free hit
counters
weird v8 engine problems - Engine/Ancilliaries - The Lotus Forums Jump to content
Sign in to follow this  
Alex Carter

weird v8 engine problems

Recommended Posts

so had the car running fine then it went weird .

1 idle is high between 2000 and 3000 seems to hold and then drop.

2 scanned the obd and its saying left bank lean right side rich 

3 cylinders 3 and 7 misfire 

4 engine rev above parameters 

5 lamder sensors in the exhausts have seamed to flat lined 1 pair at 1 volt other pair at 0.5 volts 

6 fuel value at 25% very rich

any ideas

Edited by Alex Carter

Share this post


Link to post
Share on other sites

Upgrade today to remove Google ads and support TLF.

New lamba sensors needed by the sounds of it... pretty much all of those problems can be caused by faulty O2 sensors.

Share this post


Link to post
Share on other sites

Swap the pairs over and see if symptom 2 changes. If it does, Bibs may be right and they may be kaput.

Share this post


Link to post
Share on other sites

May not be all 4. Might just be 2.

 

Do cyl's 3 & 7 come from the same coil pack? I am presuming here that the V8 runs 4 coil packs for the 8 cyl's?

Share this post


Link to post
Share on other sites

Ok so have taken the plenum off again . As I tested and looked for problems I noticed that if I squeeze the idle pipe that comes from the turbo hard pipe I can slow the idle down. So I have removed the plenum again and inspected the idle controller looking at the end and blowing it seems the piston is open I would have presumed that this should be shut .so ordered another one . Comes tomorrow . As for the miss fire I will probe the ht leads tomorrow and see what the ohm rating is and may end up replacing them too then possibly spark plugs but they arnt that old . Still dont understand why the lamders have flat lined but going through the motions

Share this post


Link to post
Share on other sites

The Idle AIr Controller is preset from the factory to be partially open with no voltage applied but if you've already received the new one, you probably already know this now.

 

Only because I recently had this problem, albeit with virtually none of your symptoms except the high idle, I would recommend you check your secondary fuel injectors for leaks. Mine would stick open after WOT and give me a 3k rpm idle. Simply spraying them with carburetor cleaner solved the problem.

Edited by billstr

Share this post


Link to post
Share on other sites

Thanks bill it turned out to be a mixture of a few things stuck idle valve increased fuel preasure poor ignition leads that too much fuel wiped out the weak spark

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  


×