timing and EGR position sensor

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Nov 21, 2008 | 07:44 AM

ewstrand

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timing and EGR position sensor

I know that my timing is off it is currently at 19 degrees i am going to fix it here today but i was wondering if this is what is causing the KOER codes of 12 and 13.

Now about the EGR system i have been trying to figure out the exact specifications for testing the EGR position sensor all i have found is that the voltage is supposed to be between .2-.4 volts or .8-1.0 volts how ever neither of these specifications were specific for a BII and were for much newer vehicles. I have measured the voltage between the Vref and Vout pins of the sensor and found it to be about 1.7 volts and was wondering if this is indeed out of range for this vehicle and if so by how much and just how important it would be to replace this sensor as it cost a small fortune. Because if this could cause problems with my smog test i would like to know before i go back and waste my free retest.

Any ideas and suggestions would be greatly appreciated.

Nov 21, 2008 | 10:18 AM

mrshorty

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From: UT

Quote:

I know that my timing is off it is currently at 19 degrees i am going to fix it here today but i was wondering if this is what is causing the KOER codes of 12 and 13.

I will say yes it is possible. Of course, just about anything else that effects how the engine runs can cause those codes as well. (anecdote: Once, one of my daughters was playing with the steering wheel during a KOER test on my BII. The varying load of the power steering pump caused enough variation in the engine speed to trigger those codes. I don't know what threshold the computer is looking for, but it doesn't seem to take much variation in engine speed to trigger one or both of those codes).

Quote:

Now about the EGR system i have been trying to figure out the exact specifications for testing the EGR position sensor all i have found is that the voltage is supposed to be between .2-.4 volts or .8-1.0 volts how ever neither of these specifications were specific for a BII and were for much newer vehicles. I have measured the voltage between the Vref and Vout pins of the sensor and found it to be about 1.7 volts and was wondering if this is indeed out of range for this vehicle and if so by how much and just how important it would be to replace this sensor as it cost a small fortune. Because if this could cause problems with my smog test i would like to know before i go back and waste my free retest.

You don't report any EGR codes, so I expect the EGR sensor is at least close to spec. Once, I put a voltmeter on my EGR sensor (can't remember which two leads I backprobed: Vref vs Vout or Vout vs. ground). I got a baseline (KOEO) reading of 2.x V. KOER it seemed that the EGR sensor controlled a feedback loop that tried to maintain a reading of ~3.0 V. So your 1.7 V seems a reasonable value, and where you aren't getting any EGR codes, I'd expect the EGR system is functioning correctly.

Nov 21, 2008 | 03:50 PM

ewstrand

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So i have set the timing to 10 degress anyways now when i do the KOER test i dont get the 12 and 13 codes but rather i get code 33.

Nov 21, 2008 | 04:59 PM

mrshorty

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From: UT

does it pass the KOEO test? SOP is to resolve KOEO codes first, then KOER codes. If you get a KOEO 33 (or similar), then the problem is in the sensor circuit. If it passes KOEO, then you also have to look at the vacuum lines, EVR solenoid, and such.

Nov 21, 2008 | 05:13 PM

ewstrand

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It passes the KOEO test

The idle seems a little weird with everything connected what should the engine be idling at my sticker says 850 but does that mean its the base curve idle or is that what it should actually idle at. Also with everything connect and the timing properly set what should the timing read, i know mine is set at 10 degrees but with the spout connected and the engine at idle its reading 30 degrees

Nov 21, 2008 | 10:38 PM

mrshorty

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From: UT

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Also with everything connect and the timing properly set what should the timing read, i know mine is set at 10 degrees but with the spout connected and the engine at idle its reading 30 degrees

That's pretty normal. Standard test to check timing advance is during the KOER test. If you point your timing light at the timing marks during the KOER test (between engine id and the goose pulse), the timing should be fixed at base + 20 (so if base is 10, you should see 30 give or take).

Where it passes the KOEO test, the first thing I'd probably look at would be the vacuum hoses to the EVR solenoid, from the EVR solenoid to the EGR valve, and the valve to the EGR sensoe. Also check the pipe from the exhaust manifold to the EGR valve (at this age, they are sometimes rusted away). Make sure the EGR valve can open and make sure the EVR solenoid is opening (I've found this most easily checked using the output state test right after the KOEO test).

Nov 24, 2008 | 05:19 AM

ewstrand

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So far i have replaces the EGR vacuum solenoid because when i tested it it was kinda questionable. I have also checked the vacuum lines one of which was broken which i have repaired and the rest of the vacuum lines appear to be fine. I have also disconnected the IAC started the engine connected a vacuum pump to the EGR valve and applied 5-10 inHg the idle appear to drop by over a 100 RPM(it idled a little rough but from what i understand thats to be expected during this test) after the vacuum was removed from the EGR valve the engine idle came back up. I have also checked the tube from the exhaust manifold to the EGR valve and the tube appears to be fine; however i recently applied some exhaust patch to where the tube meets the exhaust manifold to keep it from leaking.

BUT i am still getting a code 33 from the KOER test and most recently i got a code 42 something about O2 sensor high voltage running rich dont know if its repeatable yet.