Hard COLD start, bad ISC or something else??

[tsi1991awd]

91 Talon TSI AWD...it is hard to start in the morning. Its been cold here lately (WA) and it takes 3 or 4 times before the car starts. Then when it does start sometimes it'll stutter at a really low RPM before it starts warming up normal.

This is only on the first start of the day. Every other time it starts with no problems at all.

What could it be? I'm changing the spark plugs this weekend and the fuel filter next weekend. I have read the coolant temp sensor can cause it to have a hard start but this is only one time. It will start fine every other time. It idles fine, drives fine. Doesn't stall, die, etc. So I have no idea....

 

[DSM1G90]

(yea, the correct temp readings on the sensor came from the Chilton's...)

I'd do the thread tape - a reliable and safe procedure.

And I know all about this one with bad startups when cold - before I fire the motor, I barely press down on the throttle and then it would catch on the first hit. But, I would remain in that high idle for a few until water temp has initally began to rise, then let off on the throttle and you're back to normal idle.

The sensor, when it goes bad, tells the ECU that the water temp is at 176* even though it's more colder outside.

Reading on some of these hard starts when it pertains to this sensor I have to point towards our fuel pump, FPR's and such:

Is the fuel rail remaining pressurized, or is the rail losing all of it's pressure? Is there a bad check valve in the fuel line area causing fuel to drain back to the tank? Is our pump getting weak?

Some ideas here ... - DSM

 

[tsi1991awd]

I don't know how I would check what the pressure is in the fuel rail and such. Also, not sure about the fuel pump. Like I said, this is just a hard start first thing in the morning. I come to work, leave my car parked for 8 hours, go out to it and it starts right up on the first try. So to be honest, I would think the fuel rail is retaining pressure and that the fuel pump is OK. Since I only leave the car for oh, 8 to 10 hours at night but it gets real cold and maybe in the morning its low 30s outside.

So I don't know if its the temp sensor. Because as I said, this only happens in the morning on the first start up.

 

[2GeNTSi]

I attempted to replace this not too long ago but I couldn't find the same one I have on my car. I have a 6bolt in my 2GA TSi and I checked at Kragen and Pepboys, both of which had a different ECT. I told them to check if it varied in all the different 1G years (I checked the 2G one first) but they were almost a complete different design w/ just two prongs on the end.

The harness end for the ECT is elliptical with tabs on the left and right side which are staggered. The top has two tabs spaced out and centered while the lower tab is off center. I'm pretty sure this is what it looked like from what I can remember. I attached an image I made for reference, the intersecting lines are just to show the alignment.

 

[tsi1991awd]

Yea I noticed on a few different pictures on the net, the temp sensor only has 2 prongs sticking out, while mine has the prongs plus a plastic cap thing around it. So I was confused...guess well see when I pick the sensor up.....if I do.

 

[r1991_4g63t]

Yea I noticed on a few different pictures on the net, the temp sensor only has 2 prongs sticking out, while mine has the prongs plus a plastic cap thing around it. So I was confused...guess well see when I pick the sensor up.....if I do.

i forgot to mention that, you will have to cut the connector off and put new ends on the wires. i just used female spade connectors.

 

[tsi1991awd]

Oh....well I guess its not that big of a deal then. Does it matter which wire goes to which prong?

 

[r1991_4g63t]

nope

 

[tsi1991awd]

Whoa whoa whoa.....I just checked the sensor, after it's been sitting all night. It's super cold outside. Maybe low to mid 30s, possibly 40 I'm not sure. So I set my multimeter to 20k ohm to check, since I'm looking for 5.1-6.5k ohms supposedly. The meter reads 0.00!!! The temp sensor must be shit to hell! Going to go to Napa and pick up a new one this morning.

I put the meter onto the 200 ohm, the meter read 0.02......so either way, I think it's pretty much shot.

 

[r1991_4g63t]

Whoa whoa whoa.....I just checked the sensor, after it's been sitting all night. It's super cold outside. Maybe low to mid 30s, possibly 40 I'm not sure. So I set my multimeter to 20k ohm to check, since I'm looking for 5.1-6.5k ohms supposedly. The meter reads 0.00!!! The temp sensor must be shit to hell! Going to go to Napa and pick up a new one this morning.

I put the meter onto the 200 ohm, the meter read 0.02......so either way, I think it's pretty much shot.

its junk, thats almost exactly how mine was reading

 

[tsi1991awd]

its junk, thats almost exactly how mine was reading

Well I couldn't get the old sensor out so I broke that plastic piece off and then used the 19mm socket and got it out. Put the new one in, put the female spades to it, tried to start it and it wouldn't start.

Went out and looked and I left the damn intercooler hose off, so I put that back on and it still wouldn't start.

So I switched the wires to the opposite connectors and BOOM, started up. So I guess it DOES matter which wire goes to which connector....or I just tried so many times to start it up that it finally started. We will see as the days pass....but I did take a reading as it was warming up and it was definately working....went down to 1.5k ohms before I turned the car off.

Hopefully this fixes my cold start.....but I do know the old sensor was shot to hell.

 

[r1991_4g63t]

Well I couldn't get the old sensor out so I broke that plastic piece off and then used the 19mm socket and got it out. Put the new one in, put the female spades to it, tried to start it and it wouldn't start.

Went out and looked and I left the damn intercooler hose off, so I put that back on and it still wouldn't start.

So I switched the wires to the opposite connectors and BOOM, started up. So I guess it DOES matter which wire goes to which connector....or I just tried so many times to start it up that it finally started. We will see as the days pass....but I did take a reading as it was warming up and it was definately working....went down to 1.5k ohms before I turned the car off.

Hopefully this fixes my cold start.....but I do know the old sensor was shot to hell.

thats weird, it shouldnt make a difference but at least you got it to start hopefully that fixes your problem, either way yeah your old one was definitly shot.

 

[tsi1991awd]

thats weird, it shouldnt make a difference but at least you got it to start hopefully that fixes your problem, either way yeah your old one was definitly shot.

Yea I don't know...like I said, could have been that I had tried so many times already. I have no idea. Ill try and start it again tonight. My wife and I are over at my parents house right now, with her car.

 

[tsi1991awd]

OK, well started her up this morning....the coolant temp sensor did NOT fix it. I think it might be something with fuel delivery? I pumped the gas a few times, tried to start it and nothing....then I put the throttle down a bit, held it while starting and it started up, then I let off the throttle. So I'm clueless once again.....maybe after I change the fuel filter it'll help, but somehow I am doubtful.

 

[interex]

I hope you know that pumping the gas on a FI car when trying to start it won't "prime" your engine. You might want to check your compression all the way across, also check your TPS and o2 Sensors.

If you have low compression it will be harder to start.

*pokes r1991_4g63t*

 

[r1991_4g63t]

I hope you know that pumping the gas on a FI car when trying to start it won't "prime" your engine. You might want to check your compression all the way across, also check your TPS and o2 Sensors.

If you have low compression it will be harder to start.

*pokes r1991_4g63t*

im sorry it didnt fix his problem, it DID fix mine that why i told him to check it and either way the sensor WAS bad

 

[DSM1G90]

maybe your fuel system is losing it's prime. Turn the key on, wait a few second for the pump to prime up the fuel rail then hit the starter. Sometimes, I have to do that to my vehicle for I know that I've got a fuel delivery problem myself - could be a weak FP, stock FPR, bad check valve in the fuel line, or other abnormalities that I've got to search out on.

Gonna ask a dumb one here though: You changed out the plugs, but out of curiousity - have you cheked the plugs the next day after a good day of driving? Are they clean, or they all carbon soot black from firing cold? And by firing cold, have you seen what the spark looks like when pulled one out and have someone hit the starter to see what the spark flame looks like - a cold yellow, or a hot blue flame?

 

[tsi1991awd]

Didn't check the plugs to see what they look like yet.

Also, something I did notice is a few days ago I was ripping on the highway and in 4th gear, when I got up into the higher RPM's it felt like something was holding me back. Wasn't exactly fuel cutoff, but it felt like it bogged a bit....then I shifted, and later on it was just fine. Sooo, I'm not sure....fuel pump?

 

[dsm-onster]

maybe your fuel system is losing it's prime. Turn the key on, wait a few second for the pump to prime up the fuel rail then hit the starter. Sometimes, I have to do that to my vehicle for I know that I've got a fuel delivery problem myself - could be a weak FP, stock FPR, bad check valve in the fuel line, or other abnormalities that I've got to search out on.

Gonna ask a dumb one here though: You changed out the plugs, but out of curiousity - have you cheked the plugs the next day after a good day of driving? Are they clean, or they all carbon soot black from firing cold? And by firing cold, have you seen what the spark looks like when pulled one out and have someone hit the starter to see what the spark flame looks like - a cold yellow, or a hot blue flame?

The fuel pump doesn't activate until the motor is spinning over. But I do agree that the FPR may be going out. This will make the pressure blead down after a shut off or hard for the fuel pump to pump up the pressure initially after a long off period. My stock fpr would hold pressure for a VERY long time after shutoff. And my adjustable FPR would let the fuel rail drip dry after a few hours after the off time. Have you checked your fuel pressure during a cold start?

 

[tsi1991awd]

I haven't checked the fuel pressure...I don't know how to.

And could the fuel filter cause this? Not sure HOW, maybe if it was clogged bad? Because I'm going to be changing it this week.

 

[dsm-onster]

A fuel filter should show symptoms all the time, coldstart, warmstart, and running at higher loads.

Unfortunately, there is no easy way to check fuel pressure, unless you have an adjustable regulator with a gauge attached (or port). Or cut the line and fab up a port. There is a special t fitting that mitsu illustrates in the factory service manual. . . But, I've never seen one. I just tap the line with a t fitting with adapters and use REALLY good worm clamps. . .

 

[tsi1991awd]

A fuel filter should show symptoms all the time, coldstart, warmstart, and running at higher loads.

Unfortunately, there is no easy way to check fuel pressure, unless you have an adjustable regulator with a gauge attached (or port). Or cut the line and fab up a port. There is a special t fitting that mitsu illustrates in the factory service manual. . . But, I've never seen one. I just tap the line with a t fitting with adapters and use REALLY good worm clamps. . .

I suspect the fuel filter might play a small role in this. I mentioned somewhere earlier than up in the higher rpms on the highway it felt like it was bogging a bit, or starving for fuel. Not really a fuel cutoff, but slight stutter in 4th gear while ripping on the hwy. After I shifted it was fine. Just under city driving if I mash the gas and mess around, at times it feels like its being held back a little bit. I don't know if its just because its not supposed to be making much power in that range or what.

 

[Need2Gofaster]

I have the same problem. But my won't only not start right up if its cold, but if its really hot outside. Today was hot outside it took me about 10 minutes to get my car running. When i turn the ignition, I don't hear anything no clicking nor grinding. My starter, alternator and battery are about a year old.

The only time it starts right up is when its cool outside like 50 degrees. Could it be my CTS? I don't have time to take it out and test it. Don't i have to drain the coolant? By time i get home its almost already dark outside.

I can use my remote start and it fires right up on the first try.

 

[All_Boost16G]

I have the same problem. But my won't only not start right up if its cold, but if its really hot outside. Today was hot outside it took me about 10 minutes to get my car running. When i turn the ignition, I don't hear anything no clicking nor grinding. My starter, alternator and battery are about a year old.

The only time it starts right up is when its cool outside like 50 degrees. Could it be my CTS? I don't have time to take it out and test it. Don't i have to drain the coolant? By time i get home its almost already dark outside.

I can use my remote start and it fires right up on the first try.

Im guesssing you have a problem with the wiring on the ignition, beacuse if your remotoe start works, then everything else should work. I would check your wiring.

 

[r1991_4g63t]

Im guesssing you have a problem with the wiring on the ignition, beacuse if your remotoe start works, then everything else should work. I would check your wiring.

definitly or the ignition switch itself, the electric piece not the locking part

 

[Need2Gofaster]

Im guesssing you have a problem with the wiring on the ignition, beacuse if your remotoe start works, then everything else should work. I would check your wiring.

But it only does that when its extreme hot or cold. In the mornings its not to bad, maybe the second try it starts up. But after work if its a hot day it takes me about 7 minutes to get it running. I will look at my ignition wires.

sorry if i hijacked this thread.