So, I Have This Weird Emissions Problem...

Vehicular, not gastronomical, people.

It's time for the annual test on my OBD1 Sonoma so I make the trip to a local testing station. The tech goes through the usual routine and comes back saying he cannot get any readings to complete the test - nada, zilch, zero. WTF?

This is a '96 GMC with the 4.3 Vortech V6 and only 93,000 miles. No, the battery has not been disconnected. Yes, there was service to the fuel system but that was over four months and hundreds of miles ago. There are way more accumulated miles necessary to perform the automatic reset.

Am I most likely looking at a failed component or a botched repair/install issue? Any chance this may be related to a niggling problem with an engine that is slow to return to idle revs, weaker acceleration and worsened fuel mileage?

An inquiring mind is looking for clues before throwing money at it. Any ideas?

Are you sure you had a competent "tech" do the test? 96 should be OBD2. If that is the case, OBD2 related, I would look at the cigar lighter fuse being blown for the failure to get code data.

As to the other, might be a dying pump, but that is just a WAG.

Aren't the obd ports on the same fuse as the cigarette lighter? Perhaps that fuse is blown.

Edit: Ranger50 beat me by about 30 seconds on Tue fuse theory, damn

Its a GM, it can also be on the horn fuse.

What is this "emissions" you speak of?

Leafy wrote: Its a GM, it can also be on the horn fuse.

The horn cig and diagnostic port are usually ALL on the same circuit.

Kenny_McCormic wrote:

Leafy wrote: Its a GM, it can also be on the horn fuse.

The horn cig and diagnostic port are usually ALL on the same circuit.

Which is the #2 spot per the fuse box diagram. I pulled the fuse a little while ago and it looked fine; no visible damage at all. I replaced it anyway.

Any other ideas out there?

Got a scanner/reader yourself? Plug it in and see if it reads. If you don't have one, stop by a pepboys or such and ask them to read it.

Dirty connections are not an unknown either.

My 2001 Dodge truck couldn't be read on an OBDII scanner when I went to look at it. The fuse was fine, but I found the contacts had push out of the back of the connector. Simply pushing the wires in fixed the problem.

They plug in OBDI? Around here it's good as long as the CEL isn't on.

Is the truck OBD1 or OBD2? If he is trying to plug an OBD2 scan setup into an OBD1 vehicle it probably won't work.

In reply to Hal:

The truck is OBD2; the original post was a typo.

There is no CEL and an OBD2 scan gave nothing what-so-ever. I'm presuming that if everything was at least working correctly there would be some kind of data available, but there's nothing to read.

I would try another scanner. My older one has problems with Mopar vehicles but have never had a problem with Ford or GM.

my e36m3box passat doesnt communicate unless you hold the connector toward the rear of the car. Just a lousy connection at the port. worth a try.

use a test light to verify that you have power going thru the fuse for the lighter/OBD2 connector. you can test the fuse itself by touching the exposed metal on the fuse when it's plugged in..