thebufenator

Hi, I finally have everything buttoned up with my 383, and I cant keep the darn thing running.

I had issues with it not idling properly, it would drop to about 500rpm and die. It seems to want an idle of 950rpm. I had to crack the throttle blade with the stop screw to get it idling right. I tried to use my laptops diagnostic cable, but it wont send data at all, no idea why. I am guessing the IAC isn't doing its job, but I dont know what the IAC counts are.

When I put it in any gear other then N or P, it dies very quickly unless I keep giving it gas.......and its very sensitive to how much I give it, it likes to leap ahead if I give it too much. very touchy........I might want to go to a 52mm TB cause this is really touchy.

And lastly, my brakes aint working very well. I bled and bled them, but they aint doing very well. I also noticed a leak between the master cylinder and the brake booster. I am assuming that means I need a new Master Cylinder right?

ack........so many things to fix.....

94zgreenmachine

Are you using a stock TB or a 58MM? You are probably not getting enough air for it to idle.
I had similiar trouble with my 58MM. A quick fix (which I did) was to slot my tps hole and I used my Datamaster hooked up to adjust the tps voltage to read accceptable and also checked my throttle blade percentage. If you do it, you can go to BBK's website and they have a how-to on how to and which hole to slot. That was the quick fix.
Soon , I will be drilling out my 58MM TB holes a little larger to allow it to idle without slotting the tps. I don't know how much, so I will go slow till I get the right size hole.

Injuneer

What did the tuner/programmer set it to idle at in neutral and in gear? Without being able to watch the IAC counts, and measure whether the IAC motor is actually moving, you're sort of working in the dark.

thebufenator

yeah, I got a tune from PCMforless, and they didn't say what they were setting the idle for.

I am guessing I need to pull the throttlebody off and drill the IAC passage......

Is there a guide for that? I am also gonna keep attempting to get a connection with my laptop, maybe something is loose.....

mycarisfasterthanyours

Make sure you double check the vacuum line to the brake booster. Could possibly be the cure for the idle and the brakes.

thebufenator

well when the engine is off the brake pedal has pressure, and the pistons do clamp the pads down. When the engine is running, the pedal is of course alot softer, the pads are still clamped, but now that the car is moving I can tell that the brake pressure is weak.

thebufenator

One other thing, the engine doesn't seem to like reving too much.....like if I mash the gas it will rev up, but if I go slowly it starts going up then back down around 3000 rpm.

I am thinking I might have the valve lash set too tight. My the instructions with the rockers said to set to 1/4 to 1/2 past.....so I set it to 1/2. If I decide to try 1/4, can I just back each one off a quarter? I do I need to redo the whole thing?

mdenz3

Big cams reduce vacuum which results in less assist from the brake booster.

shoebox

Gee, don't go drilling and doing things you can't reverse, when you don't even yet know what is going on. That would be a big mistake, IMHO.

thebufenator

well yeah, but I can easily push the pedal all the way to the floor.
and it doesn't really come back quickly either.

Dtimekw

I had a similar problem with my 383. My TB wasn't drilled at all. After researching on here, the best advice (Like Shoebox said) don't do something you can't undo. Get your laptop working and check your IAC counts. Once I found out what mine were, I drilled my TB several times until I was at stock size and slowly brought the counts down. Counts are still a little high but she idles fine so I don't think I will go any further.

Dave1980

Buffenator you can also get a scanmaster if you have not, that will also give you real time IAC info.


good luck man, I am slightly behind on our almost identical build.

thebufenator

Well until I can get data flowing to my laptop, shouldn't I still atleast drill the same size hole the stock TB has? I pulled mine off and its got no hole there at all.

94zgreenmachine

Which TB are you using? If you want to see if it is the throttle blades, crack the screw open to open the blades slightly. Will it idle once the blades are cracked open?
I would try that first to see if that is your problem as to why it isn't ideling . You can always adjust it back. Drilling the holes ,with out knowing for sure ,can't be re-done. I had my datamaster working also, otherwise I would have been in the dark guessing as to where to set it at.

thebufenator

yeah if I crack the blades it runs fine.....sorta......but going into gear it still tries to die