Very difficult to start after sitting overnight.

[PJF]

MS-II, V3 board, V2.88 code, MT V2.25
Ford 4.6L V-8
EDIS-8
42 lbs. injectors
Innovate LC-1 WB O2


Hi all. I recently redid my whole MS install including the code and began tuning from scratch. Last time I ran this truck it always started easily with just a twist of the key. Now if it sits for more than about 8 hours it takes signifigant cranking to get it to light off. Once it starts it runs absolutely perfectly with a silky smooth idle. I have yet to take it out on the road but it idles perfectly. My wideband O2 shows 13.2-13.7 AFR at idle so I think my ReqFuel is pretty close being set at 8.5 due to the rather large 42 lbs/hr injectors. Once the truck has made its initial start it will start easily again for many hours. For instance I can go back 4 hours after the last run and with just a light bump of the key it lights right off.

I have set my cranking pulsewidths from a low of 7.0 up to 10.2 and it is always the same. I thought that maybe my fuel system was leaking down while sitting so I brought the prime pulse from 1.0 to 4.0 and still no luck. Last night after a long crank it started and I smelled a ton of fuel in the garage. So maybe I am going the wrong way? Is it possible I am flooding the engine and not starving it for fuel?

My other thought was a fuel pump that is starting to go out. Would low fuel pressure make it difficult to start? I thought that perhaps the fuel wasn't atomizing well and just dribbling into the cylinders making for hard starting. I don't know. I am going to pick up a fuel pressure gauge today and see what it is at the rail. To be honest I am unsure what the fuel pressure should be. Here is my dilemma, the fuel pump is the stock one that came in the truck that ran a return style system on an inline 6 4.9L engine. The engine in the truck now is from a 2002 Mustang which used a returnless system. I got a set of fuel rails from a Crown Vic that are return style. So I have three different vehicles in the equation here! But I am thinking that 40-50 lbs of pressure should be sufficient. We'll see what the gauge says though.

Thanks in advance for any help.

[loren]

I'm a newb, but my thinking is that cranking PW should probably not be more than about twice whatever your PW is at idle. Get it running and warmed up and see what your idle PW is. Set cranking PW to maybe 1.5 times that and then play with it.

Timing is another area you might want to consider looking at. Cold advance, perhaps?

[PJF]

Thanks for the insight Loren! But I think I got everything solved this afternoon.

I went to the auto parts store and bought a fuel pressure gauge. It showed 28 lbs. at idle with the vacuum line hooked up to the FP regulator and 41 lbs. at idle with the line unhooked. I figured this was fine and the engine seems to idle good so I think the pump is ok. Now I have a $42 fuel pressure gauge that I don't really need. Should I return it or would that be unethical?

Anyway, in my searching of the forums I hit upon a post that had a different method of getting the engine to fire when stone cold. It went like this:

1. Set ReqFuel to a ridiculously low value that you know won't start the engine. (I set mine to 1.0)
2. Set cranking PW to another low value that you know will give the engine no hope of starting. (I set mine to 1.0 at -40 and .5 at 160)
3. Set the prime pulse to somewhere relatively high, 8.0 MS is a good ballpark.
4. Start cranking the engine.
5. Gradually increase the prime pulse until the engine coughs. (my final prime PW is 28.0 at -40 and 21.0 at 160)
6. Once the engine coughs on the prime pulse start increasing your cranking pulse until it is almost catching while you crank. (I finished with 8.0 at -40 and 2.5 at 160)
7. At this point stick your ReqFuel number in and you should be good to start. (I ended up with ReqFuel of 8.6)

I used this method and my engine fired up within 1/2 second of starter engagement! I don't know if this is the accepted method of cold starting but it definitely worked like a charm for me. Keep in mind that while I did this it was only 4 degrees (F) outside! So I think that for me at least, this is a good method of getting cold starts under control. The priming pulse is giving the motor a shot of raw gas to get it going in these cold temps. We'll see how it works when the weather warms up.

Hope this post helps out some others that may be having trouble with cold starts. This method really solved things for me.

[loren]

There's SO much good info like that to be found on this forum. Sometimes hard to find, but it's there.

I like this one, need to try it. ("cold" is only about 60 degrees here, but I'd still like a quicker cold start)

[PJF]

Well I didn't solve my problem I'm sorry to say. But I did make headway.

I went out this morning and once again I had to crank and crank. Once it started I could restart it with ease.

So I put the fuel pressure gauge back on and just let it sit. When I came back later I found the gauge at zero. At this point I set my prime delay to 2 seconds and I am waiting until the pressure bleeds off again before I go back and try it.

But I will say that once fuel pressure is up this thing is starting better than it ever has with the method I described above.

If the delay doesn't solve the problem then I am not sure which direction to go.

I am starting to think my fuel pump is going bad and possibly not providing the needed volume to fill the rails quickly enough. I do have a brand new pump ready to go in I have just been avoiding as I don't want to drop the tank. Looks like I may have to do it now!

[PJF]

Well it isn't a fuel pressure issue!

Went back to the garage and the gauge still showed 25 lbs. I turned the key to "ON" and two seconds later I heard the injectors go "click" and watched the FP gauge jump when they did.

I turned the key to "start" and she proceded to crank and crank!

What the heck am I doing wrong?

Can anyone point me in the right direction for getting this thing to fire from dead cold without 10 seconds of cranking? I am pulling my hair out here.

Any help is appreciated!

[loren]

Maybe too much fuel?

You said something about setting your prime pulse to 2 seconds... you didn't leave it that way, did you? Seems that could easily cause a flood condition.

[devastator]

How much time is the engine running between starting attempts, (after you get it started)? Does it start then you shut it off immediately and try it again, or is it warming up a little before you try it again? Sounds like temp/cranking PW to me.

Went back to the garage and the gauge still showed 25 lbs. I turned the key to "ON" and two seconds later I heard the injectors go "click" and watched the FP gauge jump when they did.

Bet you're glad you didn't take the gauge back huh?
If you had fuel pump problems, the engine would run like crap at higher RPM as well as being hard to start. In fact, it would likely start and not run at higher RPM, or not start at all.

[PJF]

Success!

I think I finally got a handle on this thing.

Turned out to be cranking pw's after all. I just had it too lean. I now have no prime delay and a priming pulse of 6.0 @ -40 and 2.0 @ 160. My cranking pw's are at 14.0 @ -40 and 8 @ 160. This yielded a crank time of only 2.8 seconds this morning on a dead cold start!

My req fuel is now set at 9.0 too so that may have helped a bit. The cranking numbers are a lot higher than what the megamanual gave as a starting point so that is where my confusion was coming from. I am not sure why I had to go so much higher than what is recommended but it worked. Hopefully it won't be too rich when the weather warms up.

I'll keep trying the cold starts over the next few days and see what happens. The problem is that once it has run for more than about 30 seconds from stone cold it is very easy to start for the next few hours. Although I can't really classify that as a problem per se!

Hopefull

[devastator]

The problem is that once it has run for more than about 30 seconds from stone cold it is very easy to start for the next few hours.

You may still have to "massage" your starting PW a little, particularly your -40 value, but you're on the right track now.

[PJF]

The problem is that once it has run for more than about 30 seconds from stone cold it is very easy to start for the next few hours.

You may still have to "massage" your starting PW a little, particularly your -40 value, but you're on the right track now.

Hey devastator-

You are so right!

I took the truck out for a test drive today and when I got back I thought I should see if it would fire up when hot. NOPE!

I ended up lowering my 160 degree cranking PW to 4.0, then she lit right off! So more tuning to come I guess. But that is really almost all the fun of this system, at least to me. It is very gratifying to encounter a problem and then fix it yourself!

Time will tell on the -40 value.

Tomorrow I will probably be cursing this thing again, but for tonight I am a happy camper!

[devastator]

Cool! Now that you are this close, make only small, (like .2 at a time), adjustments to the cranking PW from here on out.

[amigafan2003]

I am not sure why I had to go so much higher than what is recommended but it worked.

I wouldn't worry about it - if you engine wants a certain value then just put it in.

They'll be many other things that look odd (for example my engine needs a ton of ASE and Warmup (I'm talking something like 50% on both @ 0c) - it's not normal but it's what the engine wants so it gets it. For one engine 10% is enough - for another seemingly identical engine, 15% might be required.

But congratulations on how far you've got now - it sounds like you're on the right track and understanding what's working for your engine.

And you're right, it is fun figuiring these things out ;-)

[krisr]

I found the manual's comments of;

To begin, set the -40°F cranking pulse width to about 88% of your "upper" req_fuel value, and the 170°F cranking pulse width to about 23% of your req_fuel. Those should get you 'in the ball park' for starting.

Were virtually spot on for my engine and only needed very minor tweaking after. There was a fix in the later code though where you had to remove the injector opening time value from your calculated cranking PW values.

Kris