High Idle
12-07-11, 08:36 PM
#33
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My 92 sc4 was given me some problems monday. Had it towed to local shop...ran fine for them. Got it home with it running fine. Was going to work and it shut down on me. Got it going and it idled around 1500rpm.
Had no power when tried to take off when I pressed the gas, so just let it pull itself to the repair shop (hit 25mph without touching the gas) so I could show the guys what was up. They didnt know what was up with it, did have a bad smell at the exhaust. The shop told me to find a shop for import cars lol. Could it be idling high because of too much back pressure from a catalytic converter getting clogged up. My idle issues started when the car got warmed up by the way.
Also just put a new battery on it monday by the way (750 cold cranking amps). Just tried to start the car, but wouldnt even try to do it so I think ive got a power drain somewhere on top of my problems.
Had no power when tried to take off when I pressed the gas, so just let it pull itself to the repair shop (hit 25mph without touching the gas) so I could show the guys what was up. They didnt know what was up with it, did have a bad smell at the exhaust. The shop told me to find a shop for import cars lol. Could it be idling high because of too much back pressure from a catalytic converter getting clogged up. My idle issues started when the car got warmed up by the way.
Also just put a new battery on it monday by the way (750 cold cranking amps). Just tried to start the car, but wouldnt even try to do it so I think ive got a power drain somewhere on top of my problems.
12-07-11, 09:25 PM
#34
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You need to check the ECU out honestly it sounds like. Mine was running really rich, and the transmission stopped going into overdrive (shortly before I had the above idle issues). The Vehicle Speed Sensor and EFI Main Relay capacitors were done.
12-07-11, 09:50 PM
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It goes on spells of doing the idle issue. Fuel pump works (could hear it humming when I tried to start my car earlier.) Ive read that about the problems a bad fuel ecu can cause and kinda sounds like whats going on. Gonna try the cats, then go to the ecu option.
12-08-11, 11:15 AM
#36
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Started my sc4 earlier and just let it idle and warm up. Ran fine till it did finally warm up, then spit and sputtered till it died. It did not overheat. Im thinking it has to due with exhaust back pressure, but it seems like its getting plenty of flow through the exhaust system.
Also, battery wasnt able to crank over the 1uz because.it seemed like it wasnt charged. Its a new battery. And when I disconnected the alternator, car didnt die. So alternator can be ruled out. So gotta have a bad ground wire somewhere right?
Also, battery wasnt able to crank over the 1uz because.it seemed like it wasnt charged. Its a new battery. And when I disconnected the alternator, car didnt die. So alternator can be ruled out. So gotta have a bad ground wire somewhere right?
03-11-14, 08:32 AM
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I'm going to soon, along with the clutch pedal, etc - I may have a five speed swap waiting to go whenever boost comes along and I grenade the stock transmission (if I even wait that long).
--
Back to the subject at hand, I'm pretty sure I can now tell you what the problem is.
A ground...
Yes, the left main ground that splits off into four wires on the Lower Intake Manifold was corroded from the water.
I assumed the TPS was the fix, but that was until I got home and "touched" the TPS harness and I noticed it was tight against the ground. That's when the idle shot up, and I took off the bolt, cleaned it, and put it back on - idle drops.
I should have seen this from a mile away, it smelled like it was running rich, the idle was high, the IAC worked (sometimes) - all signals of a ground failure.
D'oh
If anyone gets bored and wants to get out a digital meter and check the Ohms to each ground point I would be forever grateful. I wonder if people realize the importance of these whenever they move stuff around / modify the engine bay. The rear strap on the head that goes to the firewall is LAYING on the transmission (this weekend I'll fix that one).
Total Amount Wasted:
$50 Carb Cleaner & Elec Cleaner (I went through a LOT - cleaning up the engine bay too).
$50 IAC - hasn't even gotten here yet
$175 Parts - Full Throttle Body, IAC, TPS, etc from Junk Yard Car
1 Week Of Absolute Head Scratching & Banging - Priceless
--
Back to the subject at hand, I'm pretty sure I can now tell you what the problem is.
A ground...
Yes, the left main ground that splits off into four wires on the Lower Intake Manifold was corroded from the water.
I assumed the TPS was the fix, but that was until I got home and "touched" the TPS harness and I noticed it was tight against the ground. That's when the idle shot up, and I took off the bolt, cleaned it, and put it back on - idle drops.
I should have seen this from a mile away, it smelled like it was running rich, the idle was high, the IAC worked (sometimes) - all signals of a ground failure.
D'oh
If anyone gets bored and wants to get out a digital meter and check the Ohms to each ground point I would be forever grateful. I wonder if people realize the importance of these whenever they move stuff around / modify the engine bay. The rear strap on the head that goes to the firewall is LAYING on the transmission (this weekend I'll fix that one).
Total Amount Wasted:
$50 Carb Cleaner & Elec Cleaner (I went through a LOT - cleaning up the engine bay too).
$50 IAC - hasn't even gotten here yet
$175 Parts - Full Throttle Body, IAC, TPS, etc from Junk Yard Car
1 Week Of Absolute Head Scratching & Banging - Priceless
First time ever posting..im having exact same issue replaced my throttle body gasket after i did valve cover gaskets n all vac leaks are gone.. can u be kind enough to show a picture of these ground wires that your talking about? Thanks
03-11-14, 09:31 AM
#38
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I'll take one when I get home. The Lexus is in the garage with a busted quarter so I'm driving my Tundra around right now.
03-11-14, 10:28 AM
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Yea i saw the dates on these posts i was hoping people still got on lol but i have to do emissions this month and im trying get this sorted out before i take it.. i preciate the reply man
03-11-14, 09:46 PM
#40
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The right hand side is the original location. As you can see I accidentally over torqued it one day messing with it and snapped the bolt off in there and just haven't had time to back it out (so I moved it to the left hand side).
Disregard the dirty state, the car is up for the season due to the lady rear ending the car.
03-12-14, 09:44 AM
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The right hand side is the original location. As you can see I accidentally over torqued it one day messing with it and snapped the bolt off in there and just haven't had time to back it out (so I moved it to the left hand side).
Disregard the dirty state, the car is up for the season due to the lady rear ending the car.
(( sorry to hear that man... so first off i had vaccume leak from throttle body gasket got new one n changed it started it up n when it got warm it idled perfect 1k.. after i took it for a drive it jumped up to 1.2k. I cleaned the grounds u pointed at n ran another small ground to it just in case n nothing.. it still idles at 1.5k occasionally jumping down to 1.2k... idk if there is another ground somewhere :\
03-20-19, 07:58 AM
#42
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