Outer Limits 4x4 Board

Didnt want to dig up an old thread found here so made a new one. Hardy was the MAF sensor the problem?
im having the same trouble(1988 3.5l EFI) missfiring but only while im
driving(road/offroad) idle is fine but anything above idle IE. smallest bit of throttle while going over even the smallest bumps on the road or hard throttle it'll miss, but its random seems to be worst while cold, and tends to get better as it heats up.

at first i thought it was an electric fault somewhere, like a short or loose wire. but now am leaning towards it running too rich or timing maybe out.

Puffs alilbit of black smoke when i blip the throttle while cold from idle spits abit of liquard out also smells like it running rich so i believe the AFM is out for starters. but not the cause of the missfiring
timing is top dead centre(one notch after at 800rpm with all advance gear etc fitted.(Is this correct?? white dot appears on the top
Been jumping around on the bull bars front and rear trying to make it miss while its idling but i cant get it to miss no matter what i grab/wiggle/jump on.
Replaced; dist cap, leads(one tip/boot fell apart), sparks(new and set gaps to 0.90mm) tested compression everything between 120 and 130psi cold.


driving me nuts been under the bonnet for a week and a half straight now.

had a look at the AFM and the flap opens great it seems, i havnt checked the resistance yet but will shortly, but i dont see how going over bumps will effect the afm in a way to cause missfiring.


any ideas?
im about to give up and drop it into a LR agent :(

You won't get it to miss at idle - mine never would not even on lpg.

Did you replace all the leads or just one ?

Tom

all of them, nice big thick topgun ones :)

Had similar issues with Disco Dave 3.5 EFI a couple of times.

Was a combination of issues, first time was plug leads, Dist cap (replaced), fuel pressure (pump stuffed), vacuuum advance and coil (each stuffed).

Second time the AFM was. PS Black smoke seems typical when blipping throttle when cold, and when thrashing it between gear changes when hot.

Also, more recently missing was due to alternator failure - first noticed when tacho started to fluctuate wildly, and missing was worse when lights etc were on. Check voltage across battery.

Replaced all of the above and got the AFM fine tuned. Cost heaps! Oh and replaced the temp sensor too last time around.

Dam been busier than i thought.

Well i tried :(, same thing with a better battery, checked everything i could think of except the pickup air gap perhaps it moves around too much cuased by the big bumbs. o well took it to http://www.technobritish.com.au/ yesterday, see what they come up with.
gave em a ring today and they're having trouble finding the problem, which i totally understand, im in no rush to get it back, just want it done right aslong as its before our 27-29th cruiserpark trip! :)

Hes bringing in some special autosparky dude so hopefully its something small and easy

G`day Pete

From their site they should know what there about they will have measured the relevant sensors and tested the fuel pump and fuel reg ?

They will also know about the connector plug on the ECU and dry joints in the ECU ?

Good luck , shouldn`t take them long , hope it isn`t too many dollars .

Peter

Well...

http://www.technobritish.com.au arnt all that special after all.
i thought these guys are supposed to be awesum and like at least fucking good.
they didnt fix the dam problem. charged me $300 for a airfilter, sparkplugs(ones in it were 2 days old) and 3 hours of 'tuning'
it was exactly the fucking same as when i took it in it even felt worse but prolly just me. i didnt know whether to cry my eyes out or bash my head to a pulp on the steering wheel.

I HOWEVER DID FIX IT once i got home. yes thats right I fixed something that landrover specialist couldnt!

when it got home after putting my bullbar on i started looking for the cause for the missfire

after an hour or two i found two wires coming off a thick bundle running around the back of the engine, they had a wire connecting the two which was loose. so i made a new one and bingo problem solved.


what pisses me off is when i took it in i went through what i had done such as change sparkplugs, dissy cap blah blah, said it seemed like a loose wire somewhere, some kind of electric problem etc went through everything. if he had listened to me he would've found the problem but no, he thought it was fuel for some unknown reason.

but at least its now fixed heh.

glad you got it sorted mate, check your PMs

Tom

thanks mate
yea much happier now, today put new gearbox, shockie bushes and trying to put new exhaust(LHS) gaskets in now. got new steering rubber knuckle comming in tomorow other than that shes all good for this weekends cruiserpark trip. o yea!

sounds good dude see ya at cruiser got the last of me rangie finished put the tow points on and all is good.