Mgzt260 slight missfire

[Racerm5]

Hi all

just got my zt260 this weekend and loved driving it back from leeds

couple small things I need to iron out....sometimes when I start it there?s a a slight missfire like it?s slightly flooded and has to clear it?s throat....it?s just had a new set of coils and plugs so not sure if a sensor is misreading or the injectors need cleaning

it?s also just had an inlet manifold but before I start second guessing thought I?d ask if there?s anything common

im a rover nut and also got a rover 827 vitesse mk1 that I?ve restored but love the zt260 especially as it has the XPower exhaust on it....love the burble

also think might need front arm bushes and 4wa but will get round to it soon

regards Rick

[David]

Welcome, Rick!

Get a code-reader on to the OBD-II port and see if there any codes or pending codes showing. That may give you a clue. Do you have service history? Were the plugs and coils changed in an attempt to resolve a known misfire for example. If the intake has been changed, check that there is no coolant in any of the plug recesses. The gaskets can leak if the intake is badly torqued down (Dorman-type intakes tend to be more unreliable than the OE Ford or MGR intakes; do you have any indication of the make of intake was fitted?). If it has been raining recently, look for any sign of rainwater in plug recesses, particularly #8 is at the back, right hand side as you look at the motor from the front. That one gets the screen-washer jet/rainwater leakage sometimes.

As you probably realise, there are many possible reasons for a slight misfire, and it is very difficult to be more specific without some clues, or having the car in front of you.

Do you have the last 3 digits of the VIN, please? That may yield some information about the car's history which could help. I any event, it's a good idea to join the club as a full member, which will give you access to a wealth of valuable information, some of which is in Forum Sections for "full members only". Essential for a 260 owner.
Send a PM to Tim here to get a questionnaire (please excuse blatant advertising !!).

David

[Nich]

Welcome along Rick, I can only echo what David has already posted.

Nich.

[Racerm5]

Thanks david

ill plug a code reader in at work Thursday...

I know it’s number 107....I think he had it done at a mg specialist....I’ve got receipts so will have a look on parts etc....my mechanical work is a v8 nut and an ex hola ya race engine builder so will get him the have a look....I’m taking my race car to rollers tomorrow...Bmw v8 that one but will investigate....the car had just been washed so might be a water issue....just want to check the usuals before I start throwing money at it....really appreciate the help...love the car and looking forward to getting some jobs done on it

[Racerm5]

Sorry holbay

[David]

Thanks david

ill plug a code reader in at work Thursday...

I know it’s number 107....I think he had it done at a mg specialist....I’ve got receipts so will have a look on parts etc....my mechanical work is a v8 nut and an ex hola ya race engine builder so will get him the have a look....I’m taking my race car to rollers tomorrow...Bmw v8 that one but will investigate....the car had just been washed so might be a water issue....just want to check the usuals before I start throwing money at it....really appreciate the help...love the car and looking forward to getting some jobs done on it
Sounds good. I think the car had done very few miles over the last couple of years. When brought out of hibernation it may have had some 'old-fuel' problems. Worth looking at the fuel filter under the rear seat squab (passenger side). Could be partially blocked. Check for garbage under the filter too; often missed, and will get sucked up. Check that a plastic clip has been fitted to keep the two halves of the filter held together (so called "orange clip", but often white!).

Guess I can remove Jimmy Hutchinson's car from the 'Complete List of 260s For Sale' then :)

David

[Racerm5]

Lol...yeah jimmy can be removed...nice bloke and honest about the car so I’m well pleased with it

good call on fuel filters etc....I guess the 260 tank is quite different...are they the same as any Bmw parts

I will fully join as plan to be a long term keeper

i own a bmw approved body shop so happy to help with any body or paint issues if anyone is stuck

i also race a 4.0 v8 Bmw 1 series and have Rob from Afm racing work for me...I will look into the mustang engine for mods over time Not that I plan to modify it much but he has already talked about e92 m3 throttle bodies ��

im back at work tomorrow so will start to look into it

anywhere better for parts ?

thanks again

[SCP440]

Just because it has new coils I would check what make they are, there are some very cheap options on the market and if they were fitted by a garage who knows what was fitted.

Some of the performance options work well like MSD and make starting a lot better and not even a bad price if purchased from the right source.

Steve

[David]

I think the intake and gaskets are at least the right ones (genuine Ford PI), since the ex-owner asked me specifically which ones on the Summit Racing list of items were the best to buy. He said at the time that he was going to do the intake swap himself. Not sure if he did take that route in the end. I mentioned MSD's to him too, but again don't know which direction he took. If they are red, Rick, they are probably MSD's; not certainly so though!

The club shop sells a few handy bits engine wise, including a larger throttle body, silicon hoses, cold-air intake tube etc.
Other important bits like brake discs and pads, heater valves, shock-absorbers and so on too. Only open to you when you become a full member though.

David

[anthony27]

Mine has always been a bit hiccoughy when starting a warm engine, but works fine otherwise. It's good to leave the ignition on for 5 seconds before you turn the starter.

Do check the fuel filter - it is a 'fit for life' item and often is never changed. But it can disintegrate after 18-odd years.

Welcome and have fun with your 260 !

[ceedy]

I had a really tiny and infrequent cough/misfure when first running, did all the normal bits, but in the end a new Throttle Position sensor cured it !! :D

even though the old one tested out as ok electrically .

[Racerm5]

Thanks all

the coil packs are msd...the manifold was from summit racing so think it?s a genuine one

been on race car today so will have a plug in tomorrow when I get chance

doNt think it?s anything major just one of them niggley things I will get sorted in the end

thanks for all your advice and will let you know how I get on

[Malcolmr]

Here are a couple of photos for you Rick. Welcome from downunder, by the way. You can see how filthy a "fit for life" fuel filter gets after 100,000kms when I last replaced mine. I have now bought two new ones from Byron Rowson (see the Facebook group) who manufactures various items to higher specs than OEM, so I'm now fit for two lives, if not more...

Malcolm

[Racerm5]

Thanks malcom I think it’s worth changing.....
right I e delved a bit and plugged into it...it comes up multiple missfire under 1000rpm and missfire in cylinder 5.....

my theory is as it’s had new msd coil pack and plugs...runs well 2000rpm I’d think it could be injector...and or throttle position sensor

what’s the experts think

[SCP440]

Move the injector from 5 to another cylinder and see if the fault moves.

Steve

[David]

After you try the injector move that Steve sensibly suggested, if that doesn't work, check the connection to the COP on #5. MSD's can be a tighter fit than the OEM COP's and not properly pushed home. Examine the COP for dampness (on and in the tube part), and ensure that the contact spring is properly seating on the spark plug terminal. Finally swap #5 COP and another in the same way as you did the injector. Peer down the plug hole and see if the plug insulator ceramic looks discolored or "different" to the others.

David

[Racerm5]

Thanks steve and Dave.....sounds like the sort of thing I was going to check....sure I will sort it...might get all injectors cleaned but will swap cylinders....see if it changes...still a beast though and fancy the Accufab throttle conversion ��

[SCP440]

While you are at it move the coil pack and spark plug to other cylinders, it will not be the first time one of these have played up.

Steve

[Malcolmr]

After you try the injector move that Steve sensibly suggested, if that doesn't work, check the connection to the COP on #5. MSD's can be a tighter fit than the OEM COP's and not properly pushed home. Examine the COP for dampness (on and in the tube part), and ensure that the contact spring is properly seating on the spark plug terminal. Finally swap #5 COP and another in the same way as you did the injector. Peer down the plug hole and see if the plug insulator ceramic looks discolored or "different" to the others.

David

After I replaced all my plugs recently after a persistent low revs misfire, old 206 was initially worse. The misfire was more frequent, especially under a light load at low revs. Then one day I was driving in normal traffic when the car gave a little surge as if someone had turned on a "go faster" switch and the misfire went away. Now the car goes like a rocket! I'm still looking for that switch, but I presume what happened was one of the COPs wasn't seating properly, as David mentions, until more driving and vibration moved it into position. I had great difficulty with cylinder 4 (I think that's no 4 - the rear one in the bank on the right hand side of the car). Very tricky getting the plug in and out and then pushing the COP back into place.

Malcolm

[ColinE]

Very tricky getting the plug in and out and then pushing the COP back into place.

Easy with the engine out :~

[SCP440]

If you put a smear of dielectric grease inside the boot of the coil pack it will go on easier. Some manufacturers specify this in their manuals.

Steve

[David]

... I had great difficulty with cylinder 4 (I think that's no 4 - the rear one in the bank on the right hand side of the car). Very tricky getting the plug in and out and then pushing the COP back into place.

Malcolm
The Ford V8 convention, Malcolm, is that that one (over by the EGR system) is number 8, not 4. When looking at the engine from the front of the car, the cylinders on your left are, front to back, 1,2,3,4 (Bank-1), and on your right, front to back, 5,6,7,8 (Bank-2). There is no universal numbering system, though. GM swap the banks over I believe. That is important to know, because the car's diagnostic system will refer to cylinders in the way specified by the manufacturer.

From Ford:
"Ford Motor Company numbers its cylinders along each side from front to back. When looking at the engine, start on your actual left-hand side with the cylinder closest to you as number one, followed by two, three and four. Then look to your actual right-hand side; the cylinder closest to you is number five, moving along the line away from you to number eight."


Been trying to avoid suggesting this, but the fact that the misfire is indicated on Rick's car at #5, points to the possibility of a problem with the intake install. #5 is the plug next to the thermostat and top hose connection. IF the plug hole is wet, then it could be a coolant a leak. If it's not wet, ignore the rest of this post!

Easiest to fix would be a top rad-hose to thermostat join leakage (common; new silicone top radiator hose from club shop).
Coolant seepage could also be from the thermostat-housing to intake alloy crossover joint (O-ring, silicone grease).
(The other common problem of a leak between the alloy crossover piece and the plastic intake there, is caused by "plastic rot", so highly unlikely with a new Ford intake).
Most likely, unfortunately is that the intake was not properly fitted. Wrong torque, wrong sequence, or not torqued cold and then again finally when warm. Another very common problem when fitting a new intake, is that, although the gaskets should be fitted dry, the head alloy becomes corroded at the joints with the water galleries. A good gasket sealant should be used sparingly, on the head-side and only around those 4 points, to avoid leakage. I had that happen and I know of one more from another member a few months back. My leak was from the gasket near plug #8, so a rear gallery, caused I suspect by no sealant being used on a corroded surface and, also not re-torquing hot. Not done by me, but by my (ex-)garage.

David

[torque2me]

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i own a bmw approved body shop so happy to help with any body or paint issues if anyone is stuck
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thanks again

Where are you based? I might have a bit of bodywork (personal and also vehicle) that needs fixing!

Kev