Predator tunes

[DolSVT00]

I know I can get a mail order tune But........
I plan on upgrading my upper and lower pullies and my T stat to a 160 ( I have them in my garage)and I dont want to pay twice for a tune.
my problem is I have the 90mm maf so I use the boxed diablosport tunes currnetly, well when I load the Factory HP tune for 90mm maf everything is good and the same goes for the 87 Octane tune for 90mm maf, but when I load the 91,93 Octane 90mm maf tunes I get a missfire at low steady rpm's under driving load. Anyone know how to remedy this?

Yes I have new plugs gaped at 0.32
Yes I have checked vaccuum lines
Yes I have a new fuel filter
Yes I have new 02 sensors(all 4)
Yes I run sunoco 93 snd lucas octane boost

[Mike]

I hate tuning issues, and I can guarantee you Larry doesn't like em either.
:(


What kind of plugs are you using?

For your mods you don't need such a small gap. Without a pulley you can use stock gap. With a lower pulley keep it around .038-.040.

We could try my 90 MAF to rule out you MAF.

[DolSVT00]

I currently use autolite extreme iridium 1 step colder than stock
the 90mm maf is brand new from ford racing less than 3 weeks old
I gaped the plugs tighter for the pulley upgrade

Maybe i just need to run the stock tunes till I get the pullies and a dyno :cry:

[Whaler]

DolSVT00,
I agree with Mike. I think your plugs are gapped to close. I have run the 4 & 6lb lower pullies and JDM recomended NGK TR6 (which Mike also has in his built motor) and I have them gapped at .035-.036 . You may ask Mike, but that is about the gap (.030-.032) he runs in his built motor. The plugs would be the first thing I would try. I wouldn't run the octane booster as it may have lead in it, which will eventually kill the O2's. If the stock tune works, you may want to run it, but be careful of running it hard, especially in the cold weather. The winter is why I'm not running my 6lb pulley.


Good luck and glad you guys came over to this site.

[DolSVT00]

The tunes I run are on the stock pullies so the cold weather may not play a big part

I may play with the gaps tho, I set the plugs that tight for when I change to the 2.75 upper and the #4 lower but maybe it wasn't such a good idea since the reason I dont have the pullies on now is due to not having a tune to run them on (not to mention pegging out the maf)

the octane boost? I was alwayse told that octane boost was fine for the o2 sensors? And I was warned to stay away from race gas due to coating the o2 sensors with white powder and causing them to fail maybe they were wrong?

But I have 4 good motorcraft o2 sensors in the garage due to the fact that I changed them all because I kept getting a p0172 DTC and a check engine light, come to find out it wasn't the o2's. It was the last plug on the driver side that was about to have the ole 5.4 blow the plug outa the head syndrome. luckily I caught it and changed it before it blew.

On another note, changing those plugs made me have to go to the store and buy extensions,plires,swivel's and nuckle sockets have you guys figured out how to change those plugs without it bieng a PITAZZZ?????????

[Whaler]

Randy,
I didn't put my 4lb on until I had a tune to go with it. It's alway debated on forums, but I will eer to the safe side of things. My truck was lean with the stock pulley, and has always wanted to run leaner than I liked. The dyno tune solved that. FINALLY!

I am probably wrong, but I've been told that lead is the easiest way to bring the octane rating up on fuel. I guess I'll have to research it.

I don't change my own plugs. Period. haha I refuse to screw that up. I have a friend who is a mobile mechanic and he has changed hundreds of 5.4L plugs and told me that torqueing them to factory specs is a key to not having them blowout. He does that and I've had them changed 3 or 4 times now, and never had any trouble.

Whenever I ran 114 race fuel (50/50) mix w/93) in the truck, after driving home the exhaust tips were very clean and purple. That fuel does make a difference.

[DolSVT00]

I have the 2000 model I have alot less threads in the heads than the 2001+ model guys I have 3 compaired to your 5 (mine is more prone to plug blow) the last plug on the driver side wabbled when I put the plug socket on it and the electrode was white powder due to sucking air and thats what caused the p0172 (lean condition bank 1) to keep poping up.

I shure would like to know what the secret to getting the driver side rear plug torqued is, I couldnt even get my torque wrench in there to use it so.. I counted turns on the ratchet by marking the extension with a sharpie.

[Whaler]

I have the 2000 model I have alot less threads in the heads than the 2001+ model guys I have 3 compaired to your 5 (mine is more prone to plug blow) the last plug on the driver side wabbled when I put the plug socket on it and the electrode was white powder due to sucking air and thats what caused the p0122 (lean condition bank 1) to keep poping up.

I shure would like to know what the secret to getting the driver side rear plug torqued is, I couldnt even get my torque wrench in there to use it so.. I counted turns on the ratchet by marking the extension with a sharpie.

Actually, The extra threads went in 2003 & 2004 models only. Mine only has the three, like yours. Mike and I were talking about that on our trip the other day. Mike sold his stock 03' heads and they are actually desirable for porting. The guy who changes my plugs laughs at me when we talk about what little is holding them in. I even wonder the same thing you said about how in the world to get a torque wrench near the rear one. I will ask him to make sure he's telling me the truth.

[Lurch]

Is the misfire under a load? I went through this with Daryl's truck and it turned out to be a coil. the way I found it was put a driver in the vechicle make it misfire and unhook coil's ( It won't shock you) untill you find that it start's misfiring on two coils If you have split exhaust you can icealate the side by exhaust and from there it is easy. Daryl's wouldn't show a code due to OBD bypass due to a tuner learned that off of NLOC If you need help finding it I will Help you Thank's Mitch

[Mike]

Mitch,

I think Randy had the problem solved when he got a custom tune.

[Lurch]

Glad IT's Fixed