My car is a 1987 IROC Z with Tuned Port Injection. Here are the failed readings:

High Speed Test (2545 RPMs)
HC - 2892 (220 max allowed)
CO% - 3.73% (1.2% max allowed)

Idle Test (655 RPMs)
HC - 2005 (220 Max allowed)
CO% - 2.73% (1.2% Max allowed)

I have also noticed that my radiator cooling fans are not working properly - the primary turns on all the time making warm-up difficult, so I figure that the car was probably running a little rich to start with. I've checked the relay and it seems to be working fine, so I suspect the switch/sensor in the passenger head between #6 and #8 cylinders is bad and grounding out. The car also smells gassy - so I know it is running rich (but it goes like a bat out of hell). The timing may be a tad off as the dist hold-down bolt is a PITA to get to as well.

I have never seen readings so far out of whack! Any suggestions???

Thanks!

Dave

 

I'm getting ready to go through the same freakin BS nightmare. Whats the spec's on you car is it totally stock!!! That will help us understand why it could be failing. It needs to hit the proper cooling temp, so the fans being hosed up like that are not going to help any.

 

As far as I know it is pretty much stock. I just got the car last week and had to do a few minor things before I could take it in for inspection and smog check.

I have a motor that I rebuilt for my 79 Nova, that is sitting in my 79 Camaro right now complete with Edelbrock performer RPM intake, 600cfm carb, and Summit 1103 cam that would make my 87 IROC really fly and is VERY tempting.

Thanks!

Dave

 

I'd say start off with you're coolant fans staying on, find out why they stay on. Something might be gorund out like you said. It will run rich if the fans are on all the time. those number will drop once you fix the fans. BTW that motor you are going to replace with the stock one, that will fail emission the next time around, at least thats how it goes where i live.

 

The motor will only technically fail the test because it is a rebuilt 1972 Camaro SS motor, but unless the tech actually checks the block ID (a real PITA in the car) they can't tell for sure. The valve covers might give away something since the older motor doesn't use centerbolts, but in all seriousness I'm more concerned about puting all the emissions crap for a carb on the car (AIR and EGR mainly).

I'm going to get a new coolant temperature sensor and go from there for now. I'll probably go ahead and replace the O2 sensor since it is only about $22. If that doesn't fix it, then I might need a new MAF sensor (about $160 + $80 core).

I just reset all my trouble codes and will drive it and check them again to see if anything else creeps up. I had to replace the fuel pump relay a few days ago and after washing the motor down it tripped a code 34 and ran like crap until it dried out. I figured some water must have gotten up into the MAF sensor circuits and caused some kind of issue temporarily.

Thanks!

Dave

 

First,
Change the oil, spark plugs, air cleaner, pcv, rotor and cap.
There's no way these were done already with those numbers.
The timing is too far advanced. Bring it down (it will run with much less power) but it only needs to stay there for the test.
Reset your TPS and IAC per the instructions on the tech page.

You need to find out why its running so rich. I'm going through this right now with an LG4 carb thats just putting out too much fuel (even a new O2 and Cat did not make CO better than 3%)
Could be a couple of things like :
fuel pressure is jacked up (lower it if you can),
Air temp sensors can make it run richer due to programming of colder settings are in effect. See if they both are reading correctly.
A new O2 sensor is possibly needed as well.
The HC should come down alot with the timing reducction, pcv replacement and oil changes.
HTH

 

If your already going to replace the O2 get a heated sensor... shouldnt be a whole lot more expensive

 

After trying some of the suggestion made here, and actually getting WORSE results, I started tracing the plug wires. Turns out the previous owner had actually reversed the #1 and the #3 wires - car ran fine (it sure didn't seem like it was running on 6 cylinders - it would chirp the tires shifting into 2nd gear - TH700R4).

So after correcting the miswired problem I took it back in and it passed with flying colors!!!

So if you are ever failing miserably - check the #1 and #3 wires just to be sure.

 

Sweet ill remember that!

 

5 and 7 are even more common, next to each other on the distributer and engine.