Cold Start

Timon · 01-05-2009, 04:03 AM

I started my car a few days ago - cold start, below freezing temps. Rather than going to 2400-2500 and idling as normal, it stuttered a bit, the check engine line came on. Seconds later, the check engine light turns off, only to turn back on. Then it eventually turned off for good this time and stayed off. The RPMs returned to normal 2.5k, and slowly dropped from there as the engine warmed up.

Today I started my car, a little bit warmer, but still below freezing. A similar thing happened. The car stuttered, the check engine light came on for a few seconds, and then turned off for good.

The car wasn't stuttering at low RPMs, it was about 1200-1300. It almost felt like it was misfiring, but I could be wrong. I assume this means something to do with the cold start system is going out, and I'd rather fix it before it goes out.

Does anyone have ideas?

Jackstand Queen · 01-05-2009, 12:18 PM

When my idle air bypass valve was malfing, I had similar results. The hold down screw came loose and it was flooping back and forth some.

Timon · 01-06-2009, 08:16 AM

I'm assuming you're referring to the idle up VSV? The hold down screw came loose, so I'm assuming just tightening it up stopped the VSV from moving? Any other details would be appreciated.

Jackstand Queen · 01-06-2009, 10:34 AM

Your assumptions are absolutely correct.

Timon · 01-07-2009, 12:01 AM

I did check that (hopefully). It's on the left side of the engine bay, has a plastic looking screw with a phillips head to adjust a spring, two connectors that plug into it, and is attached by two brackets?

Jackstand Queen · 01-07-2009, 12:14 AM

Yep, that's idle by pass thingie. Or Idle Vacuum Switch Valve if you prefer.

I'm about to dump my old Throttle Body and slap on an N.A. Throttle Body. I'll let you know what my seat of the pants Dyno. test results are.

I've been looking for a 6 speed tranny lately. Mostly for the weight loss, but lower gearing in 1st through 5th for faster accelleration that way too. Being about 100 lbs lighter in the caboose ought to bring the handling in line with an N.A.'s handling.

My car has been very cold blooded since I got it running. It doesn't like to do much of anything until it warms up.

Timon · 01-07-2009, 07:22 AM

You'll definitely have to let us know about the difference. From the sounds of it I assume you have an SC model?

Well I made sure the idle up VSV is attached, and made sure the connectors were plugged in. Still throws a code randomly, but it never lasts for more than a few seconds. My guess is something is loose, but no idea what. I'll see about testing the idle up VSV per the Haynes manual once it warms up.

Do the MKIs store the previous codes until cleared? I'm pretty sure the MKIIs do, but not sure on the MKIs. I'm thinking I could probably just pull the code, and see what it thinks is wrong to narrow it down a bit.

Jackstand Queen · 01-07-2009, 11:05 AM

Yeah the ECU does hold codes that are not currently faulty or acitve. Another damn thing is: it has a learning curve. It fine tunes itself, especially in the idle area.

The Throttle position sensor, and the EGR system are both areas that can affect idle and warm up running.

Good Luck

Jackstand Queen · 01-09-2009, 11:26 PM

Hey, I just had a thought. My Sc has always been cold natured. It could be your ABV is gunked up inside and sticking when its cold. I cleaned the inside of mine out and it was filthy inside.

Eventually I replaced it with a Bosch ABV, when I couldn't get the overboost by pass mod. to work.

Timon · 01-10-2009, 01:36 AM

ABV? I'm not sure what you're referring? I haven't had a chance to pull the codes yet, hopefully I'll get to that tomorrow before work. When I do I'll post them up.

Jackstand Queen · 01-10-2009, 12:44 PM

ABV = Air bypass valve. A device found only on SC engines.

My bad, I get you confused with Mr2Tim who has an SC.

Papo J · 01-10-2009, 05:17 PM

If you've done a filter relocation mod the flapper door inside the AFM could be freezing to the AFM overnight limiting it's movement. Just an idea.

Timon · 01-10-2009, 10:13 PM

Good thought, but if the door freezes then the car wouldn't run for more than a few seconds. That door opening is what kicks on the fuel pump, it may be limiting the door from fully opening, but normally it would only open slightly at idle.

Timon · 01-12-2009, 04:34 AM

Okay, finally a real mechanically update. I pulled the code from the ECU. #2, a.k.a 2 flashes, dead for 4.5 seconds, rinse and repeat.

According to what I can pull up this is a Vacuum Sensor Signal. Trouble area vacuum sensor circuit, vacuum sensor, or ECU.

I can probably rule out the ECU. Usually if the ECU was having problems it would be much more than just a simple CEL on a random occasion.

So where to go from here on the CEL?

01-05-2009, 04:03 AM	#1 (permalink)
Timon MR2 MKI AW11 Join Date: Feb 2008 Location: Utah Posts: 652 Thanks: 13 Thanked 39 Times in 35 Posts My Google Map iTrader Rating: (0/0% )	Cold Start I started my car a few days ago - cold start, below freezing temps. Rather than going to 2400-2500 and idling as normal, it stuttered a bit, the check engine line came on. Seconds later, the check engine light turns off, only to turn back on. Then it eventually turned off for good this time and stayed off. The RPMs returned to normal 2.5k, and slowly dropped from there as the engine warmed up. Today I started my car, a little bit warmer, but still below freezing. A similar thing happened. The car stuttered, the check engine light came on for a few seconds, and then turned off for good. The car wasn't stuttering at low RPMs, it was about 1200-1300. It almost felt like it was misfiring, but I could be wrong. I assume this means something to do with the cold start system is going out, and I'd rather fix it before it goes out. Does anyone have ideas?

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01-05-2009, 12:18 PM	#2 (permalink)
Jackstand Queen Cage Fighter Join Date: May 2008 Posts: 691 Thanks: 53 Thanked 56 Times in 53 Posts iTrader Rating: (1/100% )	When my idle air bypass valve was malfing, I had similar results. The hold down screw came loose and it was flooping back and forth some.

01-06-2009, 08:16 AM	#3 (permalink)
Timon MR2 MKI AW11 Join Date: Feb 2008 Location: Utah Posts: 652 Thanks: 13 Thanked 39 Times in 35 Posts My Google Map iTrader Rating: (0/0% )	I'm assuming you're referring to the idle up VSV? The hold down screw came loose, so I'm assuming just tightening it up stopped the VSV from moving? Any other details would be appreciated.

01-06-2009, 10:34 AM	#4 (permalink)
Jackstand Queen Cage Fighter Join Date: May 2008 Posts: 691 Thanks: 53 Thanked 56 Times in 53 Posts iTrader Rating: (1/100% )	Your assumptions are absolutely correct.

01-07-2009, 12:01 AM	#5 (permalink)
Timon MR2 MKI AW11 Join Date: Feb 2008 Location: Utah Posts: 652 Thanks: 13 Thanked 39 Times in 35 Posts My Google Map iTrader Rating: (0/0% )	I did check that (hopefully). It's on the left side of the engine bay, has a plastic looking screw with a phillips head to adjust a spring, two connectors that plug into it, and is attached by two brackets?

01-07-2009, 12:14 AM	#6 (permalink)
Jackstand Queen Cage Fighter Join Date: May 2008 Posts: 691 Thanks: 53 Thanked 56 Times in 53 Posts iTrader Rating: (1/100% )	Yep, that's idle by pass thingie. Or Idle Vacuum Switch Valve if you prefer. I'm about to dump my old Throttle Body and slap on an N.A. Throttle Body. I'll let you know what my seat of the pants Dyno. test results are. I've been looking for a 6 speed tranny lately. Mostly for the weight loss, but lower gearing in 1st through 5th for faster accelleration that way too. Being about 100 lbs lighter in the caboose ought to bring the handling in line with an N.A.'s handling. My car has been very cold blooded since I got it running. It doesn't like to do much of anything until it warms up.

01-07-2009, 07:22 AM	#7 (permalink)
Timon MR2 MKI AW11 Join Date: Feb 2008 Location: Utah Posts: 652 Thanks: 13 Thanked 39 Times in 35 Posts My Google Map iTrader Rating: (0/0% )	You'll definitely have to let us know about the difference. From the sounds of it I assume you have an SC model? Well I made sure the idle up VSV is attached, and made sure the connectors were plugged in. Still throws a code randomly, but it never lasts for more than a few seconds. My guess is something is loose, but no idea what. I'll see about testing the idle up VSV per the Haynes manual once it warms up. Do the MKIs store the previous codes until cleared? I'm pretty sure the MKIIs do, but not sure on the MKIs. I'm thinking I could probably just pull the code, and see what it thinks is wrong to narrow it down a bit.

01-07-2009, 11:05 AM	#8 (permalink)
Jackstand Queen Cage Fighter Join Date: May 2008 Posts: 691 Thanks: 53 Thanked 56 Times in 53 Posts iTrader Rating: (1/100% )	Yeah the ECU does hold codes that are not currently faulty or acitve. Another damn thing is: it has a learning curve. It fine tunes itself, especially in the idle area. The Throttle position sensor, and the EGR system are both areas that can affect idle and warm up running. Good Luck

01-09-2009, 11:26 PM	#9 (permalink)
Jackstand Queen Cage Fighter Join Date: May 2008 Posts: 691 Thanks: 53 Thanked 56 Times in 53 Posts iTrader Rating: (1/100% )	Hey, I just had a thought. My Sc has always been cold natured. It could be your ABV is gunked up inside and sticking when its cold. I cleaned the inside of mine out and it was filthy inside. Eventually I replaced it with a Bosch ABV, when I couldn't get the overboost by pass mod. to work.

01-10-2009, 01:36 AM	#10 (permalink)
Timon MR2 MKI AW11 Join Date: Feb 2008 Location: Utah Posts: 652 Thanks: 13 Thanked 39 Times in 35 Posts My Google Map iTrader Rating: (0/0% )	ABV? I'm not sure what you're referring? I haven't had a chance to pull the codes yet, hopefully I'll get to that tomorrow before work. When I do I'll post them up.

01-10-2009, 12:44 PM	#11 (permalink)
Jackstand Queen Cage Fighter Join Date: May 2008 Posts: 691 Thanks: 53 Thanked 56 Times in 53 Posts iTrader Rating: (1/100% )	ABV = Air bypass valve. A device found only on SC engines. My bad, I get you confused with Mr2Tim who has an SC.

01-10-2009, 05:17 PM	#12 (permalink)
Papo J 6SPD GTE Join Date: Sep 2006 Posts: 232 Thanks: 1 Thanked 21 Times in 20 Posts iTrader Rating: (0/0% )	If you've done a filter relocation mod the flapper door inside the AFM could be freezing to the AFM overnight limiting it's movement. Just an idea.

01-10-2009, 10:13 PM	#13 (permalink)
Timon MR2 MKI AW11 Join Date: Feb 2008 Location: Utah Posts: 652 Thanks: 13 Thanked 39 Times in 35 Posts My Google Map iTrader Rating: (0/0% )	Good thought, but if the door freezes then the car wouldn't run for more than a few seconds. That door opening is what kicks on the fuel pump, it may be limiting the door from fully opening, but normally it would only open slightly at idle.

01-12-2009, 04:34 AM	#14 (permalink)
Timon MR2 MKI AW11 Join Date: Feb 2008 Location: Utah Posts: 652 Thanks: 13 Thanked 39 Times in 35 Posts My Google Map iTrader Rating: (0/0% )	Okay, finally a real mechanically update. I pulled the code from the ECU. #2, a.k.a 2 flashes, dead for 4.5 seconds, rinse and repeat. According to what I can pull up this is a Vacuum Sensor Signal. Trouble area vacuum sensor circuit, vacuum sensor, or ECU. I can probably rule out the ECU. Usually if the ECU was having problems it would be much more than just a simple CEL on a random occasion. So where to go from here on the CEL?