The Oldsmobile Connection

bobshow · Joined: 26 Jun 2004 Posts: 51

hi new too this...have a 1987.3.8.v6 cuttless ceria olds..just had a new starter replaced and flexplate.i drove it home from shop.next morning I start it up and it idles hi.never slows down,and the check engine light is on.. turn car off..and restart idles good and check engine light is off,had it in shop and no codes present.. just replaced the cts ,,thanks for yor help...

88Ciera_SC · Joined: 10 Jun 2003 Posts: 199 Location: Columbus Ohio

whats "cts" stand for..
my car does just the opisite..

start car..runs fine for about 10minutes then 1 of 4 things usually happens.

1.runs fine.
2.stalls at idle with no check engine light.
3.check engine light comes on and then dies at idle.with no codes.
4.car will jerk and then will be a very noticable lack of power and check engine light comes on and dies at idle.
if i turn the key completely off then back on the check engine light will go out..

right now i have the idle cranked up and helps alil with the just plain dieing at idle problem but if light comes on i'm screwed.
also engine races when i first start it so i'm most likely going to turn the idle back down alil.

I'm not completely car stupid but this one has really got me.
evything points me in the direction of a computer problem.

OldsGuy · Joined: 16 Feb 2004 Posts: 269 Location: Lees Summit MO

If the flexplate was removed then that means the tranny was removed which means some coolant lines and wires had to be temporarily removed or at least re-positioned, right? I would check to make sure all the wiring harness is still correct and nothing is loose and the linkage to the tranny is correct. Being a newer model with a v6 I guess the tranny is some kind of 2004r right? I don't know what kind of kickdown it uses, the TH400 uses vacumm, the TH350 uses a mechanical, if yours uses a mechanical kickdown it may be binding with the carb linkage and holding the choke on high idle at first. This is just a stab in the dark as I am not as familiar with the newer engines. In '87 the V6s might have already had fuel injection. Just trying some ideas that come to mind.

bobshow · Joined: 26 Jun 2004 Posts: 51

cts.is coolint temp sensor

88delta88 · Joined: 09 Jun 2003 Posts: 2407 Location: Canada

88cierraSC,

Check engine light is on, idle is very high... Does it use a whole lot more fuel than before?

From what you say, when you turn your idle up, your problems lessen. Check out your TPS sensor. Same symptoms as mine had. The computer expects a certain voltage out of the throttle position sensor at idle, and if it doesnt see that voltage, the check engine light will come on, and the idle will shoot up, (simulates a 1/2 throttle environment just to get you home) and the car will run terrible, and use hellish amounts of fuel.

Its a relatively cheap part to replace. The computer wont flash check engine if the voltage is high enough, which would explain why it doesnt do it every time. Check that out.

If thats not the problem, try checking out your IAT (intake air temp sensor), apparently, when its not plugged in, or if it malfunctions, warm up will be greatly affected and may die at idle a lot.

Its too bad you dont have an ALDL dash computer... it will show you voltages real time for all these sensors!!! Even if there is no code, for example the TPS wont record an error code for you to retrieve, only will show an error while the check engine light is on, the computer will show exactly what triggered the light. Everyone build one of these, they are priceless on these late 80's fuel injected cars!

Erroneous Restrictionism! · Joined: 02 Jun 2004 Posts: 266

i have 3.8 as well and mine had an idle problem too. so i replaced the TPS
O2 and IAC and the idle dropped back to its normal 750-800 RPM range(was running at 2000-2200.....in gear) now that its fixed another problem arises. i was driving today and with no warning it just died. so at first i thought it was the alternator. but when i turned on the hazards they didnt work, not the radio,not the wipers, not even the trunk release worked but the headlights, fogs, interior worked so that ruled out the battery, so im sure that it is an ignition problem, somewhere in the column. maybe a relay or shorted wires. has anyone had a similar problem to verify my theory?