Astra z18xe acceleration issue

Ardennes1944

The last few weeks ive noticed the astra having the same accelerating issue as my astra g 1.4. However it seemed to cure itself on that car it isnt going away on this one.
Basically its an intermittent problem while accelerating mostly in 1st but the odd timy bit in 2nd, the car speeds up as normal but between 1500-2000rpm there is a major flat spot, or hesitation for a second, it then pulls as normal afterwards.

A search on astra forums hasnt been bery fruitful, some suggest cleaning the throttle body, others claim its an egr valve, which mine doesnt have.

Hopefully one of you brainboxes will know.
Thanks

Hal1

I done a search for that model astra and got this:

Turned out one of the pipes had come loose from the throttle body as there isn't a proper clip to hold it in place.

Taken from here. I was thinking it could be vaccum related, like a breather hose.

Link isn't working: try google direct link for that site: http://www.astraownersnetwork.co.uk/showthread.php?94089-z18xe-throttle-problems

Sounds ignition related to me, coils etc etc, dunno the ignition set up on the Astra though.

R.O.R

Coils were my thought too. Sounds similar to issues I was having with the Octavia before it popped a coil, and most of the ED 3 Series Petrol's I've driven had stutters at low enough revs - generally a sign that at least one coil was on the way out.

Ardennes1944

Thanks guys its just strange that it only happens intermittently. If it had been the coil pack on ,y old astra how would it have fixed itself though?

It may have been coincidence but i think the problem went more or less just after i put redex into a few tanks of petrol, could this be any indication?

Ardennes1944

Ardennes1944 wrote: »

Thanks guys its just strange that it only happens intermittently. If it had been the coil pack on ,y old astra how would it have fixed itself though?

It may have been coincidence but i think the problem went more or less just after i put redex into a few tanks of petrol, could this be any indication?

Lots of ignition probs are intermittent
How long after it stopping on your old one did you keep the car for?

Ardennes1944

RoverJames wrote: »

Lots of ignition probs are intermittent
How long after it stopping on your old one did you keep the car for?

About 2months RJ. Ill be doing my spark plugs this week so ill have a look at the coilpack then. My brothers astra uses the same coilpack im sure

.... is there a pack per plug? Looking at the coils won't be overly informative as to their condition

Ardennes1944

This is what it looks like http://www.ebay.co.uk/itm/Vauxhall-Astra-H-2005-1-6-1-8-16V-Coil-pack-Free-Postage-/390384094204?_trksid=p5197.m7&_trkparms=algo%3DLVI%26itu%3DUCI%26otn%3D5%26po%3DLVI%26ps%3D63%26clkid%3D5834757802595911846#ht_742wt_922

Looking at it would be more to check for any differences berween mine and my brothers model numbers:)

Ardennes1944

Ardennes1944 wrote: »

...........

Looking at it would be more to check for any differences berween mine and my brothers model numbers:)

that's good thinking

Ardennes1944

This problem only happens also when i accelerate hard. Its only mostly if i press the accelerator pedal quickly and all of a sudden

Hal1

Maybe the car needs some of that government viagra if it's going into limp mode .

Ardennes1944

The problem does go away if my girlfriend is in the passenger seat alright :pac:

Nissan doctor

It may well be the coilpack beginning to fail.

If you remove your old plugs check them carefully for any differences in condition or deposit build up and when refitting the new ones check they are gapped correctly.

A diagnostic check should also record any misfires detected, even intermittent ones.

If it is a coil it would usually show up most when the engine is under load so try putting it in maybe 4th and foot hard down from say 30kmh and see if you get any misses.

Ardennes1944

Will do that tomorrow thank you. Ill be having a close look around the plugs when i service it shortly

Ardennes1944

just to add to this, when i changed the spark plugs about 2months ago i noticed no build up on any spark plugs, nor on the terminals of the coil pack.
another symptom that might help is if im driving, down a hill mostly, and i take my foot off the accelerator, theres a noticeable jerk in the car. it will continue to slightly jerk intermittently until i put my foot back down on the pedal.

but43r

Ardennes1944 wrote: »

Thanks guys its just strange that it only happens intermittently. If it had been the coil pack on ,y old astra how would it have fixed itself though?

It may have been coincidence but i think the problem went more or less just after i put redex into a few tanks of petrol, could this be any indication?

I would change the fuel filter first. It's cheap and it's probably dirty due to Redex. Car might not get enough petrol when you're accelerating hard.

Ardennes1944

Ardennes1944 wrote: »

just to add to this...........

Did you ever swap out the coil?

Ardennes1944

nope, my brother came home and didnt like the idea :rolleyes:

i can get a new one ebay.de for about 60e....suppose ill have to bite the bullet

Ardennes1944

Finally ordered a new coil pack but doubt it will solve it. Only cost 64 new from eBay.de at least

Ardennes1944

ANother update on this. Coil pack never arrived , long story. I cleaned the throttle body in situ about a month ago with carb cleaner and it definitely helped with the flat spot problem, however, since I have cleaned it and put the air intake system together an annoying rattle sound has started. It is intermittent and I think it is more common when the car is cold. It sounds like its coming from the alternator area and only really starts at about 2k revs and gets faster with revs after that.
In an attempt to solve this and hopefully eradicate the flat spot issue I removed the TB today and cleaned it fully and part of the manifold. The problem has gotten worse again like before and the rattle is still there.
Any ideas? As any time I pass my mechanic the noise is never there of course!
It's kind of a clicky rattle, as in you can hear sort of clicking, it's not a constant drone if you get me.

Silvera

What year is your Astra?
AFAIK, unless it is pre-1998, it does have an EGR valve.

I had the exact same problem with my 2003 Astra two years ago and the EGR valve was the problem. (A €20 s/h EGR valve solved the problem).

Also try - www.totalopel.com (Irish Opel forum).

Ardennes1944

It definitely doesn't have an egr, I almost wish it did so I could clean it out and maybe that might solve it!
I've posted up on a few forums. It's a big issue because they are loads of threads on it but there doesn't seem to be a definite cause. Most people end up living with it like the clutch judder.

The fact that both times I was at the throttle body had an effect on the issue probably suggests that it is this that's at fault?

Does the car have a map sensor? I would check out tubing (if installed check that there is no oil or other crud in the tube) and the sensor itself.

Ardennes1944

checked all tubing and all was ok. another thing to add, if i rev up the car while stationary, when it comes back down to idle the car vibrates like its going to stall ans revs itself up a bit for a second and is ok then

Silvera

Ardennes1944 wrote: »

It definitely doesn't have an egr, I almost wish it did so I could clean it out and maybe that might solve it!
I've posted up on a few forums. It's a big issue because they are loads of threads on it but there doesn't seem to be a definite cause. Most people end up living with it like the clutch judder.

The fact that both times I was at the throttle body had an effect on the issue probably suggests that it is this that's at fault?

What year is the car?

Have you also tried the 'Car Mechanics' (magazine) forum?
Try www.kelseyforums.co.uk ...or google it.
It's an excellent forum with actual car dealers and mechanics offering advice.

Bobo78

Talking from the experience, most of the random intermittently power loses, hesitations and lack of acceleration are due to dirty throttle body, idle air control valve and Maf sensor or air flow meter depending on which does you car have.

I had similar experiences with my cars and none of them ever stored any faults on the computer when you tried to diagnose it.

If I was you I would try to clean Idle air control valve as well and maf senosr defo.

All my hesitations, lack of power and flat spots on accelerations were cured by cleaning the throttle body including the iacv and maf sensor.

If you r having misfire under acceleration than it can only be faulty spark plugs, faulty ignition leads or faulty ignition coil although if the coil was faulty there should be engine light coming on.

Ardennes1944

Thanks bobo I'll look up the locations of some of them. The afm though is just a sensor with 2 bits of mesh either side, it doesn't look like there is anything to clean? Though ive often heard of people doing so

enumbers

Does your astra have the twinport engine if so sounds like it could be a issue within the inlet manifold

Waterson

Depending on the year your Z18XE engine may have a fly-by-wire throttle, i.e. electronically controlled. If this is cleaned out it must be reset using diagnostic hardware such as OPCOM to reset the throttle valve basic settings. You will have all sorts of idling issues if you dont.

Ardennes1944

It's a 05 h. Never heard of needing op com after a tb clean though!
After a quick google this seems to be the case alright! Althought only if there are issues after cleaning it it seems, like error codes and dash lights.ill do a pedal test later again