93 Metro - Could run better!

Hey everyone: 93 Metro/1.0L/MT/TB/CalCar/146K

Problem is a high idle which after a wait at a light will slowly start to return to normal. Also has a slight miss in 2nd & 3rd when rpm steady at maybe 2500. Very subtle - just enough to irritate.

History: Was working fine (minus a slight miss) and getting about 41 mpg. Suddenly began losing power. Disconnected cat at ex man and ran around block. Worked good so spliced in new universal cat from Arvin. This is when idle started going up.

Sprayed starting fluid in an effort to investigate vacuum leaks. Got a hit when I squirted the back of the EGR diaphram. Bought new one from dealer. Went to install and discovered bolts were loose. Pulled old EGR off and compared vacuum characteristics against the new EGR. Same-same. Installed new gasket and old EGR. Problem is I squirt the back of the EGR and engine starts racing! Couldn't find no other vacuum leaks.

Anyway, seemed to run better at first but 1 week later and idle is as I described above. Recent maintenance includes the above as well as plugs/wires/cap/rotor/new radiator. MPG's have dropped off to about 39.5. Not bad but - could be better. TIA, T.O.

think ony the automatics have the one mounted on firewall with screw. yours should be bolted to rear of intake manifolds just below throttle body. one hose will go to side of throttle body, other hose goes to air cleaner. you can try spraying cleaner through hose in air cleaner in case valve is gummed up or you can wait till it goes to low idle and unplug the wire going to it

Good gouge - thanks, fellas. T.O.

Installed new PCV and high idle problem seems to be fixed (or at least better). T.O.

Well - spoke to soon about the PCV. I swear it was running better - for about 2 days. But, high idle is back. Basically, I'll be cruising along until I come to a stop light. Idle remains high but slowly drops. By the time the light changes the idle is about normal. As soon as I take off, the cycle repeats itself.

on the back of the intake below the throttle body is a solenoid with 2 hoses and a wire going to it, if you wait for it to drop to low idle and unplug the wire it won't rev up like it was before. if that fixes it either solenoid yu unplugged is bad or has something sticking in it. you can try spraying carb cleaner done the hoses to unstick it

Performed test on solenoid - no joy. Idle problems same as before. Also checked TBI bolt torque - they're tight. Sprayed a lot more starting fluid and still no evidence of vacuum leak. I did notice one odd thing. Looking down into the TBI at idle, butterfly valve closed, there was gas funneling across the top of the valve. Never noticed that before. Don't know if that means anything.

Crvett69 - what is the name of the solenoid you mentioned above? After tinkering around some more, I unplugged it and the idle remained low. Last time I had it off I checked the hoses and they were unplugged. I'm going to go ahead and replace the solenoid. Oh, I'm an idiot. After reading in the book some more I discovered the fuel I noticed running across the choke plate was from the injector at the top of the TBI. For some reason I thought the injector was lower (don't have much experience with TBI). Thanks for your help.

Was feeling fairly confident about replacing the Idle Air Control Solenoid Valve (IAC) after the test I mentioned in the previous post. Had to go to the dealer for the part - $120 after taxes. Installed same and guess what, it didn't fix the problem.

I was reading in the Haynes and it speaks of an air valve on the side of the TBI. This valve allows additional air to bypass the throttle plate increasing idle. Once warm it allows the car to idle down. Problem is, even though there is a nice picture in the Hayes, I can't seem to locate it on the actual TBI. Going to go tear it apart now for a closer look.

Was feeling fairly confident about replacing the Idle Air Control Solenoid Valve (IAC) after the test I mentioned in the previous post. Had to go to the dealer for the part - $120 after taxes. Installed same and guess what, it didn't fix the problem.

I was reading in the Haynes and it speaks of an air valve on the side of the TBI. This valve allows additional air to bypass the throttle plate increasing idle. Once warm it allows the car to idle down. Problem is, even though there is a nice picture in the Hayes, I can't seem to locate it on the actual TBI. Going to go tear it apart now for a closer look.

My Chilton Manual says that "the Idle Air Control Valve is used on ported
fuel injection systems." p4-10. They even show a picture Fig 17.

That is not the Throttle Body System is it? Isn't that for the 4 cylinder,
1.3 L. engine, not the 3 cyl, 1.0 L engine...?

Am I wrong?

DoctorBill

Doc - thanks for the reply. Not sure but I would imagine you're correct. My Haynes doesn't specify which engine the air valve is associated with. I know I looked high and low on my TB and couldn't find anything that remotely resembles the illustration. Too bad to - it sounded just like the problem I have with the idle. Have a nice holiday. T.O.

Another problem. Took car in for smog. Technician stated I had high idle (oh, really!). Also that the ignition timing was off. When I hooked up timing light later it seemed to be hitting at 5BTDC (average) but drifted in a range from about 2 to 7BTDC. Question: am I missing something in the timing check sequence? Seems as if I recall that something must also be done rather than simply hooking up the timing light (although the Haynes doesn't mention anything). I did verify the engine timing - all marks aligned per the manual, #1 cyl TDC on the exhaust stroke, rotor pointing at #1 tower/wire. Also, do I have to fix the idle problem first before I set the ignition timing?

The saga continues; Replaced all the vacuum lines this weekend. No Joy - still have high idle. I think I'll be looking at compression test and replacing fuel filter next. On a happier note, I installed a new heater core this weekend. Finally, I have heat. Although after the job was compete I wasn't sure if the heat was worth it! I've done heater cores on other vehicles and you usually have to loosen the dash but can manage to get it out somehow. Not on the Metro. Had to take the whole dash out - what a pain.