TBI 350 Target Idle Speed

[MO LS Noobie]

Might try a different scanner, to see if it is lying to you. The other thing that could be causing a desired idle of 1000 would be what they call the throttle cracker, and throttle follower that basically act as the old dash pot that slowed the transition idle. Was this a manual transmission been to start with or is it converted from a automatic transmission? The automatic transmission bin has several rolling idle settings that affect idle while the vehicle is in motion.

Did you ever try plugging the hole for the IAC that I suggested much earlier?

[maronielb]

I don’t have access to another scanner and i just bought this one brand new for almost 200$, so i don’t want to buy another one and this Is a factory manual and I’ve confirmed the computer has the correct chip in it. I have not tried plugging the IAC hole, but i don’t see how this would set a desired idle of 1k anyway? If i remove the IAC and plug the hole then the truck should idle at what the base idle was set to at the factory. I’m starting to think it’s tps related since the tps numbers are the only ones that seem to be out of wack on the scanner

[ralmo94]

That's why I suggested unplugging the TPS, to see if it wants to command a lower idle speed with TPs disconnected. If it doesn't, I doubt a new TPS will do any good

[MO LS Noobie]

To be clear, you don't need to remove the IAC, just plug the hole from the top of the throttlebody.

[ralmo94]

To be clear, you don't need to remove the IAC, just plug the hole from the top of the throttlebody.

With all due respect, as the op was trying to point out, a hanging or malfunction iac wouldn't cause the ECU to command 1k idle rpm, if you cut off iac circuit air, you are still going to be the same requested idle speed, it just won't be able to attain it, unless I am missing something.

[MO LS Noobie]

With all due respect, as the op was trying to point out, a hanging or malfunction iac wouldn't cause the ECU to command 1k idle rpm, if you cut off iac circuit air, you are still going to be the same requested idle speed, it just won't be able to attain it, unless I am missing something.

Agreed, he has been chasing this issue for a while.

[maronielb]

I will do this tommorow and get back to you, last time i unplugged it the idle went higher

[maronielb]

Yes i have and I’m about to burn this truck if i don’t figure it out, i just spent 20k restoring this truck from the frame up and i can’t figure out a damn idle issue

[ralmo94]

I don’t have access to another scanner and i just bought this one brand new for almost 200$, so i don’t want to buy another one

Too bad you could have gotten a decent USB to aldl cable for about half that much, then you could pull the bin file from the diagnostic port and verify nobody has screwed with anything on it. Plus you could get a data log recording instead of just looking at a small scanner screen.

[maronielb]

When can i get the cable for $100? Last i checked it’s like $140 for. I’m still willing to purchase one if it’s $100

[ralmo94]

Boosted NW has them for $120, shows only one left in stock, RedDevilRiver if I'm reading correctly, is $55. If you had a serial port laptop you could make one, I've never done it before. There are a few on eBay for not a lot of $. Not sure who makes them

[ralmo94]

Also there is ALDLcables.com

[maronielb]

Would i use this cable with tuner pro? Also can you send me a link to the cable you have/would buy if you were in the market?

[ralmo94]

Would i use this cable with tuner pro? Also can you send me a link to the cable you have/would buy if you were in the market?

Yes you could use it with tunerpro rt, or aldl droid, or any other scanner or datalogger program for GM obd1. Tuner pro is probably going to have the most public support as most everyone on this site uses it. You'll need an adx file for your mask.

The one I have I got from moates, they are no longer in business, boosted NW has taken over their market to offer the same exact products moates used to offer, I like the idea of supporting such an effort. On the other hand the red devil river one comes with a disc, and it would be interesting to see what's on the disc.

[ralmo94]

Here is a link to $9a adx on this site. http://www.gearhead-efi.com/Fuel-Inj...ll=1#post17006