larrys93pickup

All,
I'm new to this forum, been reading alot about my pickup.
I purchased my truck brand spanking new in 93. The truck is a 22re, 4 cylinder, manual, 2wheel drive with a short bed. It has California emissions.

The truck now has about 198,000 miles, mainly freeway miles.
I had a blown head gasket last year, I changed the head gasket, and the truck runs like a champ. The only issue is that it had a small misfire. I removed the plug wire and found that removing the plug wire from cylinder number 4 caused the truck to stall. I thought that I had compression issues on cylinder number 4. I did a compression test, and all cylinders were about 2 to 3 psi off from each other, so I figured the compression was good.

I then sprayed some carb cleaner, and discovered that when I replaced the head gasket, I fubared the intake manifold gasket. It failed the first smog test, and this was due to the large intake leak near the intake for cylinder number 4. I since replaced the intake manifold gasket, and took the truck to get smogged again. It barely passed smog.

I replaced the wires, plugs, rotor, cap, air filter, all with genuine toyota parts. I changed the oil, put in some Techron injector cleaner, and the truck now idles great. I checked the timing, with te1 and e1 jumpered, and it is dead on 5deg. The idle speed is 750rpm.

I still think the truck needs to be tuned more.

Here are the readings from my smog check, it barely passed on the HC.
And think that it will not pass next time.


******************************************
15MPH (rpm 2809) results PASS
%CO2 14.3
%O2 0.0

HC (PPM) Max 95
Ave 19
Meas 93

CO% Max 0.75
Ave 0.06
Meas 0.50

NO (ppm) Max 552
Ave 136
Meas 260

****************************************
25MPH (rpm 2591) results PASS
%CO2 14.4
%O2 0.0

HC (PPM) Max 60
Ave 12
Meas 59

CO% Max 0.90
Ave 0.05
Meas 0.48

NO (ppm) Max 805
Ave 124
Meas 149

I need help understanding these readings?

Why would there be no O2 measurement?
I barely passed on the HC at both 15 and 25 miles per hour.

Any suggestions?

Thanks,
Larrys93pickup

abecedarian

O2 should be zero because any molecular Oxygen in the exhaust means that there was Oxygen in the system that wasn't used for combustion or reducing HC's or such. If O2% is not zero, there is a reaction that should occur but is not, or you've got a serious exhaust leak.

What were the compression readings on all 4 cylinders (with the throttle propped open during cranking)?

larrys93pickup

Abecedarian,

thanks for the quick response. I lost the paper with the compression numbers, but I think they were around 180psi. But I didn't open the throttle??

I had an issue with the exhaust manifold pipe, the one before the cat and after the manifold, I had an exhaust leak, I could hear it. I had a local muffler shop weld it up, and it seemed fine. I don't hear any other leaks from my exhaust, but I could be mistaken.

What if I had an exhaust leak, wouldn't the pulsation of the exhaust draw in O2 and the tail pipe sniffer at the smog station read some of this O2?

Please advise.

larrys93pickup