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Bracket maker
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3,982 Posts
Discussion Starter · #1 ·
I uploaded my new tune today from JJ with the PATS turned off and the truck started on the second crank. It was idling along when, I tapped the throttle and then the truck stalled out. I started it back up and it stalled out again. I can keep the truck running if I feather the throttle. At 900 rpm I have 13 lbs of vacuum so i don't think its a vacuum leak. At 700 I still have 12lbs of vacuum. I adjusted the tps to.99. I also swapped out my IAC with another that I had incase that was the problem and still no change.
Any ideas?

Also, my Jabsco intercooler pump isn't kicking on. Should this turn on as soon as I fire up the engine or does it have to warm up first?

I also unplugged the MAF with no change. I am seeing about 37psi of fuel at idle at the regulator.
 

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Registered
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17,565 Posts
what maf? and housing....if your maf is in backwards it can act just like that

and the pump kicks on from IAT2 temp activation
 

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Innovator of the Bombassani exhaust
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2,428 Posts
should be around 19 on the vac at idle.... But Stew is on it. My truck did the same thing when I was trouble shooting. I put the original tune back on the truck and the 2400 Maf said F U!!!
 

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Innovator of the Bombassani exhaust
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2,428 Posts
did not know you had cams.... and your maf is where mine is at.
 

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Fat Bastad
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2,756 Posts
Unless I'm mistaken I think that these trucks in stock form should be running closer to 20# vacuum vs 13 when at idle. But since I now read that you have aftermarket cams then 13 doesn't sound too far off.

Your MAF seems to be properly oriented.

My intercooler pump is stock. The only time it's not pumping is when the truck isn't running.

Roach
 

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Bracket maker
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3,982 Posts
Discussion Starter · #10 ·
I thought about that, but what I don't understand is why when I first started it that it was running just fine...it was running for about 2 minutes. Then I went ahead and just touched the throttle to see what it would do and it stalled out. Now it will start just fine but then stalls out almost immediately, unless I feather the throttle.

I am running the aftermarket rails and I do not have the resistor anymore. It smells like it is running rich, but that doesn't surprise me since its a starter tune. Are there any connections or fuses I should be looking for?
 

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Bracket maker
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3,982 Posts
Discussion Starter · #12 ·
OK, I will call in the morning. I think that is where you unplug the IAC and start the truck. Then adjust the throttle body position screw to open the throttle body to the bare minimum where the truck will idle between 600 and 700 rpm. Then you turn the truck off, plug in the IAC and start it again? Thats what I read, but maybe there is a way to do it electronically.
 

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Bracket maker
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3,982 Posts
Discussion Starter · #13 ·
OK, I did what I described in the thread above to reset the IAC and it worked and the truck is up and running fine. Thanks for the tip JJ. Never heard of that before for cammed vehicles. It idles and accepts throttle just fine. My vacuum is at 12. Fuel pressure at the regulator at idle is at 35 psi. Still smells rich, but I will do some data logging and send you the file in the am. Thanks.
 

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Registered
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4,553 Posts
Every truck with heads and cams slightly differs.
My new build, once I had all my vac lines sorted out, sits at about 13-14 lbs vac with TFS heads and TFS cams.
 

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Bracket maker
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3,982 Posts
Discussion Starter · #17 ·
Glad you got the idle figured out man. Once you get that bad boy running good we will have to meet up with ZZZZap and have a get together somewhere.
I think it may be a few more weeks since I am waiting for my bed and hood to get back. I have a fleetside bed and I am having the plastic bed rails shaved off. Also having the squirters and a body line shaved on my hood. I can't wait to see what it all looks like when its done. I should be up and rolling in Mid Sept.

Every truck with heads and cams slightly differs.
My new build, once I had all my vac lines sorted out, sits at about 13-14 lbs vac with TFS heads and TFS cams.
I think that there will be enough vacuum, but I will check all of my lines to make sure that I don't have any leaks. I will also be swapping in a hydrobooster here soon so I should have plenty of brake pedal from that. Right now the idle is real strong and its not stuttering at all.

Thanks everyone for the help. This was a long project for me since I went TAD in the middle of it unexpectedly. I will post some pics of the whole build here shortly. Can't wait to put it on the street.
 
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