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Discussion in 'The Garage' started by shane74, May 11, 2005.
Can a faulty O2 sensor make a rig run crappy?? Rough idle, running too rich, that kind of thing?
yes it can. If your o2 is bad you run on a preprogramed fuel curve which is programed rich so you do not lean the engine out to much.
Well, that is about the last thing I haven't changed. It just threw a O2 sensor code this last time after I replaced some other parts. I'll pick one up and replace it. It runs like crap at idle (it wants to die) and can't hardly pull itself up a hill (knocks like crazy). It started a few weeks ago. I parked it and started driving the K5 till I could figure out whats wrong with it. It started all the sudden, like a bad vaccum leak. It only does it at idle. Once above 1500 rpm, it smooths out and runs fine w/ exception to the serious lack of power up hills. Starting to really irritate me. So far I have replaced the;
electronic spark control sensor
throttle position sensor (yes, I set it to the correct voltage)
Oh yeah, I should mention that it's and '87 burb with a TBI 5.7/700-R4.
Anybody have any ideas for me?
when you replace the o2 sensor you might want to think about upgrading to a heated o2 sensor because they work alot better than the one wire ones
Good idea. It's all about the upgrades anyway, right?!
Replace the fuel filter.
Does that rig have a knock sensor? My TPI motor did, and it sounds like (from your description) it isn't working. I've got a scanner you can borrow for as long as you need it to check out some stuff. You can pick it up at my work if you want - I can bring it to work. PM sent to ya.
By the way, if you need ideas on the three wire O2 sensor, let me know. Not a huge improvement in our area (doesn't get cold enough but any little bit helps, eh?).
Did that when I replaced all the above parts. I knew I was forgetting something.
Is that what they refer to as a "Detonation Sensor"? If so, yes, I believe I do.
Put a vacume gauge on the intake, at idle what is the reading?
Also what is your MAP sensor reading at idle?
I don't have one. Also, not sure where to hook it up to??
I pulled the MAP sensor and had it tested. It tested out fine, so I didn't replace it. What do I need to look for?
I do know at idle, the vaccum is low until it hits approx 1500 RPM.
I would put the gauge on the map sensor line (tee d into it) or at the vacume booster for the brakes. I would recommend you buy a gauge. Getting a good vacume reading will tell alot about engine issues. Leaks, valve issues, timing, ect. It will aid your correct diagnosis of the issue without needlessly spending more money.....
Not so worried about the MAP itself but what the voltage is at idle. In other words if it is reading correctly or not.
One of the few TBI codes I linked to is for the O2 sensor:
O2 open circuit (code 13) Sounds like you got rid of that problem though?
Scanner is going to help you out, sorry I don't have links to more of the "no code" troubleshooting stuff out of the manual.
How 'bout fuel pressure readings?
Those are good.
Frank (BurbinOR) loaned me his Auto X-ray scanner today. I hope to get it figured out before the end of the weekend.
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