Possible bad ECU? Or what?...

[91AwdEagleTalonTSI]

Hey guys , so this has been an on going problem now that it's started getting cold out.

So recently with the weather change I've been experiencing problems..

Here they are..
Takes a good 10 minutes to start even when pushing the gas in then popping it when the key is turned to start. But starts first crank every time if it is warm or has been started within 4 hours.

Slight misfire every now and then.

Stalls but is sporadically and tends to not do it if I have the heat/air on as long as the fans are spinning.

Runs rich . And horrible MPG (I've stayed out of boost as much as possible and it is still horrible)

I've been told by my mech. that a new ECU is 800?! When i've seen them for like 200 so I am trying to dodge that bullet. Others have said it could be an upstream o2 sensor. There is a check engine code but it is every now and then and its for the CTS. I have no clue what it is, please help.

Thanks guys

 

[VtecvrsTurbo]

Takes a good 10 minutes to start even when pushing the gas in then popping it when the key is turned to start. But starts first crank every time if it is warm or has been started within 4 hours.

Slight misfire every now and then.

Stalls but is sporadically and tends to not do it if I have the heat/air on as long as the fans are spinning.

Runs rich . And horrible MPG (I've stayed out of boost as much as possible and it is still horrible)

I've been told by my mech. that a new ECU is 800?! When i've seen them for like 200 so I am trying to dodge that bullet. Others have said it could be an upstream o2 sensor. There is a check engine code but it is every now and then and its for the CTS. I have no clue what it is, please help.

Thanks guys

First off, dont use the gas when trying to start our cars, that is unless you put a carburetor on and didnt update your mod list.

Next, the misfire and hard starts sound like your normal maintenance stuff to me. Go through and check vac lines, fuel filter, plugs, wires, etc. Also check and make sure your fuel pressure is 43.5 (or whatever stock is). Rich conditions almost always point towards major boost leaks. (hence rich under boost) Check it out and post back!

 

[eDeclpse92]

Sounds like you could possibly either have a bad temp sensor. To check the sensor, all you need is a volt meter and ohm it out. Here are the specs:
32* - 5900 ohms
68* - 3500 ohms
104* - 2700 ohms
176* 300 ohm

On the right is degrees of motor and left is obviously your ohm reading you are supposed to get.

Like stated above, do your maintenance. Our 1g ECU's can be found for around $50 to $75. That's what I've been seeing them go for. I bought one for $60 and it was in really good shape. Our stock fuel pressure should be 37 psi I believe. Your horrible gas mileage could also be due to a bad o2 sensor. That controls your fuel mixture.

 

[RussianMax]

Im experiencing that same problem. I personally know I have vacuum leaks and boost leak, so it takes forever for it to start and also has it surge quite bad.

 

[91AwdEagleTalonTSI]

First off, dont use the gas when trying to start our cars, that is unless you put a carburetor on and didnt update your mod list.

Next, the misfire and hard starts sound like your normal maintenance stuff to me. Go through and check vac lines, fuel filter, plugs, wires, etc. Also check and make sure your fuel pressure is 43.5 (or whatever stock is). Rich conditions almost always point towards major boost leaks. (hence rich under boost) Check it out and post back!

When you push it down all the way it cuts off fuel to the injectors;
Fuel filter just replaced along with plugs and oil change and all "normal" maintence

Sounds like you could possibly either have a bad temp sensor. To check the sensor, all you need is a volt meter and ohm it out. Here are the specs:
32* - 5900 ohms
68* - 3500 ohms
104* - 2700 ohms
176* 300 ohm

On the right is degrees of motor and left is obviously your ohm reading you are supposed to get.

Like stated above, do your maintenance. Our 1g ECU's can be found for around $50 to $75. That's what I've been seeing them go for. I bought one for $60 and it was in really good shape. Our stock fuel pressure should be 37 psi I believe. Your horrible gas mileage could also be due to a bad o2 sensor. That controls your fuel mixture.

I have no way to check the sensor; as it's at the mechanics but I'll bring it up to him!

Im experiencing that same problem. I personally know I have vacuum leaks and boost leak, so it takes forever for it to start and also has it surge quite bad.

I have no vacuum leaks that I know of and I have no surges either but its been hard starting for awhile.

 

[VtecvrsTurbo]

When you push it down all the way it cuts off fuel to the injectors;

Unless 1g's are different than 2g's this is not true at all (again not sure about 1g's)

I JUST tested myself hoping to learn something new today and on my own car (99 GST) and it doesn't cut the injectors. This is the case in many other cars, but not mine (and probably not yours)

 

[91AwdEagleTalonTSI]

Unless 1g's are different than 2g's this is not true at all (again not sure about 1g's)

I JUST tested myself hoping to learn something new today and on my own car (99 GST) and it doesn't cut the injectors. This is the case in many other cars, but not mine (and probably not yours)

I was told that it did , maybe not

 

[VtecvrsTurbo]

Did you do a boost leak test? One of the most important things for these cars. If your mechanic thought that about the injectors, im sure he didnt do the boost leak test.

 

[hotrodssnova]

Usually when the coolant temp sensor goes bad, it will default to the negative degrees and report that to the ecu. The ecu will compensate for the cold weather information it received from the sensor by adding a ton of EXTRA fuel. I bet if you try to start it, stop, pull the spark plugs, they are soaked in fuel. Also check all the wires around your thermostat housing. Gets hot there and the wires get brittle and break of from their connections.
Check that stuff out and report back.

 

[91AwdEagleTalonTSI]

Usually when the coolant temp sensor goes bad, it will default to the negative degrees and report that to the ecu. The ecu will compensate for the cold weather information it received from the sensor by adding a ton of EXTRA fuel. I bet if you try to start it, stop, pull the spark plugs, they are soaked in fuel. Also check all the wires around your thermostat housing. Gets hot there and the wires get brittle and break of from their connections.
Check that stuff out and report back.

Last time I got my car he did say it was reading around -88 degrees!

Did you do a boost leak test? One of the most important things for these cars. If your mechanic thought that about the injectors, im sure he didnt do the boost leak test.

No I haven't ever done a BLT

 

[hotrodssnova]

There's your problem, or a good start. Could be bad wiring also. Need to check that also. BTW, your o2 sensor connection is in that same area I mentioned. All those wires were crunchy in the last 3 dsms I've had

 

[91AwdEagleTalonTSI]

There's your problem, or a good start. Could be bad wiring also. Need to check that also. BTW, your o2 sensor connection is in that same area I mentioned. All those wires were crunchy in the last 3 dsms I've had

Would that bad sensor make it not want to start? & Got a picture for where those wires would be around?

 

[VtecvrsTurbo]

Yes the bad sensor can cause a hard start, considering the ECU thinks the engine is a different temp when trying to start.

 

[hotrodssnova]

When it shows that cold out, it dumps tons of fuel in to get the engine started, flooding the engine. I bet your oil smells like gas! As far as the area I'm talking about, follow the top radiator hose to the engine, that is the thermostat housing. Your coolant sensor is the one with 2 wires hooked to it. Check all the wires in that area for damage and good connections.

 

[92AWDHX40]

If your car has ac one is the ac switch make sure you get the correct one the one that talks to the ecu about the cts sensor.

 

[91AwdEagleTalonTSI]

When it shows that cold out, it dumps tons of fuel in to get the engine started, flooding the engine. I bet your oil smells like gas! As far as the area I'm talking about, follow the top radiator hose to the engine, that is the thermostat housing. Your coolant sensor is the one with 2 wires hooked to it. Check all the wires in that area for damage and good connections.

I can check em tomorrow and see what they look like !

If your car has ac one is the ac switch make sure you get the correct one the one that talks to the ecu about the cts sensor.

Your post confused me Not sure what you mean man .

 

[92AWDHX40]

Check the wiring to the cts coolant temp sensors there are two on the thermostat housing one is for the ac switch the other for the coolant temp sensor. The wiring could be damaged or frayed.

 

[91AwdEagleTalonTSI]

Check the wiring to the cts coolant temp sensors there are two on the thermostat housing one is for the ac switch the other for the coolant temp sensor. The wiring could be damaged or frayed.

Haha thanks for simplifying that man haha but like I said I'll be able to check em tomorrow for ya guys!

 

[hotrodssnova]

Here's a picture in this thread:
http://www.dsmtuners.com/forums/newbie-forum/267613-cts-problem.html

 

[91AwdEagleTalonTSI]

I was able to just check it ! The wires didn't look that bad if they are the ones under the hose to the left then they weren't bad. But those wires looks like someone crimped some spade connectors to them and attached them; also it looks like my Cam Angle Sensor is leaking what looks like oil on to some vacuum lines , should I be concerned? I tightened the screw on the CAS before but never checked to see if it was still leaking.

 

[steve]

When you push it down all the way it cuts off fuel to the injectors;

Only if you have DSMLink or perhaps a Custom EPROM. The factory code doesn't do that.

 

[91AwdEagleTalonTSI]

Only if you have DSMLink or perhaps a Custom EPROM. The factory code doesn't do that.

Good to know . Thanks

 

[mjdarg]

To really check if the wires are bad, I would check continuity to the ECU. They might look okay on the outside but still be severed under the insulation.

 

[DogWhistle]

Unless some major event has happened to the electrical system of your car, the odds are much greater that this is a sensor or wiring issue, not your ecu. Since there is not a way to easily test the ecu, do what's been recommended by others here and check the wiring and for boost leaks. Most mechanics have scan tools that will check for the proper +-0.5v cycling of the O2 sensor. If having that scanned is too difficult, just get a new O2 sensor. Doing that can only help the tune of your car. Mixture issues can be difficult to track down on our cars, but you will learn so much about your engine in the process.

 

[nwBryce89]

I have had this same issue on a '90, turned out to be a coolant temp sensor. took me forever to figure out since i could not catch when the cel was on. but that is where i would start, like explained earlier it will cause all of your symptoms. good luck