More problems, help!

scruffboy · 12-05-2006, 10:37 PM

Yeah Bill, I replaced it with one that looked exactly like it, same set up. The old one looked so coroded that I'm not sure it was really working, maybe just enough to keep the engine light off, I mean I saw no metal to metal contact on the broke one. Can I run without the temp sensor? Maybe I just need to have my idle adjusted, and then hook it back up. I'm just not sure. I don't know if this could mean anything, but I did not wait for the coolant to cool all the way down before I replaced it. Could putting it in without waiting long enough have destroyed it? Thanks Bill UK, I appreciate you responding.

Scruffboy

mrnickleye · 12-06-2006, 06:20 AM

The heat did not harm it. It sits in hot coolant. I suspect other problems.

"I" would first try disconnect the negative battery cable for a few minutes, to clear the ECU. Then I would hook it up and start the car. Normally you need to drive the car for a few city miles, and start and stop the engine a few times, let it idle a few minutes, etc.

Doing all this, the ECU re-learns. Normally after this, the idle settles down to 700-850rpm.

scruffboy · 12-06-2006, 12:47 PM

I had already done everything you mentioned. I disconectted the negative battery cable for a few minutes figuring that would clear the memory. I drove around in stop and go traffic several times. I raced the engine a little bit hoping that that would "settle it down", but no go. In the morning I have to hook it up to get it to turn over. Then I pull it out just enough so that there is no connection. The Check Engine light comes on, but the idle drops to 1,000. Could the fact that we are having a cold snap here have any bearing on this? It's been dipping into the upper 20's to low 30's overnight. Anyway, I have this really good "Ultra Copper" gasket maker and I used it to put the old one back together. This weekend I will swap it out and see what happens. If I can't resolve this issue, can I go to my own mechanic, or do I have to go to a Toyota dealer? I'm not used to cars with computers and diagnostic codes and such. Would my mechanic, who I trust and is very reasonable, (I found him by word of mouth) be able to hook this car up and find out what's wrong?

Thanks,

Scruffboy

Bill UK · 12-06-2006, 03:17 PM

It does sound like your new sender unit may have the wrong resistance values, did you obtain this from Toyota ?

scruffboy · 12-06-2006, 04:06 PM

I bought it at Autozone, and I was thinking about that also. Maybe I should have went to the Toyota dealer, but I was trying to save money. Today I went for a fairly long drive, with the unit un-hooked, and it drove smoothely, but on the way back I decided to connect it, figuring a long drive at decent speeds might have "knocked its memory back", kinda like what Mr.Nickleye was alluding to, but it went back to running all jerky and lopy. When I got in the driveway I started really revving the engine, red lining it. That got it to drop a little, it went from about 2,200 rpms down to about 1800 rpms, but that is still way off. How do you adjust the idle with an EFI engine anyway? Is there something mechanical you can do, or does it have to be hooked into a diagnostic machine? I have no experience with them.

Thanks for your help guys,

Scruffboy

mrnickleye · 12-07-2006, 04:37 AM

1) a good diagnostic technician can easily work on MKIIIs, and should be able to find the problem.

2) I to am thinking the new sensor may be the wrong one.

3) The idle is adjusted by the ECU, which looks at all the data from all the sensors. The ISC valve on the intake manifold is what 'actually' controls it.

4) perhaps there is some other cause to your high idle.

5) it is a 'one step at a time' process of elimination.

Bill UK · 12-07-2006, 01:24 PM

This looks interesting may be useful for future reference.

http://www.forum.mkiiisupra.net/showthread.php?t=12132&highlight=TPS

12-05-2006, 10:37 PM	#1
scruffboy walbro fp Join Date: Sep 2005 Location: Kearny, New Jersey, USA Posts: 427	The same Yeah Bill, I replaced it with one that looked exactly like it, same set up. The old one looked so coroded that I'm not sure it was really working, maybe just enough to keep the engine light off, I mean I saw no metal to metal contact on the broke one. Can I run without the temp sensor? Maybe I just need to have my idle adjusted, and then hook it back up. I'm just not sure. I don't know if this could mean anything, but I did not wait for the coolant to cool all the way down before I replaced it. Could putting it in without waiting long enough have destroyed it? Thanks Bill UK, I appreciate you responding. Scruffboy

12-06-2006, 06:20 AM	#2
mrnickleye 1000whp postwhore Join Date: Jun 2005 Location: Mojave Desert, Calif. Posts: 1,705	The heat did not harm it. It sits in hot coolant. I suspect other problems. "I" would first try disconnect the negative battery cable for a few minutes, to clear the ECU. Then I would hook it up and start the car. Normally you need to drive the car for a few city miles, and start and stop the engine a few times, let it idle a few minutes, etc. Doing all this, the ECU re-learns. Normally after this, the idle settles down to 700-850rpm. __________________ Had a Red 1989 N/A. Automatic. Sports Pkg. w/wing. TEMS, and some nice MODS. Sold to a friend 10/08/08.

12-06-2006, 12:47 PM	#3
scruffboy walbro fp Join Date: Sep 2005 Location: Kearny, New Jersey, USA Posts: 427	Hi Mr.Nickleye I had already done everything you mentioned. I disconectted the negative battery cable for a few minutes figuring that would clear the memory. I drove around in stop and go traffic several times. I raced the engine a little bit hoping that that would "settle it down", but no go. In the morning I have to hook it up to get it to turn over. Then I pull it out just enough so that there is no connection. The Check Engine light comes on, but the idle drops to 1,000. Could the fact that we are having a cold snap here have any bearing on this? It's been dipping into the upper 20's to low 30's overnight. Anyway, I have this really good "Ultra Copper" gasket maker and I used it to put the old one back together. This weekend I will swap it out and see what happens. If I can't resolve this issue, can I go to my own mechanic, or do I have to go to a Toyota dealer? I'm not used to cars with computers and diagnostic codes and such. Would my mechanic, who I trust and is very reasonable, (I found him by word of mouth) be able to hook this car up and find out what's wrong? Thanks, Scruffboy

12-06-2006, 04:06 PM	#5
scruffboy walbro fp Join Date: Sep 2005 Location: Kearny, New Jersey, USA Posts: 427	No! I bought it at Autozone, and I was thinking about that also. Maybe I should have went to the Toyota dealer, but I was trying to save money. Today I went for a fairly long drive, with the unit un-hooked, and it drove smoothely, but on the way back I decided to connect it, figuring a long drive at decent speeds might have "knocked its memory back", kinda like what Mr.Nickleye was alluding to, but it went back to running all jerky and lopy. When I got in the driveway I started really revving the engine, red lining it. That got it to drop a little, it went from about 2,200 rpms down to about 1800 rpms, but that is still way off. How do you adjust the idle with an EFI engine anyway? Is there something mechanical you can do, or does it have to be hooked into a diagnostic machine? I have no experience with them. Thanks for your help guys, Scruffboy

12-07-2006, 04:37 AM	#6
mrnickleye 1000whp postwhore Join Date: Jun 2005 Location: Mojave Desert, Calif. Posts: 1,705	1) a good diagnostic technician can easily work on MKIIIs, and should be able to find the problem. 2) I to am thinking the new sensor may be the wrong one. 3) The idle is adjusted by the ECU, which looks at all the data from all the sensors. The ISC valve on the intake manifold is what 'actually' controls it. 4) perhaps there is some other cause to your high idle. 5) it is a 'one step at a time' process of elimination. __________________ Had a Red 1989 N/A. Automatic. Sports Pkg. w/wing. TEMS, and some nice MODS. Sold to a friend 10/08/08.

12-06-2006, 03:17 PM	#4
Bill UK AEM EMS Join Date: Jul 2006 Location: UK Posts: 891	It does sound like your new sender unit may have the wrong resistance values, did you obtain this from Toyota ?

12-07-2006, 01:24 PM	#7
Bill UK AEM EMS Join Date: Jul 2006 Location: UK Posts: 891	This looks interesting may be useful for future reference. http://www.forum.mkiiisupra.net/showthread.php?t=12132&highlight=TPS

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