84 cross fire 4spd

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Apr 27, 2008 | 07:27 PM

#21

CFI-EFI

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From: The Top of Utah

Quote:

Originally Posted by pappyfreebird

haynes!!! it simply says ifn readings not in the 535 then replace the tps...thats why i feel i ain doin it right cause its a new tps...ill get it eventually...thanks JL n cf

NO Haynes!!! The Haynes is WRONG. That is why I said, "www.helminc.com". On the 1984 through 1989 C4s, the TPS is adjustable. For the 1984, the spec is 0.525 ± 0.075 volts. You probably wasted your money replacing the TPS.

RACE ON!!!

Apr 27, 2008 | 07:46 PM

#22

JLeatherman

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From: MD

Yeah, if you loosen the two bolts you can twist the TPS and change the initial reading.

Apr 27, 2008 | 08:08 PM

#23

pappyfreebird

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thanks gentlemen...i did that...and the haynes has it ...real good description ...but im still not gittin that reading... i simpy ran 3 jumpers tunrt key on n put my multi to vdc n touch ed black to a n red to b and vice versa n no good ,,,ifn touch top c and then each of the ohters i git 525 on b n nothin on a...im going to check fer a stuck iac as JL suggested...ifn all else fails i have a freind thats done it before n has the computer thing to plug it in n set it that way...i must be doin somthin wrong on the test though...it ain that hard i just ain gitton it right...

Apr 28, 2008 | 08:33 PM

#24

pappyfreebird

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ok got her set (the tps at 530) still idled high,,,so cleaned n set the iac s...took a ride still high idle and check engine would come back on when rpm dropped below 1500 ...found that engine light prolem was a colapsing vac hose...so that ok n still idled high...so i tweeked the tps by hand (yea blind man) but shes at 800 purty consistent now (whilst was warm) hope runs that good cold ...dumd me ive never checked my timming...maybe previous owner twigged it up fer more power? my lights broke (dayum ol harleys wear em out lol ) so that be next

Apr 28, 2008 | 09:20 PM

#25

CFI-EFI

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From: The Top of Utah

Quote:

Originally Posted by pappyfreebird

thanks gentlemen...i did that...and the haynes has it ...real good description ......

BURN the Haynes

Quote:

Originally Posted by pappyfreebird

i simpy ran 3 jumpers tunrt key on n put my multi to vdc n touch ed black to a n red to b and vice versa n no good ,,,ifn touch top c and then each of the ohters i git 525 on b n nothin on a

Translation please. What the hell does that pile of typos represent???

Quote:

Originally Posted by pappyfreebird

im going to check fer a stuck iac as JL suggested...ifn all else fails i have a freind thats done it before n has the computer thing to plug it in n set it that way

The idle is changing as the engine warms up. That is proof that the IAC isn't stuck. "The computer thing to plug it in n set it that way" doesn't set anything. It only reads what it is set at.

Quote:

Originally Posted by pappyfreebird

so that ok n still idled high...so i tweeked the tps by hand (yea blind man) but shes at 800 purty consistent now (whilst was warm) hope runs that good cold ...dumd me ive never checked my timming...maybe previous owner twigged it up fer more power?

Tweaking the TPS won't change the idle speed. The idle speed is burned into the chip. If you get everything adjusted properly, it will idle as smooth as silk at 600-700 rpm. The timing won't change the idle speed either, on a computer car.

RACE ON!!!

Apr 29, 2008 | 07:42 AM

#26

pappyfreebird

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dayum cfi...i rekon youve really pointed out the fact that i dont know what the L im doing on these computer cars...and here i was thinking i just learned a little...cause these carbs are simply a rochester with some crap to control elctronically what we used to set by ear...great when they work n pia when they dont...but the things ive learnt so far is the tps is nothin more then idle skeeroo and iac s are simply the air skeeroo....my problem is i got someone in there changin cheeyut on me cause the ecm says so wahahaha....so once i git her right itll be right...ps the quote of freinds computer (well it only reads it) duh good sir! but thats how i can adjust it if keep having stupid readings on my multi meter...now for this mornings update (bs or whatever) she started fine idled 15 tell 180 then dropped to 800...thats better but i want as you state 6-700 tops warm...so any other idears there brutha...i rekon you may have awready givin me the answer and my prolem (its in the chip) possibilty heyhuh? thanks agin guys paps

Apr 29, 2008 | 09:32 AM

#27

JLeatherman

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From: MD

Quote:

Originally Posted by CFI-EFI

[Tweaking the TPS won't change the idle speed. The idle speed is burned into the chip. If you get everything adjusted properly, it will idle as smooth as silk at 600-700 rpm. The timing won't change the idle speed either, on a computer car.
RACE ON!!!

Gotta disagree with ya in part on this one CFI. The TPS CAN change the idle speed. If you've got the TPS set too high, say .550, the car will think you're pressing the gas pedal down and will increase the fuel. Since your TBs are actually still closed the IACs will open up to get the mixture right and you'll end up with a very high idle (and possible a too-rich idle if the IACs can't open far enough). HOWEVER, if everything is set properly and the TPS is at .525 the car should idle normally.

Pappy, I didn't hear you mention resetting the computer after adjusting the TPS. This is necessary after the TPS adjustment and IAC cleaning to make the changes have an affect. The car has to "re-learn" its starting points.

Apr 29, 2008 | 10:58 AM

#28

pappyfreebird

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hey JL ... good point ... resseting the computer is to unhook battery for a few minutes right? yes i did that too after cleaning the iac s...you know i think your onto something there with the tps and iac s...ifn im off on the volts then the next best move would be to git it plugged in n set it with friends computer thing...then go from there...also just a fools thought but ifn timming isa way advanced then couldnt the computer advance it evin further causeing this 100 extra rpm???ok next step get that dangnab tps set to the proper setting thanks again guys

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Apr 29, 2008 | 11:44 AM

#29

CFI-EFI

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From: The Top of Utah

Quote:

Originally Posted by pappyfreebird

I see this post starts out, "dayum cfi...". I'm not sure what that means, but I get the impression you are addressing me. We are going to need a gibberish to English translator tell me what you've posted, here. I can only make out bits an pieces of what all is garbled in there. I'm sure I can help you, but first I have to be able to understand you. Do you have any English speaking relatives that can post for you?

RACE ON!!!

Apr 29, 2008 | 11:45 AM

#30

JLeatherman

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From: MD

The timing isn't going to make the idle change. The TPS is only adjustable manually with the two bolts and twisting it. The IAC's are only adjustable if you have a whole new chip burned, the PROM in the 84 can't be changed by just plugging in a computer. If you set teh TPS at .525 and the car idled high then something is wrong. I was just saying that the TPS *CAN* change the idle to make it faster. You still should figure out why yours idles so fast with a properly adjusted TPS.

Does it have any other symptoms? The fact that the idle kicks-down at 180* means the CTS is working fine (coolant temp sensor). Really the only thing that should make it idle fast like that is a vacuum leak. I'd look around some more for a leak. The upper plenums in the crossfire are quite prone to leaking.

Apr 29, 2008 | 11:53 AM

#31

CFI-EFI

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From: The Top of Utah

Quote:

Originally Posted by JLeatherman

I understand your logic, and maybe at ridiculously high settings it will change the idle, but I have never seen it. I once experimented with higher than stock TPS settings to check the effects. At 0.620 volts, the highway speed throttle response was way too sensitive to maintain a steady speed. But my idle speed remained within spec. However, even if at the extreme, the TPS can alter the idle speed, that is not what it is for. There is no excuse to deviate from the TPS spec, especially in an attempt to LOWER the idle speed.

RACE ON!!!

Apr 29, 2008 | 12:03 PM

#32

CFI-EFI

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From: The Top of Utah

Quote:

Originally Posted by JLeatherman

The IAC's are only adjustable if you have a whole new chip burned, the PROM in the 84 can't be changed by just plugging in a computer.

The IACs are not adjustable. If they are removed and the pintles are retracted for proper reassembly, there is an acclimation [procedure to get them back on track. Namely driving the warmed up car at a speed in excess of 45 mph.

Quote:

Originally Posted by JLeatherman

If you set teh TPS at .525 and the car idled high then something is wrong. You still should figure out why yours idles so fast with a properly adjusted TPS.

That sounds familiar.

Quote:

Originally Posted by JLeatherman

Does it have any other symptoms? The fact that the idle kicks-down at 180* means the CTS is working fine (coolant temp sensor).

And that the IACs are working.

Quote:

Originally Posted by JLeatherman

Really the only thing that should make it idle fast like that is a vacuum leak. I'd look around some more for a leak. The upper plenums in the crossfire are quite prone to leaking.

That sounds familiar.

RACE ON!!!

Last edited by CFI-EFI; Apr 29, 2008 at 02:27 PM. Reason: correct Typos.

Apr 29, 2008 | 01:20 PM

#33

pappyfreebird

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well on the( freinds computer )i simply mean he has said he can plug it in to car n get the tps reading thru that (he said he has set a few this way) meaning he plugs it in gets the volts n moves the tps and my thought ok then lets try it..ain got nuthin ta loose but a hundred or so rpm...preciated both you guys...more i dink with it the more it prolly is a vacuem prolem ...ive read a lil on them crossfire manifolds n the plate leakin etc and have found a couple brittle vac lines...but hey fellas shes fun to drive!!! and i ain itno fast gear bangin stuff,,,simply a nice toy to play with...but still these couple of bugs towerk out of her...oh cheeyut n then the paint well lets nawt evin go there !yet! have a good one fellas

Apr 30, 2008 | 07:53 AM

#34

pappyfreebird

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well we plugged her into buds scope thingie and set tps to 525,,,still 800 at lowest...no codes ...but did list two possible checks ...and they were the intake possible leak n the egr valve...we plugged n unplugged egr n the differnce bud said its fine...so prolly hafta pull intake n find a gasket...again i fill in the final verdict...when find it

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