1.2 nz won't start

[marc69]

My 1.2 spi engine was running badly for the first few minutes each day but now is not starting at all.


There doesn't seem to be any spark. After lots of turning over, spark plugs 1,3,4 are wet whilst 2 is dry.

I have tried changing the leads, dizzy cap, coil (and thing under it) and no difference at all.

Any ideas please as I am at a loss.

[meritlover]

Being spi, all cylinders must be getting fuel unless the valves arent opening.

If the fuel pump is turning and the injector is squinting then the cam pick up must be working and so is the FP relay which powers the coil/ignitor.
Remove the center lead from the cap (king lead) and see if it sparks against the block. If it does the fault is in the distributror cap/rotor arm. If it doesnt its in the ignitor/coil or associated wiring.
Check the notch on the distributor aligns with the lind cast on the cam carrier. This is the rough base timing setting. It may have moved and its just the timing thats out.

[marc69]

Thanks, the coil is sparking, and I retested lead 1 with a spark plug and it sparked.

I checked the ignition timing marks which were out by about 3 or 4 mm, I have just reset it. Would the ecu not compensate for that anyway? Once running after a few minutes the car is usually fine but it won't start at all today.

Fuel is reaching the injector housing but I don't know how to check the injector itself?

[meritlover]

it cant compensate for base timing. if its off it will offset the whole map.

if the plugs are wet the inj is working. you can lift off the air cleaner and crank the engine, if you see it squirting then its working. otherwise, remove the distributor, turn on the ign and spin over the shaft and you will see it squirt and spark.

[marc69]

Thanks, I'll leave it for a few hours incase it's flooded and try again.

If the timing is out and it has trouble for cold starting...is the ecu then sorting it out the first few minutes?

[meritlover]

on a cold start its likely advanced the timing over what it can run smoothly at, as it cools down the timing is retarded to a more 'normal' advance so it runs better. sometimes the timing map is advanced to take the load off the ICV.

check all the usual stuff like the vac hose to the MAP. The TPS does very little on these other than transient accel enrichment.

if its flooded, remove all the plugs, give it WOT and spin it over a few times.

[marc69]

I changed over the dizzy, etc.

Checked the injector, changed the plugs still no joy.

So my mate towed it and for about 5 minutes it just kangarooed but after about 2 miles it started to go, and actually drove home.

My mate said it is stinking of fuel and actually it is.

Is it likely that on a cold start it is flooding? If so what would be causing it? I have already put in anew coolant sensor.

[meritlover]

if its not firing properly then it will be stinking of fuel. check the cam timing. there is virtually nothing on these injection systems to fail, and yours seems to be working.

the only other 2 things are the lambda sensor and the RON plug.

[marc69]

Thanks, once it was going tonight, it went fine again, it just seems to be difficult to get it going. Although it was warm and running fine, it still smelt of unburnt fuel.

I don't know what a RON plug is,

will the lambda sensor stop it from starting?

[meritlover]

Its a reversible plug on a socket which selects between 2 different octane values depending on country of export. It wont be broken, im just saying there is little else.

I really doubt it will be the lambda sensor but single wore sensors are very cheap to replace anyway. You should consider checking the engine mechanically..ie timing and compression test.

[marc69]

Thanks, the engine is great when it goes, lively and smooth...it has just gotten progressively harder to start until today when it refused full stop, and sometimes when it does start it runs lumpy at first.

I will replace the lambda sensor tomorrow but otherwise I am stuck.

[therealnovaboy]

[QUOTE=marc69;2260994]the engine is great when it goes, lively and smooth...QUOTE]

sounds like you have a problem then, ive never heard of an SPI described as "lively"

[marc69]

I meant as in lively for a nz!

[marc69]

I have just put in a new lambda sensor and another new set of plugs (another fifty squid) and here are the the old ones. I don't know what a used lambda should look like but the plugs were cleaned last night and only did a 10 mile drive today......looks like the car is over fueling?

Is this the fault of the lambda?

If the plugs are getting this sooty is this why it is difficult to start when cold?

http://i988.photobucket.com/albums/af5/69marc/Photo856_zpsql5o3tuq.jpg

[meritlover]

If that was the state of the lambda when it came out then it may well be.
Its clearly knackered and needed replacing anyway. Old plugs would have come good again with a good blast in a clean running engine.

[marc69]

Thanks, I have just done the afternoon's running in the car and checked the new plugs which have come out as black as the ones in the pictures so I assume the car is still over fueling?

Any ideas what could be causing this?

[Stuart]

an air leak in the exhaust

[marc69]

thanks, I have just checket it and especially the exhaust manifold. It all seems fine.

[meritlover]

Check the fuel return isnt blocked.

[meritlover]

I have been giving this some thought and it feels like something MAP sensor related. Either its not piped properly and seeing vacuum or its knackered. If it was constantly reading atmospheric pressure it would always be fuelling for wide open throttle and may explain the hardness to start and the rich running. Swap with a friend or check the hose. I think they are the same as the spi corsa as well.
You can check the function with a volt meter but its easier to swap them.
Maybe try unplugging the connector while its running if there is no change its probably dead.

[marc69]

Thanks, I have a spare MAP sensor from a nz that I I scapped. I'll swap them over. The hose is fine and if you blow/suck you can hear it in the manifold.

I'll try swapping the sensor tonight.


Apart from sooting the plugs (and eventually not starting) it is running very nicely.

[marc69]

I also forgot to mention as I assume it is not connected..the temperature gauge in the car occasionally goes off the scale just on start up, switch the ignition off and on a few times and then it is fine. I will fit another temperature sensor for ths too.

[meritlover]

The gauge sensor has zero influence on the running of the engine...unless its genuine and your engine is actually over heating..

[marc69]

The gauge sensor has zero influence on the running of the engine...unless its genuine and your engine is actually over heating..

That's what I thought.

[marc69]

The ecu flashed a few times today, I took the Nova out on dual carraigeway for a blast at 70mph. I came home, switched on the code reader and got code 45 which is lambda mixture too rich.

Does this mean the ecu has found the problem and will weaken the mixture or is there still a problem?

After the run on dual carraigeway I checked the plugs and ther are a perfect light grey...

[marc69]

It struggled to start today and was not on even four cylinders for the first minute or so today. The only common feature of the bad starts seems to be very cold mornings. ( we get a few of those up here).

Any ideas why it struggles in colder temperatures?

[meritlover]

all engines are harder to start when cold. it just exacerbates any weakness in the system.

have you done a compression test? checked the timing belt marks?

there are so few components on this EFI system its hilarious
http://www.skandiasauna.de/opel/astra/F/Plan/1200.jpg
Inputs:
Coolant temp - changed?
cam trigger - clearly working
throttle position - ?
MAP sensor - ?
Lambda sensor - changed
Octane plug - negligable input

Outputs:
Idle valve, - who cares.
injector - must be working in some fashion
coil trigger - working
fuel pump relay - working

the only thing can be a mechanical fault, stuck injector (or a wiring fault pulling the injector to ecu wire to ground) FPR or return line restriction. Try disconnecting the TPS to remove all doubt. I seriously dont think it does much other than accelleration enrichment.

the fact that you have consitantly had uneven running, plug colour/wetness suggests theres something else going on.

[marc69]

Wow,you really know your stuff, it has taken me a few reads to understand half of it lol.

I really appreciate you taking the time.

I changed the cambelt a few weeks ago and the timing marks were all correct and as said once running the car runs very nicely so I assume the timing is correct.

I'll do a compression test on Monday, I am also running my 1.2 carb Nova so I'll get an initial reading from that to compare.

As there is ovefueling, I am going to change the coolant temperature again just incase this is the fault.
Throttle position sensor...I haven't looked at this before, but you mentioned disconnecting it, I'll give that a try.
The Octane is on 95 so it should be fine.
I can change it for a second hand injector but as you said it must be working as again the car ruins sweet once going.

FPR, is that the fuelpump relay? Would it only play up on startup?

I'll see how I get on this week, in the back of my mind I have had the crazy thought of... I do have a 1.2 carb head if it will fit a nz block, failing that I have a complete 1.0 with box, but these are only possibilities if I can't solve this.

[marc69]

I also forgot to mention, it sat the Mot yesterday with the new plugs and lambda, it just passed the emissions apprently.

[marc69]

I checked the throttle position sensor by taking the wire connection off and the idle speed bcame irratic.

I checked the compression, all were about 40.

I put on the other map sensor, after 2 days running it gave code 34 which is low voltage map sensor so I put the original one back on.

I put on another coolant sensor.

The ecu is still also giving code 45 (lambda too rich mixture) and the plugs are again quite sooty.

Is there any way of changing the mixture?

[meritlover]

I hope you mean 140?
There is no way to adjust the mixture.
The only thing left is the tgrottle body assembly which might rule out a fuel pressure regulator (FPR) or stuck injector.

Can you tell/show me where you MAP sensor is connected to on the manifold?
Was this engine ok before you changd the timing belt?

[marc69]

I can't remember exactly what the gauge said but the pressure was consistent in all 4 cylinders and was the same as my 1.2 carb (reliable) nova.

I wonder if the previous owner has fitted a different injector? He ran with the ignition timing advanced (makes it feel slightly faster..) and said the temperature gauge had died a year ago (this was actually the failed thermostat so the engine never fully warmed up) Would that have damaged the lambda? (He also had lovely blue leds etc inside!)

I have a full throttle body etc from another 1.2i I had if it's worth swapping?

The car refused to start and then spluttered at first the second day I owned it which is why I went for a full including cambelt service.

The Map sensor map is connected just beneath the fuel pipe at the back of the manifold, above the pipe which goes to the box thing (can't remember what it's called) at the back of the engine, (goes to the air filter)

When I got the car, the pipe going to the air filter was full of sludge and put some into the inlet which I cleaned, there has been no sign of any since.

Will the ecu adapt immediately to the change in ignition timing, new lambda etc, or will it take time and running to adapt and lower the mixture?

[meritlover]

It should instantly be better if either of the sensors were broken before. It may take a while to self learn although I dont think there is any adaptive mapping. Only closed loop control on cruise.

The map should be connected to the tapping on the manifold under the throttle body. Check its clear. There should be a strong vacuum from it at idle with the pipe disconnected at the map. Its job is to measure the vacuum in the manifold so it mustn't be spoiled by being tied into airflap tappings.

Maybe he fitted a 1.4i TB in the hope that it would be faster? I dont know what the crack is with the injector sizes between them. But if you have a spare 1.2i unit its getting to the stage where its worth swapping. Its not a big job at all.

The ign timing is suspicious. Its worth playing with after youve done the other 2 things to see if it makes a difference. You can always move it back.

[marc69]

The car hasn't failed starting since the sensors were replaced and the ignition timing was changed but I don't want to speak too soon.....

The plugs are sooty but not yet as bad as before.

There is a strong vacuum from the map pipe at idle and I removed my finger and the car instantly stalled. It isn't tied or twisted in any way and I blew to ensure it's clear.

I'll probably leave the ignition timing where it is supposed to be, the car drives more lifeless (like 1.2i lol) I did a similar thing with ignition timing when I was young until I damaged the spark plugs.

One thing I haven't considered...will a bad cat make the idle too rich?

[meritlover]

No. The lambda is pre cat so it doesnt care whats going one once the gas has passed the lambda.

Would only make a difference if the cat was choked.

[marc69]

Thanks, I assume if the cat was choked the car wouldn't go at all. Another thing ruler out.

[marc69]

I have driven the same journeys the last two days as I did last week and here is the plug this week compared to the one I removed last week. There is a slight improvement.

http://i988.photobucket.com/albums/af5/69marc/Photo858_zps1amxswcb.jpg

The ecu light came on again when I was idling for a while and the same two codes are there, 34 and 45, map and lamba too rich. I am wondering if the lambda is sending the message at different revs regarding the mixture? Hopefully.

It was only yesterday that I had on the other map sensor that brought that code up, I have put it back to the original map sensor.

[marc69]

The car has started everytime since the lambda was fitted and the dizzy was set right. I'm not sure which was making it awkward to start but just fingers crossed that's it now. Thanks for all the help and advice.