Miss Since Service.....

[TheOriginalMrP]

Hi everyone, I mentioned this 3 weeks ago, but i'm refreshing the subject in the appropriate area to rule out suggestions.

Had a service 3 weeks ago, where only the following were changed....

Engine oil
Gearbox oil
Coolant
Starter Motor
Spark plugs
(Dizzy cap, rotor, and fuel filter were on the cards, but left alone due to their awkwardness. Dizzy cap and rotor arm for obvious reasons, fuel filter cos the screws kept turning, and didn't seem worth taking all the cowling off to get to the back of them)

The car starts fine, and ticks over fine, no problem on all 6 cylinders.

Under acceleration today, while still cold - ish, the car bogged down until the throttle was released a little in a few gears - never done this before.

When the engine warmed, that part seemed to be ok, but when accelerating, there seems slight hesitance until it gets to a certain revs, then it picks up fine.

Even when I rev the car from the engine compartment, it seems to lose a cylinder about 2000 rpm, then get it back about 3000 rpm, but its far more noticable when in gear accelerating gently.

I watched the guy change the spark plugs, and i'm almost certain that all the leads are secure by pushing them home as best as I can get to them.

While they were attemting to change the dizzy cap, the first clip was removed, but it wasnt long before it was put back on ! Think it was a job more suited with the engine out....... did they disturb something there?

Is there anything "Simple" that I should be looking for here ?

I understand something else could have thrown a wobbly, but i'm working on the priciple that the car drove fine to the garage apart from the starter, which is fine now.

I'm also annoyed that my radiator is dripping a little since the job, although I have a brand new one to go on, but never seen it lose anything before, even though ChrisS advised it was leaking slightly. I was weary of letting the mechanic of fill the coolant system via air extraction to a point where all the hoses contracted, but thats another issue. I just think that's a fast way of doing it on modern cars, not older more delicate ones.

Suggestions please guys, everything else seem ok!

Ben

[A Van]

Hi Ben

Does the fault disappear when warm?

If so try replacing the oxygen sensor, I had the same thing happen on my old car...I think unplugging it first cured it.

[TheOriginalMrP]

Cheers Al

I'll check to see if its still connected first, it may heve been disturbed..... if it's ok, i'll disconnect it anyhow, and see if that solves it.

I've been doing some research, and my plugs, although Bosch equivalents may not have the correct gap.

I didn't buy them off a delorean vendor, they came off ebay.

Next week, I might put the old plugs back in. or check the gaps.

They were hanging around in the garage for about a year too, but that shouldnt have made any difference. I presume a spark plug gap could cause this problem though, so thats where I should look first, although I wonder why its ok on tickover - thats usually what suffers first.

[Tourettes Tony]

sounds like fueling to me or split vacuum pipe or poss cpr TT

[bozzzydmc]

Hi Ben

Sounds to me like an electrical misfire

I know its is a little fiddly but the cap and rotor can be done with the 'top end' of the engine on. Plus a bit of room can be made if you move the fuel dis /metering head forward by undoing the w pipe and fixing bolts. No need to undo the fuel lines. I actually did mine by plugging all the ignition leads into the cap first and then seating it.

I see they unclipped the dis cap on one side , it could be this isn't seated quite correctly now. if you take the air filter off and lay down on top of the engine you can check if this is the case.

You could remove the easiest spark plug and check the gap should be 0.6 - 0.7 mm

Interesting link someone sent me recently

http://www.scribd.com/doc/2546911/DeLor ... ers-Manual

[TheOriginalMrP]

bozzzydmc Wrote:Hi Ben

Sounds to me like an electrical misfire

I know its is a little fiddly but the cap and rotor can be done with the 'top end' of the engine on. Plus a bit of room can be made if you move the fuel dis /metering head forward by undoing the w pipe and fixing bolts. No need to undo the fuel lines. I actually did mine by plugging all the ignition leads into the cap first and then seating it.

I see they unclipped the dis cap on one side , it could be this isn't seated quite correctly now. if you take the air filter off and lay down on top of the engine you can check if this is the case.

I think this is the most likely actually.

When the first clip came off, it was quite distorted and I'm wondering if its been put back on correctly.

I'll bring the car up here next week, and see if I can see any obvious movement in the cap, and check them plug gaps out.

I took the air filter off today, and when I put it back on, i'm pretty sure it was running slightly better, but I never actually went back out, and i'm sceptacle as to weather it was just incorrectly placed.

We'll see!

Cheers all.

Ben

Oh, and maybe I ought to check fuse # 1 to see if thats blown, i've read that may cause some issues...... Why might it blow you may ask? Well when the starter was dodgy, it took most of the battery current away virtually taking full power from the car, and then back again at several turns of the key - could quite easily have nuked it.......

[NickT]

A quick way to check for a misfire is to put a clamp over timing light over each spark plug lead in turn and see if you get regular flashes. (Don't point the timing lamp straight in your eyes !)

I would go for distributor cap by the way you have explained things.
That or one of the spark plug leads was pushed down without the metal contact clipping over the end properly.

Good luck

NickT.

Plug gaps are 0.65mm I think.......

[TheOriginalMrP]

Well I'm glad to say this has been peacefully resolved......

The culprit?

Spark plugs.



These have the same part number HR6DC and have a 0.7mm gap (was that the problem?)

But although these are "Super", the ones I took out, or that are back in there now are "Super Plus", and supplied by Ed in 2007.

The plugs ChrisS had in there I never seen, but they functioned fine too......

Maybe closing the gap would have helped, but she's running sweet again now, and i'll get "Super Plus" replacements ASAP

The dizzy cap was fine too, if it aint broke, dont fix it is my motto from now on.

She aint leaked any coolant in the last week either...... :?:

Thanks for everyones input, and if I can change the spark plugs in an hour, anyone can.......

Ben

[Dan6457]

Hi Ben, Glad to hear she's running fine again. I might put a set of plugs in my D when she's back together as I have no idea when they were changed last.

Why does your 106 have pink flowers and an L plate all over it? :lol:

[TheOriginalMrP]

Teaching Kelly to drive is the L plates.

The flowers are also her idea, as I have my 2 to do what I like with, so its only fair. Besides, she wanted a pink spray job, but vinyl flowers are as attractive, cheaper, and can be removed! LOL


Anyway, i'm eyeing up a new toy to replace the merc......



Another Merc!

Ben

[Dan6457]

I think you should buy my dad's toyota prius instead. :wink:

I actualy passed my test in one of those 106's. A lovely 1.5 diesel with no turbo, no powersteering, nothing. It was my mum's car back then but is long gone now. It was a very tough little car though to be fair.

[TheOriginalMrP]

Lucky you with the 1.5 diesel...... this is the 1360cc (1.4) variant.

More go in a friction powered sherman tank.

But 675 miles on a full tank (41 quid) seems to overlook the poor performance......

And its rattling its tits off with either a dodgy water pump bearing, or timing belt tensioner....... who cares? LOL

Ben

[TheOriginalMrP]

Well i'm afraid this old chestnut returns. Located some 'super plus' plugs and fitted them last week without gapping them as they seem pre gapped. Ran the same as before, missing under load until a certain revs.

Again, i cleaned the old ones up and noticed one thing i didn't notice last time. Four of the plugs have a groove in the electrode, two don't. They came from ed so why would that be?

Same part number but different number on the side. Same size. Surely the car should run best with plugs all identical. But now they are back in, its running better but not spot on like when i first took them out. Something dodgy going on here. Think i'm going to go with some NGK's this time. Had nothing but bad luck with bosche.

Then again, i'm suspecting that spitfire multi spark lead i fitted over three years ago too. Just how much difference can slight spark plug gaps or types make?

Incidently now the old plugs are back in there, there's not much chance they went back in the exact order i took them out.

But its better than the new ones. Damn car LOL

Has anyone else had spark plug issues? Come on, who gaps a spark plug these days?


Cheers guys

Mr P

[Birksie]

Does the main lead from the coil to the dizzy have a good enough contact? Or a dodgy lead?
I'm not the most technical minded when it comes to engines, but it sounds to me like an uprated coil wouldn't go a miss. Seems to be a bit 'too picky' with the new plugs.

[Guinney1971]

I'm a bit old school, in that my dad taught me alot about basic mechanics,
and I was always told to check spark plugs with a feeler gauge, they could
all look right, but one could be a tiny bit out ....

I had issues with Flopsy's running a few years ago after lots of work, and
this was resolved by changing the king lead.

Phill has a bit of a lumpy running issue with Sorbet at the mo, he's just ordered
a complete lead/ignition set off the DOC Online Shop, so that will be fitted
before we make the trip down to Shropshire next month.

Hope you manage to get things sorted ok.