Opel Utility rev problem on cold start

[Wolfeh]

Hello

I have a issue with my Opel utility that I cannot resolve and am hoping for some advice/ideas. I have checked https://mybroadband.co.za/forum/threads/the-corsa-problem-solver.1009672/ on here but could not find a similar issue.

The car stood a while over the holidays. On my return it was very difficult to start. I checked the battery beforehand and while it was not ideal (~6,5v) I figured there was enough power to try starting it. I managed to get it running after about 30 starts. The next day I put the battery on a trickle charger and got it full again. Within in a few days the car would not start at all.

On starting there was a bad miss and the idling was very rough. Once it heated up, it ran a lot better.

So, went to the mechanic and eventually fixed/replaced the following things:

-all injectors(two of them were not delivering the correct amount of fuel)
-coil( it was time, the old one wasn't great anymore)
- the composite sensor on the coil
-spark plug leads (one of the leads was leaky)
-spark plugs(I mean why not, if doing everything else)
- compression was tested and is fine
- the throttle body was cleaned and all sensors checked and cleaned
- o2 sensor was cleaned for good measure
- The car had a full service about 150km ago

Now there is a problem that the above did not resolve.

On a cold start the engine idles fine(a bit high 1000rpm instead of the usual 800). The idling is a bit rough. If I depress the accelerator the revs drop. If I persist the car dies. This is in gear/out of gear/any variant. After a few minutes of idling, the problem disappears and the car runs fine. There is a fuel smell in the car. The current fuel consumption is horrible. My working assumption currently is that the car is over-fueling/running rich and killing the spark plugs with fuel. I am just not sure why.

I would appreciate your thoughts.

 

[ArmatageShanks]

Check the Manifold Pressure sensor, make sure its plugged in and that the vacuum line from it to the intake manifold is connected and in good condition.

 

[TheChamp]

The most troublesome part on those is the coil, since you have replaced that as well as sparks and leads, them the next thing to look at should be fuel or air related, from experience I would lean towards fuel.

Check the fuel relay, they do go bad from time to time, resulting in intermittent fuelling and misfiring symptoms as well as lack of power.

It is on the drivers side footwell on the side of the accelerator on the hatch, not sure about the bakkie.

 

[longboy]

Fuel/Air problem by the info you provided. Also check intake valves/sensors and the manifold sensors.

 

[B-1]

As said above I would check all the vacuum hoses are connected and dont have cracks at the throttle body.
The next thing I'd check is the fuel pump relay.
And I know you said injectors were done but the symptoms are typical of a leaky injector as well.

 

[Wolfeh]

Thanks for the feedback so far. I will check all the above.

 

[TheChamp]

Thanks for the feedback so far. I will check all the above.

Try to be systematic and not to go with the overly disruptive approach, and by that I mean the practice of replacing too many components at once, you could inadvertently introduce a fault and end up chasing your own shadow.

Try to go through what you have already done first before moving on to replacing other stuff, check the injector wiring, it's easy not to replace the plugs properly when putting everything together.

Check the coil again, even if it's new, it's very easy to get a defective part, has happened to me a couple of times, check if it is firing for all the cylinders. Plugs and leads are generally not troublesome so I doubt there could be an issue with that.

The way I do it is that if I replace a part and it doesn't make a difference, I put the old part back, I do this so that I can properly pin point the fault instead of replacing everything and having the car jump into life and you don't know what was the problem.

 

[Wolfeh]

I agree.

The above changes were also done gradually. First the coil was replaced as it was the most likely cause of misfire, then the leads, then the injectors, and finally the spark plugs.

The work was done by my mechanic whom I have faith in. Presumably the work was done properly.

After the injectors were replaced, the old coil was put back on, but the car ran worse, so the new one was put on again.

 

[Wolfeh]

Update.

The following things were attempted, but the issue was not resolved:

• Fuel pump relay - replaced
• Cambelt slipping/worn - checked
• Crank angle sensor - checked
• Mass airflow sensor - replaced
• 02 sensor - replaced
• wire from injector wiring loom to ground - checked
• Get the Timing and CO checked - checked
• crank pulley - checked
• Temperature sensor - replaced
• Malfunctioning idle air control actuator - checked
• Malfunctioning Throttle Position Sensor - replaced
• Blocked air filter - checked
• broken fuel pressure regulator - checked
• lack of ground/earth of the oxygen sensor - checked
• Manifold Pressure sensor - make sure its plugged in and that the vacuum line from it to the intake manifold is connected and in good condition. - checked
• check all the vacuum hoses are connected and don’t have cracks at the throttle body - checked
• The (all new) injectors were checked for injector drip

Running out of ideas here.

 

[TheChamp]

~6,5v) I figured there was enough power to try starting it. I managed to get it running after about 30 starts. The next day I put the battery on a trickle charger and got it full again. Within in a few days the car would not start at all.

I am still in awe of how you managed to get the car started at 6.5V. Check the battery voltage with the car running and see if the alternator is okay.

Besides that you might have a well hidden wiring problem check all the sensors and see if the wires are still intact.

 

[soulie]

Update.

The following things were attempted, but the issue was not resolved:

• Fuel pump relay - replaced
• Cambelt slipping/worn - checked
• Crank angle sensor - checked
• Mass airflow sensor - replaced
• 02 sensor - replaced
• wire from injector wiring loom to ground - checked
• Get the Timing and CO checked - checked
• crank pulley - checked
• Temperature sensor - replaced
• Malfunctioning idle air control actuator - checked
• Malfunctioning Throttle Position Sensor - replaced
• Blocked air filter - checked
• broken fuel pressure regulator - checked
• lack of ground/earth of the oxygen sensor - checked
• Manifold Pressure sensor - make sure its plugged in and that the vacuum line from it to the intake manifold is connected and in good condition. - checked
• check all the vacuum hoses are connected and don’t have cracks at the throttle body - checked
• The (all new) injectors were checked for injector drip

Running out of ideas here.

have you reset/recalibrated the TPS .do you have any obd error codes,i can see if our carsoft machine pulls them up .

 

[Wolfeh]

I am still in awe of how you managed to get the car started at 6.5V. Check the battery voltage with the car running and see if the alternator is okay.

Besides that you might have a well hidden wiring problem check all the sensors and see if the wires are still intact.

I checked the battery voltage using my el cheapo multimeter and got some strange readings. Apparently my battery is at 40v. This is the same multimeter I got the 6.5v on making that reading highly suspect.

I got a different multimeter and tested the alternator.

Battery:
When car is off: 12,65v
Idling (800-1000rpm) - 14,35v
2000 rpm - mostly 14,36v, varies up to 14.41v

The wiring was checked(though I can't say for certain to 100%).

 

[Wolfeh]

have you reset/recalibrated the TPS .do you have any obd error codes,i can see if our carsoft machine pulls them up .

There are no error codes.

I will check and confirm tomorrow whether this was also done, but I am certain it would have been done when it was replaced.

 

[TheChamp]

I checked the battery voltage using my el cheapo multimeter and got some strange readings. Apparently my battery is at 40v. This is the same multimeter I got the 6.5v on making that reading highly suspect.

I got a different multimeter and tested the alternator.

Battery:
When car is off: 12,65v
Idling (800-1000rpm) - 14,35v
2000 rpm - mostly 14,36v, varies up to 14.41v

The wiring was checked(though I can't say for certain to 100%).

That looks fine so the alternator is working okay.

 

[TheChamp]

There are no error codes.

I will check and confirm tomorrow whether this was also done, but I am certain it would have been done when it was replaced.

Did you manage to check the coil?, yes the same new one, I know mechanics are not flexible and set in their ways, just do it yourself and see, somethings till tells me the problem is not complicated and you are missing it in all the troubleshooting.

I went back to your original post and I saw the fuel smell thing, you can only get fuel smell if fuel is leaking or you are pumping fuel that is not being burnt, hence my insistence on checking the coil.

 

[TheChamp]

I don't see anything about the fuel pump, that should also be checked.

 

[Wolfeh]

Did you manage to check the coil?, yes the same new one, I know mechanics are not flexible and set in their ways, just do it yourself and see, somethings till tells me the problem is not complicated and you are missing it in all the troubleshooting.

I went back to your original post and I saw the fuel smell thing, you can only get fuel smell if fuel is leaking or you are pumping fuel that is not being burnt, hence my insistence on checking the coil.

Yep, check the original post. The coil was replaced,and after everything else the old coil was put back, it performed worse so the new coil was reinstalled.

 

[Wolfeh]

I don't see anything about the fuel pump, that should also be checked.

I mean, I can hear the fuel pump when I turn the car on. Fuel pressure on the fuel line from the fuel pump was checked. The relay was replaced. I don't think the issue is there.

 

[TheChamp]

Yep, check the original post. The coil was replaced.

Yes, and I ask that you check it again even if it's new because they do come faulty from the shop sometimes, especially when it's the non OEM variety.

I don't know if I am the only one but I don't get a lot of confidence from your current mechanic, I am just thinking with so many things replaced and he still cannot pinpoint the problem maybe he is not the right person for the job.

Try look for someone with experience in Opel, there is just something that tells me your current guy is missing something, it just doesn't make sense to me, those cars do have their issues but when they work they work, when they don't they don't, they are not really troublesome cars with baffling electronic problems.

 

[Supervan II]

Do an ECU reset , which was the first thing to have been done before going on a wild goose chase.