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It worked before I took it apart!

Posted: Thu Jun 04, 2020 9:17 pm
by Bikergonebald
I’ve just replaced both cam cover gaskets on my Mx-6 V6 as well as the fuel filter and I wasn’t surprised that it didn’t run right. I found a vacuum pipe left off and I reset the throttle position sensor but it’s still not right.

It starts perfectly and revs freely sounding great at first but if I let it drop back to tickover it nearly stalls and then it won’t rev again. As soon as I touch the throttle it dies, if I let go quickly it catches and ticks over. If I turn it off and immediately restart it it’s fine at first but the same thing happens.

Any suggestions?

I’m reasonably certain it’s something stopping fuel being injected rather than anything ignition related. The Engine fault light isn’t on.

Thanks
Kevin

Re: It worked before I took it apart!

Posted: Fri Jun 05, 2020 12:44 pm
by Jon G 24V
First thought is why did you feel the TPS needed to be reset.
Sounds like a Base Idle / TPS issue.
Get the car up to full Temp, switch off and Pop the link in Ten / Gnd.
Ignition on but don't start and recheck TPS position. With the Link in place the slightest touch of the Throttle should kick the Fans on. Let the throttle go to rest and the Fans should stop.
Once this is correct then start up and see where the Idle sits.
If it dies then it's too low so adjust via the Screw in the Top of the TB. Also hook up a Timing Gun and check the Ignition Timing.
To get the Idle correct it's a balancing act between the Timing and the Idle Screw as the Idle should be 650 - 700RPM at 12 Deg BTDC.
This all has to be done with Link in place as the Engine then runs without any influence from the ECU or Sensors etc hence the Term Base Idle 👍👍

Re: It worked before I took it apart!

Posted: Fri Jun 05, 2020 1:28 pm
by Bikergonebald
Thanks Jon. I will try that this afternoon.
I checkEd the TPS because it had been removed from the TB, although I had been careful to put it back in the same place. Haynes said to remove TPS but I now see it probably wasn’t necessary.

Fingers crossed your procedure will get it working. I might have to go and buy a timing light, mine hasn’t worked since I dropped it.

Thanks again.

Re: It worked before I took it apart!

Posted: Fri Jun 05, 2020 2:12 pm
by Bikergonebald
I’ve fixed it :D

While out on my first drive in 3 months (in my daily) I was thinking about what would stop fuel going in and thought about the MAF sensor. Got home popped the bonnet and it wasn’t plugged in!

When I disassembled to change cam cover gaskets I put coloured tape on everything I disconnected and removed it when I Reconnected, that way I would see anything I missed.

BUT

I had refitted the air box and MAF then removed it again to change the fuel filter.

Now for my first drive in the Mazda for 3 months. V happy. 😁

Re: It worked before I took it apart!

Posted: Fri Jun 05, 2020 3:02 pm
by Micron
D'oh :shock: :lol:

Glad it's sorted, it might still pay you to check your TPS as per Jon's instructions just to make sure 8-)

Re: It worked before I took it apart!

Posted: Fri Jun 05, 2020 3:03 pm
by Jon G 24V
Glad you it sorted mate.
Can't remember how many times I've forgotten to plug the MAF back in and wondered why it rang like a bag of nails 😂😂😂