Weird First Startup

Performance mods and Advanced Stroker discussion.
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George Dickel
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Weird First Startup

Post by George Dickel »

Getting right to the point: The first startup was very odd in my opinion and here's why. The ONLY way it would crank is if I held the gas pedal to the floor until it fired up. :doh: (BTW, I've been dealing with this every day for a week since it fired up once after correctly indexing the dizzy.) I broke in my cam properly and everything is fine! But after I shut it off, I had to do the same thing to get it to crank again. I'm thinking the IAC valve is bad. Nevermind that this was a complete restore and every single part including all of the sensors is new. It won't be the first brand new part that I've had to replace along this journey! Anyway, I'm posting this thread in the event someone else comes across this issue. Once I replace the IAC, I'll post any pertinent follow-up info.

Oh, I almost forgot-----MY FREAKIN STROKER RUNS!!!!! :cheers:
GD
'98 Wrangler Sport, 4.6L Stroker

'04 Mustang GT, 4.6L with a few bolt-ons
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Muad'Dib
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Re: Weird First Startup

Post by Muad'Dib »

Do you really have to hold it on the floor, or do you just have to push the pedal enough to open the butterfly valve more than where it idles? Once you get it started does it run fine? What happens after you start it, and then turn it off? Can you restart it easily, or do you have to do that whole procedure again?
If it feels right, then STROKE it!
You're lucky that hundred shot of CAPS LOCK didn't blow the welds on the forum!!
George Dickel
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Stroker Displacement: 4.6L
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Vehicle Model: Wrangler
Location: Mississippi Gulf Coast

Re: Weird First Startup

Post by George Dickel »

I have not tried it in any position yet other than WOT. That is obviously something I need to do tomorrow. Once running, everything is fine even at idle. Since I've only performed the cam break-in and not yet "set the rings", I've not let it idle too long or cranked it more than 4 times. I've still got to bleed the brakes and at least install the driver's seat :lol:
'98 Wrangler Sport, 4.6L Stroker

'04 Mustang GT, 4.6L with a few bolt-ons
George Dickel
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Re: Weird First Startup

Post by George Dickel »

It appears that it wants to be at WOT to start. It did fire up today as I was applying pressure to the pedal and was only slightly depressed. I was told by a mechanic buddy that at WOT, the computer will cut out the injectors. I think since everything is new including the PCM, it just has not had time to map out everything yet. Only time will tell... :huh:
'98 Wrangler Sport, 4.6L Stroker

'04 Mustang GT, 4.6L with a few bolt-ons
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SilverXJ
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Re: Weird First Startup

Post by SilverXJ »

I know some vehicle will cut fuel to the injectors if the pedal is on the floor, its a mechanism to clear a flooded engine. I'm not really sure the injectors are putting too much fuel in... it would have to be a LOT of fuel for the engine not to even start.
jeepinwi
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Re: Weird First Startup

Post by jeepinwi »

Have you checked fuel pressure yet? Once it builds pressure, does it drop over the course of a minute? If so, you may have a bad fuel pressure regulator or fuel pump.
99 Cherokee SE - 2 door, 4x4, 4.6L stroker, 5 speed, 8.25 rear, 60mm TB, stock exhaust
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dwg86
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Re: Weird First Startup

Post by dwg86 »

The fuel pump is suppossed to run for a few seconds when the key is switched on, and the stop if the engine is not running. This builds pressure in the fuel rail for start up. Check and see if you can hear the pump run when the key is turned on before you start it.
George Dickel
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Re: Weird First Startup

Post by George Dickel »

While the fuel pump is new along with everything else, I am not naive enough to think it wouldn't be bad. I hooked up the fuel pressure gauge and had about 44 psi with the key on and actually a little more while cranking it over.

Update on today's cranking: SOB fired right up at first turn of the key and touching nothing else. JUST LIKE IT'S SUPPOSED TO. This is the damnest thing I've seen and I hope I don't see it again. Ya'll gotta hang in there with me while I continue to get road worthy. The only part that is original is the brake master cylinder and it's getting changed Wednesday evening. Then maybe I can go for a ride and get this new PCM adjusted to it's new life.
'98 Wrangler Sport, 4.6L Stroker

'04 Mustang GT, 4.6L with a few bolt-ons
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Muad'Dib
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Re: Weird First Startup

Post by Muad'Dib »

When checking the rail pressure, did you possibly bump the CPS connector / wiring? Try just unpluging the CPS and plugging it back in. See what happens then.
If it feels right, then STROKE it!
You're lucky that hundred shot of CAPS LOCK didn't blow the welds on the forum!!
George Dickel
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Posts: 48
Joined: January 1st, 2009, 10:13 am
Stroker Displacement: 4.6L
Vehicle Year: 1998
Vehicle Make: Jeep
Vehicle Model: Wrangler
Location: Mississippi Gulf Coast

Re: Weird First Startup

Post by George Dickel »

It seems to be fine now and whatever it was has hopefully vanished forever :? But for what it's worth, I triple checked all connections under the hood to make sure I hadn't bumped something or unpluggled or missed something. I'd like to think it was the PCM learning it's new environment.
I'll keep ya'll posted once I can get road worthy this weekend and get out for some driving...thanks for the opinions.
'98 Wrangler Sport, 4.6L Stroker

'04 Mustang GT, 4.6L with a few bolt-ons
hatem61
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Re: Weird First Startup

Post by hatem61 »

SilverXJ is right, if you really floor it to WOT, it cuts off the fuel. I experienced with Jeep ECU's that sometimes if the battery was disconnected, it cannot hold the idle and I have to maintain some throttle opening for a while until ECU learns the idle motor's correct steps.
George Dickel
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Posts: 48
Joined: January 1st, 2009, 10:13 am
Stroker Displacement: 4.6L
Vehicle Year: 1998
Vehicle Make: Jeep
Vehicle Model: Wrangler
Location: Mississippi Gulf Coast

update

Post by George Dickel »

After a week of running and finally some further test driving, the issue was apparently PCM getting used to the Stroker. Since it was new and flashed with all the recent updates, I didn't know what to expect. The motor continues to fire up and run normally.
'98 Wrangler Sport, 4.6L Stroker

'04 Mustang GT, 4.6L with a few bolt-ons
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Muad'Dib
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Posts: 1497
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Vehicle Model: Cherokee
Location: Bend, Oregon
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Re: Weird First Startup

Post by Muad'Dib »

Great .. cant complain about that!!!
If it feels right, then STROKE it!
You're lucky that hundred shot of CAPS LOCK didn't blow the welds on the forum!!
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