Help, IAC Valve problem
08-23-17, 03:14 PM
#31
Driver School Candidate
Alaskan and Spartan...this kind of sounds like my problem. I have a ow idle and rough idle and when i hit the gas she falls flat on her face. I replaced the ECU and nothing changed. right now I have the back seat out ready to replace the fuel pump.....but could it be a faulty coil insted? Thanks for any help.
Trey
Trey
08-24-17, 11:23 PM
#32
Intermediate
Thread Starter
Alaskan and Spartan...this kind of sounds like my problem. I have a ow idle and rough idle and when i hit the gas she falls flat on her face. I replaced the ECU and nothing changed. right now I have the back seat out ready to replace the fuel pump.....but could it be a faulty coil insted? Thanks for any help.
Trey
Trey
08-24-17, 11:46 PM
#33
Intermediate
Thread Starter
One more thing i forgot to tell. Turn your car keys to the on position, unplug both coil harnesses and test the wires of both coil with continuity tester tool to make sure that there is current coming to both coils.
08-26-17, 05:21 AM
#34
I just got my ECU back yesterday and I installed it, there is a performance difference for the positive but the issue came back, it's not as bad and does run better, but the issue remains.
Here is what my current line of thinking is...
Faulty fuel pump (can get an entire Denso pump and assembly kit for $89 USD)
Faulty fuel pump resistor
I am going to replace the fuel filter anyway, it's still the factory one and it's 25 years old with 86,500 on it, I prefer to replace them every 50K miles or 10 years, see YouTube videos on this showing the differences in filtered fuel with an old one with 60K miles on it.
Faulty MAF or Dirty MAF, if faulty would need to replace
For those interested or have questions about my ECU replacement, it was repaired by LSCowboyLS, the same one from these forums, he used Yamae's instructions on proper Japanese low esr high ripple capacitors, he is very knowledgeable on the ECU issues plaguing our cars.
As for my reasoning behind my thoughts...
When "cold" the engine runs perfectly, idles at around 750 RPM, as it warms up it drops to around 350 RPM, once at running temperature and or 20 minutes in (I did a test drive around my neighborhood for 3 miles, and idled in my driveway for 7 minutes) it starts to have issues that get worse the longer the car is on, until it does not want to work anymore.
I am thinking it's the fuel pump, and I want to replace the fuel filter anyway, the cost for a new one is not that bad, and mine is still the factory one at 25 years old.
Here is what my current line of thinking is...
Faulty fuel pump (can get an entire Denso pump and assembly kit for $89 USD)
Faulty fuel pump resistor
I am going to replace the fuel filter anyway, it's still the factory one and it's 25 years old with 86,500 on it, I prefer to replace them every 50K miles or 10 years, see YouTube videos on this showing the differences in filtered fuel with an old one with 60K miles on it.
Faulty MAF or Dirty MAF, if faulty would need to replace
For those interested or have questions about my ECU replacement, it was repaired by LSCowboyLS, the same one from these forums, he used Yamae's instructions on proper Japanese low esr high ripple capacitors, he is very knowledgeable on the ECU issues plaguing our cars.
As for my reasoning behind my thoughts...
When "cold" the engine runs perfectly, idles at around 750 RPM, as it warms up it drops to around 350 RPM, once at running temperature and or 20 minutes in (I did a test drive around my neighborhood for 3 miles, and idled in my driveway for 7 minutes) it starts to have issues that get worse the longer the car is on, until it does not want to work anymore.
I am thinking it's the fuel pump, and I want to replace the fuel filter anyway, the cost for a new one is not that bad, and mine is still the factory one at 25 years old.
Last edited by Spartan536; 08-26-17 at 05:24 AM.
08-26-17, 09:47 AM
#35
Intermediate
Thread Starter
Wait a second before you spend more money on unnecessary things that u actually don't need to replace on car. The easiest way to check MAF is, let the car warm up and when it reach optimal temperature for driving, unplug MAF if the car shuts off that would mean your MAF is working fine. I had MAF problem last winter, on cold start it use to idle fine but after warming up, it would start stalling. After replacing MAF that problem went away.
08-26-17, 10:32 AM
#37
Wait a second before you spend more money on unnecessary things that u actually don't need to replace on car. The easiest way to check MAF is, let the car warm up and when it reach optimal temperature for driving, unplug MAF if the car shuts off that would mean your MAF is working fine. I had MAF problem last winter, on cold start it use to idle fine but after warming up, it would start stalling. After replacing MAF that problem went away.
I thought if you unplugged your MAF the ECM would go into "limp home mode" which is a default mapping for AFM?
08-26-17, 10:46 AM
#38
Intermediate
Thread Starter
The orthodox way of testing AFM is with multi-meter. I have gone through hell because of faulty AFM. I am going to attach PDF file download it and read it. This pdf will explain how to test it with multi-meter. The easy way to test AFM is, once the car reach running temperature, unplug the AFM if the car don't shut off and it is still running and having rough idle that is the sign of bad AFM. But to be 100% sure, use multimeter for testing MAF/AFM.
08-27-17, 04:07 AM
#40
I just did that MAF test, got it to operating temp, and unplugged the MAF with the car running, car kept running.
Also my climate control unit (the thing with all the little A/C buttons on it) randomly turns on and off, and it's literally random. I had it work flawlessly for 1 week then just turn off, back on, turn off, back on, turn off back on, ect...
Let me explain this so there is no confusion...
1. I am NOT talking about the A/C compressor
2. I am NOT talking about it not blowing cold air, when it's on it works and will put Cairo in icicles (I live in FL, might as well be Cairo).
3. I am referring to the actual climate control unit itself, the clock always works no matter what, it's just the A/C controls turn on and off.
What have I done?
1. Sent Climate Control Unit to Tanin Auto Electronix for service and upgrade, when they got it on their test bench they said there were no issues, and I had them change some of the LED's to White (kept the indicators to OEM green).
2. Sent my ECM out to LSCowboyLS, this is a brand new rebuilt ECU, rebuilt correctly as per Yamae's instructions by an ex-NASA engineer, his reputation on here is stellar (pun intended).
3. My mechanic said the system has a full charge since he last filled it (when I bought the car), this was over 6 months ago, and he put a dye in the system, was unable to detect a leak, the recent diagnostic/check up was as of 2 weeks ago.
I will attempt to get some video of the issue if my current clarifications are not up to par.
1 thing to note is that I did have the A/C / Radio fuse blow before (this was a couple of months ago), I replaced it with the correct Japanese fuze of the correct amperage according to my owners manual, since then no blown fuses.
Any ideas?
Also my climate control unit (the thing with all the little A/C buttons on it) randomly turns on and off, and it's literally random. I had it work flawlessly for 1 week then just turn off, back on, turn off, back on, turn off back on, ect...
Let me explain this so there is no confusion...
1. I am NOT talking about the A/C compressor
2. I am NOT talking about it not blowing cold air, when it's on it works and will put Cairo in icicles (I live in FL, might as well be Cairo).
3. I am referring to the actual climate control unit itself, the clock always works no matter what, it's just the A/C controls turn on and off.
What have I done?
1. Sent Climate Control Unit to Tanin Auto Electronix for service and upgrade, when they got it on their test bench they said there were no issues, and I had them change some of the LED's to White (kept the indicators to OEM green).
2. Sent my ECM out to LSCowboyLS, this is a brand new rebuilt ECU, rebuilt correctly as per Yamae's instructions by an ex-NASA engineer, his reputation on here is stellar (pun intended).
3. My mechanic said the system has a full charge since he last filled it (when I bought the car), this was over 6 months ago, and he put a dye in the system, was unable to detect a leak, the recent diagnostic/check up was as of 2 weeks ago.
I will attempt to get some video of the issue if my current clarifications are not up to par.
1 thing to note is that I did have the A/C / Radio fuse blow before (this was a couple of months ago), I replaced it with the correct Japanese fuze of the correct amperage according to my owners manual, since then no blown fuses.
Any ideas?
Last edited by Spartan536; 08-27-17 at 04:17 AM.
08-27-17, 05:37 AM
#41
I just got my ECU back yesterday and I installed it, there is a performance difference for the positive but the issue came back, it's not as bad and does run better, but the issue remains.
Here is what my current line of thinking is...
Faulty fuel pump (can get an entire Denso pump and assembly kit for $89 USD)
Faulty fuel pump resistor
I am going to replace the fuel filter anyway, it's still the factory one and it's 25 years old with 86,500 on it, I prefer to replace them every 50K miles or 10 years, see YouTube videos on this showing the differences in filtered fuel with an old one with 60K miles on it.
Faulty MAF or Dirty MAF, if faulty would need to replace
For those interested or have questions about my ECU replacement, it was repaired by LSCowboyLS, the same one from these forums, he used Yamae's instructions on proper Japanese low esr high ripple capacitors, he is very knowledgeable on the ECU issues plaguing our cars.
As for my reasoning behind my thoughts...
When "cold" the engine runs perfectly, idles at around 750 RPM, as it warms up it drops to around 350 RPM, once at running temperature and or 20 minutes in (I did a test drive around my neighborhood for 3 miles, and idled in my driveway for 7 minutes) it starts to have issues that get worse the longer the car is on, until it does not want to work anymore.
I am thinking it's the fuel pump, and I want to replace the fuel filter anyway, the cost for a new one is not that bad, and mine is still the factory one at 25 years old.
Here is what my current line of thinking is...
Faulty fuel pump (can get an entire Denso pump and assembly kit for $89 USD)
Faulty fuel pump resistor
I am going to replace the fuel filter anyway, it's still the factory one and it's 25 years old with 86,500 on it, I prefer to replace them every 50K miles or 10 years, see YouTube videos on this showing the differences in filtered fuel with an old one with 60K miles on it.
Faulty MAF or Dirty MAF, if faulty would need to replace
For those interested or have questions about my ECU replacement, it was repaired by LSCowboyLS, the same one from these forums, he used Yamae's instructions on proper Japanese low esr high ripple capacitors, he is very knowledgeable on the ECU issues plaguing our cars.
As for my reasoning behind my thoughts...
When "cold" the engine runs perfectly, idles at around 750 RPM, as it warms up it drops to around 350 RPM, once at running temperature and or 20 minutes in (I did a test drive around my neighborhood for 3 miles, and idled in my driveway for 7 minutes) it starts to have issues that get worse the longer the car is on, until it does not want to work anymore.
I am thinking it's the fuel pump, and I want to replace the fuel filter anyway, the cost for a new one is not that bad, and mine is still the factory one at 25 years old.
08-27-17, 12:03 PM
#42
Intermediate
Thread Starter
I just did that MAF test, got it to operating temp, and unplugged the MAF with the car running, car kept running.
Also my climate control unit (the thing with all the little A/C buttons on it) randomly turns on and off, and it's literally random. I had it work flawlessly for 1 week then just turn off, back on, turn off, back on, turn off back on, ect...
Let me explain this so there is no confusion...
1. I am NOT talking about the A/C compressor
2. I am NOT talking about it not blowing cold air, when it's on it works and will put Cairo in icicles (I live in FL, might as well be Cairo).
3. I am referring to the actual climate control unit itself, the clock always works no matter what, it's just the A/C controls turn on and off.
What have I done?
1. Sent Climate Control Unit to Tanin Auto Electronix for service and upgrade, when they got it on their test bench they said there were no issues, and I had them change some of the LED's to White (kept the indicators to OEM green).
2. Sent my ECM out to LSCowboyLS, this is a brand new rebuilt ECU, rebuilt correctly as per Yamae's instructions by an ex-NASA engineer, his reputation on here is stellar (pun intended).
3. My mechanic said the system has a full charge since he last filled it (when I bought the car), this was over 6 months ago, and he put a dye in the system, was unable to detect a leak, the recent diagnostic/check up was as of 2 weeks ago.
I will attempt to get some video of the issue if my current clarifications are not up to par.
1 thing to note is that I did have the A/C / Radio fuse blow before (this was a couple of months ago), I replaced it with the correct Japanese fuze of the correct amperage according to my owners manual, since then no blown fuses.
Any ideas?
Also my climate control unit (the thing with all the little A/C buttons on it) randomly turns on and off, and it's literally random. I had it work flawlessly for 1 week then just turn off, back on, turn off, back on, turn off back on, ect...
Let me explain this so there is no confusion...
1. I am NOT talking about the A/C compressor
2. I am NOT talking about it not blowing cold air, when it's on it works and will put Cairo in icicles (I live in FL, might as well be Cairo).
3. I am referring to the actual climate control unit itself, the clock always works no matter what, it's just the A/C controls turn on and off.
What have I done?
1. Sent Climate Control Unit to Tanin Auto Electronix for service and upgrade, when they got it on their test bench they said there were no issues, and I had them change some of the LED's to White (kept the indicators to OEM green).
2. Sent my ECM out to LSCowboyLS, this is a brand new rebuilt ECU, rebuilt correctly as per Yamae's instructions by an ex-NASA engineer, his reputation on here is stellar (pun intended).
3. My mechanic said the system has a full charge since he last filled it (when I bought the car), this was over 6 months ago, and he put a dye in the system, was unable to detect a leak, the recent diagnostic/check up was as of 2 weeks ago.
I will attempt to get some video of the issue if my current clarifications are not up to par.
1 thing to note is that I did have the A/C / Radio fuse blow before (this was a couple of months ago), I replaced it with the correct Japanese fuze of the correct amperage according to my owners manual, since then no blown fuses.
Any ideas?
For AFM get a digital Multimeter from Walmart or radio shack. Don't buy a high end multi meter buy one that is not more than 20 bucks. Mulitimeter is always handy and good to have one in toolbox.
Using multimeter check the resistance of AFM as described in pdf that I uploaded to this thread. For instance If the temperature in florida is 60 degree Fahrenheit, it's resistance should be between 2 to 3 ohms.
Read that table carefully which explains the resistance of the AFM based on the temperature around you. If you don't understand what I am talking about. I can make a quick video showing how to check the resistance and send it to you. If the resistance is within the range then don't waste money on AFM, if not buy used AFM from ebay which is around 20 to 40 buck based on what seller you buy it from.
08-27-17, 03:08 PM
#43
For the climate control buy one with busted display from ebay and try it, If it fixes your A/C problem that would be great. If not, you can simply return it to the seller from whom you purchased it or sell it yourself on eBay. Changing busted clock display is piece of cake. I have done mine and it cost me 30 bucks for parts, I didn't send it to anyone to replace the display for me, I did it myself.
For AFM get a digital Multimeter from Walmart or radio shack. Don't buy a high end multi meter buy one that is not more than 20 bucks. Mulitimeter is always handy and good to have one in toolbox.
Using multimeter check the resistance of AFM as described in pdf that I uploaded to this thread. For instance If the temperature in florida is 60 degree Fahrenheit, it's resistance should be between 2 to 3 ohms.
Read that table carefully which explains the resistance of the AFM based on the temperature around you. If you don't understand what I am talking about. I can make a quick video showing how to check the resistance and send it to you. If the resistance is within the range then don't waste money on AFM, if not buy used AFM from ebay which is around 20 to 40 buck based on what seller you buy it from.
For AFM get a digital Multimeter from Walmart or radio shack. Don't buy a high end multi meter buy one that is not more than 20 bucks. Mulitimeter is always handy and good to have one in toolbox.
Using multimeter check the resistance of AFM as described in pdf that I uploaded to this thread. For instance If the temperature in florida is 60 degree Fahrenheit, it's resistance should be between 2 to 3 ohms.
Read that table carefully which explains the resistance of the AFM based on the temperature around you. If you don't understand what I am talking about. I can make a quick video showing how to check the resistance and send it to you. If the resistance is within the range then don't waste money on AFM, if not buy used AFM from ebay which is around 20 to 40 buck based on what seller you buy it from.
My issue is that my A/C system will randomly turn on and off entirely but the clock always works. When the unit is on everything works perfectly.
08-27-17, 04:12 PM
#44
Intermediate
Thread Starter
Climate control unit I believe has sensor inside that tells the A/C temperature. What I think is that sensor has some problem and sending false info to the A/C due to which A/C turns on and off. Have you had problem with the AC before rebuilding your climate control?