore anything pertaining to it. You don't even have to change the TS settings from "dual wheel", the engine should start and run fine, even though injection will not be full-sequential. Another simple "sanity check" is to disable fueling, disconnect power from the fuel pump and injectors, then try starting with a quick blast of starting-fluid into the intake. If it fires and runs, even briefly, like that then you have some confidence the ignition is at least workable and you *only* have a fueling problem. If it won't fire with the starting fluid, then we have to focus on spark timing, compression, basics like that. I say to disable the fuel so that there is no chance of flooding the engine such that the starting-fluid test is invalid. Was ignition timing checked with a nice simple strobe light, not a dial-back one?

[Laminar]

What year Explorer motor? I'm using a '97 so my cam sensor is a Hall-effect. The '99-up used a VR sensor.

The '93 Mustang GT tune you used was a great starting point for me and much of it remains intact so far, but I have the stock cam in place. I'm running LS coils so I have full COP.

I've attached my tune so you can compare and also a log file of my engine starting up and revving. With the stock cam, MAP drops to about 85kPa during cranking and sits at around 38 at idle.

I see you're set up with 2 squirts per cycle. If your fueling is sequential, you should switch that to 1.

My Ignition Input Capture is set to Falling Edge, you're set on Rising Edge.

Try taking your Cranking RPM down to 300.

Turning on the idle "Run Valve Before Start" can help the engine catch more quickly. I turned mine off to stop the buzzing but it takes an extra second or two of cranking to get it to fire.

Which MS ignition channels are connected to which cylinders? Have you double checked all of that?

[alex240]

I took the MS3 apart and dialed the MS3X trim pots all the way counter clockwise. I will have a chance to try another start tomorrow night. That being said:

billr- yes it was checked with a simple stobe style timing light. I will try the sanity check and see if she starts!

Laminar- I will try those settings, thanks. The motor is originally from a '97 explorer but I purchased a new cam sensor from summit: http://www.summitracing.com/parts/rnb-6 ... /make/ford

I have everything set up in the wiring and megasquirt assuming it is a VR cam sensor, and now that I am looking at summit it looks like that sensor^ is for a 99-01 explorer confirming it is VR, correct?

I double checked the firing order and the spark outputs- I have 1-3-7-2-6-5-4-8, with 1-A, 3-B, 7-C, 2-D, 6-A, 5-B, 4-C, 8-D.

I also have a question about the cam sensor phasing- when the crank has tooth #5 lined up with the crank pos. sensor where should my cam tooth be? I put it just to the left of the sensor window (rotates counter clockwise) so that immediately after TDC it will pulse. Is this correct?

[Laminar]

Laminar- I will try those settings, thanks. The motor is originally from a '97 explorer but I purchased a new cam sensor from summit: http://www.summitracing.com/parts/rnb-6 ... /make/ford

I have everything set up in the wiring and megasquirt assuming it is a VR cam sensor, and now that I am looking at summit it looks like that sensor^ is for a 99-01 explorer confirming it is VR, correct?

Yes, it's listed as being for the '99-'01 Explorer so it's a VR.

I also have a question about the cam sensor phasing- when the crank has tooth #5 lined up with the crank pos. sensor where should my cam tooth be? I put it just to the left of the sensor window (rotates counter clockwise) so that immediately after TDC it will pulse. Is this correct?

The cam sensor assembly came with a black alignment tool (with the arrow on top). Pull the sensor from the assembly and install the tool - it will only work in a very specific orientation. Set the engine so #1 is at TDC on its compression stroke (use the markings on the crank pulley to find TDC, use your thumb on the spark plug hole to find compression stroke). Then stab the cam sensor assembly into place, ensuring the arrow's point is parallel with the crank line - straight forward toward the front of the car. It might rotate a bit as the sensor's gear meshes with the crank, that's fine.

[alex240]

Ok I will make these changes and try again tonight. Thanks!

[alex240]

OK I turned the cam pots on the ms3x board counter clockwise (it was way more than the seven turns specified in the manual) until they clicked, restabbed my camshaft syncronizer with the tool it came with, applied the settings you gave me and attempted another few starts. It looks like the same issue ( double cam pulse) but with the pulses closer together? I also tried unplugging the cam sensor as billr suggested but that didn't work at all...just got a cam fault and nothing- it wouldn't catch at all like it did the first few times. Also of note is that the first night I tried starting it it would start and get to 300 rpm before cutting out and displaying cam fault....tonight it didn't even try to start once so i feel like I've gone backwards!

Laminar, also of note was that I tried setting my ignition capture to falling edge and it would show TWO teeth on the tooth logger and didn't read RPM ....so I switched it back to rising edge and crank signal came back. I'm not sure why mine is opposite from yours...different year sensor maybe?

Anyways, I have attached some datalogs to this and subsequent posts and am stumped.

[alex240]

And with the cam sensor unplugged:

[alex240]

I also tried changing the settings to single wheel and semi sequential fuel with the cam sensor unplugged and it still wouldn't work. here is the .msq and datalogs for that attempt:

[Laminar]

Laminar, also of note was that I tried setting my ignition capture to falling edge and it would show TWO teeth on the tooth logger and didn't read RPM ....so I switched it back to rising edge and crank signal came back. I'm not sure why mine is opposite from yours...different year sensor maybe?

That triggered some déjà vu - I had the same two tooth pattern, so I swapped the + and - wires on the crank VR and that fixed it. Switching from falling to rising edge must functionally be the same thing as switching polarity.

I don't know what the VR cam sensor signal should look like.

After cranking, are your plugs wet? I see your PWM duty registers but the throttle is closed. My first few startups I had to open the throttle manually to get it to catch.

[alex240]

I did not check the plugs but there was definately was a strong fuel aroma coming from the exhaust.

[Laminar]

Do you have a spark tester or timing light you could use to verify spark?

[billr]

The OP has a strobe light:

"billr- yes it was checked with a simple stobe style timing light. I will try the sanity check and see if she starts!"

Was the starting-fluid ever tried? Have you verified spark timing on all cylinders (a good check that your wiring is really the way you intended)? Have you verified the firing order, by looking at valve operation or feeling for compression pressure while rotating by hand? That may sound kind of silly, but my understanding is the Ford has used different firing orders in the same basic engines. How about compression readings, what are those?

[Laminar]

That may sound kind of silly, but my understanding is the Ford has used different firing orders in the same basic engines.

The Explorer engine uses the HO firing order, which he has set correctly in his tune.

[billr]

Does that mean it is impossible to put a different cam in that engine?

[alex240]

I took the firing order right off of my cam card from comp. As I understand it, you can install any cam with any firing order as long as the firing order settings in the megasquirt match. Also I checked the spark output with a spark plug outside the engine and everything is wired properly. I did notice however that cylinders 2-4 spark plugs werent fully connected because my headers are too close...I had put boot protectors on em and shoved em on and thought they were on the plugs but evidently not ...The fabricator who made the headers has agreed to fix it so the car is dissassembled right now.

Ive been doing some reading and have a few questions on the cam sensor- does the extra pulse from the cam VR sensor indicate that the polarity is wrong? Im just thinking that when you have the polarity wrong on the crank VR sensor it shows two teeth, so wouldnt the "two teeth" from the cam sensor be an indication of the same issue?

http://www.diyautotune.com/tech_article ... _index.htm
Also, I found this page^ on VR conditioner circuits and it sounds like I should have turned the pots on the ms3x board CLOCKWISE not counterclockwise: "if you are seeing pulses that shouldn't be there, turn R56 clockwise until they disappear." So I will try that once I get the headers back.

[alex240]

Also I almost forgot to mention- I cut out a piece of a soda can and slipped it in between the throttle body and iacv to block it off before trying to start last time and the map read lower- around 82kpa from an ambient 95kpa. So I feel confident that the map sensor/vacuum leak fear is unjustified.

[alex240]

OK! So I resolved my header issue and spent today trying to get back on track.

I changed all the settings to non sequential fueling, bought some starting fluid, cut power to pump and the car starts....with starting fluid! I have attached a datalog of one of the attempts with starting fluid- you can see the RPM get up to 1600 at one point. It sounds mean

However I still can not get it to start normally. I cranked and checked the spark plug for fuel and they were soaked in fuel, So I tried playing with the cranking pulsewidth settings, going as low as 150% (from the default ~200%) before it backfired out the intake and scared the crap out of me. I did notice that my fuel pressure drops slightly while cranking due to the low voltage seeing 7-8volts- it drops down to like ~35 from 42psi. Could this be an issue that would keep it from starting? Or do I have a setting wrong somewhere? Anyways I'm stumped so any help is appreciated.