Hi everyone,

Please forgive my inexperience on diagnostics in advance, but the only way to learn is to ask since I really want to know more about this area of my cars.

I recently acquired a Snap-On OBD 1 scanner but not really sure what I am looking at when the information is displayed on the screen. Is there a thread that gives basic information about each of the parameters and what is normal for a stock 305 or 350 TPI engine?

Thanks,
Jason

 

Did the owners manual give you any info?

 

Ronny,

There are manuals with it and I am still reading up, just trying to understand what the scanner is telling me about the different readouts on these engines.

Jason

 

Man that is a huge subject!!!

First use the scanner to make sure you have no codes set!

Then I guess just ask/learn what each one is measuring and telling you.

Information changes, there are some that have acceptble varibles and set limits, all things change when driving... just to many subjects to ask one overall question!

 

im guessing you have the MT2500, or red brick as its known in the trade.
the owners manual doesn't have anything as far as what the readings from the ECM are.
hook it up and write down what you see, such as Int, Blm, TPS, MAP and so on. then do a search for those terms.
don't really worry about writing down the numbers from the scanner as right now you just need to find out what each item is, what it means, and what is normal.
for an example, Int is short term fuel trim, range being about 96-160 with 128 being target/perfect. about the same range for Blm but it means long term fuel trim.
TPS = Throttle Position Sensor, varies from ~ 0.8 up to ~5.00 volts.
also probably shows a TPS% from 0-100. MAP has about the same voltage range but is for Manifold Absolute Pressure, or better know as vacuum. also will show as varying PSI or kpa depending on what its set to in the scanner.
also, if you have the trouble shooter cartridge, it has some info on what the readings mean as well as some diagnostic info for trouble codes and some symptoms.

 

That information is what I am looking for - what each item is, what it means and what is normal. I am going to plug it back in this morning and try to write down terms and numbers and search them out. Once I do that I'm sure I'll have questions. Thanks DENN_SHAH!

 

Ok,

I just ran a scan on the 5.7 Formula and here is what I pulled after the car ran for a few minutes:

NO CODES

o2(mv) - 188
Integratr - 128-131 (fluctuates)
Open/closed - closed
TPS(v) - 0.64
Block Learn - 125
FT cell - 4
IAC Position - 62
Learned IAC - 42
o2 ready - yes
o2 crosscounts 18-30 (fluctuates)
Base PW(ms) - 1.9
Decel EN LEAN - NO
Desired Idle - 763
A/F learned - yes
MAP (kpa) 36
MAP (v) 1.40-1.42 (fluctuates)
Spark ADV 11-14 (fluctuates)
MAT(c) - 25-28 (fluctuates)
Knock - NO
Knock retard - NO
Prom ID - 571

The only thing I was wondering about was the OXYGEN readout fluctuated between rich and lean.


Based on these readings, does anything look out of line? I am going to do some searches to learn specifically about each parameter.

I don't know if it matters, but this car has no cat in the exhaust.

Thanks in advance for the help and patience!

Jason

 

the o2 sensor is supposed to switch from rich to lean....if it's not switching, then you have an issue.