2JZ-GE idle revs up and down in P or N
04-24-12, 02:02 AM
#1
Intermediate
Thread Starter
2JZ-GE idle revs up and down in P or N
Hi,
First i'd just wanted to clarify that i have a 1GS. I haven't been on the forums in a LOOOOONG time, and my first thought was to ask in the 1GS forums, but as soon as I get there, I see the "1GS is a ghost town" thread
. So I decided to try my luck here seeing they're both the same engine. If the mods want to move this back to the 1GS, that'll be ok too.
I did a quick search on the topic, but nothing pops up, so here goes. I hope someone can help me diagnose the problem.
Background info:
1994 GS300 2JZ-GE
- No major engine mods.
- Injen intake, Torque Master sparkplugs.
- Recent major mechanical issues fixed within the last 6 mos: Alternator, starter, timing belt, new battery, tensioner.
Problem:
So after I changed the starter on my car, our mechanic told us that our fuel pump might be going bad because the car had a hard time starting. We finally got the car running after a bit of coaxing, and it ran great for a few weeks. Come the weekend of my sisters wedding, the Lexus suddenly dies when we try to start it up. The car will start right up, but if the gas isn't being pressed, it'll just choke out. If I pressed the gas a little when I started it, it will keep running until the gas pedal is released again. Our mechanic looked at it for a bit and came to the conclusion that the idle speed control module was going bad. He took it out and cleaned it up a bit and put it back in. The car ran ok again, so we were able to drive it home.
The next morning, we tried to start the car again, but it choked out again right after. We stepped on the gas a little letting the engine warm up a bit, and the car was ok again after that. Throughout the day (while the engine was still warm), the car started right up, and never died after, but the next morning, the car would always die on the first few startups if the engine was cold. We took the car back to the mechanic, and he told us he couldn't reproduce the problem (he didn't hold the car til morning), but he did clean up a few of the other parts next to the idle speed control module. He also said he tweaked the idle up a notch to see if it helps.
We took the car back, and lo and behold, the very next morning we had the same problem. I decided to order another idle speed control module online which took a few days to get here. In the meantime, the we would warm up the car in the morning, and the rest of the day it drove fine.
The module finally gets here and I install it. Not having started up the car for 2 days prior, the car started right up and stayed on with a cold engine.
NOW...the car will idle at 2500-3000 rpms when you first start it, and it won't go down. I tried to adjust the idle lower via the hex screw + the nut on the throttle body, but when I turn the idle down, it will rev the engine up and down. Kind of like someone is stepping on the gas and letting off over and over again. I tried to get a balance before the high rpms & the up and down revving of the engine, but no go. It's either up & down revving, or a stable 3000 rpm idle.
I have no idea what to do next. I'm hoping someone has had some similar experiences so I know what step to take next. One of my friends suggested I reset the ECU by disconnecting the battery for 10-15 mins. I did that, and it's still the same.
Anyone have any ideas?
First i'd just wanted to clarify that i have a 1GS. I haven't been on the forums in a LOOOOONG time, and my first thought was to ask in the 1GS forums, but as soon as I get there, I see the "1GS is a ghost town" thread
. So I decided to try my luck here seeing they're both the same engine. If the mods want to move this back to the 1GS, that'll be ok too. I did a quick search on the topic, but nothing pops up, so here goes. I hope someone can help me diagnose the problem.
Background info:
1994 GS300 2JZ-GE
- No major engine mods.
- Injen intake, Torque Master sparkplugs.
- Recent major mechanical issues fixed within the last 6 mos: Alternator, starter, timing belt, new battery, tensioner.
Problem:
So after I changed the starter on my car, our mechanic told us that our fuel pump might be going bad because the car had a hard time starting. We finally got the car running after a bit of coaxing, and it ran great for a few weeks. Come the weekend of my sisters wedding, the Lexus suddenly dies when we try to start it up. The car will start right up, but if the gas isn't being pressed, it'll just choke out. If I pressed the gas a little when I started it, it will keep running until the gas pedal is released again. Our mechanic looked at it for a bit and came to the conclusion that the idle speed control module was going bad. He took it out and cleaned it up a bit and put it back in. The car ran ok again, so we were able to drive it home.
The next morning, we tried to start the car again, but it choked out again right after. We stepped on the gas a little letting the engine warm up a bit, and the car was ok again after that. Throughout the day (while the engine was still warm), the car started right up, and never died after, but the next morning, the car would always die on the first few startups if the engine was cold. We took the car back to the mechanic, and he told us he couldn't reproduce the problem (he didn't hold the car til morning), but he did clean up a few of the other parts next to the idle speed control module. He also said he tweaked the idle up a notch to see if it helps.
We took the car back, and lo and behold, the very next morning we had the same problem. I decided to order another idle speed control module online which took a few days to get here. In the meantime, the we would warm up the car in the morning, and the rest of the day it drove fine.
The module finally gets here and I install it. Not having started up the car for 2 days prior, the car started right up and stayed on with a cold engine.
NOW...the car will idle at 2500-3000 rpms when you first start it, and it won't go down. I tried to adjust the idle lower via the hex screw + the nut on the throttle body, but when I turn the idle down, it will rev the engine up and down. Kind of like someone is stepping on the gas and letting off over and over again. I tried to get a balance before the high rpms & the up and down revving of the engine, but no go. It's either up & down revving, or a stable 3000 rpm idle.
I have no idea what to do next. I'm hoping someone has had some similar experiences so I know what step to take next. One of my friends suggested I reset the ECU by disconnecting the battery for 10-15 mins. I did that, and it's still the same.
Anyone have any ideas?
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