issues setting IAC & TPS?

[channer]

Hi all

I've been trying to set my TPS & IAC since Saturday... using Steve's instructions.

I set the TPS, key on... engine off to .42, once I start the engine... it immediately jumps to .46.  whatever I set it at, it always jumps 4 point.  Is jumping 4 point normal?

As for the IAC, I set it to 20 with engine on in park...  I take it for a quick drive, come back and the IAC shows 0.  It stays at 0... no matter how much I turn the idle screw.... but in the mean time, TPS gets all wacky... and I have to reset everything again.  Should IAC go to 0, after I've set it to 20?

Could the be something wrong or worn with the IAC or TPS?


TIA.... dave


PS: I finally figured my off-idle stumble.  I changed my cam sensor

[Steve Wood]

usually, most cars jump 0.2v but as long as it is no more than 0.46v, it is okay.  I would set it with the key off to 0.38v to0.40 for some margin.  If the tps goes past .046, it will kick the car out of idle mode and that could cause a problem

As the iac and tps are interconnected, it the iac is acting up, it can affect the tps...going to zero will make the tps go up.

First I would set the tps lower, then set the iac when the engine is fully warmed up.  If it suddenly drops to zero again, I would suspect either the iac or the wiring to it....

[channer]

thanks Steve

I`ve set the TPS to .40 and IAC to 20 after a quick drive tonite

I`ll check the IAC wiring tomorrow since I had disconnected the wiring... to get to and replace the cam sensor.  I do remember the TPS jumping only 2 points before the cam sensor change


dave

[1KWIKSIX]

Hey Dave,


Glad to hear you've figured out what was causing your "stumble" 
I know that it was driving you crazy! 


  
dave

[Pyro6]

IAC to zero? Could it have a vacuum leak?

[channer]

Tonite... I jiggled/played around with the AIC wiring, disconnected the IAC harness, removed IAC & cleaned it.... and did not make any difference.

The TPS still jumps 4 points from 0.40 to 0.44 at startup... The IAC was 60-70 cold... dropping to 20 when warmed up... but goes to 0 after driving around. 

It may be time to buy another IAC to see what happens.  I'll take another look around for vacuum leaks.

I fix one problem... another pops up!!!!

dave

[Steve Wood]

So what else is new?  LOL....I feel that way every time I start working on one of mine.  It may be that the solenoid in the iac is giving up the ghost when it gets hot?

[madcow]

Throttle shaft bushings have a lot of play?

[channer]

Steve...

While we are on the topic... fix one thing, something else goes wrong!!!

within the last couple weeks, my fan which use turn on at 170f... now seems to be turning on at 200f.  about a month back, the high fan turn on after I shut off the car.  It never turned off... so I disconnected the relay switch. 

Do you think the temperature sending unit is also a goner!!!!


Madcow... that 62mm TB is another worry.... but I've had that for 5-6 years.  The seller said it was a S.Munroe ported TB... but reading/remembering some posts from yester-year... in which Steve describes what he does (new shaft, brass screws, etc)... my TB doesn't look anything like that!!!

time to play with the car some more!!!

dave

[Steve Wood]

The low speed fan is turned on by whatever temp is programmed into the chip.  Eric sets his around 167-168 as I recall.

The sensor that controls this is the ecm temperature sensor that has a couple of wires on it...sticking out of the front of the intake on the driver's side of the intake.

If your ecm appears to be reading close to the right temperature on the SM, then the sensor should be okay.

Factory chips turned the fan on closer to 200 degs.

The high speed fan was triggered by a couple of means.  If you turn the AC on, the high pressure side sensor by the compressor, turned the high fan on by grounding the wire that went to that sensor.

Or, if the AC was off, and the temp got up to well over 200 degs, then the temp sensor on top of the intake grounded the wire out to trigger the relay.


A leaking (vacuum) throttle shaft won't have much affect on the iac unless the shaft is so worn that it is kicking the tps sensor around.

[PacecarTA]

ive had a couple monroe TBs with bent throttle blades
basically the door is open and you may not be able to back the screw off enough to get the iac off zero once the car warms and the program idle goes down
the fix ,bend the blade back to flat


fan sounds like the low speed relay went on driver fender

the tps will change from set at key on to when you have it running because the voltage changes when the alternator is running ,  battery should be around 13 , alternator output is 14.2 (depends on temp and load )   .you may have a low voltage issue with your battery and  might be time for a new one

[channer]

I've got one of Eric's chips for my 50lber.  My Scanmaster shows +200f when the fan kicks on.  It use to turn on around 170f... and my car never reach 200f.  Now my car runs 200-210... and is a slug at the temperature.

My AC doesn't work... so vent/fan are always off... and window rolled down.

Are the high and low fan relays switches the same?  I was thinking swapping the switches and see if the fan turns on at 170f

Battery seems fine... but I'll check my voltage tomorrow and get the battery that I was trying to sell... charged!!! 


dave

[Steve Wood]

yes, the relays are identical

[tb3]

pardon my usual ignorance, but how is the tps adjustment done on the newer stuff these days?
I'm assuming there is no tps adjustment on the 3800's?

[PacecarTA]

pardon my usual ignorance, but how is the tps adjustment done on the newer stuff these days?
I'm assuming there is no tps adjustment on the 3800's?

how does what you do on 3800 pertain to this thread
and what newer 3800... 80s , 90s , 2000s, 2010's,