Starting issues

Morning All,

I have been a member on here for years and love the z22se.

My own I have owned years. That much so its been my daily for the last 11 / 12 years.

I lightly modded it in the early days and maintain it year on year.

3 weeks ago was the first time recovery was called out.

The car would not start, just weakly turning, then bang, I thought the chain snapped, smoke and it would not turn at all. The morning after started first time.

Weeks have gone by.

Cleaned the TB
New plugs
New CTS Sensor
New Crankshaft Sensor
Coil Pack swapped

It has been great for two days then when it's warm it won't start. It cranks but struggles to fire sometimes it then won't crank. It also doesn't do it every time. So 70% you can go to start and it does, both cold, warm and hot.

I am at a loss and close to chuck the towel in.
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Senior Member
Do you have any codes showing up?

It may be worth checking the two purple relays located in the rectangular black box that sits on top of the ABS unit. They are identical, one is the fuel pump relay and the other nearest the front of the car is the engine management control relay. Ensure the ignition is switched off to ensure no EML light appears, take them out one at a time and clean the terminals with some emery paper then lightly smear some vaseline on the terminals and replace them.

If either of the relays look brown or are bulging then best to replace it.

The GM part # for both relays is: 90494959
KevinH Thanks for replying so quick.

No there has not been any EML, apart from once when it started then 30 secs later was rough as a box of spanners sounded like it was mis-firing, went into to limp mode, EML was on and so was slippy car symbol, My code reader wouldn't give a code but on clearing it started just fine and was for days after.

I will go and look at the replays now.


Senior Member
One more thing, in your first post you mentioned you put in a 'New cam sensor' but the Z22SE's don't have a camshaft sensor as this is done by the silver coloured module on the coil pack using CSI (Compression Sense Ignition) which was developed by Delphi.

When you swapped the coil pack was it a genuine GM one, as aftermarket coil packs are known to cause trouble.

Was it the crankshaft sensor you replaced?
Sorry KevinH , i get confused it was the Crankshaft sensor that was replaced with genuine Delphi part, as was the CTS was Delphi, to get to it you had to remove the starter motor.

Yes the Coil pack was a genuine coil pack as well, this is the only second hand part used but was from a good running car.


Senior Member
Well, the relays look OK to me.

The only other things I can suggest is the FPR (Fuel Pressure Regulator) and MAP (Manifold Absolute Pressure) sensor and to check all earthing cable points for any corrosion.
KevinH thanks for your helps, where are the locations for the above FPR (Fuel Pressure Regulator and also MAP (Manifold Absolute Pressure) , is the FPR part of the fuel rail on the Astra G ?


Senior Member
Yes the FPR is located on the end of the fuel rail and the MAP sensor is located under the throttle body which you have to remove to get to the sensor.

Hope that helps. :)

ps I must say your Astra looks in pristine condition. (y)
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KevinH thanks for your help it seems the map sensor is common across multiple vauxhall models.

With FPR would be better to get a full fuel rail?

Thanks for the comment on the condition its OK for its age, and it's done 211k. Not that good when it won't start though.
Could be the starter motor that is faulty.
I would check the wiring going to the starter and round to the alternator make sure the terminals are clean
Possibly bench test the starter to make sure it is functioning as it should. But before doing that get a multimeter to check voltage going through the wiring.


Senior Member
By chance, is there anyone close to you that has OpCom or Tech2 as I suspect it may be throwing a code.

I'm just thinking that if a code is stored it may give you a clue as to what is causing the problem as replacing part after part becomes rather expensive.

A few years ago I had a problem with my Vec B SRi 150 where it would either not start or if it did start then cut out after a couple of minutes. After checking there was fuel at the rail by pressing the valve, I then noticed the engine management relay was slightly discoloured so I replaced it and all was well again (I replaced the fuel pump relay as well, sod's law if one fails the other would soon after). I think they were ~£15 each.

When you switch the ignition on can you hear the fuel pump 'whirr' and prime the system for a couple of seconds and checked that you are getting good fuel pressure at the rail by pressing the valve which should squirt out a jet of fuel.

Fuel Injection Pressure Regulator with Seal - GM part # 9198979 (appx £87.00)
Inlet Manifold Vacuum Sensor - GM part # 28074365 (appx £108.00)
the starter motor / battery don't seem powerful enough to turn the engine, might be worth swapping them over.

once it runs the engine seems to have too much fuel for a few seconds, so changing the MAP sensor is also a good idea
Thanks Everyone.

I also thought about changing the starter motor when the crank sensor was out.

The strange thing is it fires first thing when cold and strong.

I could really do with someone with opcom / tech 2 but I don't know anyone in my area.

I will get the Battery and starter tested and also will see if MAP and fuel rail helps.

As for expense you are right KevinH it's getting close to either pulling parts and scraping or chucking the keys in for good.
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vocky battery was new not long ago but will get tested, what you say about fuel, the first time it failed when it did start it had a almighty bang and black smoke then would not start again till the morning after. Guessing it ignited a bucket load of fuel and back fired.


Senior Member
Far to good to scrap Si ! :eek:

We all get a bit depressed when our 'pride & joy' goes wrong or has issues, but with a little help and moral support from this forum, I'm sure you'll have your Astra purring away soon. ;)