Evo 3 misfiring under load

[ozeclipse]

I am having an issue that I can't seem to figure out.
My Evo 3 engine (in a CC coupe) splutters when I dig the boot in more than about 60% of throttle range. I've replaced my spark plugs and fuel filter, n my ignition leads are fairly new.
It has left a black build up on my old plugs and now my rear bar but doesn't seem to be burning oil...
Its messing with me cos I just found that the wastegate actuators rod popped off so it wouldn't spool up at all. I hope it hasn't done serious damage...
Out of curiousity, I turned the boost down to 6psi, it drove fine, revved out perfectly so I don't think its electrical.
Any help would be great! I'm hoping to get this car back on the road very soon, after getting a spray job! After 6 years my Eclipse project is almost complete!!

 

[youda]

i think its either leads, or coils. i would double check.
running without the waste gate actuator rod on wont damage the motor at all, may runn a little rich though.

 

[Dean]

What fuel pump are you running?

 

[mannynz]

What petrol octane rating are you using ?

 

[JETGSR]

try closing the plug gap down to .7mm if it still misses put a multimeter on your spark leads.

it should read about 2000 ohms per meter, also check that the plug connector is connecting to the plugs correctly

Lastly if your ignitor has been wet recently that can give the same problems your are having.
my guess is the plug gap is too big!

 

[Hypo]

Have you checked the timing?

 

[evopwr]

Could also be incorrect spark plugs. Remember evos need special spark plugs, not the generic ones. I had the same issue on a dyno awhile back and after replacing spark plugs with recommended ones the pinging was gone.

 

[EIII]

plug gap as mentioned

 

[ozeclipse]

Thanks for the help guys...
I think it was my boost controller (stock mitsubishi item)
I joined the vacuum lines together and unplugged the boost controller and took it for a spin. It ran beautifully, although it still needs a decent tune!
Does anyone know why my car won't run properly when I put a pod filter on my AFM? It just bogs down like its getting too much air?

 

[JETGSR]

It still is probably plug gap! as you lower boost the plug gap becomes less critical.

define not run properly?

bad idle?
lots of black smoke out the exhaust?
misses and farts?
no power?

sounds like a air leak any unmetered air entering the pipework after the AFM will upset the cars performance. Check all hoses are connected.

 

[CLuTZ]

Check all hoses are connected.

+1 and make sure the seal on the j-pipe is good

 

[cbgsr]

for plugs run a bp8es they are gapped to 0.8 already

 

[mannynz]

for plugs run a bp8es they are gapped to 0.8 already

??????

Mmmmmmmm........ So far every spark plugs I've purchased and used like BP5, 6, 7, 8 are all gapped to 0.7 to 0.8mm

 

[milkandoj]

8's thats pretty dam cold, how much power you making. 7's would be the go for most moderate engines. 8's are only if you making insane power.

 

[ozeclipse]

I was using Bosch Super 4s... specified for an Evo 3... Since the misfiring, I replaced them with the recommended ones... nmo change at all. I replaced the fuel filter... no change, but I take the pod filter off and switch back to the panel filter (I put the pod filter on when I replaced the fuel filter) and it runs great again! Its breaking traction in second when it boosts
So I'm putting it down to the boost cut-off or whatever it is called... I have an ECU upgrade planned in the future but for now, paintjob, roady and rego are all I have planned!
Its been 2 years since this car has been registered so I just wanna drive it again!

 

[OLDIE]

I have seen the same thing happen on an NA V6 camry (not mine )when it was changed from stock to a custom ss pipework with the AFM relocated in the new pipework .They ended putting it back to factory

 

[blackvr]

Dont discount the hi tension leads... I had an Evo 3 the other day misfiring under load and the spark was jumping clean thru two phenolic tubes to the head. To test... GENTLY lift the leads off the spark plug one by one until the air gap gets too great for spark to jump to the spark plug. Its pretty obvious if the leads are "leaky" as the spark will jump thru the lead to the head. BE CAREFUL and only lift the lead for the minimum time as coil packs arent keen on having no where for spark energy to go!

 

[milkandoj]

but I take the pod filter off and switch back to the panel filter (I put the pod filter on when I replaced the fuel filter) and it runs great again! Its breaking traction in second when it boosts !

I wonder if the adaptor you used to attatch the pod was skewing you afm readings, and you were leaning out, causing the missfire.
When you put the panel filter and box back in the afm read correctly and the mixtures are correct.

A differnt shaped filter alone wont do it, it must have changed the way the afm was reading the actual airflow.

Ive go two adaptors at home for a pod of an 055/609 afm, one with one wiht a 3 inch inlet one with a 4 inch inlet, the 3 inch channels the air in a small part of the afm.

 

[evopwr]

Reviving an old thread - I have a similar issue. Driving, under load the car pulls fine and then at or around 4000 rpm it starts pinging (or misfiring) but basically does not want to go any further.
Free revving, it goes past 4000rpm.

I haven't had a chance to look under the boot but what could cause this? I haven't driven the car in a while and the only thing that changed since last was a full tank a v-power (was empty before) and a new exhaust.


-alex

 

[(2much)]

alex, get your ecm data logging on!.... find out what is going on..

no doubt you will have this sussed in 1 drive