Stalls at idle

1990 TOYOTA PICKUP
150,000 MILES • 6 CYL • 4WD • MANUAL
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DENNYT
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Hi , my truck starts and runs in colder temps( 30-40 degrees) for about 5-20 mins then the engine light comes on and the engine dies. Theres also black smoke out of the exhaust before it dies. On warmer days,15 50 degrees and up it may run for 1-5 mins then dies. I've spent 1500 dollars on two mechanics and neither one could figure it out. The problem occured slowy over a period of months and now happens quickly and is predictable. I would appreciate any help on this matter. Thanks Denny
Oct 6, 2009 at 4:45 PM
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SERVICE WRITER
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The black smoke is a sign of a rich condition.


What codes are present in the computer?

What work has been done so far?

How long does it take to restart?

Was the thermostat operation checked? A stuck t-stat can cause a rich condition as it takes too long to heat up the engine causing a rich condition.
Oct 7, 2009 at 8:01 AM
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DENNYT
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the trouble code was code supposedly code 42 ( i don't know if the mechanic knew what he was doing)the starter relay switch was replaced the thermostate was replaced the fan clutch replaced. the muffler replaced. the engine will restart right away when I pump the gas, but usually die's right away.
Oct 7, 2009 at 11:17 AM
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Pump the gas? This one is carbureted I assume?..
Get the codes read and post them.
Oct 7, 2009 at 8:03 PM
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DENNYT
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No it's not carborated and the only code i gave you is the only code a mechanic could conger up.....code 42 which has to do with the odiomiter cable which was also replaced! But on a different note, I took a air hose and blew some dirt and such off the engine and it seem to run longer and if I pull on the throtle cable to increese the idlel it does'nt die out as soon as it use to, but the black smoke still comes out of the exhaust pipe. I also checked the distributor cap today and it seemed ok. I don't or won't want to take it to any mechanics cause they cant seem to find any more codes(i can't drive it very far) so with this information and the other information I emailed you maybe somebody can begin to make some sence of this problem. Thanks Denny
Oct 7, 2009 at 10:43 PM
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First thing I would check is the CTS since you are unable to verify codes. A bad cts can cause a rich condition.


https://www.2carpros.com/forum/automotive_pictures/30961_toycts_1.jpg


https://www.2carpros.com/forum/automotive_pictures/30961_toycts1_1.jpg


https://www.2carpros.com/forum/automotive_pictures/30961_toycts2_1.jpg

Is this sensor in spec?
Oct 8, 2009 at 6:19 AM
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DENNYT
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i'll try to check it out today. thanks
Oct 8, 2009 at 9:20 AM
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DENNYT
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I can't seem to locate this sensor I have the 3.0 6cylinder fuel injected motor. Can you tell me where that cts is located or send me a better diagram. I would really appreciate it. Thanks Denny
Oct 8, 2009 at 9:55 PM
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SERVICE WRITER
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It is in the coolant passage at the rear of the intake manifold.


https://www.2carpros.com/forum/automotive_pictures/30961_toyloc_1.jpg


https://www.2carpros.com/forum/automotive_pictures/30961_toyloc1_1.jpg


https://www.2carpros.com/forum/automotive_pictures/30961_toyloc2_1.jpg

Check for wire colors if you aren't sure. Getting good information thatis clear in the industry isn't always available.
Oct 9, 2009 at 6:00 AM
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DENNYT
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I replaced the collant temp sensor and did'nt sove the problem....what's next? Thanks Denny
Oct 9, 2009 at 8:46 PM
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Unplug the mass air flow sensor and see how it changes the symptoms. Also check the air snorkel for any cracks that may be allowing unmetered air.
Oct 10, 2009 at 5:55 AM
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DENNYT
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My truck is the3vz-e engine the book I'm looking at has a volume air flow metet(vaf) on the next page it shows a mass air flow meter (maf) but it's for different enging models than my truck. can you send me a diagram of this sensor? and where is the air snorlel?. Thanks Denny
Oct 10, 2009 at 9:59 AM
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https://www.2carpros.com/forum/automotive_pictures/30961_toymaf_1.jpg


https://www.2carpros.com/forum/automotive_pictures/30961_toymaf1_1.jpg

Oct 11, 2009 at 6:49 AM
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DENNYT
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Hi, I need to get an ome meter but i figued out how to do the codes and this is what I got. code 24,31, and 41 hope this helps... hope were are getting close!. Thanks for your help.Deny
Oct 12, 2009 at 2:58 PM
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we are getting close
air intake temp sensopr, mass air flow and throttle position sensors are the fault code circuits.

I'll update later.
Oct 12, 2009 at 4:11 PM
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Codes 24 and 31 fall under the same test procedure. IF this were mine, I would get some electrical cleaner spray and clean the mass air flow meter and the air temp sensor. If symptoms still exist I can post a troubleshooting chart for the code. I expect these two codes to be related. For the code 41 the tps, there is 3 charts. Run through this one first.


https://www.2carpros.com/forum/automotive_pictures/30961_toy41_1.jpg


https://www.2carpros.com/forum/automotive_pictures/30961_toy41a_1.jpg

Oct 13, 2009 at 5:37 AM
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DENNYT
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Hi I just replaced the throttle position sensor and that did'nt change things so I'm down to the air flow meter and the ecm. the air flow meter seems to test ok with the ohm meter so could you tell me how to test the ecm? also the temp gauge seems to stay cool for longer that it should ex. the engine runs for about six minutes and insteed of moving to about 1/4 up the temp gauge the needle stays right at the "c" for cold mark on the gauge. I've replaced the enging collant temp sensor also. Thanks for you help. Denny
Oct 20, 2009 at 10:36 AM
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DENNYT
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I figured out how to reset the ecm and the new codes are 24,31,32 and 41 I'm not sure if I'm testing the volume air flow meter correctly with the ohm meter.Thanks. Denny
Oct 20, 2009 at 11:07 AM
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Denny, did you unplug the MAF and see how the perfomance changed?


https://www.2carpros.com/forum/automotive_pictures/30961_af_1.jpg

Oct 20, 2009 at 4:14 PM
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DENNYT
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yes i did unplug the maf and the engine died. I don't know how to test the maf with the ohm meter, do I unplug it fron the electerical connecter ? I'm not sure how to do this step. Thanks Denny and thankd for hanging in there with me!
Oct 23, 2009 at 9:15 AM
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Un plug it and check the resistance with your ohm-meter on the terminals noted. Move the measuring plate....(throttle plate, I believe ). The resistance should fall between the value on the chart.


https://www.2carpros.com/forum/automotive_pictures/30961_30961_toymaf1_1_1.jpg


https://www.2carpros.com/forum/automotive_pictures/30961_30961_toymaf1_2_1.jpg

Oct 23, 2009 at 11:29 AM