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All Spark and No Bark


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Just to revisit a discussion from earlier - I actually had a flat/sticky tappet briefly in the ambulance while away on holidays last week, started in the morning just setting off and then cleared up of its own accord a few miles up the road.

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I think everything is getting enough oil. I'm going to run it and see if it goes quiet, but to do that I need to get it MOTed.

However, it seems like I am destined to experience every MS build issue going. I realised I couldn't make the car stall by covering the wing intake, so I tried directly covering the filter and the piping contracts under vaccuum but doesn't get anywhere near a stall.

I have now sealed the intake manifold to the plenum base, and the plenum to that. Still can't make the car stall, so there is a leak somewhere but it did seem to completely mess up the tuning and now it won't reliably idle, dying unless part throttle is applied.

And I've still not solved the leak...

Nothing like a tight deadline to motivate.

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just remove the whole lot of pipework and put your hand over the throttle butterfly as the piping to the wing could be well leaky. Also, your tunerstudio MAP KPA is pretty low so I doubt theres much of a leak there. When mine had a leak (near the 3mm barb I was reading around 80kpa with the engine idling (remember 100 is atmospheric). I think I also said last time that your VE values looked high to me (you cant compare directly but still).

Given youve said you definately do not have a PWM valve then its a matter of playing about with the idle air screw on top of the plenum and the VE table on and around the cells where its tending to idle. Trial and error until you have it about right. Once its idling ok you can move onto sorting the rest of the VE table and everything else but until you do its probably going to buck like a bronco and be unpleasant to drive.

Also the timing of events in starting/idling and when it dies can be a clue. The timing can indicate where to look. i.e. cranking>ASE>WUE etc.

I know I mentioned it last time..... but stick some new plugs in and get the lambda sorted. If the plugs are fouled its like having both arms tied behind your back at this point lol, and lambda can turn it from bad to ok just by itself.

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Yesterday I cancelled the MOT an hour before I was due. It was running like a bag of nails and the brakes were spongey-er than a Victoria.

The tappet noise is still not going away and is getting louder when the engine is warm, which seems a bit wrong to me. The worst issue is that holding at any point between 1000-2000 revs will result in the whole car vibrating roughly. I don't think I have a misfire, all injectors are working and the HT leads are all to the correct cylinders, so I'm not sure what would cause this.

I can't see/find an idle air screw and Google only shows 3.9s with them, where can I find it? It will eventually idle when warm but wants to stall without throttle applied. However, throttle response is great with no hesitation or stuttering.

I'm in a catch 22 with the lambda and spark plugs. I've bought new ones, but what's to stop these from getting fouled up before I get everything sorted? I need to get it at least stable before changing them.

So all in all a really disappointing day.

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I did wonder if that was the screw but couldn't work out how to get at it. Knowing it's a destructive process makes sense though I'll hate having a hole there!

I need to do more work on the vacuum leak, I got bored of it and put it on the 'after MOT' list, but looks like I'm doing that list now.

I like to understand what's causing an issue rather than just fix the immediate symptom, so what would cause an engine that was running well to suddenly not be able to idle? In sealing up the intake area did I change the AFR that it had been working on? I guess the idle screw replaces that lost air?

It just seems counterintuitive to me that it ran better with more leaks.

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whats the MAT KPA showing after youve sealed it up in tunerstudio? if its a different value it will be using a different cell in your VE table; if that cell is quite different from what it was using before then voila thats why. when diagnosing these issues on mine i had the laptop on it all the time and theres some stuff you can only diagnose using the laptop and looking at what the efi is doing.

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If your idle valve isn't connected yet, it's possible the factory idle setting isn't what you need for running without an idle valve. Sadly this is a bit counterproductive when you're trying to sort out idle issues by disabling the idle valve :)

So just go for a good baseline there, and get all the leaks sealed up.

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Changed the title as it hasn't been about a lack of spark for a long time now, and is definitely about its ability to keep running.

I have accessed the idle screw and it seems to make zero difference. I've gone to the extremes of travel and it doesn't make it better or worse, so I'm concerned now that I've somehow blocked it when I bunged up the stepper motor - is that possible? I can't look without un-sealing the pipework I've now glued everything.

Talking of which, I have confirmed that a hand over the plenum will stall the car easily. Given that I have Tiger Sealed every join between there and the filter, it's a bit of a mystery why the same over the filter does not produce a stall. There must be a hole somewhere in the pipework, which is really annoying as it was very expensive but I have seen splits around the clamps so I think there must be some I haven't seen and sealed.

I initally wanted to go with Wyrem hose but at £300 for a minimum order of 6m, I don't think that's an option. Any other recommendations?

I am increasingly concerned that the rough running when warm and the louder tappet-type noise are linked, to the point I think they're exactly timed. I'm going to check the lobes again but what could cause this? The valves not opening enough because the lifter isn't lifting?  I don't want to take it all apart if the running quality is down to MS and not something physical (and the noisey tappets are just noisey) but I think I'm almost beyond that point.

 

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I didn't like to mention liners as I have been down that path myself.

They sound exactly like an ill-adjusted tappet, however, typically when the engine is cold they may not make a noise at all, but as it gets hot the ticking starts, which can build up to quite a racket depending on how many are slipping.

Did you take photographs of the block when the heads were off?

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22 minutes ago, Chazza said:

I didn't like to mention liners as I have been down that path myself.

They sound exactly like an ill-adjusted tappet, however, typically when the engine is cold they may not make a noise at all, but as it gets hot the ticking starts, which can build up to quite a racket depending on how many are slipping.

Did you take photographs of the block when the heads were off?

Those are my exact symptoms. I did have a noisy tappet or four, as seen they had not fully filled with oil but on taking the valley gasket off today, all are now rock solid. On cold start, the engine now sounds really good.

It was the noise getting worse when hot that has led to Turner's to suggest it might be slipped liners. It is cylinder 5 or 7 - exatly where I heard the tappet noise before rebuild, which I had blamed on the bad cam. I had the block pressure tested, cleaned, etc, etc but if they didn't look for slipped liners, they wouldn't have found it (I'm told).

I've just reassembled it after replacing the tappets so tomorrow I'll start it, if it does it again, I have my answer but I am now quite sure I know.

I know I have a predisposition to assuming the worst case, but at what point am I allowed to be entirely peed off with this build?

 

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All three of those liners have a circular gap where they meet the aluminium. My engine had one looking as bad as your RH one and 2 others with the gap starting to show.

Hard luck! Turners can re-sleeve it for you. It is worth doing, my engine runs superbly now, much better than it has ever done. Just need to install the Megasquirt,

Cheers Charlie

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That does it. Started up, sounded good for a few minutes then clacky. It does sound like it's more over the cylinders than the tappets though I know these noises travel around. If I had to guess, I'd say one majorly slipped on the passenger side and one or two just about moving, with another going on the driver side.

I'll be emailing Turners now. I think I can strip it down to a bare block in-situ, the issue will be getting the crank out. And reassembly of course, but I'll cross that one when motivation comes back.

To think I was within an hour of heading off to the MOT. I don't have words.

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That's a right kick in the sack :( what can I say except that when you eventually get it up & running & driving around the pain will be forgotten and you'll have a vehicle you can enjoy and be proud of. I've had similar setbacks from the 109 over the years, some days I've wanted to take a match to it or stick it on eBay but once it's sorted it's always been worth it in the end.

If it helps, I'm sure I've seen sleeves from other suppliers and more general engine shops more than capable of doing the work for a lot less than some of the LR/Rover outfits seem to charge - they're a bit of a trek but Banda in Portsmouth have done work for quite a few club members, myself included, and have always done a proper job for very low pennies - might be worth asking around see if anyone local can do it.

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