I was just wondering what a factory or "normal" idle for an 89 2.8 is? When my car warms up, it sits at around 1000 to 1100 RPMs. I have an autometer tach in there. (came with the car) the autometer tach is what reads 1000-1100 RPMs. The stock tach reads only bout 100RPMs off. Not as drastic as some stories I've heard. Sometimes the autometer will drop to about 900 or so, but go right back up. Usually only does that after hard driving and coming to a quick stop. Doesn't always though. I've heard that my stock idle is supposed to be anywhere from 700-800 RPMs. Is this true? If so, how can I adjust this?

 

Yeah 700-800 is about right.. Try adjusting you throtle position sensor its located on the passenger side of the intake. That should do the trick.. but there is a certain way to do this (im not qutie sure the right way) so you may want to find out more about it before backing out the bolts.

 

Anyone know the right way to adjust the TPS? I know on my brother's Cobra, his isn't adjustable. Just bolts to the TB. His was off when he bought a bigger TB. Turned out they sent him a defective one. Lol, sorry to get off subject. My car's completely stock. Didn't know you could adjust a TPS. Well, if anyone knows how to, I would greatly appreciate the input. And if you think it's something else, I would love to hear your opinion. Thanks!

 

As for adjusting the TPS, check the tech articles. You'll find one specifically for adjusting TPS and IAC.

However I would not set the idle by adjusting the TPS (or IAC), you have to adjust the idle set screw. On your 2.8, there is a protective cover preventing you from adjusting the screw outright. You'll have to remove this with a small punch or a small screwdriver; unless it's already been modified, in which case you may already have access to it.

As far as idle RPM speed is concerned, check out your VECI sticker under the hood, it should have that information there.

~Toast

 

Is the VECI sticker the emissions sticker? Cause if so, I don't have the stock hood. That's the only thing different on the car. Came with aftermarket hood. I would guess that's where the sticker is and the hood is not at my house. The only sticker under my hood in the engine bay is the one that shows you how to route the belt.

 

VECI stands for "Vehicle Emissions Control Information." In that case, i'd call up Pontiac (or Chevrolet), give them the VIN number, and have them print out a new VECI. Who knows, they might be nice enough to just tell you the information you need over the phone. But it's really good to have, and it should not be too expensive.

 

I'll have to check my stock hood when I get a chance. It's in my grandmother's basement. Don't have a basement or anywhere to put it at my place. When I check it, I'll let ya know.

 

havent had a chance to check the sticker yet, but where is the idle set screw? is it on the throttle body? if so, where?

 

Right side of throttle body, kind of behind the WOT Lever that connects your gas pedal to your throttle body it has a plug in it because its factory set, if it hasnt been removed most likely you need to adjust your TPS.

stick a sewing needle into the middle terminal of your TPS, do not damage your wire it is fairly simple just stick it in the green part of the TPS connector right above middle wire using pliers (hard stuff to get into with fingers wear saftey googles yes! its geeky but sometimes the needle snaps when u try to place it in). But the good news if u go exactly right about the middle wire meaning flush with it you'll get it right in.

connect volts meter ground the neg term, connect pos to sewing needle, loosen both TPS screws.

move TPS up/down depending on VOLTS!!

should sit around 0.54-0.58

i have mine at .54 exactly.

thats not 5 volts! it's less than a half so you know!

have a good day partner..
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btw, im in Terryville CT !

 

Just thought I'd let everyone know that I finally got around to adjusting my idle set screw. Well, when I back it out a lil bit, the spring on the WOT plate was a lil tight so I had to push it back with my finger. The idle did go down. However, when I went to rev it a lil with the gas pedal, the RPMs went up, but it wouldnt go back down all the way. I tried driving it and when I would push in the clutch and come to a stop the RPMs would sometimes stay at 2k until I tapped the pedal and then it would go down. Other times when I'd be sitin at a light and it would stumble down to round 600 and 500 RPMs and it would die unless I tapped the gas. Also, when it would sit at 2k after depressing the clutch, sometimes the check engine light would be on and other times it wouldnt. This is the only car I have so it's my daily driver. To fix this problem, do I need to some how adjust the throttle linkage as well or is something wrong with the throttle body that it doesnt return to the correct position? I have a feeling it's the linkage cause when I first hit the pedal after adjusting the screw it would stick a lil bit. If someone has a stock 2.8 and their idle is around 700-800 RPMs please count the threads on the set screw. Maybe I went too far. Also, if anyone thinks it's the linkage, I would love to know how to adjust it. Please, any suggestions besides my own are greatly appreciated. I really just want this car running correctly. Thanks for all the help.

 

Did you check the TPS signal to? That not being adjusted to the right voltage will cause what you are describing. Did you set the idle the correct way with the IAC? Do a search on the corrct way to set idle, it may be in the technical articles.

 

LOL the tps doesn't really effect the idle. It's controlled by the throttle valve and the IAC. The TPS needs to be reset after adjusting the minimum air at the throttle stop screw for best drivability. Start by cleaning the IAC and passages, along with the throttle blade and bore behind the blade. Then set the minimum air and TPS to specs.

 

I have already cleaned the passages and bore behind the throttle blade. however, I have not taken the IAC off to clean it. Is throttle body cleaner ok to clean it with? Also, how do I set the minimum air and TPS to specs? thanks so much already

 

TB cleaner is fine for cleaning the IAC. Just don't pull the pintle on it or you will mess it up. For the TPS you need a digital voltmeter.

 

What's the pintle? is that like a lil needle valve inside for the IAC to work properly? Also, what are the stock specs for minimum air and with the digital voltmeter, where do I hook it up and how do I adjust the settings? a detailed step by step from the begining on how to set the idle would be greatly appreciated. Never set an idle on a fuel injected engine. Thanks so much for your help so far

 

the pintle is on the IAC component on top of the throttle body it has a four wire connector connected to it, unscrew the IAC and you'll see a pintle attached to it, clean the passages and make sure depending on your type of pintle it is down to were it needs to be mines was 1 1/8 i believe i have a 88' 2.8 v6, anyway, as for the TPS if you have slender probes with the volts meter, detach the backing off of the TPS its two little clips, then stick the red probe in the middle of the TPS, and find a good ground for the black probe, turn ignition on, and loosen the TPS adjust voltage to 0.54-0.58 depending on your car (not sure what ya got) mines is at 0.54.
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correct me if im wrong the stock specs are 550 in D with IAC disconnected?

you have to hook a paper clip to connectors A&B on the ALDL to ground your diagnostics, then after 30 seconds unhook the IAC connector (not the IAC just the connector) then turn the ignition off unhook the EST wire, go in car and remove paper clip, start engine, replace paper clip same place, watch engine light, should flash rapidly then after 2 mins or so it'll slow down about once every second thats how you know your in closed loop put emergency brake on, put car in Drive, then adjust it to 550 in D with a tachometer, be it in car one(if reliable) or outside tachometer, turn car off reconnect everything, THEN YOU DO THE TPS ADJUSTMENTS AFTER THIS 0.54!!!

THEN RESET BATTERY

 

correct me if im wrong the stock specs are 550 in D with IAC disconnected?

you have to hook a paper clip to connectors A&B on the ALDL to ground your diagnostics, then after 30 seconds unhook the IAC connector (not the IAC just the connector) then turn the ignition off unhook the EST wire, go in car and remove paper clip, start engine, replace paper clip same place, watch engine light, should flash rapidly then after 2 mins or so it'll slow down about once every second thats how you know your in closed loop put emergency brake on, put car in Drive, then adjust it to 550 in D with a tachometer, be it in car one(if reliable) or outside tachometer, turn car off reconnect everything, THEN YOU DO THE TPS ADJUSTMENTS AFTER THIS 0.54!!!

THEN RESET BATTERY

 

Very detailed and I appreciate it greatly, but I have a 89 camaro 2.8 5spd so I cant just put it in drive and go under the hood. lol. So what do I do since it's not an automatic?

 

this is credited to LinuxGuy and all those who helped him put it together unless it was just him, not sure :-P, read it btw its 600 Neutral from Manual Transmission this is in detailed what to do..

Multi-Port Injection (MPFI)
2.8L Engine
1.) Using an awl or equivalent, pierce the idle stop plug and remove it. This is the plug covering the idle speed adjustment screw (aka idle stop screw, aka minimum air adjustment screw) on the back side of the throttle body.
2.) Leave the Idle Air Control motor connected and ground the ALDL diagnostic terminal (connect a wire between the A & B terminals on the ALDL connector). Turn the ignition to the ON position, but do not start the engine.
3.) Wait 30 seconds, and with the ignition switch still in the ON position, disconnect the Idle Air Control connector. (Since the A & B terminals are connected on the ALDL, the ECM will place the Idle Air Control Valve in the park position. Disconnecting the IAC connector will keep the IAC at this setting.)
4.) Turn the ignition switch OFF. Disconnect the distributor set-timing connector. (i.e. - The wire on the firewall you disconnect before adjusting timing.)
5.) Remove the ground wire from the ALDL connector. Starting the engine with this jumper wire in place may damage the ECM. See more info from "Vader" here: https://www.thirdgen.org/techbb2/show...hreadid=211733 (Why you don't start engine with "A" and "B" terminals grounded......)
6.) Start the engine, then connect the A & B terminals on the ALDL again. This will place the ECM in Field Service Diagnostics mode which will flash the SES light according to open/closed loop status. Allow the engine to reach operating temperature and go into closed-loop operation. Watch the Service Engine Soon light on the dash. When the light is flashing 2-3 times per second (i.e. - rapidly), the engine is in open-loop mode. When the light is flashing about once every second (i.e. - slowly), the engine is in closed-loop mode. Once the engine is in closed-loop mode, continue to step 7.
7.) Adjust the idle stop screw to 500RPM in D if equipped with an automatic transmission or 600RPM in neutral if equipped with a manual transmission.
8.) Turn the ignition OFF and reconnect the Idle Air Control connector and and the distributor set-timing connector. Remove the A & B jumper wire from the ALDL connector.
9.) Adjust the throttle position sensor to 0.54v at closed throttle since adjusting the idle screw has changed the position for closed throttle. Start the engine and check for proper idle operation. You will have to disconnect the battery to clear the code set from disconnecting the distributor set timing connector.

 

Wow, greatly detailed and greatly appreciate it. Just one question. I obviously tried doing this myself before asking for help (stupid me) and when I adjusted the stop screw, the throttle blade didn't move with it. I figured my spring was a lil stiff so I cleaned it up a lil bit and it moved just a little. but I have to push it back the rest of the way. Also, when I would hit the gas pedel it wouldn't return back to the screw. It would stay away from it. It kind of felt like my linkage was binding on something and getting stuck so it wouldnt go all the way back to where it was supposed to be. Any suggestions on that? I shouldnt have to adjust my linkage when doin my idle should I? Well, I greatly appreciate all the info you've given me. You've been a great help.

 

the gas pedal linkage is a constant you shouldnt have 2 adjust it in any means, the trans linkage(DEDENT CABLE in case u need 2 ever replace it) has a metal tab on the side push it in via finger or flathead screwdriver, then push the line all the way back until that oval black piece hits the bracket holding the line, then push the throttle WOT all the way down manually, it should click and auto adjust.

remove both linkages if the throttle plate moves freely then it's your linkage, if it still "sticks" or is not returning, replace the bushings and or spring at the throttle plate lever.

 

Thanks for all your time and patience with me. Greatly appreciated....Sorry to keep this going, but since I have a manual transmission, what's the cable for exactly? I could see if it was a kick down cable for an automatic, but I'm lost on this once. And just so I'm not mistaken, the dedent cable is the one farthest from the throttle body right? not the one that's kind of underneith the lever.

 

keep forgetting it's a manual lol, unhook the gas pedal cable see if it moves freely from there, if there is another cable remove that as we'll then go from there if it moves freely u need 1 or the other cables, if it doesnt u need either a replacement in throttle body bushings or spring, or a new throttle body peiece.

 

Just so I'm clear, the "A" and "B" terminals are the two on the top of the connector all the way to the right correct? If I'm wrong plz tell me. This needs to be done soon. It's getting worse. I just hit 40 miles after filling up and I'm already at half a tank. Well, thanks for all the help!

 

yes, the top two are A & B.