any fix for code 48?

[Venom SHO s7]

My project car failed emissions by near twice the limit on everything. Since, i've changed the valve cover and all intake gaskets, and new plugs and wires.

I ran the codes after i did the above maintenance and came out with 24 and 48.

24 Intake Air Temperature (IAT) or Vane Air Temperature (VAT) sensor out of range - IAT VAT
This I read during a search wont cause much of a problem at all.

48 High flow unmetered air (check for large vacuum leak, inlet hoses etc.)
Electronic Ignition - coil primary circuit failure - Ignition Systems

The car runs a little rough when i start it cold too.
I dont think i have a vac leak since i just did all the gaskets and i took my time to do it right, i also have new plugs and wires, which leads me to think its the coil pack.

I searched, but didnt find anyone who specified a solution for code 48.

Oh yeah... i didnt get a code for the o2 sensors, but im going to do them while im at it, whatever helps me pass emissions.

 

[Bizzy]

Just out of curiosity, after you did the work did you clear your old codes before you pulled these? It's a pretty good idea to do that so you don't get old information that the EEC is storing.

According to SHOTimes.com code 48 is Coil 3 primary circuit failure. You may want to try a spare coil pack if you have one.

 

[Venom SHO s7]

Yeah, I had the battery off the whole time i worked on the car. But just incase im going to take it off again and run the codes one more time... after i put in the coil pack from my 89.
thanks for help Bizzy

 

[Venom SHO s7]

I got code 11 after i changed the coil pack and o2 sensors.

Its still iddling really rough at times though, and it has NO power compared to my 89.

Im stuck... i dont know what else to try.

 

[rangerj]

Code 48 from a running condition indicates a "measured air flow high at base idle". This would tend to indicate a vacuum leak or an open crack in the snorkle tube, or an idle air problem.

If the code 48 was from the continuous memory then it would indicate a circuit failure in DIS coil pack 2, or loss of secondary tach (IDM) - left side coil 3 primary circuit failure.

I have posted the tests for the DIS several times and it can be found under my signature. The test are done with a Digital Multi-Meter (NOT ANALOG) and a LED ( NOT INCANDECENT) light probe. The tests include the coil packs, as well as the CID and CPS.

The rough idle you describe sounds like it is sucking extra air from somewhere. Check this out first. Check the snorkle tube for cracks, loose clamps, etc. Check the throttle body gasket, intake manifold gaskets, including the plennum connection hoses and clamps, and the vacuum lines. Also check the IAB connection. Is it clean? The IAB would be low on my list because it did not cause a code.
rangerj

 

[rangerj]

Additional thought! Did you reset the idle after doing the work?

 

[Venom SHO s7]

Yeah. I had the battery off the whole time while i changed the gaskets and all.
Then after i did o2 sensors, switched the maf and ciol pack i reset it.

I drove it, and it feels extremely powerless, and the clattering sound is louder while driving than it is at idle.
I also noticed some 'steam' coming from the front valve cover, it's not leaking oil though, so i thought it might be an exhaust leak at the header, eventhough its pretty clear-it doesnt smell like exhaust...

at this point, if it doesnt pass emissions, im thinking of either looking for a low mileage 3.0 or just selling the car.

 

[91 SHOplus]

Perhaps you have a clogged cat? That would give you reduced power, bad emissions, and it would stink, too. Take a broom handle and tap each converter. If it rattles, it's beat.

 

[Venom SHO s7]

Hmm... good point. Ill checkout the cats, also, im going to get a driving permit so i can drive the car around and get rid of all that old gas in there.
The p.o. said it was sitting close to a year.
You think gas that old would make that big of a difference in how it runs?

 

[oh_SHO]

Was the car running poorly before you did the maintence?

 

[SHOZ123]

Make sure the power plug going to the coil pack is securely seated and making good contact. I had the rubber gasket bunched up and it caused two cylinders not to fire due to no contact at the 12V plug.