1994 4runner need help passing smog
12-02-2010, 01:28 PM
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1994 4runner need help passing smog
My 4runner wont pass smog I replaced the egr and it still is giving the cel code for egr. It also idles rough here is my scan results. Any ideas?
12-02-2010, 02:38 PM
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Code 71?
The FSM suggests:
• Open in EGR gas temp. sensor
circuit
• Open in VSV circuit for EGR
• EGR vacuum hose disconnected,
valve stuck
• Clogged in EGR gas passage
• ECM
(The clogged EGR passage seems to afflict a lot of older trucks. While mine wasn't so bad it threw a code, I had difficulty pulling the EGR tube out of the plenum there was so much gunk.)
But that's NOT what's causing you to fail (well, the CEL alone will fail you). Your high HC is likely caused by running too rich. First, check the O2 sensor; jumper TE1 to E1 and read the voltage on VF1 while running. It should flop from about 0.5v to about 5v 8 times in 10 seconds.
The FSM suggests:
• Open in EGR gas temp. sensor
circuit
• Open in VSV circuit for EGR
• EGR vacuum hose disconnected,
valve stuck
• Clogged in EGR gas passage
• ECM
(The clogged EGR passage seems to afflict a lot of older trucks. While mine wasn't so bad it threw a code, I had difficulty pulling the EGR tube out of the plenum there was so much gunk.)
But that's NOT what's causing you to fail (well, the CEL alone will fail you). Your high HC is likely caused by running too rich. First, check the O2 sensor; jumper TE1 to E1 and read the voltage on VF1 while running. It should flop from about 0.5v to about 5v 8 times in 10 seconds.
12-02-2010, 03:21 PM
#3
Yeh ,super high HC. Do you have black smoke at your tail pipe?
Is the truck missing, aburnt valve can cause really high HC.
In addition to what scope103 said , I would also check your coolent temp sensor.
Is the truck missing, aburnt valve can cause really high HC.
In addition to what scope103 said , I would also check your coolent temp sensor.
Last edited by sam333; 12-02-2010 at 03:24 PM.
12-02-2010, 05:14 PM
#6
Do a compression check , I bet you have a low cylinder( to tight or burnt valve). If thats ok, check your coolent temp sensor. Do you have any codes showing? besides the EGR ? What do your plugs look like?
Last edited by sam333; 12-02-2010 at 05:23 PM.
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