OBD-1 PC based scanner

snipped-for-privacy@nospam.net wrote in news:ec2bjv$dc6a$ snipped-for-privacy@usenet.osg.ufl.edu:

Your "OBD-I" scanner is a paper clip.

You short the Service Check connector on top of the ECU with the paper clip, turn the ignition ON, then read the Check Engine light flashes.

See here:

page 15.

Thanks for the pdf. I was hoping for something more substantial, like hooking up the serial port of a PC, running some OBD tool, to a diagnostic port of the car and collecting performance data. I must be dreaming.:) I am specifically interested in learning about which cylinder is misfiring during engine idle. What other options do I have? There is no problem with CEL.

snipped-for-privacy@nospam.net wrote in news:ec2gmp$d82m$ snipped-for-privacy@usenet.osg.ufl.edu:

Why do you think you have a misfire? Did you fail emissions on high HC?

Your ECU cannot store or display that information. I don't know how you'd do it on your pre-OBD-II car.

When the engine idles the flow of gas out the exhaust is not smooth. There are occasional bursts and stops.

Can I do an ECU mod? I have seen some info at

and Any advise on that would be appreciated.

ok, so that's the real issue you're getting at. messing with the ecu won't fix that. and diagnostics on the obdcII ecu aren't that sophisticated either.

in relation to the exhaust, the gas flow dynamics are not optimized for idling, they're optimized for driving. flow will not be entirely "smooth". that said, if the flow is worse than normal, it's easily fixed.

yes you can, but it's massively expensive overkill and won't fix this problem. go to

and read about their conversion kits if you want to do it the factory ecu way. getting back to your existing situation, check the ignition system and oxygen sensor. non-oem sensors are often abysmal and confuse the heck out of the ecu - don't use them. fresh ignition components help significantly too because the voltage needed to spark an idle mixture is greater than that needed to spark a running mixture. weak or failing insulation on the plug leads means it may run ok on the freeway, but give weak spark on idle. same for old plugs, worn distributor cap, etc.

lastly, check the ignition timing. when doing it, [with the service connector on] check to see whether the timing marks are lashing back and forth. if they are, the timing belt could be loose - the ignition sensors run off the distributor which runs off the cam. loose belt means the whole timing for the vehicle is subject to "noise" and again, that affects smooth idle. correct valve lash helps too.

How, please elaborate.

Forgive my ignorance, at boomslang.us I do see parts they are selling but no docs that explain what to do with them. Do I need the OBD1 to OBD2 Conversion Harness, and then use OBD2 scan tools?

A friend has offered to let me use his timing light, is that the best way to see what's happeining with ignition timing?

Interesting that you mention a loose timing belt may cause this behavior. This problem started after timing belt was replaced. I will check ignition timing with a light asap and report back what I learn.

Thanks for the advise.

snipped-for-privacy@nospam.net wrote in news:ec2gmp$d82m$ snipped-for-privacy@usenet.osg.ufl.edu:

There aren't any diagnostic ports on OBD-I cars. Diagnostic port did not come until OBD-II.(1996 models)

(probably due to the lack of it on OBD-I)

Jim Yanik wrote in news:Xns9823796897314jyanikkuanet@129.250.170.84:

No such thing as "OBD-I"

i did - that's what all the verbage on the oxygen sensor/ignition/timing system was about.

yes

yes. but don't do it because you'll need a second oxygen sensor, the obdcII ecu data recorder could be used against you in the event of a crash investigation, and you'll be speed limited.

yes. with the service connector in place, if the belt is loose, you'll see the timing marks jumping back and forth. if the belt is tensioned correctly, they'll be rock solid - assuming the rest of your ignition system is working well of course.

"TeGGeR®" wrote in news:Xns9823EC248CE2Ctegger@207.14.116.130:

1994-1995 Integras;OBD-I,96-01;OBD-II.

what do YOU call it?

some of us call it obdC. but i think we all know what you mean.

Jim Yanik wrote in news:Xns9823F22302F93jyanikkuanet@129.250.170.84:

ODB was the original standard SAE-derived system installed from 1988 to

1995 in some California vehicles. The rest of the US (and Canada) used automakers' own proprietary diagnostics system.

Starting in about 1994, the entire US was forced by US federal law to begin phasing in an updated version of California's original OBD. This updated system was known as OBD-II.

After some thought here, I suppose you *could* logically call the original OBD "OBD-I". World War I was not called that until they had a second war, so the logic is similar. However, Honda's diag system is not the same thing as the original OBD.