Pls house my Nisan partfinder needed plug changing because of misfire, so the day i change just two the car was firing fine but the moment i change the third one, hard a poor firing and can't start again. Even wen decided to change the rest of the plug, it started for a while with poor performance and shut down. And since then cranks but can't start. I have checked fuel pump, plug cap, and fuel pump relay everything works fine. What's your advice pls? I need help.

Pls experts in the house

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Do you have spark at plug and pulse on the injector?

Okonyeleo:
Pls house my Nisan partfinder needed plug changing because of misfire, so the day i change just two the car was firing fine but the moment i change the third one, hard a poor firing and can't start again. Even wen decided to change the rest of the plug, it started for a while with poor performance and shut down. And since then cranks but can't start. I have checked fuel pump, plug cap, and fuel pump relay everything works fine. What's your advice pls? I need help.

Put the old plugs back. Are you sure you got the order of installation of the spark wires correctly?

empron:
Do you have spark at plug and pulse on the injector?

Yes rewire came said everything is fine the electrical system

weyreypey:

Put the old plugs back. Are you sure you got the order of installation of the spark wires correctly?

Ofcourse sir

Okonyeleo:
Ofcourse sir

Then reverse all you have done. Undo them

Let the rewire check if there is current on the plug coil and also prepare your mind it might be the brain box.

I've had this happen on a couple of cars. A Benz and an fx35. Both times, it started with a misfire, plug and coil change and then no start.
Solution was to change ecu (brain box).
Your electrician should be able to get a working brain box to test in the car. If it works, good.
He should also make sure there are no other problems so he doesn't ruin a perfectly working replacement ecu (brain box).
However, start with a scan to know what is working and what's not working.
I believe you would have checked for fuel, air and spark by now.

Okonyeleo:
Yes rewire came said everything is fine the electrical system

if there is spark,injector pulse,fuel pressure 45psi above i think he needs to check the coil connector if he has not interchange coil 1 to coil 3 or coil 2 to 4,Also engine compression and check the security light if it is steady or blinking when ignition is on

9icetoo:
I've had this happen on a couple of cars. A Benz and an fx35. Both times, it started with a misfire, plug and coil change and then no start.
Solution was to change ecu (brain box).
Your electrician should be able to get a working brain box to test in the car. If it works, good.
He should also make sure there are no other problems so he doesn't ruin a perfectly working replacement ecu (brain box).
However, start with a scan to know what is working and what's not working.
I believe you would have checked for fuel, air and spark by now.

Don't do this, if the car was working before and the only thing replaced was spark plugs it's either the replacement was bad or wrong plugs. Only use new ones per OEM parts. It will be on the emission sticker on the bonnet. If you bought fake plugs , don't go messing up other things that were good

sultaan:


Don't do this, if the car was working before and the only thing replaced was spark plugs it's either the replacement was bad or wrong plugs. Only use new ones per OEM parts. It will be on the emission sticker on the bonnet. If you bought fake plugs , don't go messing up other things that were good

If I wasn't there when these two cars failed to start, I wouldn't even write it.
The mechanic was a friend and called me to share his experience.
We bought new plugs, we installed new coils, nothing worked.
His rewire tried all he knew, nothing worked.
I observed the ECU light wasn't even coming on when the ignition was turned on.
I plugged in my small Bluetooth scanner and couldn't communicate with the ECU.
That was when he accepted to try another ECU.
On Monday, ECU was installed and car started at the first attempt.

The other car, an fx35 had same issue on the same day but in another location.
The owner is a friend and called me to relay his predicament. He was worried that his mechanic wanted to change his ECU. I asked him what they had done so far (they had done the same things we did on the Merc).
I told him to change the ECU. Same outcome. Car started at the first attempt.
I am not saying this is the op's case but it points to that.
The issue on Blboth cars started as misfires.
Plugs were changed and nozzles serviced.
Both cars refused to start.
The two mechanics thought village people were after them.

But ECU does not just die like that, something else had happened,I am working strictly on the premise that all he did was take out a spark plugs and replaced it with another.If he had disconnected the battery prior to working on the car it is likely to start rough. I like to keep things simple. It seems Nigerians replace ECU more than their engine oil. I have never had a problem with one in 20 years of driving

sultaan:
But ECU does not just for like that, something else had happened,I am working strictly on the premise that all he did was take out a spark plugs and replaced it with another.If he had disconnected the battery prior to working on the car it is likely to start rough. I like to keep things simple. It seems Nigerians replace ECU more than their engine oil. I have never had a problem with one in 20 years of driving

So both cars had histories of misfires.
On the Benz it was really bad.
That was the second time the technician was changing the plugs. Cylinder number 2 and 5 if I recall correctly.
The fx35 was in a similar situation; long history of misfire.

Usually, plug change doesnt require battery disconnection. I am not aware it's part of the procedure.
I've been changing spark plugs myself on quite a few cars and never had to disconnect battery to do that.

From what I learnt online, it is one of the tell tale signs of a failing ECU if all else checks out.

Sometimes, these things just happen.

sultaan:
But ECU does not just for like that, something else had happened,I am working strictly on the premise that all he did was take out a spark plugs and replaced it with another.If he had disconnected the battery prior to working on the car it is likely to start rough. I like to keep things simple. It seems Nigerians replace ECU more than their engine oil. I have never had a problem with one in 20 years of driving

Very true, i have seen 100s of post where people are advised to change ECU over a simple

its seems like mechanics/rewire in nigeria fry ECUs of all the cars they touched

It might be an earthing problem

baconline:
It might be an earthing problem

how do you mean sir? I don't understand this at all

Okonyeleo:
how do you mean sir? I don't understand this at all

He meant "bad ground" connection.

1-Timing chain slack, do an adjustment,while someone is trying to start it simultaneously. 2-Check all pulleys.

Okonyeleo:
Pls house my Nisan partfinder needed plug changing because of misfire, so the day i change just two the car was firing fine but the moment i change the third one, hard a poor firing and can't start again. Even wen decided to change the rest of the plug, it started for a while with poor performance and shut down. And since then cranks but can't start. I have checked fuel pump, plug cap, and fuel pump relay everything works fine. What's your advice pls? I need help.

Okonyeleo:
how do you mean sir? I don't understand this at all

Did this car eventually start?
What was done to make it start? Update thread.

Turn the ignition to on not start.. observe the dashboard.. if the check engine light doesn't come on, you have a bad ECU. Replace and the car will start one time.

9icetoo:

If I wasn't there when these two cars failed to start, I wouldn't even write it.
The mechanic was a friend and called me to share his experience.
We bought new plugs, we installed new coils, nothing worked.
His rewire tried all he knew, nothing worked.
I observed the ECU light wasn't even coming on when the ignition was turned on.
I plugged in my small Bluetooth scanner and couldn't communicate with the ECU.
That was when he accepted to try another ECU.
On Monday, ECU was installed and car started at the first attempt.

The other car, an fx35 had same issue on the same day but in another location.
The owner is a friend and called me to relay his predicament. He was worried that his mechanic wanted to change his ECU. I asked him what they had done so far (they had done the same things we did on the Merc).
I told him to change the ECU. Same outcome. Car started at the first attempt.
I am not saying this is the op's case but it points to that.
The issue on Blboth cars started as misfires.
Plugs were changed and nozzles serviced.
Both cars refused to start.
The two mechanics thought village people were after them.

yeah, ECU is a likely culprit if he has checked out the entire fuel and air system.
But I will still recommend a scan first. It might reveal that the crank sensor or the start sensor is bad. They are cheaper to change, in comparison to the brain box

Evolution12:
1-Timing chain slack, do an adjustment,while someone is trying to start it simultaneously. 2-Check all pulleys.

this is highly possible too, especially for vehicles that use a distributor system to power and fire the spark plugs, rather than the more recent coil system.

The misfiring plugs might have caused the timing chain not to be properly aligned. This affects the ability of the distributor to supply power to all the lead wires of the plugs. Adjusting the distributor and the timing belt should take care of the problem