Mi16 Backfire And Won't Rev

[peter 20]

Hi,

 

Just done conversion, she starts and idles fairly ok if you give it a little throttle but As soon as you press the accelerator it backfires/sputters/mis-fires/chugs! And will not rev up.

 

It's a 2 row ecu, and it's not the head gasket as that's new.

 

Any ideas?

[Matt Holley 11]

Sounds like air flow meter or the wiring to the airflow meter, when I did my mi conversion years ago I had it all running sweet in the garage then shut the bonnet and when to drive it and it wouldn't rev and sounded rough and that turned out to be the bonnet pushing on the plug for the afm.

[peter 20]

It has got a vauxhall afm But it has the same part number.

 

The battery also just touches the afm plug, will it run without the afm at all?

 

The valve timing could quite possibly be out, as I've changed the crank but as it has vernier pulleys I'm not quite sure what they should be set to.

 

it basically sounds like it has anti-lag when I open the throttle

[Matt Holley 11]

I don't think it will run without the afm.

 

The bast way I can describe the fualt I had was you could hear the air being sucked in but the engine took a few seconds to do anything and the revs would die rather than rev unless you tickled the throttle then you could get it to increase revs.

 

You have the afm round the right way don't you?

[jonnyturbo 3]

my turbos doing similar to this revs ok a couple of times the misfires like hell pops and bangs etc, changed everything bar the knock sensor and its still doing it lol

Edited December 18, 2011 by jonnyturbo

[peter 20]

Well ive just got a different afm today to see if that helps, so ill try that.

 

Could it be the valve timing due to the adjustable pulleys?

 

 

The turbo one sounds like the head gasket tbh ive had a few 8v turbos, but i know mine isnt due to 200psi compression...

[peter 20]

Problem fixed! I think haven't fully tested it yet but I've changed the IGNITION AMPLIFIER it starts up much easier idles smoother and revs up freely. Just the occasional misfire, but haven't fully sorted the exhaust and a few other things.

[peter 20]

Problem not fixed, it did make it alot better but now massivley back fires when letting off the throttle, it sounds like its missing quite a bit too

[luggy 13]

Check the fuel and ignition relays, the relays on my MI had a green and maroon coloured plastic housing where the wires are housed, the connections wouldnt seat properly causing all sorts of fuelling and ignition problems. Ditched the plastic housing and put spade connections direct to the relays, top tip mark the wires up before removing them from the plastic housing.

 

 

[peter 20]

Haven't touched the relays as ive only just seen this post. I have changed however the; ECU Temp seonsor Air flow meter and an ignition lead which seems to have sorted it.

 

One AFM i have appears to make the car lumpy on idle though but it does have some sort of higher lift cam, so not sure if its that?