Newly Installed Mi Won't Start

[Dave_McC 0]

First attempt at starting newly rebuilt Mi yesterday - at the moment I've not got the rad plumbed in - just trying to check it will start first.

 

Yesterday I cranked it without plugs in to get oil pressure (which it did). I didn't have the king lead attached to the coil at the time and noticed a healthy spark jumping from the top of the coil to the coil body. Fitted plugs and ignition leads and tried to start it - it was occasionally trying to catch but wouldn't actually start - and then the battery died!

 

Put battery on charge overnight and tried again this morning - no hint of even trying to catch. Took king lead off distributor and stuck a spare spark plug in it earthed against one of the cam cover bolts. Also hooked up jump leads to the wife's car (with her engine running for good measure). Now don't seem to get any spark except a single spark as I release ignition key. Also when I removed the king lead from the dizzy it's no longer sparking across to the coil body.

 

Checked battery voltage - 13.75V without cranking starter, just over 11V while cranking - which I should have thought would be ok.

 

Can anyone suggest what to check next? Really want to know it will start!

 

Cheers

 

Dave

[dcc 855]

not suggesting this is the issue of your sparking problem, but could you have flooded the car when the plugs were removed (ie, did you disconnect the fuel pump when cranking?)

[large 33]

You should have a relay putting 12v to the coil I would start off looking at that, also check your earth to the engine/gearbox.

[EdCherry 34 1 Cars]

What phase is the car?

[Dave_McC 0]

Thanks for comments so far - a bit more info:

 

Car is a phase 1.5 (G reg). Engine came from an early BX - 1988 - and loom came from the same bx, along with all the ancillaries (coil etc).

 

I've replaced (brand new) the dizzy cap, rotor arm, HT leads, plugs.

 

When I turn the ignition on, one of the 2 relays in the loom clicks. When I turn to starter position, I can feel the 2nd relay click.

 

When I cranked for oil pressure, the fuel tank was empty (and I mean completely empty - I'd removed the tank previously to replace brake line).

 

I've just removed all 4 plugs again and cranked - again with king lead removed from dizzy and a spark plug stuck in end of king lead and grounded against cam cover. Again, I'm getting a single spark as I release the ignition key - but nothing whilst the key is held to starter position. I can see a mist of fuel vapour coming out of the plug holes - so the injectors are firing.

 

I also swapped the ignition amp for the one that came with the Mi engine (I've been using the one which ran the 1600 engine - hence know it worked). No spark at all - so looks like the spare ignition amp is completely dead.....

 

Thoughts? The strange thing is it was trying to fire yesterday, and there was definitely a stream of strong sparks from the coil HT post to the coil body with the king lead disconnected - now there's nothing.

 

Coil died??

 

Cheers

 

Dave

[DrSarty 90 1 Cars]

Sounds like something in the sparking chain has become disconnected or has failed. Do checks and swapsies with known, good components and you'll find it: you're only missing spark which was there. Can't be far away.

[large 33]

Try changing the relays or shorting them (or the one that gives power to the coil )out.

when you say you turn to the starter position you hear the 2nd relay click do you meen when the starter motor is turning?

as i am running a bx loom and both my relays come on at the same time. When the key is at position 2.

[Dave_McC 0]

Try changing the relays or shorting them (or the one that gives power to the coil )out.

when you say you turn to the starter position you hear the 2nd relay click do you meen when the starter motor is turning?

as i am running a bx loom and both my relays come on at the same time. When the key is at position 2.

 

I'm running 2 row ECU if that makes a difference - 1 relay energises with ignition at position 2, the 2nd relay only clicks on when the ignition switch is at position 3 - I had assumed this was right at the ecu is sensing the engine turning via the CAS signal and hence energises fuel pump relay. I know some have been wired differently though.

 

Dave

[kyepan 291]

didn't bennet418 have the same issue?

[Dave_McC 0]

OK - tried swapping the 2 relays. Seems to make no difference at all.

 

Watching the spark from the king lead, I'm actually getting 2 sparks - 1 just as I move the key to position 3, and 1 more when I release key. Again nothing while key is held to operate starter. As the coil is producing these 2 healthy sparks each time, my suspicion is on the ignition amp at the moment. Will have to try getting hold of another ignition amp and swap it.

 

Dave

[Dave_McC 0]

Update on this - the good news is it started yesterday - and I've now plumbed the rad in and run it all up to temp and bled the cooling system.

 

The bad news is....... I haven't changed any of the ignition components (even though I'd borrowed a replacement ignition amp, coil and CAS sensor to swap) - so I'm none the wiser why it did start yesterday but wouldn't before. I've tried wiggling the wiring with it running, but no difference.

 

It does however have an occasional mis-fire - I was running it at a 2,500 rpm idle yesterday to bed in the new cam - and every now and again it would do a single miss - the rev counter dropping momentarily - before recovering - so something's not quite right.

 

The other problem I have is the oil pressure reading - the engine has an uprated oil pump pressure spring. On cold start, the gauge read about 3/4 - which seemed low as the original 1600 read that with std pump spring. As the engine / oil heated up (I'm running the water/oil cooler which heats the oil quickly) the reading dropped until with the engine and oil up to temp (oil temp reading 1/2) the pressure gauge was only just out of the red section at idle.

 

When I rebuilt engine I used the pressure sensor which came with the Mi engine (I assume these are the same as for the GTI???) and with my finger over the pressure sense hole I cleaned it up with engine degreaser, washed it off and then painted it. However, I did notice that there was some oily gunge weeping out around the spade terminal for a long time afterwards. Could I have knackered the sender unit?

 

Finally - the only way to check is going to be to swap over the pressure sender - I still have the one off the 1600, so I know it works - is it possible to swap this without removing the inlet manifold - looks pretty tight to get at in situ.

 

Cheers

 

Dave

[GLPoomobile 958]

It can be removed from underneath without taking off the manifold, but it's a fait old kerfuffle. Patience is a virtue!

[Dave_McC 0]

Cheers GLP - I was hoping that was the case. Do I need a short handled spanner? - from memory when I fitted it the only way I could get a spanner on the nut was from above - and that will foul with the inlet manifold now that's fitted.

 

Dave

[GLPoomobile 958]

The shorter the spanner the better. I managed with a long spanner, as it was all I had. But everything gets in the way, like the wiring, the engine mount, the oil filter etc. Just meant lots of playing around with angles and re-positioning the spanner after making tiny turns. The good thing is you only have to loosen it a bit until you an turn the sensor body by hand.

 

Make sure you use a new copper washer when you refit it. And whilst that should be sufficient, after the hassle I went through with mine, I'd recommend using plumbers PTFE tape on the thread to help it seal when you refit it. Only cost me about 20 odd pence for a little roll from a DIY shop, and I'd always use the stuff from now on. Better than putting it all back only to find it leaks and you have to take it out again.

[Dave_McC 0]

Cheers - I've got some PTFE tape so I'll add that for good measure. Really looking forward to doing this...... not!!

 

Then fingers crossed that it's showing a sensible oil pressure - otherwise the engine will be coming out again....... Sounds good running though - no knocking or other funny noises - and manoevred around the drive under its own steam - so I'm hoping all's ok and it's just the sensor.

 

Dave

[brumster 135 1 Cars]

Dave, I had an identical symptom on my 1.9 8v which eventually turned out to be the ignition amp. Would spark on crank and de-crank (if you see what I mean) turn of the key. It was a bit intermittent but I ended up replacing everything and it went away after the amp module was swapped out. Quite typical for the amp to give problems, apparently, particularly if it's not seated on the plate properly or a bit 'rusty'/dry where it sits on. It did seem to be heat related too - would be fine starting it cold but once some warmth was in there is started to get worse. Was a come-and-go thing but progressively got worse. I'd try that first from my experiences (or connections to it).

 

Fancy that - all the way down there, all the way back home and then I read this

 

Thanks for the crank

 

Laters,

Dan

[Dave_McC 0]

Cheers Dan - I've got a spare ignition amp which is currently "on loan" - I'll try swapping it and see if that fixes it.

 

Good luck with the engine build - good to meet you today.

 

Dave

[C_W 3 1 Cars]

not suggesting this is the issue of your sparking problem, but could you have flooded the car when the plugs were removed (ie, did you disconnect the fuel pump when cranking?)

 

This usually doesn't (can't?) happen with the plugs out as the fuel is just ejected out of the plug holes.

[pug_ham 242 3 Cars]

If your loom also came from a BX, have you got the earth wire from the ignition amp plug earthed to the chassis? There is usually a wire with a ring terminal on the end coming out of the amp plug that has to be earthed.

 

Without this wire earthed you won't get a spark but I can't see why you have a mighty spark when you switch the ignition off.

 

Graham.

[trialster 0]

just for reference, i had all the same symptoms including the spark when turning ignition off. turned out one of the earth leads wasnt earthing properly.

 

Will

[Dave_McC 0]

Thanks for the suggestions. It is a BX loom, and yes the earth lead coming from the ignition amp connector (ring terminal) is under one of the screws attaching the ignition amp mounting plate to the inner wing. It does sound though as if it may not be making a good connection - I'll clean it up at the weekend.

 

Also found another couple of problems - both doubtless a result of the car sitting outside for the last 5 months through snow etc with the wiring loom all disconnected and the terminals exposed to the elements - my right hand front and side indicator don't seem to be wiorking (with the back flashing very fast), and the driving lights (which I stripped to repaint the metal frames) are also not working. Bit more searching with the multimeter needed!

 

Dave

[hcmini1989 16]

right having the same problem and if i unplug the injectors it starts but how is this the dizzy cap i thought it would be more to do with the temp sensor for the ecu is always reading cold

[hcmini1989 16]

right having the same problem and if i unplug the injectors it starts but how is this the dizzy cap i thought it would be more to do with the temp sensor for the ecu is always reading cold

sorry some one messaged me saying mine is probably the dizzy cap mine has an irreegular spark some times it does some times it doesnt and it wont start from warm unless i unplug the injectors so how would this be the dizzy cap any ideas does yours start from warm and sounds lke yours has the same problem as mine so next time it doesnt start try it with out the injectors

[Dave_McC 0]

Mine certainly doesn't seem to have any link with the injectors - they seemed to be firing all the time (mist of fuel coming out of spark plug holes). Wasn't the dizzy either - I wash checking for sparks with a plug in the end of the king lead - ie before the dizzy. Therefore fault had to be in coil, ignition amp, ecu or related wiring.

 

Earth's (or lack of a good earth) seem to be favourite - Dan Taylor also suggested earth fault when I was down at his workshop last week. Will clean up earths at the weekend and try again.

 

Dave

[Dave_McC 0]

Further update. I eventually got the car to start yesterday after swapping the oil pressure gauge sender and the ICV and cleaning up the ignition amp earth - seemed to be flooding - the plugs were sopping wet when I took them out. Still had what looked like a good spark - ended up getting it started by hooking up jump leads and cranking with the fuel pump fuse out - it eventually started to fire. I then put the fuse back in and it sprang into life.

 

Took it for a short drive round the block, and it didn't feel great and mis-fired quite badly at anything over 4k revs.

 

This morning I swapped the ignition amp for a spare (the one that came with the Mi engine - a Bosch - as opposed to the one which was in the car - not a Bosch but seemed fine on the old 1600) and engine immediately sprang to life - much less vibration. Drove round block again - wow, what a difference. Much much smoother and pulled much better.

 

I still had a couple of moments with complete ignition cut - both times at over 4,500 revs and earlyish in the drive. However, it then seemed to clear itself and revved cleanly up to about 6,500 revs - didn't take it any further up the revs yet as it's only run at high idle for 20 mins so far to bed in the new cam. I do however subscribe to the "drive it hard" method of running in - so won't be long before it gets some stick.

 

I have still got what looks slightly low oil pressure - I'll start a separate thread on that one though.

 

Thanks to everyone for the help along the way on this instal. Much appreciated!

 

Dave