my car dont want to stay on after i changed the iac and reset it like the book says too also did the idle screw adjustment and tps sensor to 0.55v. when i set the timing to 6btdc it runs like crap so i advance it then it dies out. maybe i did something wrong

 

How Did you set the timing? You shouldn't be able to, as it's computer controlled. Go back and check what you did with that as the starting point.

 

Is the point where things first went wrong, right after you changed the iac and THEN you started trying to fix that issue? If so, let's start there. When you changed the iac, did you clean out the passages behind it after pulling the old one? Secondly; what led you to change the iac in the first place? Did you have an idle stumbling issue? Nitro-Nicky

 

it happened after iac swap.
i changed iac cause it had a bad idle then i cleaned the build up in tb. i tryed to reset iac and the idle adjustment screw like the book says too . this is how i did the timing first i disconnected that wire on passenger then loosened the distributor hooked up number 1 sparkplug then set timing to 6btdc then it felt like crap still dies out

 

Remind me if your 91 is a MAP or a MAF. At this point then we should be able to say that either something went wrong with the installation OR the part (iac) is bad. I would suggest that you do NOT make any other improvements until you verify which is the problem. Go back and install the old iac and see what happens. Maybe by retracing those steps you will see something you might have missed or not plugged back in tightly.
Again on the timing, at least on the MAF computerized cars, you don't adjust the timing as the computer reaches right back in and takes over. Could you have bumped loose one of the distributor spark wires while attempting to turn the distributor? Do a 'Search' under Timing & MAP and see if you can even change timing with that system. MAP's are supposed to be super sensitive and cranky and unforgiving of mistakes. Nitro

 

Here are some copied instructions just to verify that you did it all correctly:'

1. Timing- There are 2 ways to do this.
a. disconnect the bypass wire and set timing to 0° at idle when warm. procedure- warm up motor then turn off. unplug bypass. Start motor. Set timing to 0°. Turn off motor. Reconnect bypass. Unplug ECM to clear fault code.
b. leave bypass connected and set timing to the value listed for your idle rpm and MAP setting at idle, based on your specific BCC-broadcast code. Procedure-start motor and warm up. Set timing to the value listed in the spark table.

2. IAC reset/min idle speed- This sets the throttle plate on the throttle body to a specific rpm. I recommend about 500 rpm for most engines. Procedures- Go to sheet 7 of the pinout diagrams. At the top is the ALDL connector. You need to put a jumper between pins A and B of the connector. These are pins A9(wht/blk) and A12 (blk/wht) on the ECM. This puts the ECM into aldl mode. Turn the key on (not start) and the IAC should drive completely closed. You will normally hear a buzzing from the IAC. If you have the winaldl up and running on your laptop, you should see the IAC went from 145 to 0. Now unplug the IAC connector. turn the key off. Remove jumper. Start motor. If the idle is too low you may have to keep it running. On the front drivers side of the throttle body is the adjustment screw. It may be behind a silver plug. If so just use a nail or punch to poke it and remove it. Then use a #20 torx bit to adjust the idle speed to at least 100 rpm less then your warm idle speed. if 600 then set to 500 rpm. You are looking for the lowest consistant idle your motor will do. When set, turn off motor and reconnect the IAC. I try to keep the IAC count to at least 40 with the motor warm and idling.
This is a good time to verify the operation of the IAC. When the jumper is in and the key is on the IAC is driven closed. So while it is idling to set min rpm put a finger over the IAC port just above the IAC. There should be no air being sucked in and you should be able to see the pintle on the IAC.
When the IAC is connected and operating there should be a small amount of air being sucked in the port at idle and should increase as you apply some throttle.

3. TPS-throttle position sensor. With the idle set, you need to now set the TPS. This need to be set to about .54V. I normally shoot for about .6V.
The TPS is on the passengers side and will have 2 screws holding it on. The factory TPS will not have much room in the holes for adjustments so I use a drill bit or file to elongate the holes as needed. To adjust, just loosen the screws and trist the TPS. You can monitor the voltage on Pin B of the connector with the key on or at pin C13 of the ECM. You can also see it on the sensors tab of winaldl!! Anything away from .54V will also show as a percent of throttle. Such as .2 percent or 1.7 percent...depending on how far from .54v you are. I try to keep the idle setting to within 1 percent.
This is also a good time to check your TPS. Once it is set, just watch the voltage as you open the throttle. you should see a steady rise in voltage up to about 4.5-5V at WOT-wide open throttle. If it jumps up and down or skips some then you may want to replace it.

Does this jive with what you did? Nitro

 

its not a maf. i plugged everything in the way it came out but ill check again to be sure will also install old iac. thanks

 

DTL1, $155.25.

Ask 91VERT. Call Theo, then call Rocklin Automotive.

 

the timing part i did. i will try to do iac this way without laptop see what happens . tps i did it this way.

 

?

 

 

When you're done w/ Forum Diag's.

Call us.

 

for? i have no idea what you mean

 

did you disconnect the computer controlled timing wire before setting it to 6degrees?
single wire plug on the passenger side of the distributor..

 

yup

 

My bad, I thought you needed some help.

 

Basically when your done trying to figure it out yourself. Call him he runs Rocklin Automotive.

 

i do need help.i was a lil confused with the msg anyway i just call that number and ask for you?

 

when is a good time to call? cause im tired of doing the same thing over and over again

 

Give me a call on Monday & mention TGO if I dont answer and we'll work something out.

 

 

marc is awesome in my book for what its worth

 

Thanks, for its worth, it's $155.

 

Got some Comedians on this board huh

 

jus kiddin.

 

Well I knew that..just sayin we have some comedians on this board for real haha

 

But; back to pjp209- Hey There, Let's FOCUS Dude! You asked for help, I offered you some and requested that you reinstall the old IAC and tell me what happens or changes. Did you do that yet? Nitro

 

put old iac back in this time i set idle with the car in drive it stood on after i did it just idles at 1350 in p or n. ima try to set it a lil lower

 

Wait! Don't try anything!! What we need to do is compare the two results now and figure out what happened that things got worse when you installed and 'adjusted correctly the new IAC'. Don't jump the gun- Send me your phone number and the best time of day for me to call you.

Do you have another vehicle to drive while we diagnose this? By slowing down, we'll most likely solve your problem(s) faster. If you keep throwing multiple bandaids at it, we'll just end up having to re-examine each one of those. Are you available tomorrow at all? Nitro

P.S. I sure hope you didn't set the idle with the idle screw; that's a closed loop system and should not be touched unless you really know what you're doing. Did you touch that idle screw?

 

I think that was one of the first things to get played with.

 

WOW! did you really elongate the holes in your TPS?

I would get a new TPS, DO NOT elongate the holes. Install new TPS and adjust the idle screw until the TPS reads .54v. in theory that should get you back to the factory setting.

 

That 'elongate the holes in the TPS' was really popular advice, once upon a time. I wish I had noticed it in that list quicker before I pasted it up for him to look at; which is why I've been trying to get him to communicate back with me for the past few days. It's possible he just needs to learn the hard way.

pjp209- Don't ask for help and then **** around. My time is worth much more than that. Good Luck to ya- Nitro

 

i touched it a lil but it didn't help me any with the car being in park till i put the car in drive then i set it to 550rpm well i tryed to. i cleaned old iac and put it back in idle seems a lil better just a lil higher in park it doesn't die out anymore. new iac was bad or wasn't the rite one so i took it back. cell is under water

 

 

New parts aren't always good parts. I went through 3 TPS sensors not long ago, all had a reverse voltage sweep. Finally ended up getting the right one through Delco.

 

yup for electrical AC delco for GM's is my first choice