BT? Who is that?

 

Brian Tooley.

How do you know you need exactly 7.425?

 

At least your tuner seems to be on top of things - you didn't measure for proper pushrod length when you assembled the long block? Tsk, tsk, tsk...lucky you didn't do some serious damage during those WOT pulls.

 

i do not know for sure. He gave me some procedures to do then call him back and he will tell me exactly what i need. The way he explained it to me, at TDC I need to tignten the pushrod down till it bearly touches the lifter then count the number of rotations until i reach 22 ft lbs. based on how many rotations he will be able to point me in the right direction. He said it should make atleast 2 full turn down into the lifter and he is guessing based on what he hears that it likely is not currently. Does that seem realistic to you folks? I should have mentioned that but 7.425 was his estimation based purely on experience.

 

Unless you're over .600 lift, you should only need 7.4s.

7.425 will put to much preload on the lifters.

 

Ok so he is having a little hick-up tuning the thing. Everything is fine at idle and going into reverse, but when he puts it in drive it enters open loop. Any ideas?

 

He is using the bolt turn method, which is clumsy at best. The best way is to get the pushrod checker tool from comp. Its like $10.

 

Do not ask me the specific details, for i do not fully understand it.

Well he got it to idle great in park and in reverse but when ever he put it in drive it went into "open loop" the way i understand it is when this happenes it pulls its running info from fuel tables and not where it should be(sensors i guess). Long story short, it fires right up, idles well, then when you shift to drive it strugles to maintain an idle.

When all this happened he noticed that it had a low vaccume, he speculates that this could be due in part to the short pushrods but really was not 100% sure.

He wants me to grab a push rod length checker (well he wants me to do the bolt tighten thing, but i am just gonna grab a checker to be sure)and check them out, in the mean time he is gonna do some research. He says if this does not solve our problem that he recommends putting in a 2001 computer because apparently they have more tables for fine tuning certian attributes.

It was bittersweet today, sweet cause my truck hauls ***** by comparison to stock, but bitter because its not done.

Does anyone have some ideas to bonce around with out knowing the specifics of the tune?

This guy did something i never expected.. when we called it a night i asked him what i owed him.. he said bring it back when you check out the pushrods and let me fix it.. you dont owe me anything for this! What an honorable fellow, not something you see everyday these days.

 

He should have the tables tuned so that it being in closed loop vs. open loop should be almost invisible. The vacuum sucks because it's on the verge of stalling it sounds like. Pushrod length would have nothing to do with that if it idles okay

 

if i am understanding you correct, it should make no difference(or hardly any difference) weather it is in closed loop or open loop. Am i understanding that corect?

Yes you are right, it is on the verge of stalling but it only does that when brake is applied in drive. In reverse and neutral everything acts as it should.. additionally it works in drive but only when the brake is not applied. This is the problem.

Well i got a length checker from a local shop and yup.. 7.400 is the magic number. 7.400 hardened pushrods are on the way. I hope we can solve this riddle about it having trouble staying at idle in drive by then