Hard time starting the engine up?

Tiny
SARGON KHABEER
  • MEMBER
  • 17 POSTS
So I did some research and found out that only denso sensors are good with Toyota. The new maf was purchased from advance auto. I scanned the live data and the IAT was reading 132 when the temp outside was only 83. So took the new one out and put the old one in, IAT read 100. But gave me MAF code. Also the ECT was reading 199. Here are some pix of the live data. I'm thinking about getting a denso maf
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Friday, June 17th, 2016 AT 6:09 PM
Tiny
SATURNTECH9
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The coolant temp read 199 but what was the actual coolant temp?Sounds lie you have to do something about the maf if the iat is reading that far off.
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Saturday, June 18th, 2016 AT 12:36 AM
Tiny
SARGON KHABEER
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How would I get the actual coolant temp compared to the scanner reading?
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Saturday, June 18th, 2016 AT 3:07 AM
Tiny
SATURNTECH9
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With a infrared temp gun I usually measure where the top radiator hose goes into the head. Within 10 degrees of what computer says.
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Saturday, June 18th, 2016 AT 7:18 AM
Tiny
SARGON KHABEER
  • MEMBER
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Update. So I cleaned the maf and tested it with a multimeter and it's all good and car starts right a away with no problem. I still have the p0171 code and on the ready page on the scanner, everything has a green check mark except the cat and o2 sensor with have red x mark. Could that be causing the p0171? The upstream o2 sensor is good and new. Could the downstream o2 sensor be causing this?
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Tuesday, June 28th, 2016 AT 12:11 PM
Tiny
SATURNTECH9
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The down stream o2 sensor monitors the health of the cat. By comparison of the upstream o2 readings verus the downstream o2 sensor readings.I would say ove 90 percent of the cars I have seen with a code p0171 have been caused by a vacuum leak somewhere.
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Tuesday, June 28th, 2016 AT 12:27 PM
Tiny
SARGON KHABEER
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So then do you suggest that the vacuum leak or p0171 is causing the cat and o2 sensor to not read ready?
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Tuesday, June 28th, 2016 AT 12:52 PM
Tiny
SATURNTECH9
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The o2 sensor is effected so that could effect the cat from being ready since it has to use the o2 sensor readings to tell the computer how its working.
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Tuesday, June 28th, 2016 AT 1:03 PM
Tiny
SARGON KHABEER
  • MEMBER
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Ok so I put a new maf sensor and still the same. Did a vacuum leak test and nothing. But, I put my hand under the catalytic converter and there is hot air coming out from a very small hole at the front side of the converter. Not the joints. Could that be causing the problem since the scanner showes cat and o2 sensor not ready?
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Saturday, July 2nd, 2016 AT 5:17 PM
Tiny
SATURNTECH9
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No that won't set a lean code the upstream o2 sensor monitors that. From what I saw intake manifold leak number one by far and second place is mass air flow sensor and O2 sensor is way down on the list for causing that code.
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Saturday, July 2nd, 2016 AT 6:12 PM
Tiny
JEREMY STONE
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Did you ever get this resolved? Having similar symptoms with a 2007 Camry - P0171 code running very lean. 45% LTFT. It won't start when engine is hot until it cools off. Have done smoke tests, intake manifold gasket, valve cover gasket, plugs, fuel injector service, MAF, upstream O2, and a number of other things. Fuel pressure and crank sensor next I guess.
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Tuesday, January 3rd, 2017 AT 8:23 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
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Hey JEREMY,

This sounds like a weak fuel pump, if there is a filter replace that first, if not I would suspect the fuel pump int he tank.

Do a fuel pressure test first to make sure here is a guide that will show you what you are in for.

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Best, Ken
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Saturday, January 7th, 2017 AT 11:50 AM
Tiny
ASHRAF_AK
  • MEMBER
  • 6 POSTS
  • 2005 TOYOTA COROLLA
  • 4 CYL
  • 2WD
  • MANUAL
  • 170,000 MILES
Very hard to start, some time 3 or 4 times need to try but some time starting smoothly
I checked pugs all are OK
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Friday, October 16th, 2020 AT 10:04 AM (Merged)
Tiny
RASMATAZ
  • MECHANIC
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Check fuel pressure and coolant temperature sensor then comeback
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+2
Friday, October 16th, 2020 AT 10:04 AM (Merged)
Tiny
ASHRAF_AK
  • MEMBER
  • 6 POSTS
As you said, I checked coolant temperature sensor then found loose connection on the connector.
After I connected properly, the probles is solved
Thank you very very much
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Friday, October 16th, 2020 AT 10:04 AM (Merged)
Tiny
MANAN123
  • MEMBER
  • 4 POSTS
  • 2005 TOYOTA COROLLA
  • 1.3L
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 170,000 MILES
Sir.

This car has a unique problem as it does not start once engine is cold. It requires a long key-self to start. Immediately after starting its starting is okay, but a second attempt even just 30 minutes after parking it requires a long starting. And immediately after starting when the engine is either cold or hot.
I have changed spark plugs, fuel pump, salf, heat sensor and battery. Everything seems okay.
Your kind suggestions please.
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Friday, October 16th, 2020 AT 10:04 AM (Merged)
Tiny
MANAN123
  • MEMBER
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Furthermore I have checked it at many mechanics including the dealership, but so far problem still exists. I also had a complete tune up done. But it still requires a long starting after being parked. Second start immediately after engine switches off is okay.
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-1
Friday, October 16th, 2020 AT 10:04 AM (Merged)
Tiny
HMAC300
  • MECHANIC
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Scan for codes and check fuel pressure with a gauge in US auto parts rent it. It may be losing fuel pressure due to many things should be 44-50 psi and not drop after 5 minutes.
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Friday, October 16th, 2020 AT 10:04 AM (Merged)
Tiny
MANAN123
  • MEMBER
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Sir, fuel pressure I just checked with a guage. It is not losing the pressure, it remained normal even aftr 30 minutess. Your kind view please.
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Friday, October 16th, 2020 AT 10:04 AM (Merged)
Tiny
HMAC300
  • MECHANIC
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We really do not have Toyota's with that size of engine here in USA, so the spec I gave may be incorrect, but it has to stay at minimum pressure otherwise it is too low. Scan for codes as well.
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Friday, October 16th, 2020 AT 10:04 AM (Merged)

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