Mi Engine Running Rough Up To 2k Revs

[adam_young 0]

My engine runs very rough up to 2k revs. After that it seems to pull fine throughout the rev range.

 

It makes no difference if the engine is cold or warmed up.

 

The idle is eratic - 900-1400rpm and the engine just seems to chug up to 2k (the entire car shakes!)

 

The dizzy cap and rotor arm were changed today. The plugs and leads have only been on for 6 months/1000 miles.

The coil has been swapped for another one after the old one failed.

 

Any help much appreciated.

[Mandic 0]

Air leak?

[DaveW 6]

air leak for sure..

[Guest akroblade954]

Air leak?

 

Or corrosion / bad connection on AFM plug

[j_turnell 137 3 Cars]

May well be worth checking all pipes are nice and tight on the induction side. Sounds like unmetered air.

[adam_young 0]

Consistant answers so that can only be a good sign.

 

I'll check everything out tomorrow.

 

It cant be anything major as that would surely show up throughout the rev range....

 

I mostly use the car around town so its imperative I get it to run ok at low revs.

 

I will post tomorrow and let you know how I get on.

[adam_young 0]

Ok so I have just been out and taken off all the hoses. In particular I took off the large hose that runs from the AFM and has the two (breather?) hoses plugging into it. I inspected it for holes, but its tight.

I did however notice that it wasn't 100% over the end of the throttle body (if that what it connects to LOL). When I put it back on I pushed it on nicely and the entire AFM/air filter etc now sits nearly a cm further to the left.

The car does run slightly better. The idle is around 1000, but it still feels like its hunting. The rev counter is wobbling and the entire car shakes at idle (you can see the engine juddering in the bay). It also stutters on light throttle up to 2k revs still and on one occasion it back fired when chaging down for a junction (again as it dropped below 2k).

 

Any other idea's? It might now sound that important, but for a towny like me its bloody annoying. Plus it used to run and idle lovely so I know it can do better.

[j_turnell 137 3 Cars]

If it backfired i'd start looking at ignition components. plugs, leads, coil, ignition amp, crank sensor, etc check for a good spark.

[nick 3]

Which way up is the AFM mounted?

 

Nick

[adam_young 0]

Which way up is the AFM mounted?

 

Nick

 

Er dunno, will have a look and perhaps take a picture - which way should it be?

[maxi 36 1 Cars]

Air flow meter...... Take it off and check the flap inside moves freely with no glitches. Is it smoking black when its chugging? If the flap isnt sticking change it anyway. Im sure its a fueling problem.

 

Maxi

[adam_young 0]

Ok so I found the motivation to have a quick look at the car after work tonight.

 

The air flow meter was mounted on its side (plug connection was facing upwards). So that could have had some effect. It seemed fine inside though, but I gave it a real good clean and removed all the dirt anyway.

 

Now in my defence I think I know why the AFM was mounted on its side - it wouldn't fit the correct way round when I put it back on last week. The reason for that being that someone had forgotten to tighten the battery bracket down so the battery had moved forward in the bay....

 

Also noticed that my K&N filter was proper filthy so that got a wash.

 

Waiting for it to dry before I put it back on the car tomorrow.

 

Fingers crossed.

[adam_young 0]

Got the AFM back on the car last night. I cant get it to sit horizontal as there just isn't enough space (even with the battery as far back as it will go in the tray). Its sitting at at about a 45 degree angle....

 

Anyway the car runs a tad better, but basically the original problem is still present.

 

What next - new plug leads (mine are a few months old)? try someone elses AFM?

[205turbo 32 2 Cars]

there are small vacume pipes on the bottom of the throttle has one of these got a split in

[Anthony 1,003]

there are small vacume pipes on the bottom of the throttle has one of these got a split in

On an Mi16? AFAIK all the breather/vacuum type connections are on top of the throttle body and inlet manifold, and underneath the throttle body is just a couple of coolant pipe connections?

[adam_young 0]

I checked all the pipes that run from the top of the throttle body as part of the initial check to make sure everything between the AFM and the throttle body was sound and not split.

 

I will double check again though.

 

Just to confirm it makes little odds if the engine is cold or warm. In fact the idle seems better when cold. When warm I have seen 1400rpm idle speeds.

 

Like I say I know its not the end of the world, but it is annoying and at the end of the day it did used to run sweet as a nut before it went in for the new gearbox. I will double check all the air pipes again.

[Alan_M 66 1 Cars]

Have you checked the throttle body?

 

The main throttle barrel through the body had seperated inside, and caused a huge air leak. Idle was all over the place and was a right pain in the arse until I located a new TB.

[adam_young 0]

Car is now sorted (haven't used it over the winter).

 

I booked it in to Chevron motorsport as its only 200 yards from my house and they do know there Mi16 engine's. The garage said that there was a pipe coming off the underside of the Inlet manifold that should have been bunged up. For some reason it wasn't.... They also set up the fueling and it now idle's spot on and is very smooth.

The mechanic that did the work had finished for the day when I picked the car up otherwise I would have got a proper explaination.

 

So as most people thought it was indeed an air leak. Annoying that I had to pay two hours labour to get it sorted, but I guess its worth it.

[paul205mi16 4]

pipe should have been bunged up? if u get the chance can u ask the mechanic which pipe it was as i have the same issues m8.

cheers

Paul.