Misfire when 1/3 warm

Post by **foggyjames** » 22 Dec 2005 02:40 pm

Just remembered I need to specify which car this is now

It's the 360...(although Nessy is giving the exact same symptoms, albeit for a totally different reason (idle solenoid and/or air leaks).

Slightly random problem this one. I suspect this is a simple tune-up issue (for a start, my plug leads are ancient, and new ones are going to be ordered next time I'm making a shopping trip to the stealership), but the limited 'window' of water temperature it happens in has got me wondering...

Basically, after the car has been running for 5-10 minutes, it suddenly won't idle. Lift the revs to 1500-2000 and it'll keep running, but sounds like it's running on two pots. Depending on the type of motoring, it'll go away usually within 2 minutes. If you're in traffic, that's a major PITA.

Apart from the leads (which are known to be shot), the carbs could do with a rebuild, and the sealing to the manifold is 'dubious' at best. However, vacuum leaks wouldn't particularly explain the limited timescale (unless the manifold expands in a manner which only affects it at certain temps....shrug...). If I had the wideband installed, that would help me on that front...

Ring any bells? I'm fairly sure it's entirely due to the leads, but I just thought I'd throw it open to the floor...

cheers

James

Post by **pettaw** » 22 Dec 2005 06:49 pm

OK, so is this as the car's warming up and you're pushing the choke in? I suspect electrics actually, the dizzy cap may have moisture trapped in it which takes a few minutes to dry out. Sometimes as it dries out it moves around? I dunno, but would suspect a new cap and leads would help.

I didn't see any problems with Nessy on that front. Has this just developed? 1.4s are not renowned for air leak problems unless something has rattled loose, but considering its only just been put together......

Post by **foggyjames** » 22 Dec 2005 07:39 pm

Due to my silly carbs, choke is unnecessary beyond about 5 seconds of running (or maybe for the first minute, if you start off having to climb a big hill). This is definitely a 'fault', rather than pilot error. For a start, it's only just started doing it (and since the start of the cold spell, so it isn't icing).

Moisture in dizzy cap...could well be actually, didn't think of that. The cap is recent though - less than a year old. When my cap was shafted before, the symptoms were a lack of power at low RPM, rather than poor idling.

As for Nessy...pass... She started making some fairly alarming rattling sounds latterly (sounded like the air pan), but I just didn't have time to even look at it. I suspect something had worked loose. I haven't had chance to put the new studs in yet, so I may have to replace the inlet / exhaust gasket. In the end, it was a crazy rush - I was literally home for about 30 minutes after collecting her before leaving for Derby.

I'm sure it's an easy fix, and I'll have good news on that front in January.

cheers

James

Post by **Carl** » 22 Dec 2005 07:45 pm

Some new leads, maybe a a dizzy cap, rotor arm and plugs would sort you out I reckon.

Had a similar problem with the Swift a few weeks ago - took the dizzy off, cleaned up all the contacts give it a spray of WD40 and wiped it out and all has been fine since!

Post by **classicswede** » 22 Dec 2005 09:48 pm

You are still running the daft rev limiter rotor arm? I have found these to be nothing but trouble and have weired faults.

Replace all the electrics!!

Post by **pettaw** » 22 Dec 2005 10:18 pm

Its probably where I've connected the idle solenoid, it was only a push fit of the wire into the connector, you really NEED to put a spade connector on there before it fails completely. It really was supposed to be just a temporary repair.

On the rattle I don't reckon anything would have rattled loose in that time, The bolts I stuck the air intake with was fairly stiff to get in so I don't think it would have shaken off. The air intake on 1.4s is a bit rattly because it only hangs in the engine bay and isn't connected to anything but other than that I can't think of anything.

In the cold and damp weather anything that's not 100% electrical wise will be exposed very quickly, so I would get new leads and a new cap and rotor and fingers crossed it should solve your problems.

Dai I've got the rev limiting rotor arm in mine, and they need changing all the time because the damn springs rust and then cause silly problems. I probably should junk it and put a normal one in. The Renix limits the revs well before the rotor does anyway.

Post by **classicswede** » 22 Dec 2005 10:35 pm

I always dump the rev limiter as they are unreliable and expensive.
Aother thing to point out ( but NO WAY do think this is what the problem is) 144 from aprox 1973 have a problem wher the cam wears resulting the the valves barely lifting this can cause odd missing problems. I see it often on range rovers the cams wear very badly causing missing on gas but still run ok on petrol - take the cam out and some of the lobes can be flat!

Post by **foggyjames** » 22 Dec 2005 10:41 pm

Pulled the plugs today...guess what...they're all sooted up

I think I might be running rich, what dya say Andy

Plugs, rotor arm (late model, not rev limiting) and cap are all recent - only the leads are old. I'll start with those, and report back.

For Nessy, the idle solenoid will naturally be my first port of call...with a replacement carb

Remind me about the fuel cut-off relay Andy...will it start working if I connect that ground correctly...and if so...where do I need to connect it to get it working? IIRC we put it in the wrong place (but on paper still an effective ground), and it didn't want to play properly.

Dai...I don't think Nessy's cam can possibly be worn - she pulls like a train! She matched the B200K 360 (although I'm fairly sure the old carb was on the way out) on "the Drum Hill challenge" (ie: how fast can you go over the top of a big and very long dual carriageway hill.

cheers

James

cheers

James

Post by **pettaw** » 23 Dec 2005 12:24 am

The easiest way to explain it is on a parts diagram, its 3267716, it attaches to a connector behind the spring of the throttle stop screw, it detects when the throttle is closed, dunno how, but that's where it connects anyhoo.

You don't need a replacement carb, you need 1 male spade connector and you need to do it before it comes out and leaves you stranded or worse shorts out and blows a fuse. It'll take you about 5 minutes with a connector and a crimper.

Post by **foggyjames** » 23 Dec 2005 12:55 am

Ahh...I see...it's like a washer with a spade connector on it!

When I said about the new carb, I was referring to the cracked top plate and the need for replacement gaskets...but if you think I'd be better off just replacing the gaskets, and finding an unbroken top plate, I'll do that.

Hugh has a brand new boxed idle solenoid, so I can see a nice solution to this problem...

cheers

James

Post by **Chris_C** » 23 Dec 2005 01:23 am

Oi, I had dibs on that soliniod

Though as it's an inbreed car/part dilemma, I might let you have it. I have a feeling I don't have one connected on Kar, as I remember pulling a bit of wire off one day, thinking "This goes to a piece of plastic... hmmm, doesn't seem useful"

Post by **foggyjames** » 23 Dec 2005 03:36 am

I think if you didn't have the idle solenoid connected, you'd know about it...or did you mean the fuel cut-off?

cheers

James

Post by **Chris_C** » 23 Dec 2005 12:08 pm

Theres supposed to be two wires?! I better go and have a look

Post by **foggyjames** » 23 Dec 2005 02:59 pm

Indeed there are. As you've probably gathered, I only have one at the moment anyway

cheers

James

Post by **fidgad** » 23 Dec 2005 05:37 pm

I have one wire which goes to the idle solenoid and there seems to be a spare spade (female) connecter attached to that.