ok was on track yesterday at combe... had an annoying misfire all day ..
eventually changed plugs and coil ( a group and c57's set at 25 tho) this cleared it ... also rotor arm , cap and a different set of leads..only thing not changed was the ignition amp..

when it does do it the rev counter goes off the scale. someone noted thet the actuator looked like it had been wound out (clean threads showing) so it could of been longer but that should give me less boost

but took martoon out on the last session and it reappeared with me only being able to get a top speed of 100 down the straight(was hittin 125 when it ran right)

it only did it on boost and didnt do it on every session . it was ok on the drive home and was faultless on boost... .


spec is a1 stage 3 chip,greens and 3 bar running 20 psi on standard turbo and possibly standard copmression/engine (103000 miles) but it dont smoke or anything like so i think its had a rebuild at some stage was set up by madevelopments about a year ago and has been fine untill combe

anyone got any ideas ... im getting quite miffed at the thing now

 

Sorry eagle but i dont know what age car you have...

It sounds like a late 4x4 though as its very much a "late 4x4 rear wiring harness plug" type problem ive seen many times before..

 

its a h plate stu ... i have checked the 3 plug connectors that go over the back of the cam cover ... all look ok (did look proper like not just glance) ermmmm it does spit a bit of water out of the header tank on a session so the h/gasket is getting changed for a group a one before n/d ..

where can i look for this "wiring harness plug" or is that the same as the 3 plug thing???

thanks for the reply stu

 

Those are the suspect plugs mate and ideally require cutting out and soldering.

If the rev counter sometimes goes haywire and almost always does it with the missfire, then you are picking up stray RF in these plugs and interfering with the ignition LT signal amongst others.

Sometimes earthing the penum to battery and the ignition heatsink to battery can cure it.

Best of luck.

 

aahhhhhhhhhhhh ok .. will have to sit there with the soldering iron then... what a mind numbing job thats gonna be.......
will deffo do the earthing thing aswell .. just annoying as its not a constant thing

 

I was just going to post the very same thing - good job i read all the posts first..

Check/clean the loom earth tag connections (brown wires) on the plenum chamber, but ideally make up a stout earth lead to go directly from the battery neg terminal to the plenum chamber where the others bolt on.

Sorry Pete - didn't really think about these issues talking to you yesterday.. too busy thinking about my own I guess..
It's the nutty tacho bit that gives this problem away.

 

Whilst ultimately gotta agree with Stu, doing the other bits solved my similar problem in the past without resorting to soldering up the connectors.

 

yeah the thought of 10krpm is a bit worrying

 

Morning Rich.. thought it about time i pipped you to the post with an answer in this forum

Ive just remembered something ive noted over the years... HEAT... if these connectors get hot the problem rapidly worsens, so ensure the wires arent dangling onto the cam cover as ive seen that many times due to broken clips etc etc... bottom line is its a poor design by Ford instalation team IMO as these plugs really shouldnt be here and its arguably the untidiest wiring harness in automotive history...

 

i did think why put them in such a completely toss place ???

so any ideas on your problem then rich???

 

I presume the connectors are to separate the vehicle loom from the engine loom, so they can prefit the engine loom before it all goes into the car?? Bit like the big connectors under the bonnet vent on Escos (another totally toss position!! )

Pete - I'm looking at my spanners..
I PM'd Stu last night, but don't think he's picked up the message yet -

Stu did u get my PM ?

 

ermm .. still lookin at them spanners then rich

 

erm... I've sorted out the ones I'm gonna need..

Thanks for your reply Stu

 

did ya fix it mate???

 

hell noooo - I'll need to consider the plan over a good few cups of tea first!!

 

 

ok ... updated ...

eventually got round to fitting a thick ish wire from the earth on the battery connection to the ignition amp securing screw and a bolt on the plenum...

it seems tobe working ik... so i hope its fixed now...

 

sometimes i have this prob to. so its a common 4wd saph prob. good to know how to solve it

 

very common... combination of old age wiring and crappy design in the first place

 

so a new set of wires is an option to.