Mazda Rotary Club

Cars by Model Type => 2nd generation RX-7's => Topic started by: andymac1970 on September 18, 2011, 04:22:00 PM

Title: Misfire below 2.5k
Post by: andymac1970 on September 18, 2011, 04:22:00 PM
Hi All,
 
I\'ve just bought my first RX7 after YEARS if wanting one.
 
It\'s a 1989 FC N/A which I intend to hillclimb next year in and around Yorkshire - Harewood, Prescott and Curborough are all part of the "tour" planned as well as at least 1 track day at Croft.
My car has a misfire below 2.5k and I\'m struggling to diagnose it very well.
Can anyone help with potential culrpits, maybe there are a few "favourite" possibility\'s out there ?
Thanks a lot and hello to everyone:wave
Andy
Title: Misfire below 2.5k
Post by: m1tch on September 18, 2011, 04:38:42 PM
Firstly welcome to the forum! Get some photos up :D

Are there any mods on the car or is it 100% OEM? It might be something simple like the HT leads failing, an air leak or a leaking injector. The FCs are now getting on a bit, so some vac lines or rubber tubes can start to perish, causing issues.
Title: Misfire below 2.5k
Post by: B.Martin on September 18, 2011, 05:03:46 PM
Welcome to the club, pics please :)

Regarding problem Mitch\'s thoughts are a good place to start!
Title: Misfire below 2.5k
Post by: micha^fc3s on September 19, 2011, 07:32:43 PM
My Turbo has some Problems with air leaks at the moment where i bought it . The Effect was missfire but i am with martin . Air leaks or Injector Leak .
Title: Misfire below 2.5k
Post by: B.Martin on September 19, 2011, 08:22:28 PM
It\'s Mr.Martin :Giggle

Any luck Andy?
Title: Misfire below 2.5k
Post by: andymac1970 on September 20, 2011, 06:47:00 PM
Thanks guys
 
Will add some pics and start tinkering to see what I come across based on your suggestions
 
Will keep you up to date with how I get on
 
Thanks again
 
Andy
Title: Misfire below 2.5k
Post by: m1tch on September 20, 2011, 06:56:44 PM
Awesome :) might be an idea to take the plugs out and see how they look, sometimes a fresh set of plugs makes a massive difference :)
Title: Misfire below 2.5k
Post by: micha^fc3s on September 20, 2011, 07:05:16 PM
Yes , with my old Plugs i had some Problems to Start the Engine . A set of new one and the engine runs without a problem .
Title: Misfire below 2.5k
Post by: m1tch on September 20, 2011, 07:06:25 PM
Just make sure you don\'t try and fit piston style spark plugs!
Title: Misfire below 2.5k
Post by: XRMike on September 20, 2011, 09:29:18 PM
My car has similar issues. I will let you know when mine gets fixed.
Title: Misfire below 2.5k
Post by: Kamatari on September 20, 2011, 09:56:43 PM
Is there any recommended plugs to get?
Title: Misfire below 2.5k
Post by: m1tch on September 20, 2011, 10:15:14 PM
MRP is suggesting these:

http://www.mazdarotaryparts.com/bset-of-4--ngk-br10et-spark-plugs-for-rx-7-egib-1182-p.asp
Title: Misfire below 2.5k
Post by: Lacey on September 20, 2011, 10:16:56 PM
I use NGK9\'s in mine, and have 10\'s as a spare set for emergencies
Title: Misfire below 2.5k
Post by: Skifledanabit on September 21, 2011, 01:12:31 AM
Quote from: Lacey;789581I use NGK9\'s in mine, and have 10\'s as a spare set for emergencies

what NGK\'s are they? where did you get them from?
Title: Misfire below 2.5k
Post by: Lacey on September 21, 2011, 07:07:03 AM
Quote from: Skifledanabit;789602what NGK\'s are they? where did you get them from?

Which ones are what?

The NGK10\'s that were in the car when I bought it were used, SOAKED in  petrol, and it was having massive issues starting. They\'ve dried out fine now though and with some carb cleaner will come up in reasonably almost-new state, havn\'t tested the spark on them though. Swapped to NGK9\'s  (from Prof to go in his T2) and it started pretty much straight up.

I suspect the 10\'s are perfectly fine and it was just majorly flooded by the previous owner, I just wanted to swap them at the time when it was having starting issues to eliminate one more possibility. Probably changed nothing apart from the spark temp though.

No idea what the 9\'s are, they\'re just \'NGK9\'s\' to me, but I have the 10\'s in the garage, why? You want a picture? You need plugs or something? :p
Title: Misfire below 2.5k
Post by: splinter53 on September 21, 2011, 07:16:06 AM
Bad earth maybe?
Title: Misfire below 2.5k
Post by: kiwimazda on September 21, 2011, 07:20:51 AM
Housings shagged? But probably best to get it to a good rebuilder for proper diagnosis rather than listen to every ones 2p worth
Title: Misfire below 2.5k
Post by: B.Martin on September 21, 2011, 07:28:05 AM
It doesn\'t hurt to try all the inexpensive options first though mate.
Title: Misfire below 2.5k
Post by: Lacey on September 21, 2011, 07:40:56 AM
Quote from: B.Martin;789619It doesn\'t hurt to try all the inexpensive options first though mate.

Very true. I bought mine as a non starter, was prepared for rebuild costs as the previous owner said it lost most of its power (went into limp mode) and became almost undrivable.

Changed the plugs to NGK9\'s, put in a small green can of fresh fuel, and after realising the "foot to the floor fuel cut when turning the engine over" doesn\'t work on the EGI, and de-flooding it, AGAIN, it fired straight up, and run like a beast out of hell, whilst making me deaf and killing me with the fumes of richness.

Backfiring a lot seems common on EGI\'s, mine does it, Skif\'s does it, yours does it and Kamatari\'s does it, and all 4 are still going, can\'t be all that bad!
Title: Misfire below 2.5k
Post by: B.Martin on September 21, 2011, 07:42:59 AM
They only backfire so much due to running so rich, i\'m pretty sure its just unburned fuel getting into the hot exhaust pipes. Nothing to worry about :)
Title: Misfire below 2.5k
Post by: Lacey on September 21, 2011, 07:44:27 AM
Exactly. Flames + loud noises = bragging rights. :Laugh
Title: Misfire below 2.5k
Post by: Skifledanabit on September 21, 2011, 10:22:43 AM
Mine clears the flooding when my throttle is pushed right down
Title: Misfire below 2.5k
Post by: kiwimazda on September 21, 2011, 10:26:40 AM
Quote from: B.Martin;789619It doesn\'t hurt to try all the inexpensive options first though mate.

I totally agree, but as I have learnt in the past with these engines be prepared for the worst mate
Title: Misfire below 2.5k
Post by: RotorHeid on September 21, 2011, 11:05:01 AM
Quote from: andymac1970;789021Hi All,
 
I\'ve just bought my first RX7 after YEARS if wanting one.
 
It\'s a 1989 FC N/A which I intend to hillclimb next year in and around Yorkshire - Harewood, Prescott and Curborough are all part of the "tour" planned as well as at least 1 track day at Croft.
My car has a misfire below 2.5k and I\'m struggling to diagnose it very well.
Can anyone help with potential culrpits, maybe there are a few "favourite" possibility\'s out there ?
Thanks a lot and hello to everyone:wave
Andy

My ears hurts,  very good for you,"The hillclimb"
 you must come to Doune hillclimb too and also Shelsley Walsh
I\'ll be at doune next years and I\'m expert on a FC with weber/dello only....
I do not got the Rex now and but drived a single seater " big boys toys"LoL.
there\'s another Rex up in Scotland do the hillclimb\'s good friend of mine drive a Rx8PZ
good to see Rx going up the garden path at speed.

here\'s video from Doune, brill Lee Adam/GWR raptor and enjoy
http://www.youtube.com/watch?v=lpJ-Y-9otO8&feature=related
Title: Misfire below 2.5k
Post by: RotorHeid on July 07, 2014, 12:42:51 PM
Hi,  British championship rounds at Harewood at past weekend. I am just wondered andymac1970 did entered with a FD car?
If yes and good for you.
Cheers.