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| Mystery P0400 | |
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| Tweet Topic Started: Apr 4 2014, 07:44 PM (570 Views) | |
| 3220onr | Apr 4 2014, 07:44 PM Post #1 |
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Alright metroheads lets see what you got! 1997 3/5 with 10000 miles after rebuild. Speedy gets 42 mpg avg. Car runs smooth. After rebuild the idle was around 650-700 rpm. Recently, I have noticed that the rpms have been averaging about 750 to 800 best guess by looking at the tach at idle. I recently picked a little OBD2 and ran a scan. The CIL has always been on for a O2 sensor voltage issue and I thought for certain that the code for that would pop. To my surprise that code did not show at all but the P0400 did. Now here is a little history... I put on a new EGR valvle just before the rebuild. During the rebuild I replaced all vacuum lines and did the wire in the drill cleaning of all the EGR passages. Today I took off the EGR and checked all the vacuum lines for blockage and found none or any carbon build up. The EGR diaphram does operate like its supposed to, I have had the engine running and boosted the throttle and can see the diaphram move. I have been reading the FSM and its not really helping. Any tips as to what to check next? My next step even though I dont want to do it is take the entire intake manifold off and re-clean everything. |
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| dayle1960 | Apr 4 2014, 09:25 PM Post #2 |
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Fastest Hampster EVER
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http://geometroforum.com/topic/5379119/1/ Check compression. Maybe a burned valve. Yes, I saw where it only has 10K on a rebuild, but a compression test is cheap insurance and a quick way to disprove a burnt valve theory. |
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| Memphis metro | Apr 4 2014, 09:42 PM Post #3 |
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With the car idling and you work the egr valve by hand does the engine stumble? Test your vaccum switch http://geometroforum.com/single/?p=750715&t=4464045 You can also recheck the passages for a blockage with a short piece of hose like this, http://geometroforum.com/single/?p=529035&t=4464045 |
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| 3220onr | Apr 5 2014, 05:13 PM Post #4 |
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Heyall...(thats one word way down here in mississippi) I would like to thank you all and I hope its not to premature but the check engine light has stayed off for 5 cycles now. I took Big Rhino's tutorial out to the garage with me and tested the vacuum switch. It tested fine just had to clean the outside. Could blow thru one side with a hose to the exhaust but could not blow thru the side going to the throttle body. Took my cleaning wire and drill and cleaned out the passage. Lots of carbon. Put everything back together and car runs fine and no CIL. Hope it stays that way. |
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| Memphis metro | Apr 5 2014, 07:09 PM Post #5 |
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Nothing like a solved mystery. |
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| 3220onr | Apr 5 2014, 10:45 PM Post #6 |
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The only reason I can think of why the port was plugged is during the rebuild I did not run my cleaning wire in far enough. I guess I was focused more on the other port leading to the exhaust manifold and did not give the other one enough attention. At any rate, the entire EGR systen is good to go now. Probably will not make a hoot in difference in regards to MPG's. |
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