alright i have a 388 built engine with the largest of everything i can run. i'm having problems starting the motor without holding the pedal to the floor. my tunner says because of the lack of vacum off the cam that's the only way possible to start this beast. anyone else heard of such a thing with tpi motors and any size combo???

 

He screwed something up and doesn't want to fix it!

 

well as much as i appreciate the opinion what would be your basis or theory on the matter as to why it won't start that way then.

or in otherwords why would something be "screwed" up?

 

First off the crap about not enough vacuum is just that, crap, lord I should know, I've had cars with very little vacuum at idle, but they all started just fine, idled at 1000 rpm or higher due to the huge cams in them and then ran like a raped ape. Something is screwed up if you have to hold the pedal down at all to start your car with a TPI. You need to get it figured out and throw the flag at your tuner.

 

well i went to check progress last night and it wouldn't start at all now....? the tps sensor was off on the laptop so i replaced it and nothing changed. is there some sort of filter sensor on the TB that could get clogged causing this?

i have the cam specs if that would help?

 

how does it run after started? the timing could be way off

 

I would like to know the cam specs, even though I don't think that's the problem.

87350IROC is right, how does it run after it starts? When it starts?

 

like a raped date.......

i have the spec sheet in front of me but it has quite a bit of info on it. what specific would you like to know?

 

Lift, Duration and LSA. If you give me everything I can plug it into Desktop DYNO.

 

i'm not sure as i have gross valve lift, tappet lift, valve timing, etc.

the last specs are

duration @ .050 intake 230 exhaust 236
lobe lift intake .3890 exhaust is .3800
lobe separation is 111.0

 

Learn how to tune it yourself and u dont have and/or can fix these kinds of problems

been there, done that

later
JEremy

 

I need your rocker arm ratio to figure out valve lift. Your car is speed density still? If so who did the chip? If it won't start right but runs great after it starts it could be the chip.

 

the rr's are 1.6.

i assume it is the chip since everything else is brand new. i'm trying to figure out what is needed to change in order for it to work. car is currently down since the shop burnt out the damn starter from being a bunch of asses.

this problem keeps getting worse and worse.

 

I have pretty much the exact motor set that you have in my gta.I had the same problem with my car. it would only start if i gave it gas especially after the motor was hot. But i found it to happen right after I put on a 1000 cfm edelbrock throttle body. well to cut a long story short it turned out to be an improperly set tps sensor throttle position sensor.

 

so how did you correct it?

mine seems to be going haywire even though i replaced it with another one just recently it still gives trouble now and again?

 

well there are two ways to attempt to get it right. 1 way if you can get someone to run a diagnostics tool to your ecm. i believe it has to be set at .55 millivolts. I set mine with a volt meter at one time by poking through the wires going to the sensor before the harness .
2. another way to try and trouble shoot it with out a meter or diagnostic tool.would be to loosen the two torx head bolts for the adjustment but not too loose just enough for you to move it(they strip easy so use the right size tool for the job) with a firm hand. barely move the sensor up and down with extremely small increments like 1/16ths or smaller because it is extremley sensitve and it I noticed when I moved mine just a small amount it took the computer about 3 seconds to respond with a different reading . So barely move the sensor wait a few seconds then try and start it eventually it should start right up but dont keep doing it over and over because you will flood your spark plugs.

I had a question what kind of chip do you have ?? if you do do you know if your car runs in open loop?