Emissions question
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New User
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From: Suffield CT.
Emissions question
i have 87' XLT 4x4 2.9L EFI and trying to pass emmissions test. everything is great except HC. limit is 160 and i got it down to 171 with minor tune up stuff.
paid to have it diagnosed and they want to replace the O2 sensor, coolant temp sensor, EGR valve, and EGR sensor.
In your opinion which of these parts would best effect the hydro cardon reading so i pass ?????? $ is short so trying to find what will help the most and buy parts as needed. I get one free retest then its 20$ again.
for example EGR valve 37$ if i fail after free test then cost of parts and 20$ for next try. etc.......
I think truck is running to rich, but the CATs still are working i think even with over 200,000 miles.
paid to have it diagnosed and they want to replace the O2 sensor, coolant temp sensor, EGR valve, and EGR sensor.
In your opinion which of these parts would best effect the hydro cardon reading so i pass ?????? $ is short so trying to find what will help the most and buy parts as needed. I get one free retest then its 20$ again.
for example EGR valve 37$ if i fail after free test then cost of parts and 20$ for next try. etc.......
I think truck is running to rich, but the CATs still are working i think even with over 200,000 miles.
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Joined: Dec 2001
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From: UT
When they diagnosed it, did they pull codes from the computer? What codes did they pull (please note which type of code, too: KOEO, KOER, or continuous memory)? If someone asked me to look at their '87 BII that just failed emissions, that's the first thing I would do (pull codes) and go from there.
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From: Suffield CT.
Don't have that info except its the typical code 33 for EGR valve.
I'm guessing this put in CT the emissions machine will detect things like O2 sensor and show i graph of what its doing. It's up to the mechanic to check the graph with manuals or some knowledge base to know if O2 sensor in my example is okay. I don't think the machine helps any more than that.
the shop is also a testing place so they pretty much know what will make it pass but i think they are a little shaddy so I wanted opinions on educated guesses if you could only replace one or two parts.
thanx in advance. -ALF
I'm guessing this put in CT the emissions machine will detect things like O2 sensor and show i graph of what its doing. It's up to the mechanic to check the graph with manuals or some knowledge base to know if O2 sensor in my example is okay. I don't think the machine helps any more than that.
the shop is also a testing place so they pretty much know what will make it pass but i think they are a little shaddy so I wanted opinions on educated guesses if you could only replace one or two parts.
thanx in advance. -ALF
Postmaster
Joined: Dec 2001
Posts: 3,742
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From: UT
So the only code it's outputting is an EGR code? Is it a KOEO, CM, and/or KOER code? You're not getting an O2 sensor code? How does the machine "detect" the O2 sensor?
If it were me, and I were getting only EGR codes, I would start by fixing those codes and see if that fixes the problem. It is possible for a sensor (like an O2 sensor) to be bad and not trigger codes, but I would start with what is known to be bad (the ones triggering codes: EGR in this case) and go from there. Once you get all pass codes and still have a problem, then go on to checking sensors one at a time.
If it were me, and I were getting only EGR codes, I would start by fixing those codes and see if that fixes the problem. It is possible for a sensor (like an O2 sensor) to be bad and not trigger codes, but I would start with what is known to be bad (the ones triggering codes: EGR in this case) and go from there. Once you get all pass codes and still have a problem, then go on to checking sensors one at a time.
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Joined: Dec 2004
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From: Suffield CT.
thanx for taking time to reply,
the 33 code is from me going to parts store and did it myself for free. these yahoos didn't say if any codes were triggered.
if there weren't but the sensors are bad like you said then they would only know by being able to interpret the "readings" they are getting from the sensor. I will ask them if it triggered any code when i pick it up from them.
thanx for advice....
BTW you ever heard of power braking the vehicle to try and get the EGR you open? these yahoos tried and popped a brake line on me. Can't wait to get it back before they brake something else
the 33 code is from me going to parts store and did it myself for free. these yahoos didn't say if any codes were triggered.
if there weren't but the sensors are bad like you said then they would only know by being able to interpret the "readings" they are getting from the sensor. I will ask them if it triggered any code when i pick it up from them.
thanx for advice....
BTW you ever heard of power braking the vehicle to try and get the EGR you open? these yahoos tried and popped a brake line on me. Can't wait to get it back before they brake something else
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From: Suffield CT.
Just to conclude this. I ended up replacing the O2 sensor and left the EGR and engine coolant temp sensor alone. Also changed 32" super swampers for 24" tires and got tested again. Passed with flying colors. CO was what was getting me. limit 160 got 171 then after these 2 little changes got a 147.
I think speed sensor may give info to computer, that's why changed tires.
thanx for all the help.
Fazang out......
I think speed sensor may give info to computer, that's why changed tires.
thanx for all the help.
Fazang out......
