87z28maro

for the past several months i have had code 45 coming up when im at cruising speeds. even sitting in the driveway if i rev it up to 2000 rpms if i hold it there for a couple minutes the code pops up again. i have checked all of my adjustments over and over again. i just cant figure it out. i have followed the flow chart that is in the old school chilton's manual and the results of that was that the code is intermittent. im completely lost with thing. can anyone help me?

This ad is not displayed to registered members. Register your free account today and become a member on ThirdGen!

five7kid

Any other codes?

Code 45 is O2 rich. Assuming the ignition is not causing a problem, the other probability is a fuel leak into the intake manifold. The most likely source of that is the well plugs on the bottom of the fuel bowl. They are lead, and are known leakers.

87z28maro

yes 45 is the only code. how would i go about fixing that?

Damon

I'd replace the O2 sensor first, just to rule that out. If you still get the code then you need to figure out WHY it's running rich and fix it. Could be a number of reasons. Choke not opening like it should is another classic QJet issue.

87z28maro

replaced the o2 already. choke is fuctioning normally. tps is good. mcs is good. accelerator pump is good. timing set right. im not really sure what else it can be. the well plug sounds plausible. but im open to other suggestions

DoubleV

Did you check your dwell?

Just to rule it out, disconnect the bowl vent/cannister purge lines from the carb and plug em up.

87z28maro

yes ive checked dwell over and over again. still the same results. i took the carb down to only having the vacuum line to the map sensor connected. all others were plugged. same results.

DoubleV

Connect your dwell meter/scanner and note dwell. Remove your PCV hose from carb ( don't let car die though ). Your dwell should drop a good amount. If it does,, this means your ECM is able to respond to changing conditions. If it does not drop, either your O2 is bad, there's a short from your ECM terminal ( don't know which one ) to battery, or your ECM is bad.

This is not a 100% perfect test, but it might help you out.

87z28maro

ok. ill check that and get back to you

naf

Does it trip the code at idle? or at cruise? Does it run fine otherwise? Mileage good?

Does the dwell vary at idle, swing back and forth +/- 5 degrees or so, with engine warm? An easy check is to choke the carb throat with a rag, the dwell should respond by attempting to lean the mixture (increase). You could also pull open a vacuum line and the dwell should respond by decreasing (richening the mixture).

If the dwell doesn't respond there are several possible causes. Get back to us and let us know what it's doing.

__________________
"A man who voluntarily drives a car like that and still manages to maintain such impervious confidence that it will faithfully start the next time he turns that key is an encouragement for us all to take greater risks in life."

87z28maro

sorry i havent been on. been doing a lot of work around the house and such. im going to try to do the test tommorrow and ill let you know how it goes