Vauxhall Owners Forum banner

1 - 7 of 7 Posts

·
Registered
Joined
·
4 Posts
Discussion Starter #1
I bought a zaf gsi and has had a z20lel 170 bhp astra sri engine fitted due to z20let blowing a gasket.
The car has never run right since the engine was changed
The car once warmed starts to hold back and splutter, and kangaroos badly untill you back off accelerator or change gear.
The car has had a coolant sensor changed, a boost solinoid changed, a lambda probe changed, and a maf and injectors from a vxr astra put in as mechanic thought issue was either maf or injectors.
Car is still driving like crap and im baffled to what else it could be
The car is also not throwing up any fault codes at all which is making it hard to diagnose
Any help appreciated thankyou
 

·
Registered
Joined
·
501 Posts
Has the map been changed to accommodate all of the component changes? The VXR injectors and MAF will make the car run really badly until the map is sorted.
I have to ask why you didn't just change the gasket on the z20let? They are not expensive and it's often better to stick with the engine you have unless there's been a catastrophic failure.
 

·
Registered
Joined
·
4 Posts
Discussion Starter #3
Thankyou for your reply
The car was running poorly before the maf and injectors were fitted, they were fitted just to see if it made any diffrence.
The car drives fine until warm then holds back does not go through the rev range, the turbo appears to spool then it backs off boost which made me think it might have been a seized wastegate the car splutters, shudders and is undrivable, new coolant temp sensor has not worked
Compression all good, its baffling.
The z20let got a recon head skimmed etc valve stems done but mechanic fitted it and said it was pouring out white smoke and bubbling coolant and said just get another engine, im not mechanical minded so just presumed he was right
 

·
Registered
Joined
·
501 Posts
Ideally to diagnose the issue you will need to get some live data, but some basic checks could be done first. Unless you change the map for the VXR components, I would suggest swapping back to the original engines z20let injectors and AFM. If the ECU is calibrated for these, it will never work properly with the VXR parts and will just over-fuel all over the place. You could start by looking for any boost or vacuum hose leaks, and as you suggested test the wastegate with a bike pump. You don't say if the car misfires at all, but it will also help to make sure you have a decent coil pack (borrow a known working one to test) and the correct new spark plugs (The Astra VXR plugs are ideal).

You also mentioned a mechanic was involved, should they not be sorting this issue for you?
 

·
Registered
Joined
·
4 Posts
Discussion Starter #5
The garage has the car at the moment, i have been looking online for any ideas as to what the issue could be
The car with there diagnostics plugged in is not showing any fault codes at all however i did a pedal test and it showed up a flashing sequence but he said his diagnostics would have picked anything up, its just dragging on now and costing more than it should
 

·
Registered
Joined
·
501 Posts
I hate to say it, but it sounds a bit like the garage are not really sure what they are doing. I hope they won't be charging you for all the parts they have fitted that haven't sorted the issue. A generic fault code reader won't always pick up a fault code if there is one stored, really an Opel/Vauxhall specific diagnostic reader is generally more useful (the garage may have this?).
It sounds like a back to basics approach to checking everything is needed. What parts were used from the replacement engine, and what was originally carried over from the z20let? i.e. coil pack, injectors, sensors etc? If the Z20let was running fine before all the issues (apart from the head gasket), you have a starting point.
 

·
Registered
Joined
·
4 Posts
Discussion Starter #7
Nothing was carried over, the z20let was taken out, the full engine z20lel was taken car to car and plugged in the car was driving great untill its warming then it starts jerking like your on off with the accelerator, i was hoping it was maybe a coolant sensor but with no fault codes showing its hard to diagnose
 
1 - 7 of 7 Posts
Top