OBD2 scanners (not code readers)

Long story made short:

Wife's PT Cruiser has an idle weirdness (pulsating while in gear at idle or VERY low throttle angles, mostly when cold) - I did the routine maint that was due, plugs and wires etc, no dice. No codes. I cleaned the IAC and it made the overall idle much smoother and lower, but it didn't really fix the problem. It's either the temperature sensor (I believe the coolant temp sensor is also the gage sender, and the gage reads fine) in the inlet tract, the IAC again, or the tps or the coil. I don't like throwing parts at it.

I have heard that really good scanners (Dad has one, 1000 miles away that cost a few good grand) can give you voltage readouts of all of the sensors from the OBD data stream. I can't program (well), but I know I've seen it done with a laptop too. Does anyone have tools like this, or know how I could easily check the readings one by one with some fancy programming and a connector? Don't say poke the wires with a paper clip, please. I am looking for a bit more sophistication.

Any ideas?

On my 95 Caprice (OBDI), the Helms manual would give diagnostic info on voltage drops across sensors. If you can find this information (not sure on Chrysler), you can use a good multimeter to see if the drop is withing specs. Better than throwing new sensors at it and hoping.

GRM chose one as one of their "best of 2010" feature :) I picked one up, it's kinda nice. You can log, view real-time displays or poke around with trouble codes. http://www.innovatemotorsports.com/products/ot2.php

Also... http://www.griffintechnology.com/products/cartrip

http://www.scantool.net/

http://www.autotap.com/

Most of the PC or smartphone based ones will show real time info.

I have not tried it yet, but I bought a super cheap ODB2 - USB interface off of eBay recently. It is supposed to work with the EasyObdII software available for free here:

http://www.easyobdii.com/index.php?act=viewProd&productId=15

The free software claims to show live sensor data. My USB interface was under $20 with shipping, if I recall correctly. If this is something you're interested in, I'll try it and report back the findings.

Paper clips into the connector haven't failed me yet working on Chryslers.

I know you said you cleaned the IAC, but did you clean the throttle body? For some crazy reason, the blade itself carbons up and doesn't return to a normal position.

Also check the IAT is working OK and not getting a blast of "cold" air from another source.

I can go on and on and on with the 2.4 in PT's with weirdness to them.

Brian

Ranger50 wrote: Paper clips into the connector haven't failed me yet working on Chryslers. I know you said you cleaned the IAC, but did you clean the throttle body? For some crazy reason, the blade itself carbons up and doesn't return to a normal position. Also check the IAT is working OK and not getting a blast of "cold" air from another source. I can go on and on and on with the 2.4 in PT's with weirdness to them. Brian

I did the IAT with a bag of ice and then the palm of my hand with no noticeable difference, and yes, I cleaned the throttle body as best as I could with cleaner and a rag. Nothing huge, but there wasn't much dirty there at all.

How is a paper clip going to tell you the voltage at a sensor from the OBD2 port? It's serial data. Do you mean poke it through the wires? No thanks.

dculberson wrote: I have not tried it yet, but I bought a super cheap ODB2 - USB interface off of eBay recently. It is supposed to work with the EasyObdII software available for free here: http://www.easyobdii.com/index.php?act=viewProd&productId=15 The free software claims to show live sensor data. My USB interface was under $20 with shipping, if I recall correctly. If this is something you're interested in, I'll try it and report back the findings.

Sounds dubious, but yes, if you have success I may be tempted to try it.

Keith wrote: GRM chose one as one of their "best of 2010" feature :) I picked one up, it's kinda nice. You can log, view real-time displays or poke around with trouble codes. http://www.innovatemotorsports.com/products/ot2.php Also... http://www.griffintechnology.com/products/cartrip http://www.scantool.net/ http://www.autotap.com/ Most of the PC or smartphone based ones will show real time info.

Not too bad on price... no Iphone Igadget, Icar, Ihouse here, though, so only PC based stuff.

I will try to give it a shot tonight. It's pretty simple stuff, really it's a USB to EIA232 serial converter with an ODB2 plug since the output of ODB2 is just regular old EIA232 serial. So the only reason the USB interfaces cost more than a few bucks is price gouging because it's "new." Hopefully this works; I'll drop a line later tonight with an update.

tuna55 wrote: How is a paper clip going to tell you the voltage at a sensor from the OBD2 port? It's serial data. Do you mean poke it through the wires? No thanks.

No.... At the sensor itself. I have seen the wires get chaffed and have excessive resistance. You are backprobing the sensor at the sensor. Sometimes this is the only way I have found out what is going on. As even the factory scan tool is "lying" to me.

Ranger50 wrote:

tuna55 wrote: How is a paper clip going to tell you the voltage at a sensor from the OBD2 port? It's serial data. Do you mean poke it through the wires? No thanks.

No.... At the sensor itself. I have seen the wires get chaffed and have excessive resistance. You are backprobing the sensor at the sensor. Sometimes this is the only way I have found out what is going on. As even the factory scan tool is "lying" to me.

No offense, but no thanks.

Keith wrote: http://www.scantool.net/

I like these - anyone have experience with the SX?

Shoot, ended up with dinner plans at a friends house and forgot to try the scanner last night. I'll put a reminder in my phone and do it tonight.

The cable I bought off eBay looks just like the the SX, for a lot less money. We'll see if it works.

It sounds like the software is the special part - and the hardware to convert the ODB2 serial to USB is no big deal. I hope that's the case. Then it's just the quality of the software that you got vs what they are offering.

I finally got a few minutes to try out the OBD2 interface. I can't seem to get it to work. Windows recognizes it, and the led lights up when I plug it into the car, but it doesn't actually work with either the included software or the downloaded easyobdii.

So, at least for now I can't recommend the cheap eBay USB-OBD2 interface. It was really, really cheap so I'm not out much. The Scantool SX sounds like a good one, then.

Have Dad FedEx you the fancy scanner he owns, ship back when done? Cheaper than a decent reader if you're not going to use it often enough to justify the purchase.

Keith wrote: GRM chose one as one of their "best of 2010" feature :) I picked one up, it's kinda nice. You can log, view real-time displays or poke around with trouble codes. http://www.innovatemotorsports.com/products/ot2.php Also... http://www.griffintechnology.com/products/cartrip http://www.scantool.net/ http://www.autotap.com/ Most of the PC or smartphone based ones will show real time info.

Can anyone who knows more about this than me comment on whether the innovate ot-2 or the scantool sx would be better? I don't mind paying the extra $100 to get the ability to hook it to my iphone, but I would rather get the one that does more or is easier to use. Any input?

pigeon wrote: Have Dad FedEx you the fancy scanner he owns, ship back when done? Cheaper than a decent reader if you're not going to use it often enough to justify the purchase.

Too much $$$ liability and he needs it for his shop (its kind of what he does)

Never used the scantool, but the OT-2 will interface with a PC. It'll also connect to other Innovate inputs so you can log outside sources such as a wideband. Haven't tried to do that myself yet. I can tell you it is really easy to use, although I would like a little more customizationability of the gauge display in terms of number of gauges and layout. It's okay right now (one big, two small readouts with a central number and a ring of "leds" around it) but I'd like the option of bumping up the information density. You can view a screen that does show all the raw data for your selected parameters in real time, though, so I guess there's my other option.

Well I bought a scantool. Huh. Neat. I still don't know anything, though. I can't figure out how to tell this thing to give me PWM info for the injectors or misfire information. That's what I really want. I have vacuum (looks a bit low) and a bunch of other info (O2 sensor voltage etc) that looks good, but nothing except for an odd looking screen with TID $XX where the XX is a hex code for something with mins and maxes. One of mine fails at 15 with a low of 17, but I don't know what TID$16 is.

Time to peruse those scantool forums I guess.

Sounds like the fuel trim tables. If you are at 15 and 17's that is VERY bad. Usually the next to highest number TID, in your case, is probably the idle fuel trim in park. The highest number TID is idle in gear. This is how the DRB3 and StarScan tools are setup, except they give you a grid to look at.

2.4's never have what seems to be a lot of vacuum. I rarely saw one with more 18".

Injector PW's should be available in ms. I don't know if your scan tool will have the proper 400/1000 cycle counter for misfires, but it should be available.

That wasn't fuel trim - the trim was available elsewhere with short term and long term numbers. Short term hovered right around 0, which I expect, but long term was around 15, which is a bit high. I didn't run it down the road, mind you, this is idling in the driveway.

As far as vacuum, it's roughly 2:1, since mechanics speak in inches of mercury and I speak in PSI. Think about 11" hg.

The TID numbers were all over the place, and each was intended to self diagnose SOMETHING, with mins and maxes listed for every one except in cases where it was a single ended tolerance zone (ie, mine 15, max N/A like TID 16 was). Since the actual nominal varied so much, I doubt that was fuel trim.

What do you mean available in 'ms'?

Ahh - mode 06 data.

Injector PW = pulse width = time measurement, amount of time the injector is open each time it opens. ms = milliseconds.

dculberson wrote: Injector PW = pulse width = time measurement, amount of time the injector is open each time it opens. ms = milliseconds.

Of course, I thought he was telling me where the data was, not what unit it was in.

The mode 06 data is not typically stored in engineering units, from what I see, typically a multiplier that's factory specific to get any usable unit out of it.

I can't find the injector PWM anywhere though, not even in mode 06