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without graphing jack squat.. i can tell you that "Pugly" the ugly tug starts only if you push the pedal... when i first picked it up it was a long crank with no start. on the second try i pushed the throttle out of muscle memory... it banged into life. granted i have never read its code as all i care about is that its is a rolling collection of spare parts. yet it fires right up with, and only with a slight application of the pedal..
refer to my threads to look at that ugly government POS.
Take this data with a grain of salt - I was curious and gave this a try this evening. Just one test at 20% APP, and one at idle (13% APP). I should do a few more to see how variable this experiment is.
Moved the go pedal to about 20% first, watching APP on FORScan, then cranking the cold engine. As expected, RPM exceeds idle for just a bit until I let off. I used time from start of crank to reaching 700 RPM as a benchmark for a running engine. Results below:
Waited about an hour, and tried this again with the go pedal at idle. There was a measurable difference in start time. Note the max values. It is interesting that ICP peaks about 50psi less, and FUELPW peaks at almost 2ms more than the 20% APP test. Not sure why peak PW would be higher for an idle start.
Here is a cold start chart from January - outside temps much colder at 36 degrees F. RPM at idle is higher than 700 on cold start, as commanded by the PCM. IPR is higher, ICP is lower, and PW is much higher than the previous charts. Time to 700 RPM is same as having the pedal down a bit.
Sorry about the different horizontal scales - the charting tool autoscales depending on how many data points come in.
So what to make of this? The data seems to say that giving a bit of pedal results in a quicker start.
What is not intuitive is that the first chart with the pedal pressed a bit should have had a larger FUELPW, similar to the January cold start, but it does not. I will do a couple more tests to verify this data tomorrow.
Originally Posted by kenn_chan
without graphing jack squat.. i can tell you that "Pugly" the ugly tug starts only if you push the pedal... when i first picked it up it was a long crank with no start. on the second try i pushed the throttle out of muscle memory... it banged into life. granted i have never read its code as all i care about is that its is a rolling collection of spare parts. yet it fires right up with, and only with a slight application of the pedal..
refer to my threads to look at that ugly government POS.
The plot thickens. So now the question is, why are we told it isn't necessary and does nothing when it appears it does? Aliens...? Government conspiracy...? Illuminati...?
Oh and is that Pugly or Phugly? Cause one is an Addams Family character and the other is that chic you load up when the bar is closing.
I need to learn the ForScan tool better, and make some charts.
my single experiment scared me too much to try pressing the go pedal during cranking again. But, I don't know what the Pedal % was, I just pushed down a bit.
I wonder IF,
I set the Hydra Tuner back on 00, or Stock programming, what difference that would make?
I'm thinking sluggish starts are indicative of a less-than-perfect HPO system. I've never added throttle to get the engine going, but I have had a leaking injector or two that I corrected with a full set of Alliants. Cold start was always good, but hot starts were more of a "tapering up" and then it would run ok with a bit of roughness at very slight throttle settings. The new injectors cleared all of that immediatly and the engine now does that characteristic Powerstroke "bark" without any regard whether it's first start in the morning all the way up to running for hours and a restart after a 5 second shut down and anything in between. MAYBE two or three seconds of cranking and "bark" it's running.
The plot thickens. So now the question is, why are we told it isn't necessary and does nothing when it appears it does? Aliens...? Government conspiracy...? Illuminati...?
Oh and is that Pugly or Phugly? Cause one is an Addams Family character and the other is that chic you load up when the bar is closing.
You may be right on the chick. The Addams family character is Pugsley. Maybe Pugly is a mix of the two, which might be even worse.
I'm not aware of anything amiss with any injectors, sensors, regulators, pumps, or modules in my truck.
It starts easier with pedal partially depressed.
In the first few years when I ran Motorcraft FLA batteries, I would invariably be greeted with weak batteries when wanting to start the truck.
A partial (not full) depression of the pedal has always made the difference between cranking the truck over, versus starting the engine, under the challenging condition of weak batteries.
As the engine starts (rather than just crank over) I immediately release the pedal.
After I've driven for a while, when it is time to start again that same day, I do not bother partially depressing the accelerator pedal at all.
But when stone cold, not driven for weeks, or with weak batteries... I tell the PCM that more mass fuel is desired on start up by partially depressing the accelerator pedal. I've done so for the last 23 years.
Not sure why it results in faster starting, I will have to dwell on that a bit more. But for those familiar with mecnannical injection pumps of yore, those actually inject a greater qty during start than they do at max pedal. Once they get going the weights on the spinny bits adjust the sliding bits such that the injection is limited during operation. So apparently there is something about starting a diesel that likes a lot of fuel to get going that is still relevant for the 7.3 powerstroke engine. When you give it some pedal it must be overriding that feature. Interesting stuff!
I own three diesels, the Ford F550, and two VW ALH cars. All three of them are idling within 3-4 seconds of engaging the starter. Every other vehicle I've ever owned that wasn't carburated, same result. Never have to touch the accelorator pedal unless there's a problem that needs addressing.
Just my thoughts, since your engine likes additional air to start (foot work), have you considered cleaning the throttle plate and throttle bore ? If the TB is coked up, it will restrict the flow..
Just my thoughts, since your engine likes additional air to start (foot work), have you considered cleaning the throttle plate and throttle bore ? If the TB is coked up, it will restrict the flow..
Your solution would have the opposite effect though. Fuel enrichment at cold start is enabled by choking air. Hence the "choke" on carbureted cars and lawnmowers. So in your hypothetical scenario of sarcasm, a coked up TB would actually be preferable for cold starts.
Up until just this past year, Ford trucks with fuel injected gas engines were programmed with fuel enrichment tables at cold starts. But Ford reports that CARB (the agency, not the device) said no more enrichment allowed.... which forced Ford to make a surprising number of physical changes related to heat management to several truck platforms. It wasn't just a simple matter of reprogramming the PCM.
What is the name of that stuff that people spray into their engines to get them to start... it typically has ether in it... and it is always a bad idea to use it in diesels (yet people do anyway). I want to say "starting fluid", but that doesn't sound like the right term. It comes in an aerosol spray can, and whatever it is called has slipped my slowly slipping mind. Anyway, the desired effect of spraying that stuff in at cold start is to deliver enrichment.
Up until just this past year, Ford trucks with fuel injected gas engines were programmed with fuel enrichment tables at cold starts. But Ford reports that CARB (the agency, not the device) said no more enrichment allowed.... which forced Ford to make a surprising number of physical changes related to heat management to several truck platforms. It wasn't just a simple matter of reprogramming the PCM.
No government, no matter how arrogent they get, can not in any way rewrite the laws of nature. The lunatics have been running the insane asylum for quite a while now.
Your solution would have the opposite effect though. Fuel enrichment at cold start is enabled by choking air. Hence the "choke" on carbureted cars and lawnmowers. So in your hypothetical scenario of sarcasm, a coked up TB would actually be preferable for cold starts..
No sarcasm intended, just a passing thought from a 75yr old engineer.. I will go back to ruminating..
