Auto xray and Corvette

[Nazgul]

Hello Again Forum,

My 85 has been suffering from slowly degrading performance....it only has about 75,000 miles on it and I am trying to stem the tide of age as is , I would guess, everyone else with older cars. I purchased an auto xray scanner hoping to get some clues as to what is going on in there. First thing I found out is the trouble code clearing function would not work with my car because it wasnt supported in 85....ok...I can live with that.....when I looked into scanners in general auto xray advertised that this scanner was virtually invisible to the system....which lead me to believe it just sort of snoops on the ecm operation and displays whats going on. I have noticed a mulitiude of problems....first of all...when i scan.....the car immediately jumps up in rpms...at the same time all dash information pertaining to any milage...or fuel economy goes to zero. Temps all seem to function normally. Same with oil readings. Based on readings from this scanner I seem to have a few issues that need to be worked out. My air inlet temp only reads either 123.8 or 204 degrees......starts up with inlet temps of 123.....I bought a relocating sensor from Ecklers and nothing changes. My knock sensor is reading about 135...I replaced the sensor first.....and then the knock module and it too is unchanged. I recently put a borla exhaust and a new high flow cat in but these readings were the same before that modification.......park/neutral does not register a change......only intermittently for a second or two and goes back to detecting park/neutral while I am driving....I seem to be always calling for A/C......even tho I am not......o2 sensor fluctuates.....IAC...TPS....coolant temp,..all seem to move normally.....coolant temps and vehicle speed match almost exactly to dash readings....I once had a voltage too high code although recently get no codes.......does anyone have this type of scanner and a year close to mine so I can find out just what IS supported......I dont know much about these cars yet.....car runs almost ok when cold and then begins to run awful when warmed up.....could my ecm be crapped out and I am running on the "cal-pac" when the computer tries to take over???? I am lost right now. Any guidance would be GREATLY appreciated.......
Thanks Geoff

 

[Vettefan87]

Your car will naturally run worse the hotter it gets, or at least my car does. When I put the snap on scanner onto my car the trip, and range and all that went to zero like you said, so that is not uncommon. As far as it running worse when it gets hot I am not sure about. What codes are you getting as of right now? Sorry if I missed it in the above post.

 

[WhalePirot]

You might be suffering from too much information, while expectin that the scanner is your only diagnostic tool. I suspect you have already replaced some parts that were not faulty.

The scanner puts the ECM in a diagnostic (like limp-home) mode, so I expect the dash indication are normal. It is similar to "open loop", where the sensors are not 'driving' the ECM's outputs. Please don't run out and buy one.

Heat-up issues can be from many sources. The 'old days' still apply, meaning that ignition breakdown, due to faulty wires, cap or coil; vacuum leaks or electrical shorts that are heat related, are always the first line of troubleshooting, before the scanner comes in to play. Visual checks and a painstaking look-see of all hoses and wires may point to the problem. I still use a vacuum gauge, with good result.

Is the vacuum normal when it's hot? Similar to the cold reading?

Does the spark stay strong and blue-colored, then?

It there a miss on a cylinder(s)?

Was any work done just prior to the symptoms appearing?

Does the weakness appear just as the car switches to closed loop?

 

[Nazgul]

My car has a 180 degree thermostat......temps are always in and around 180. Seems to make no difference......General malaise even after starting....but much worse just as the temp reaches the 180 area about 10 mins after starting....I just ran the car with the air inlet temperature sensor completely disconnected and it ran the same.....and the scanner still showed upon startup the inlet temp of 123 degrees....even with the sensor wire disconnected. The only major work done was the exhaust I mentioned above...and about 15,000 miles ago a new high performance (high torque and hp rated) transmission. Trans seems to work great....coolant sensor....TPS....speed all seem to read on the scanner in decimal increments...very sensitive to change...inlet temp only reads those two readings....even when disconnected and knock sensor always at around 130 even after changing the sensor and module......just put the timing light on all cyllinders and got a positive current to operate the light so I know all are firing.......I pulled the plugs not too long ago...about 2 weeks....and they all seem normal.....no oil fouling or any other obvious visual abnormalities......I took the panel down from under the ecm to check for anything unplugged and saw nothing obvious there....Is there a test I can run to check the ecm???....I just cant find anything that asks me to start down a certain diagnostic path to figure this out......

 

[WhalePirot]

I just ran the car with the air inlet temperature sensor completely disconnected and it ran the same.....and the scanner still showed upon startup the inlet temp of 123 degrees....even with the sensor wire disconnected. ....I just cant find anything that asks me to start down a certain diagnostic path to figure this out......

RU sure? Then, what's all that about?

I really think the ECM is doing its job, but may be getting bad input from (perhaps) this sensor. Is the sensor bad or is the wire the problem?

 

[Vettefan87]

RU sure? Then, what's all that about?

I really think the ECM is doing its job, but may be getting bad input from (perhaps) this sensor. Is the sensor bad or is the wire the problem?

Yeah, I don't know anything about ECM's, but it I would imagine that if it went bad it would really go bad and the car wouldn't run. Like pirot said I would look at the sensor and the wiring. It seems you have some electrical gremlin somewhere in there. Good luck.

 

[jan-erik]

Hi.
I have an 85 4+3 and bought an Auto xray. There has been a lot of problems as the scanner does not read the ECM ....870. I have to manipulate with the year of vehicle and some characters to read different parameters. This has made me not trust the figures totally.
I have found a real good scanner SW on the net and it is free of charge. That is WINALDL. Just browse on googleand you will find it. It works very well and you will get good info on the ....870 ECM as in the 85. I am going to sell my Auto Xray to some that has newer ECMs as the 870. The 86 Corvette and up it works very well.
Hope this has helped a little

Hello Again Forum,

My 85 has been suffering from slowly degrading performance....it only has about 75,000 miles on it and I am trying to stem the tide of age as is , I would guess, everyone else with older cars. I purchased an auto xray scanner hoping to get some clues as to what is going on in there. First thing I found out is the trouble code clearing function would not work with my car because it wasnt supported in 85....ok...I can live with that.....when I looked into scanners in general auto xray advertised that this scanner was virtually invisible to the system....which lead me to believe it just sort of snoops on the ecm operation and displays whats going on. I have noticed a mulitiude of problems....first of all...when i scan.....the car immediately jumps up in rpms...at the same time all dash information pertaining to any milage...or fuel economy goes to zero. Temps all seem to function normally. Same with oil readings. Based on readings from this scanner I seem to have a few issues that need to be worked out. My air inlet temp only reads either 123.8 or 204 degrees......starts up with inlet temps of 123.....I bought a relocating sensor from Ecklers and nothing changes. My knock sensor is reading about 135...I replaced the sensor first.....and then the knock module and it too is unchanged. I recently put a borla exhaust and a new high flow cat in but these readings were the same before that modification.......park/neutral does not register a change......only intermittently for a second or two and goes back to detecting park/neutral while I am driving....I seem to be always calling for A/C......even tho I am not......o2 sensor fluctuates.....IAC...TPS....coolant temp,..all seem to move normally.....coolant temps and vehicle speed match almost exactly to dash readings....I once had a voltage too high code although recently get no codes.......does anyone have this type of scanner and a year close to mine so I can find out just what IS supported......I dont know much about these cars yet.....car runs almost ok when cold and then begins to run awful when warmed up.....could my ecm be crapped out and I am running on the "cal-pac" when the computer tries to take over???? I am lost right now. Any guidance would be GREATLY appreciated.......
Thanks Geoff

 

[Moonunit 451]

And, if you don't have a laptop that's got the right port, I've got an IBM thinkpad with the WinALDL program and the cable that I'd let go cheap if ya wanna go that route. I'm not familiar with the AutoXray, but might consider a trade.

 

[maxrevs85]

I have an 85 also and auto exray. Ive had no problems . This is after many mods and a new chip. But same ecm. I know thats not what you want to hear. But ive had no issues using it. Its been a couple years since I've used it. So I cant remember any specifics. I'm alot of help huh?:eyerole Sorry.

What I dont understand is why the ECM wouldnt be suspect and possibly processing the info wrong?
Dave

 

[Nazgul]

Well....that sounds like two entirely opposing viewpoints and experiences.....I was working on my car today installing the inlet temp sensor relocator kit from ecklers.....I removed the small pigtail from under the intake plenum....ran the new sensor up front by the air filter......no difference in either the operation of the engine or the readouts on the scanner......still only reads either 123...or 204 degrees. I put new plugs....again....new mmsd helicoil wires.....nothing.......I did download the winaldl and to be honest that looks great......I will order a cable right after dinner.....will it be a problem to work through a 9 pin to usb adapter?....i get information on the auto xray.....but Jan-Erik says it cant read his ecm.....I have updated to the latest software for it.......i am just getting many questionable readings......I will look for a new ecm and original chip and see if there is any change. What would the symptons be for a bad timimg chain?......and what would the symptoms be if plug wires were not routed exactly as original? after hooking back up the battery this afternoon...the scanner said the TPS was too low......but at idle the scanner reads .54 volts....which is pretty close to normal.....also said #52 calibration pack missing....and #54 fuel pump relay failure.......that was replaced anout 6 months ago....when I turn the key I can hear the fuel pump charge the rails so......?????? Thanks for all the input good people.......
Geoff

 

[jan-erik]

Hi again.
Nazgul, thereadings you have is the same as for me. The temp is fixed to a number much higher than it really is. The O2 sensor looks like it do not function as it should do (with the alternating readings). That you get a rise in the idle is normal. The integrator readings and block learn module readings are not correct. I know that the ECM works allright as I have had the ECM scanned with professional scanner. Autoxray is a very nice itemwith newer ecms there has been some od operation with 870 ecms and it may be that there are some versions of the 870 that works ok with it.

 

[77-85]

Hello Again Forum,

My 85 has been suffering from slowly degrading performance....it only has about 75,000 miles on it and I am trying to stem the tide of age as is , I would guess, everyone else with older cars. I purchased an auto xray scanner hoping to get some clues as to what is going on in there. First thing I found out is the trouble code clearing function would not work with my car because it wasnt supported in 85....ok...I can live with that.....when I looked into scanners in general auto xray advertised that this scanner was virtually invisible to the system....which lead me to believe it just sort of snoops on the ecm operation and displays whats going on. I have noticed a mulitiude of problems....first of all...when i scan.....the car immediately jumps up in rpms...at the same time all dash information pertaining to any milage...or fuel economy goes to zero. Temps all seem to function normally. Same with oil readings. Based on readings from this scanner I seem to have a few issues that need to be worked out. My air inlet temp only reads either 123.8 or 204 degrees......starts up with inlet temps of 123.....I bought a relocating sensor from Ecklers and nothing changes. My knock sensor is reading about 135...I replaced the sensor first.....and then the knock module and it too is unchanged. I recently put a borla exhaust and a new high flow cat in but these readings were the same before that modification.......park/neutral does not register a change......only intermittently for a second or two and goes back to detecting park/neutral while I am driving....I seem to be always calling for A/C......even tho I am not......o2 sensor fluctuates.....IAC...TPS....coolant temp,..all seem to move normally.....coolant temps and vehicle speed match almost exactly to dash readings....I once had a voltage too high code although recently get no codes.......does anyone have this type of scanner and a year close to mine so I can find out just what IS supported......I dont know much about these cars yet.....car runs almost ok when cold and then begins to run awful when warmed up.....could my ecm be crapped out and I am running on the "cal-pac" when the computer tries to take over???? I am lost right now. Any guidance would be GREATLY appreciated.......
Thanks Geoff

I have an 85 with a 4+3 and I noticed many of the same problems as you did with the AutoXray scanner. Some of the things you will notice:

1 - With the car running the scanner puts the engine into diagnostic mode and your IDLE will be set at 1000 RPM (mine goes to 1000).

2 - As you have noticed, the Manifold Air Temp reading is always wrong, the park/neutral reading is wrong, the AC requested reading is wrong, and the Open/Closed loop flag is not reliable.

3 - Information related to EGR function is incorrect.

As others have said, if you want a good free scanner, use WINALDL, I tried it, and it does not exibit any of the problems that the AutoXray scanner does. The only problem with WINALDL is that it requires a PC and it is not as handy to take with you if you want to scan whilst you drive.

Although the AutoXray scanner is not perfect, I have found that the following functions work fine:

- RPM
- Vehilcle Speed
- Water Temp (reads sensor ECM uses, not the one the guage uses)
- Knock reading (this is a number that increments when knock occurs)
- TPS sensor
- Oxygen sensor
- MAF sensor

I generally use the AutoXray scanner when I need quck info without having to go get the old laptop (without a working battery) out of the closet, but when I want complete information, I use the WINALDL program.

I actually bought the AutoXray scanner because I could not get WINALDL to work. Turns out that the Serial port on my PC was bad, and I had to find another old labtop on which to run WINALDL. (Note that most new PCs do not have a serial port which is required for WINALDL).

 

[Moonunit 451]

(Note that most new PCs do not have a serial port which is required for WINALDL).

This was the same problem I had, thus the older laptop with a serial port. I don't know if an adapter will work, I've had lots of trouble with them in the past.