Engine Codes

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Sep 28, 2003 | 08:08 PM

joeychuck

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From: Texas

Engine Codes

Hello everyone, here is my issue. I have a 1988 F350, 4X4, 351w, auto, srw. In the KOEO test I get code 11 (system pass). When I checked my continuous code in the KOEO I got the codes 34 (EVP voltage above closed limits) and 41(No HEGO switching detected). When I do the KOER test I get the codes 33 (EGR valve not opening) and 42 (HEGO sensor curcuit indicates system rich). I have checked my vacuum lines for leaks, none. I have replaced the EGR valve, EVP sensor, and the EVR solenoid. What is it that tells the EVR solenoid to open and send vacuum to the EGR valve? I have checked the new EGR valve and it doesn't leak. I have also checked the new EVP sensor and the new EVR solenoid and the check out fine too. I am fairly new to this whole EGR headache and any help would be appreciated.

Thanks,
JPF
wrenchinfool at earthlink.net

Sep 28, 2003 | 11:11 PM

circledirt

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From: kansas

The red vacumn line to the EGR solenoid should have full time vavumn when engine is running. There should be 12 volts to this solenoid in two wire connecter. ECM pulse grounds the other wire to transmit vacumn to EGR valve. Position sensor on top of EGR valve tells ECM that EGR valve has moved. Remove vacumn line from EGR valve and connect vacumn gauge. Watch gauge during KOER test. No vacumn?-use a test light to confirm ECM pulsing soenoid. I,ll check back.

Sep 29, 2003 | 12:38 PM

joeychuck

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From: Texas

I did the checks suggested and found that there is a plug which is in between the actual EVR solenoid and the wire harness plug. When I went to disconnect that plug it cam apart and there is a diode of some sorts in there that had broken away from the contact and was not connected. I removed the plug extension, I hope that it won't do anything to hurt it, and my code 33 has gone away but I stil have code 42. Thank you very much for the help. Can you give me any insight on why I still have code 42.

JPF
wrenchinfool at earthlink.net

Sep 29, 2003 | 10:45 PM

circledirt

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From: kansas

Could be bad 02 sensor. Is exhaust black and burns your eyes? Fuel pressure regulator malfuntion. Screwy MAP sensor, also, maybe. A bad intake air temp sensor or coolant temp sensor can also make it run too rich.

Sep 30, 2003 | 07:45 AM

joeychuck

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From: Texas

I cleared my codes this morning and took it for a drive. I got the Check Engine light and when I got home I checked my continuous codes in KOEO and it was 41 (no HEGO switching detected). That tells me that the Oxyegen sensor is not working. Am I correct in that assumtion? Would that make it run rich during my KOER test? Thanks for all the input.

JPF
wrenchinfool at earthlink.net

Last edited by joeychuck; Sep 30, 2003 at 08:33 AM.

Oct 1, 2003 | 10:50 PM

circledirt

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From: kansas

If truck runs ok probably is bad 02 sensor, especially if its original.

Oct 2, 2003 | 08:00 AM

joeychuck

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From: Texas

That extension plug I took out from between the EVR and the wire harness is needed. It has a resistor in it and when I ran without it I got a code 35 (EVP above closed limits). I repaired the resistor and installed it and the code went away. Now all I have left is the o2 sensor. Thanks for all your help. I'll post how it turns out.

JPF
wrenchinfool at earthlink.net