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S4s runnning rough/stutters

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Does the CEL come on with the ignition & extinguish when you start the engine?

If not then the bulb has gone & that will limit the boost :-)

 

Yes, CEL comes on with the ignition and extinguishes when I start the engine - so bulb seems fine.

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OK, then you need to get the codes read with Freescan or Espritmon.

 

That should always be your first action with any engine problem. If the codes are zero then you know it's a physical problem.  :thumbup:


Cheers,

John W

http://jonwatkins.co.uk

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I have a tangentially related question - I solved my original stuttering problem by replacing the plug wires.  And am now debugging the lack of full boost. However, in the test drives I have done, the plug wire for cylinder #1 keeps disconnecting from the spark plug.  I made sure to have enough slack in the plug wires, but it keeps happening and when it happens, that's when I notice the strong fuel smell.  

 

Do the plug wires lock into place or do you just push them in as far as they will go?  I have attached the metal tubes on the end of the plug wires before attaching the plug wire onto the spark plug.  I am not sure what purpose the metal tubes serve, but I thought I pushed them onto the plug wire as it was originally.  Has anyone else ever had this problem?

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hmmm...good suggestion. I will take a look at your photographs - perhaps one of them will show me where the engine mounts are located.

 

The plug wires do not appear short and have a fair amount of slack, but I will see if I can increase the slack in the plug wire to cyl #1.

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engine mounts are one leg on each side of the middle of the engine block. Each leg has 3 small bolts into the engine, and one large bolt and a rubber isolator into the chassis.

 

You can see the left leg here

P3251820.JPG

P4011831.JPG

 

right leg is just behind the AC compressor and below the oil filter.

IMG_2768.JPG

 

Plug wires should have slack.

IMG_2821.jpg


Travis

Vulcan Grey 89SE

My Lotus Photo and Projects Album

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Travis - you are a Gentleman, thank you sir!  I will inspect this weekend and report back.

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Travis - I was browsing your engine rebuild pics - is this the water temp sensor that (circled in red)?

post-17016-0-44726800-1396649068.jpg

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Here's an update:

 

1) I checked the engine mounts and they both look good - I also paid more attention to the engine while running (at idle), and the engine doesn't shake at all

2) I fed more slack to the plug wire for cyl #1 and readjusted the plug wire clips that keep the plug wires connected to each other

 

The result after two test drives is that my plug wires now seem to stay connected to the spark plugs.  So now I am back to the lack of full boost.   Based on pictures above, I know exactly where the coolant temperature sensor for the ECU is located, but am I correct that it is not visible from engine bay?  i.e. there are a bunch of hoses and wires that obstruct a direct visual of of the sensor and even if I could see it, it certainly would not be possible to get a tool in there to remove it without first removing other hoses first.  So my questions are:

1) Is the coolant temperature sensor for the ECU typically replaced from the engine bay or from underneath the vehicle?

2) And assuming the answer to #1 is from the engine bay, what else should be removed to provide enough space to see and remove the sensor?

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I usually remove the boot floor. Can be a pain but i removed all the rusty fittings and replaced with alloy rivot nuts. Can now undo and remove in around 15mins.


It's Oogies turn to boogie

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Just a quick question, is it normal when pulling of a plug wire that the engine doesn't seem to care too much ? Only when I try to accelerate on 3 cylinders it gets some stuttering ?

 

I am asking because I have some damaged plug wires (bitten in multiple locations right to the wire core) So I was testing what would happen if I were to pull a wire of.

 

Here is a ultra high resolution picture of the engine room and its plug wires (you can see the damage)

https://farm8.staticflickr.com/7391/14117062066_25d5dea5c6_o.jpg

 

Steven

Edited by rotaryspeed

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Aren't these weatherproof Delphi connectors ? (The ones from the coils to the loom)

 

It seems to me that the engine is running a bit too shaky, thought this was the work of faulty plug wires. I will check resistance tomorrow.

 

BTW how hard is it to replace the wires (In terms of stuff to remove to get to the wires) ?

 

Steven

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Very, very simple.


88 Esprit NA, 89 Esprit Turbo SE, Evora, Evora S, Evora IPS, Evora S IPS, Evora S IPS SR, Evora 400, Elise S1, Elise S1 111s, Evora GT410 Sport

Evora NA

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Actually Steven, you don't need to remove anything to get to the plug wires.  Simply disconnect a plug wire from the coil pack and tie speaker wire (or anything similar) to the end of the plug wire you just disconnected from the coil pack.  You will want to use speaker wire of length ~2x the length of the plug wire just to be safe.  Then gently pull the plug wire from the spark plug end.  The goal is to fish the speaker wire all the way through.  Once fished, you can untie the speaker wire from the old plug wire and tie the speaker wire to the new plug wire and reverse the process, i.e. gently pull the speaker wire hanging near the coil pack.  Once fished, untie and reconnect the new plug wire to the coil pack.  Repeat for all 4 plug wires!  As Bibs said, very very simple.

 

-Karim

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@Karim

 

Now, thats a neat trick ! I absolutely have to try that one ! I just hope it doesnt get stuck midway through XD

 

Brgds

Steven

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The bigger risk is the speaker wire coming unattached to the plug wire while you are fishing it through! Make sure to secure it properly!

 

-Karim

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Wires are ok a bit fidfley but you dobt need to rrmove anything. Check the coil packs. I have known many go also clean the connectors and check the bottom bolts on the coil packs as these earth them 5.5mm head


It's Oogies turn to boogie

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Wires are ok a bit fidfley but you dobt need to rrmove anything. Check the coil packs. I have known many go also clean the connectors and check the bottom bolts on the coil packs as these earth them 5.5mm head

 

Good info Peter, will chek this.

 

Brgds

Steven

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