High idle when starting

[mmccourt1]

I just bought an '87 Grand National, and once it gets going, it runs great and is FAST. When I start it when it's cold, the engine revs up to about 2500 rpm's and sits there, causing the oil pressure to go through the roof. After cutting it off and starting it 2-3 more times, it settles in at 1000 rpm's and sounds great. I just had the vacuum lines replaces anf the throttle was supposedly adjusted, but it still does it, only when started cold. Does anyone know what this is about? Appreciate it.

 

[bmackinnon]

Welcome to the darkside!!

You need to do a ton of reading here and at Turbo Regal Web Site ..... select 'technical info' in the resources pulldown.... hours of req'd reading there...:wink:

Regarding the idle issue, it sounds like a tps (throttle position sensor) adjustment and iac (idle air control) reset is in order.... if you don't have a scan tool of some sort, make that your 1st purchase.... at least a Scanmaster so you can read what all the sensors are doing...

FWIW, idle should be like 1200-1400 rpm cold, and settle down to 750-800-ish as it warms up.... something ain't right if it's idling warm at 1000.....

IAC Reset Procedure (note the tps adjustment link at the end of the procedure)

hope this helps!

 

[DailyDrifter]

Could be some carbon in the IAC housing. Definatly read and educate yourself, it will save you money :biggrin:

 

[pajo]

vacoom

All of the above and double check for vacoom leaks ..

 

[RegalT-type85]

Great buy by the way

Agree with above, should be a the IAC/TPS.
but check all your vac lines.

 

[paulg]

you said your throttle was adjusted so im asuming someone played with the idle stop screw. everytime that is moved the voltage to the TPS changes so you will need to reset that between .40 - .44 volts
start reading. Vortexbuicks-etc.com has done wonders for me. Be a little picky about who touches your car. our cars require some special attn that the local mechanic may not be aware of. best thing is to learn things yourself to save you money! congrats on the new ride!

 

[BlackBandit]

I don't know what you've read so I'm just going to say it. That little screw on the side of the throttle body that looks like and idle adjust screw IS NOT AN IDLE ADJUST SCREW! If you've been playing with it you've mucked up your tps and iac settings and will need to reset both. Just so you know the idle is programmed in the chip.

 

[paulg]

That's what i said isnt it?

 

[BlackBandit]

That's what i said isnt it?

Yes and no. Your post was right on but did not specify that it would change the iac as well. I also wanted him to know that the idle adjust was in the chip. To someone that doesn't know that they might just assume that you could adjust the idle with that screw if you reset the TPS afterward. Basically just wanted to make sure everything was clear. You were my inspiration though!

 

[paulg]

youre right I left out some good info but I gave him the link with it! =)


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