1997 E350 lambda problem
Thread Starter
|
New User
Joined: Aug 2014
Posts: 4
Likes: 0
1997 E350 lambda problem
Hi guys. I'm new to the forum and live across the pond where we most probably have different emmissions testing. I bought a '97 E350 7L V8 Chinook motorhome and imported it over to the UK. All was fine for a couple of the annual MOT tests but now, after 3 years and not many miles I am failing on Lambda - too much oxygen in the exhaust. CO and CO2 and NO2 are just fine. We thought we found the problem when looking at the Lambda sensor as the wires had been chewed through by a rodent and were cut and touching. Repaired to start - no change. replaced the sensor. No change. Checked for air leaks with a smoke generator and it looks like the EGR was leaking a bit - so I got rid (blanked the ports but left the valve in place to keep the ECU happy).
I still have a reading if 1.2 -1.4 and it has to be 0.9 - 1.03. I'm running out of ideas.
As the O2 sensor was definitely disconnected, and then connected again and it made no difference I wonder if the wires shorting together has damaged the ECU? I thought there should be an ODB diagnostic plug but it appears it does not have one.
Anyone have any sensible ideas to keep me sane
I still have a reading if 1.2 -1.4 and it has to be 0.9 - 1.03. I'm running out of ideas.
As the O2 sensor was definitely disconnected, and then connected again and it made no difference I wonder if the wires shorting together has damaged the ECU? I thought there should be an ODB diagnostic plug but it appears it does not have one.
Anyone have any sensible ideas to keep me sane
Lead Driver
Joined: Nov 2002
Posts: 9,558
Likes: 45
From: Concord, NC
Lambda 1.2-1.4 indicates a pretty lean mixture. Where are they taking the measurement? If the engine has a smog pump it could be giving a false reading at the tailpipe due to the additional air being pumped into the exhaust. Also make sure you have correct fuel pressure. A mixture that lean would probably cause stumbles and be low on power. There should be a diagnostic port somewhere, and could be the older OBD-I style depending on where the vehicle was originally sold.
Thread Starter
|
New User
Joined: Aug 2014
Posts: 4
Likes: 0
taken from one of the tailpipes. The engine runs just fine - doesn't feel lean and temp is spot on. It does have some pipework going into the exhaust manifold which could well be a smog pump. Can't find any ODB port - I think it should be under the dash on the drivers side (LHD). Vehicle came from Florida, originally made at the Chinook plant. I will check the plugs when I get back - that will tell me if it is really running weak.
Lead Driver
Joined: Nov 2002
Posts: 9,558
Likes: 45
From: Concord, NC
If you don't find the standard OBD-II port under the dash, check for an OBD-I connector under the hood. Here's instructions on how to get codes - EEC IV Self Test hookup - just leave out the volt meter/test light if your check engine light works and count the blinks there. There's also a diagram of the shape of the connector.
Thread
Thread Starter
Forum
Replies
Last Post
WilliamKG88
1983 - 2012 Ranger & B-Series
38
Jul 31, 2016 08:17 PM
flareinkfifeo
1980 - 1986 Bullnose F100, F150 & Larger F-Series Trucks
6
Sep 4, 2010 03:46 PM
jonny5
1987 - 1996 F150 & Larger F-Series Trucks
5
Jan 2, 2007 10:28 PM
timothy47129
Explorer, Sport Trac, Mountaineer & Aviator
13
Feb 13, 2006 10:09 AM
