[tommckay]

Took my Astro out on the freeway for the first time and got the "Service engine soon" light. there was no irregular running and and the gauges all looked good. When I slowed down at an interchange to transition from 1 freeway to another and it went out, but as soon as I was back up to freeway speeds for a minute it came back on. When I slowed to exit, it went off again. So, it only comes on at highway speeds (60+mph) and goes right out once slowed to below 55mph.

I took it to AutoZone & Advance to have it scanned on advice given in another thread. Turns out mine is an OBD1 system and they can only scan OBD2 systems. So I May be in for the 'ol "paperclip" trick and counting flashes. But, I'm not sure which holes to put it in, and I definitely don't know how many flashes mean what.

Any information you could give me would be appreciated.

 

[thyubernoob]

My 95 does the same thing, but still runs great, was told it may be the O2 sensor :2:

 

[Mr_Bowtie]

Pic on this page shows you which ports to put it in: http://www.gnttype.org/maint/malf.html

 

[tommckay]

My 95 does the same thing, but still runs great, was told it may be the O2 sensor :2:

That's what I'm thinking it is, but I would like to know for sure. Reading posts here, it seems that there are a few different O2 sensors and a couple are a PITA to get to.

Pic on this page shows you which ports to put it in: http://www.gnttype.org/maint/malf.html

Thanks for that, now I know. Do you know how the codes are flashed? is it like this:
"flash_flash-flash___flash_flash-flash___flash_flash-flash" indicating a code 12 three times?

 

[Leeann_93]

Do you know how the codes are flashed? is it like this:
"flash_flash-flash___flash_flash-flash___flash_flash-flash" indicating a code 12 three times?

All code reporting will start with code 12. All codes are flashed 3 times. When you return to code 12, the codes are done.

And yes, it'll be flash_flash-flash for 12.

 

[tommckay]

Do you know how the codes are flashed? is it like this:
"flash_flash-flash___flash_flash-flash___flash_flash-flash" indicating a code 12 three times?

All code reporting will start with code 12. All codes are flashed 3 times. When you return to code 12, the codes are done.

And yes, it'll be flash_flash-flash for 12.

Thank you!

 

[tommckay]

Ok, I finally got a chance to do the ol' Paperclip trick, I ended up with a code 45. I understand that means a O2 sensor indicating a rich mixture. That actually makes sense based on the way the exhaust smells & some horrible gas mileage.

Any advice?

 

[Leeann_93]

I'd suspect a fuel leak under the plenum first and foremost. Pull the Vortec cover, pull the round valve (IMTV) underneath and look inside with a flashlight. Any washed-looking (goldish) areas mean a leak. Black carbony gunk is normal.

Post back what you see on which side (passenger or driver's)...

 

[tex star detail]

My 95 did the same thing. Engine light only came on at highway speeds, and only after maybe 5 -10 minutes of steady 60-70 MPH speeds. I was told it was the O2, so I replaced it. It didn't help. When the light comes on, it doesn"t go off until I turn the van off. When I turn the van back on, the light is off. It came back on the other day so I took it to Autozone. Of course they they have to shut it off to check the codes. Some will read the ODB1 for you and look up the code. Mine came back with a stored code for the MAP sensor. I took it off and brought it in for them to test. It tested good because I had them test one they had on the shelf. (though the guy testing it didn't look like he knew what the hell he was doing.) I bought a new one anyways and installed it. Only time will tell if it was the culprit.

 

[tommckay]

Tex- Yours stayed on? Mine goes back out as soon as you drop below 65mph, then comes back on when back up to 70 for a minute. It does not come on at all around town, and boy does the exhaust smell funky! And getting about 10mpg SUCKS!

Based in the good info here and talking with others (My brother happens to be a certified Master Mechanic), I believe the common problem of a fuel leak from the regulator is the culprit. I'll be verifying that today.

 

[tex star detail]

Tex- Yours stayed on? Mine goes back out as soon as you drop below 65mph, then comes back on when back up to 70 for a minute. It does not come on at all around town, and boy does the exhaust smell funky! And getting about 10mpg SUCKS!

Based in the good info here and talking with others (My brother happens to be a certified Master Mechanic), I believe the common problem of a fuel leak from the regulator is the culprit. I'll be verifying that today.

Please get back with me on your findings! PM if you have to. Mine never came on during normal city driving, only highway driving, then stayed on until I turned the van off. My exhaust smells funky too. Pretty bad actually. When I swapped rear ends the other day, the rubber hose connecting the gas filler neck to the gas tanks was loose. Squeezed it and gas came out. Had to tighten the clamp. I know that wasn't the problem, hell, not even sure why I typed it... :lol:

But please get back to me on your findings. Very interested to see if we have the same problem.

 

[tommckay]

Verified that the pressure regulator under the plenum is leaking. Having it repaired now. If anything else is discovered during dis-assembly I'll post it up.

 

[tommckay]

Well, Van's all fixicated! No other issues found when pulling it apart to replace the bad fuel pressure regulator. The van runs real nice now, seems to have better acceleration and idles smoother.

Very cool that y'all called it. Thanks.

Now it's time to just enjoy it. I got my aftermarket stereo head unit installed with a set of 6x9's I had sitting around hooked up in the back. But alas.... this was bought as my rain & winter beater. If it's above 40 degrees and not raining, I'm on my motorcycle. As I've said in my introduction thread, I bought this van to replace my F-150. That truck got a total of 8,000 miles in 2 years, this van will get more because my commute will get longer as my job is moving me a little further from home.

 

[tex star detail]

Good that you got the van fixed. I will look into what you did after I can fix my rear end vibration. :doh:

 

[Leeann_93]

Great! Glad you got 'er fixed with a minimum of fuss.