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Spark Plugs Fouled With Black, Wet Stuff...

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My '89 Esprit SE is turning into a real drama. During acceleration from the traffic lights (after a 3~5 mile run), at about 25mph, the engine seems to hesitate for about 10~15 seconds (and the car will not accelerate... but doesn't stall).

After lots of wild goose chases, I pulled the spark plugs out and found all of them covered with a black wet substance. I wasn't really sure if it was oil or a really bad case of over-rich fuel. Anyway, I looked at possible causes of oil somehow getting into the cylinder heads.

A little bit of history:

The last time I had the car serviced, the mechanic put spark plugs and oil NOT recommended by the manual. The oil was a lighter grade than normal (the engine sounded really noisy... but I assumed the guy knew what he was doing). Anyway, I replaced oil with the correct type a few weeks ago, the engine sounded much better... but I'm wondering if the previous oil had a bad effect on the car. Maybe the oil seals on my turbocharger were affected by this lighter grade of oil???

I was also wondering if a crankcase breather problem might cause oil to get into the cylinder heads. I pulled the green CBV apart.... looking for a valve... but there was none! (I have since found out there isn't supposed to be one, but I don't understand why the earlier Esprits with the orange CBV had one and mine doesn't???). I hear you can add an inline filter to stop too much oil getting into the intake, but I'd rather know for sure what is causing the oily spark plug problem before spending too much money on mods that may or may not help. If the turbo is about to blow up, I think I should save my pennies for that... .or if the oil is coming from the bottom end of the car... save my pennies for an engine rebuild :hope:

There is a fair amount of oil residue in my airbox (but it has never been cleaned since I bought the car) and there are signs of oil contamination on the orange pipes going from the turbo to the chargecooler and to the intake manifold. Strangely, rest of the intake manifold looks fairly clean.

Any/all suggestions welcome.

Cheers.

Ian.

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I would get the right plugs in first and give it a run. If the plugs are too-hot ('R'), they are for race track, high rev conditions and at low rpm they will just fill with black gunk and foul - sound familiar?

Just a thought to begin with. Next up after that is a compression check or preferably a leak-down test.

Iain

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Check plugs, wires, and coil packs. Could be any of the three. Start with the easiest/cheapest and then go from there.

Over-rich can also = no spark.

Get the proper NGK plugs

The oil in the cam towers is normal for a cam tower leak, which is quite common. The sealant around the base of the cam towers can leak over time, replacement is with new Loctite 518 or Permatex anerobic sealant. But that requires removal of the cam towers and timing belt. Also replace the o-rings around the brass plugs for the cam tower bolts, and the rear cam tower o-ring seals.

Oil in the intake is somewhat normal, the breather on top of the engine just has some screens, which don't stop much. But excessive oil can point to a compression problem like bad rings. Get a compression check, or leak-down test.

Edited by Vulcan Grey

Travis

Vulcan Grey 89SE

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Thanks, guys.

I had a compression test done about 12 months ago (no problems reported). I've replaced the plugs with the correct type and also changed the ignition leads recently.

The oil in the cam towers is normal for a cam tower leak, which is quite common. The sealant around the base of the cam towers can leak over time, replacement is with new Loctite 518 or Permatex anerobic sealant. But that requires removal of the cam towers and timing belt. Also replace the o-rings around the brass plugs for the cam tower bolts, and the rear cam tower o-ring seals.

Sounds like something I can afford.... but finding the right person for this will be troublesome.

Anyway, I'll see how the plugs and leads go, then try the coils... then work from there.

Many thanks.

Cheers.

Ian

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...and the very next day... things started to get worse... Pulling away from the traffic lights, the car died...not just slowed down. I got it started again, but further down the road it stopped again and wouldn't start. I called the local motoring association and they sent someone out. Of course, as soon as he arrived, everything was ok :)

He seemed to think it was a fuel problem... maybe the pump (but having had the pump changed 10,000km ago, I doubted it... although that was about 7 years ago).

When I got home, I pulled the pump out of the right hand tank. I noticed a fancy plastic washer beneath the pump. It was probably big enough to block the pump, but the cavity where the pump sits is so small, surely I would have seen this problem a lot sooner? Note: It didn't appear to be part of the pump.

If it was the washer causing the problem, that's one cheap fix... but I doubt I'd be so lucky. The pump wasn't the easiest thing to get out, so I'm thinking I'll change the pump anyway whilst it's out.... UKP 138.09 from SJSportscars (unless I can find one cheaper). However, if I do all this and STILL have the problem.. I've wasted my time and money :)

Decisions, decisions :)

Suggestions welcome :)

Cheers.

Ian

P.S. By the way, there is a foam rubber sleeve around the pump... Any idea what it's there for?

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Hi Ian,

Very unlikely its fuel starvation if the plugs are as you describe,as suggested above do the required tests before splashing out. If you give the guys on here the findings pretty sure they can talk you through the problem.

Trevor


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Hi Ian,

Very unlikely its fuel starvation if the plugs are as you describe,

Trevor

Thanks, Trevor... but I think I have more than one problem here. The plugs haven't really had time to foul, so I'm looking at fuel supply: In an effort to chase this problem down, in the last few months, I've changed two fuel relays, 6 injectors and the fuel filter (twice).. so the only thing left is the pump (I bought a fuel cutout (inertia) switch, but I haven't figured out how to remove it yet).

In the ignition circuit, the only thing left is the ignition coil pack.

The Engine Management system is not throwing up any faults... so I guess that's a good sign. I guess it must be something basic like fuel or spark(?).

Cheers.

Ian

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If you had fuel starvation issues... you're plugs would be white. I seriously doubt it's fuel starvation.... however.. can you smell fuel on your plugs when you pull them? could you take a picture of your plugs to help us determine the source of the problem? spark plugs will show evidence of engine trouble in a matter of seconds... in fact... when I tune a car... that's how I do it.. I "read the plugs" to determine my fuel mixture and detonation amount.


Modifying esprit's.. now that's fun..

PS... I AM NOT A CERTIFIED MECHANIC.. I Have chosen to help those in need, in the past and must not be construed as being a certified technician.

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Don't know what I've done, but now my Check Engine Light won't come on. I found the 7.5amp ECM IGN fuse blown. The manual says look for a short, but I can't find anything wrong with the wiring from the fuse to the ECM (via the Direct Ignition Module). There doesn't appear to be any shorts to earth. I'm using Sheet 3 "Starter, Alternator, Ignition and ECM-93.5 M Y" as a reference (downloaded a service manual a few months ago.

Either the ECM has an internal short or the Direct Ignition Module has an internal short... or there is something spliced into the circuit that is not shown on the diagrams (or I'm not reading the diagram correctly).

I'm going to buy a bag of fuses tomorrow and see if I can isolate the problem.

Cheers.

Ian.

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