Cold Hard start

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Old Nov 24, 2008 | 08:39 AM
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Cold Hard start

do you guys think having a bad o2 sensor or removing the o2 sensor would make my SR have a cols start problem..

i cant think of anything else right now it runs perfect even have very good air fuel ratio it only goes a little rich after i let go of the gas but thats expected because of my blow off valve.

but yea the colder it is the harder it is to start when the engine is warm or has been running already it will start right up. but i just hope its not an 02 problem right im hard on money cant spend money on a new 02 sensor...

but the only reason i wouldnt think its an 02 sensor is cause my KA had a bad o2 and it always started fine
Old Nov 24, 2008 | 09:03 AM
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by "hard start" do you mean that it turns over slower than usual, idles rough or both?
Old Nov 24, 2008 | 09:54 AM
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no not slow just have to crank for a while before the motor starts
Old Nov 24, 2008 | 10:50 AM
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am i correct in assuming that you removed the charcoal canister? if so don't worry about it it's normal in colder weather, or so i've been told.
Old Nov 25, 2008 | 06:23 AM
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no not normal lol i carry around another batter because when its cold enough my battery dies before the car starts thats how long it takes when its colder
Old Nov 25, 2008 | 08:38 AM
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no that doesn't sound normal at all. when i temporally removed the canister from my car it took about 3 or 4 seconds for it to start and that was a long time to me. other than the usual lose or dirty connections on the alternator, battery, and ignition components there is one thing that i can think of.

your battery may not have enough amps to start cold but after the engine starts and the alternator takes over it may retain enough amps to start initially after being turned off but not after it sits for a while. that or a leaky injector, now i'm just guessing thought.
Old Nov 25, 2008 | 09:45 AM
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nah i know its not the battery cause this battery never had a problem starting the SR. and i mean hard start i have to crank 30-40 seconds somtimes or more. could be leaky injector but wouldnt that make the car run funny?

but now that you said charcoal canister i never blocked off the line from the canister to the hard line its just open it may be that i will block it off now and how that goes
Old Nov 25, 2008 | 11:34 AM
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yeah a leaky injector could cause it to run funny if it's staying open at start up. after than you may not notice it. it's happened to me on two separate occasions with two different cars so it's possible. i'm still leaning toward the charcoal canister though.
Old Nov 27, 2008 | 10:48 AM
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I have the exact same problem with my SR.
I don't know what it is either.
Takes about 20 secs to start, havent drained a battery though.
I have to hit the gas to get it to start.
Starts right up when the engine is hot.
I don't think its the injectors, because i've had leaky injectors in my KA.
I don't have a carbon canister either.
Old Nov 27, 2008 | 06:33 PM
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Check ECT(engine coolant temperature) sensors under cold starts the PCM uses this as the high authority sensor until O2 is at operating temp then it goes into closed loop. Until it goes into closed loop you PCM is reading this and using short term fuel trim to decide how much fuel to add also called open loop you will run rich at this time.

There are some other possible causes I'll check back
Old Nov 27, 2008 | 06:35 PM
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Ohh..

how check you ECT get a DVOM and back probe the sensor with T-pin and as the temp goes voltage should increase.
Old Nov 28, 2008 | 09:14 AM
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Originally Posted by drifterxxl180
Check ECT(engine coolant temperature) sensors under cold starts the PCM uses this as the high authority sensor until O2 is at operating temp then it goes into closed loop. Until it goes into closed loop you PCM is reading this and using short term fuel trim to decide how much fuel to add also called open loop you will run rich at this time.

There are some other possible causes I'll check back

you may have something there but i'm not sure this holds true with heated o2 sensors.
Old Nov 28, 2008 | 04:30 PM
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Originally Posted by jramosthe1st!
you may have something there but i'm not sure this holds true with heated o2 sensors.
Still holds true with 2, 3 and even 4 wire heated O2 just heated O2 will go into closed faster usually about 5 to 10 secs if working properly. During that short time the PCM still needs to deliver fuel. You can do KOEO ( key on engine off)
Even with the heated O2 the vehicle will still run in open loop until the PCM reads the voltage signal usually 2 cycles of rich and then lean. O2 sensor works off 1 volt switching. Above .800v you have a rich mixture and below .200v you have a lean mixture. Let me know if you have any other problems.
Old Nov 28, 2008 | 05:46 PM
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well only reason i dont think its the o2 sensor is cause my obd2 KA had a bad o2 sensor and never had a problem starting it just ran rich. now my SR has a problem starting yet has and almost perfect AFR (yes i have a wideband) it only goes a little rich when i let off the gas but thats to be expected because of my Blow off valve.

anyway not sure how to test the ECU temp sensor a new one isnt bad though $30 can just get one from an auto parts store the 91-94 s13 KA temp sensors work.
Old Nov 28, 2008 | 09:20 PM
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The richness after throttle is not due to blow off valve. Any vehicle will run rich after throttle NA and Forced Induction, the throttle plate is closed not allowing air to pass by. At the same time The PCM has not changed the pulse width of the injector. Soon as O2 sees the rich mixture PCM reads that and changes the pulse width. Therefore after throttle you should see a rich signal, what your wide band is showing you.

To test you ECT sensor with it still in the vehicle you measure voltage with a DVOM ( Digital volt ohms meter). Get some T-pins and back probe the sensor plug and. With you meter lead connected to reference wire on Ka's it's light orange( don't remember what the Sr color is). and your negative lead to good ground source. Start your vehicle and as you vehicle warms up and gets up to operating temp the voltage should increase cause resistance decreases as temp goes up. If the meter you would be using is not auto ranging, set to 20vDC

The sensor is not a pricey one but to rule it out I would check it first



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