Mi16 Running Problems - Tried Loads Of Things!

[axnutty 10]

Just before I do give up entirely and opt for a carb conversion route I thought Id have one last go at getting my Mi16 to run right.

 

 

Here are the symptons:

 

Cold start:

 

Turn key, engine fires instantly, revs settle at ~1500rpm. Runs fine. For the next minute maybe it will be absolutly fine.

 

As water temp rises over a couple of minutes the rubber pipe that feeds the ICV starts to make a really loud "church organ" noise. If you look at this pipe its sucking so much air through its closing up on itself. Hence the sound. If I open the throttle at all the engine revs decrease and it trys to stall. Returning it to the throttle stops the engine will hold tickover again albeit lumpy and with this pipe sucking like mad.

 

 

If I physically hold the ICV pipe round in shape, and open the throttle, you can get the engine to increase in revs but its very lumpy and seems very rich... although its hard to tell because im under the bonnet not round the back!

 

If its hot and stalls, it simply will not start!

 

Things Ive replaced:

 

Water temp sensor

Throttle body

Coil

TPS

 

Things ive quickly checked and cleaned out:

 

AFM

All rubber hoses including oil hoses and the AFM pipe for splits or blockages

Waggled as much wiring and connectors as possible whilst engine is running

Cleaned out ICV (second hand replacement bought today - so will be changing that soon

Dizzy cap & rotor arm

Plugs & leads

Ive tried waggling the throttle body spindle to induce play, but none.

 

 

 

 

Really getting fed up with this, anyone got any ideas? Please help? Are there any pipeways in teh throttle body that could have got gunked up?

Edited February 11, 2009 by axnutty

[nick 3]

I' would guess that the ICV is stuck shut and the vaccum from the inlet manifold is collapsing the pipe. Have you tried disconnecting the ICV (but keep the wiring plug on) to see if it is working, it should be flicking open and shut like mad.

 

Nick

[axnutty 10]

If I pull the rubber hose off the ICV the car stalls. So I cant see whats going on. Tried starting it again just now, but its still warm so not having it. I will have to try again tomorrow with that one.

[axnutty 10]

Tried again today pulling hose off ICV... only car wouldnt even start now at all (Hose on or not)! Strong smell of fuel after turning over for 20secs. Mind youd expect that! Really at a loss here people. Any other ideas I can try?

[nick 3]

If you block the ed of the pipe whe you pull it off it should start but not idle properly. If you can keep it running you can look into the icv and see if it's working.

 

Nick

[Anthony 1,003]

When it won't start, try unplugging the injectors and cranking it over - if it fires into life momentarily, it'll be flooded.

 

My Mi used to give similar symptoms when it (frequently) killed a dizzy cap - would normally cold start, but would be an absolute pig when hot unless you kept the revs up, overfuelled to the point of black smoke out the back, and would flood if you stalled it and tried restarting. Pulled my hair out with that one trying to work out why it killed dizzy caps all the time, and (we think) eventually tracked down to the alternator, which although it appeared to work fine (14v when running) clearly wasn't.

 

Certainly that engine is in my friends car now, and has run sweetly for 2-3 years - using a different alternator.

 

Had another friends Mi that was overfuelling very badly when warm and would barely run - that turned out to be the ECU that was at fault.

 

Not saying that either is the problem on yours, but certainly it's enough to say that Mi running issues can be caused by a fault seemingly unrelated to the obvious...

[axnutty 10]

Ok tried what you said Anthony, unplugged injectors, and cranked her over, it started and ran. So I guess it wasnt starting today because it was flooded and suffering from major bore wash. (It is an old engine after all)

 

With it up and running, I did what you suggested Nick, removed and blocked the ICV feed and started her again. Quickly grabbing the throttle spindle, and keeping her running (idle very irratic), I looked down the ICV and the wheel was moving maybe 2 or 3mm with respect to my movements on the throttle. Certainly no more than this amount and the movement was uniform. Not flicking open and shut like you describe. Is this correct? Or is it just my ICV playing up?

 

 

I'll try to get my hands on an ECU and spare dizzy cap as well then. Are the alternators different to 1.9 GTi items? As ive got one of those spare!

 

 

What else should I try?

Edited February 12, 2009 by axnutty

[crossie 0]

did you not get my text about the ecu for sale on ebay?

[luggy 13]

How about doing a compression test when the engine stalls after its warmed up.

Im just thinking along the lines of possibly worm rings and liners possibly causing excessive crankcase pressure feeding back into the inlet and causing these issues?

Might be an idea to disconnect the oil filler breather pipe to the inlet rubber thingy and block it off see if that makes a difference?

[axnutty 10]

Ed - yes I got your text, but the guy is a cock and im not spending that much on the ECU... but ill drop him an email, because it hasnt sold 3 times now so he maybe getting desparate

 

Compression is down on 2 cylinders yes. Not massively but worn none the less. However ive already tried removing crank breathers to no avail. It cant possibly be crank case breathing causing this can it?

[Cloverleaf 1]

I've seen an Mi before that was sucking the ICV pipe in, and mine does it a fair bit but runs and idles fine so maybe it's unrelated to this and it's sending you in the wrong direction.

 

If it always starts cold but has trouble when hot then maybe it's something breaking down under heat.

 

Have you tried the obvious i.e spark when warm? Connection to ignition module? Different coil? Just an idea...

[philfingers 5]

you say water temp sensor and not wanting to state the obvious but was it the Blue one for the ECU or the one for the water temp gauge on the dash? Ign Amp- is it a bosch on and is it earthed properly.

The guy I bought my Mi off had basically given up on it as it had so many problems. just electrical really. The day we pulled it out the car I was amazed it ran at all. There were broken injector plugs held on by prayer and tape, bad earths, ign amp was loose. I was suprised it ran at all TBH. Worth just going around and making sure everything is in order

[axnutty 10]

Yeah I see what your saying but the ICV pipe is literally just just open. It cant be right. I havent tried swoppping the ign amp, leads, or dizzy cap yet (although I did check them for obvious wear signs) So maybe ill try replacing these... this is where the mate with the nice working Mi16 would be a God send....

 

I did the engine conversion and it was running fine for 2months. So dont think I missed anything out. All loom adaptions were done carefully with solder and heat shrink, no twisted wires and tape... not that means anything I suppose.

 

Ill have a good bash at checking wires etc tomorrow in the daylight though

 

Yes it was the blue 2 pin water temp sensor below dizzy cap that I swopped. That the right one?

[axnutty 10]

Right update:

 

Started it again this morning and it just ran on tick over, couldnt open throttle without it dieing. So I fitted a replacement ICV and cleaned it out along with throttle body and AFM with carb cleaner. Tried again.

 

It ran and I could coax it up on throttle now, the ICV pipe doesnt seem to be sucking in so much.

 

So as people keep mentioning Dizzy cap, arm and Ign Amp I turned my attention to those. I removed the cap and cleaned off the deposits (again - I did this 6months back when i was rebuilding it) and tried again. There wasnt that much crap in there, but its made a big difference. Ran spot on! Even took it out for a 5mile drive and was A1!!

 

So maybe ive cured it!?! But question is, why would you get a build up of crap on the contacts that quick and how would that manifest itself in the way it has? Really dont see how it could cause bad hot running?

[philfingers 5]

no idea really! at least you got to the bottom of it tho!

 

Phil