Will a logger help with long time to start and running bad?

[panamarojo]

I just got a data logger and I am just wondering if it would help me out at all on diagnosing my problem.

My car has a problem starting. Long cranks, but once it does start, it has reving problems, and drives really bad.

So do I just hook cable and data logger up and turn it on? or do I need the car running? Which readings should I be looking at? I am using that MMcd software i think its called. I noticed it has under the test menu, something about the fuel pump and another one for pressure. What are these for?

 

[rush2252]

Crawl before you walk.


List your car. 1g or 2g?

Check MAF fuel pressure and describe of any past problems. If its slow to start it might be a fuel related problem. The logger is used to log data once the car is running. Depending on the logger you might be able to use it as a code reader.

 

[Lofty]

A logger is exactly what it is, it's a logging tool, not a tuning tool. Check all the things that rush said and work from there.

 

[habitatguy187]

You can use the logger to see if your CTS (coolant temp sensor) is bad, which can cause hard starts. Turn the key to the "On" position and check your coolant temp, if it's way off from the ambient temp then it's bad.

 

[steve]

The test menu is for checking the error codes, testing the solenoids while the car isn't running and for testing the injectors/cylinders when it is. I typically first check for codes to make sure the ECU and datalogger are speaking to each other and to make sure there aren't any stored but not active error codes. I then activate the Purge, Pump, Pressure, and Boost solenoids and make sure I hear each click. You can only push one at a time and about six seconds later it will go off.

The injector buttons are useful when the car is running rough. The buttons turn off that injector and it the car runs worse you know that cylinder was working, if it makes no difference then you know it wasn't.

Before starting the car I open a new log and select RPM, KNCK, O2-R, TPS, TIMA, COOL, AIRT, BARO, INJP, BATT, ISC, FTRL, FTRM, FTRH, FTO2, AND MAFS and put the logger into graph mode while logging RPM, O2-R, TPS, COOL, ISC, and FTO2. Then turn the ECU on and unclick the pause.
COOL and AIRT on a cold car should be about the same as the outside temp, the ISC steps should be between 90 and 120 depending on the ECU model and the current engine coolant temp. Once you start the car the ISC steps should ramp down to 0 during warmup and then back up to between 10 and 30 once the car reaches operating temps at idle. The O2-R should be 0v and once started go to about 0.9v once the sensor gets hot. Once COOL reaches 86F (109F on 90's) or after 10 seconds if it's already that hot, the O2-R should start cycling and FTO2 will also start updating. Once COOL reaches 186F the fuel trims will start moving. FTRL is the low trim used at idle. BATT should be 12v+ and high 13v, low 14v when the engine is running.

So I always start logging before I start the car to see if the sensors are behaving normally, then start the car and watch how it warms up and if it enters closed loop. If the ECU wasn't just plugged in check the fuel trims will indicate if there is a problem with the backup power and if the sensors are bouncing around before you start the car you know the ECU is having problems sampling the analog voltages.

Logging while tuning the car you would use a smaller set of parameters so you get the best resolution and focus on things like RPM, INJD, KNCK, TIMA, and perhaps MAFS if your checking for overrun.

 

[panamarojo]

Thanks Steve, thats just what I needed to know. Ill let you all know how it goes here soon.

 

[panamarojo]

Anyone know why I would have a comm error, everything is hooked up. Do I have to push the hotsync button at all thats on the palm pilot charging stand? Also it has a plug in for a wall power cord, do I need the power hooked up for it to work?

Also I dont think its the ecu, cause steve just fixed it and the check engine light comes on when key goes to the on position, and the stock boost gauge goes to 0. And I get a heart beat, sounds like a blinker, I am using a 12v buzzer.

The cord I just got from team-dsm.com It says its for a palm, but imma get a null modem adapter and test it out, radio shack has one for like 11 bucks. Imma try and test it out on another dsm once I get ahold of the dude. I am using a palm vx with mmcd. Serial comm error. Nothing comes up not even the sensor readings.

The pins on the diag port has the 1 and 12 pin, and three other pin on the other side of I think the 12th pin. Any help will be helpful, thanks.

 

[steve]

The cord I just got from team-dsm.com It says its for a palm, but imma get a null modem adapter and test it out, radio shack has one for like 11 bucks. Imma try and test it out on another dsm once I get ahold of the dude. I am using a palm vx with mmcd. Serial comm error. Nothing comes up not even the sensor readings.

Honestly you need to ask the supplier what's up with what they sold you.
If it has a male connector then it should connect to your Palm serial hotsink cable.

You may be suffering from a "auto-on" cable failing to put the ECU into diagnostic mode. That seems to happen a lot with 90 ECUs.

 

[panamarojo]

Thanks for the info Steve, I always thought my car was a 1991 which it is on papers, but in driver door jam its oct 1990. I have been looking into this and it seems like I need the cable with the extra 12v power wire that goes into the fuse box. I want to make this one, any diagrams for this exact cable? and you wouldn't happen to remember what year my ecu was? I remember you told me it was an eprom.
Thanks again.

 

[tunethis]

Thanks for the info Steve, I always thought my car was a 1991 which it is on papers, but in driver door jam its oct 1990. I have been looking into this and it seems like I need the cable with the extra 12v power wire that goes into the fuse box. I want to make this one, any diagrams for this exact cable? and you wouldn't happen to remember what year my ecu was? I remember you told me it was an eprom.
Thanks again.

A lot of cars are built within the year before. 1991's were built starting in 1990. So you're okay. The paper work is correct.

 

[steve]

I have been looking into this and it seems like I need the cable with the extra 12v power wire that goes into the fuse box. I want to make this one, any diagrams for this exact cable? and you wouldn't happen to remember what year my ecu was? I remember you told me it was an eprom.
Thanks again.

You sent a 90 California AWD EPROM ECU MD145902. Since the car is a 91 you should have either the Federal 166262 or California MD166263 for a 91 AWD manual car. You can use the 90 ECU but pins 6 and 14 on the harness should be swapped.

You don't need an active datalogger cable (the powered kind). My guess is you need pin 10 and 12 on the DLC connected so that the ECU goes into diagnostic mode. Pin 12 is ground, so your grounding pin 10 to put the ECU into diagnostic mode. Pin 10 on the DLC is pin 2 on the ECU.