I am getting scan readings with my XP240 that are questionable. Mainly though, I have a slightly rough idle with a mostly stock .030 over L98 in a '88 GTA. Just got through putting in injectors cleaned by RICH at CruzinPerm. Replaced all the Vacuum hoses and sensors except the MAF.

First off, when I turn on the scan tool the idle raises from 500 to 1000. WTF? There are several readings it is not giving me like desired RPM and etc.. Anyhow, look at these readings:

EGR 0%
RPM 1000 (turn off Autoxray and it goes down!)
Coolant Temp 173 degree's
Closed Loop On
O2 Cross counts going up several per second
O2 roams from 380-682mv (Bosch O2)
TPS is .56 (.54 when off)
Int varies from 114 to 119
Knock Sensor 10 counts (!!!! at idle!!!!)
BLM=108 (and it smells a little rich out the back)
Inj Pulse is 1.3 ms

Now get this:

MAF = 2544 g/sec !!!! Am I reading this wrong?
With ignition off = 1280 g/sec
Should I chunk the MAF or the AutoXray itself.....

Opinions welcome. Thanks..

 

BTW, disconnected the MAF completely.. Still says 1280 g/sec with the engine not running. This AutoXray is buggy for some reason.

 

"First off, when I turn on the scan tool the idle raises from 500 to 1000. WTF? "

Sounds like you are in one of the optional ALDL modes. Check out your scanner manual to see how to get the ALDL mode to "normal".

 

Brent

I am checking on it. Though I took the Scanner to my '94 Chev Truck and it is working correctly. But I am going to follow your lead.

You or anyone seen reading on the MAF like that? It can't be true else the computer would be throwing a code at me. Beginning to wonder if I should have bought the new EZLINK from Auto xray. www.autotestsys.com has them for $150 with case, free shipping and the cable if anyone is looking for one.

Pat

 

Normal
Also normal
Yep, you're running rich ,all indications point to it.
Are you sure you aren't missing a decimal point in there?
At 600-650 Idle RPM I read about 9.6 gms/sec. If you are idling at 1k (which is normal when in ALDL mode) it could very well be reading 25.44 gms/sec

 

Morley

I hear what you are saying. I went out there three times to look at that number.

1) I don't understand why I am running rich, but first off is this question:

2) Why am I getting this incredible number for the MAF when the computer doesn't seem to argue with it.

Anyhow, I attached a picture of the scanner. Sorry so fuzzy, kinda hard to take a pic of it. There are no decimals in that figure.. Help!! I am lost on this one.

Btw, Fuel Pressure is at 38 lbs with vacuum connected.
Timing is at 7 degrees, but I need to recheck that. Still doesn't explain this number.

 

Ok, from the looks of the scanner it is reading correctly but the decimal point is missing 12.80 gms/sec is pretty close to normal for idle. Either the decimal point isn't working (bad LCD pixel) or it simply doesn't have one. Check the documentation on the scanner and see if it mentions it at all. If it doesn't, see if you can lay hands on another one and try it on your car or call the mfg of the scanner and put the question to them.

I would be curious as to what a laptop hooked to the ALDL and running Craig's software would show for air flow. Somehow I just like and trust a laptop running scanning software better than an actual scanner. You can see much more data at once and the on screen instructions are easier to use.

 

Well, that 1280 g/sec number is with key on/engine off. With or WITHOUT the MAF hooked up.

At idle, it is running 2544 g/sec which you theorize is 25.44 g/sec.. That one is out of range. Unless you have any ideas, I guess I better go the laptop method with C. Moates software and see what it says.

Thanks..

 

Just looked at the Autoxray again. It isn't missing a decimal. It displays a decimal like another digit in the readout unlike a hand held calulator that puts a decimal between two digits. So I guess I am at a loss right now. I've got to either find another car like mine and try it or go ahead and get Craigs software and cable made. Guess I'll start another post once I get all of this figured out.

 

Well if you are running at the 1k RPM idle then 25 gms/sec isn't too far off for that speed. I think that at 1k RPM i see almost 20 gms/sec.
If you can, verify the scanner readings against a laptop. A nice cheap laptop can be had for $50 or less on Ebay and the cable can be made for about $8, much cheaper than a scanner, and more versitile.

If the laptop sees the same readings as the scanner then you have either bad wiring or ECM/PROM, that could be why you are running rich. The computer thinks it is seeing more airflow than is really there and adds too much fuel.

 

I have a old Pentium laptop I can try. Wish my buddy had his '89 GTA to try, but oh well. You answered my question though, if it is indeed 2500 instead of 25, then I guess my ECM/Prom is bad. Again, Thanks for your replies!

 

10 counts on the knock sensor.

I'm just wondering if it is retarding the timing any?

 

doubtful. I get 13 counts on startup and none after that.

 

Can someone tell me what BLM stands for?

 

As far as the 1000 rpm's go that's because the Auto Xray puts the ECM in "Service Mode". It sets the rpm's to 1k and "Fixes the timing". Read the Auto Xray user manual page 23. I wrote a post on this a little while back and got no respose. I called Auto Xray and nothing can be done to correct this. I dont trust it with some readings. My load numbers make no sense but the maf numbers look good. I cant even read knock counts with mine. I have 870 ECM.

 

Block Learn Multiplier

 

Ever figure this MAF reading out?? My "Scantool" OBD1 scanner reads the same basic thing for my 86 MAF reading!!! No SES light or anything though to make me think the MAF or wiring/relays are bad!!