Hello guys,

I have a 1992 bridge ported rx7 with a single turbo conversion which was running fine up until tonight, when I start if from cold it's abit spluttery and hesitant but it use to clear when engine was warm...now it doesn't clear atal. Sounds like a misfire but if I build up the boost to drive (half throttle) it seems ok until I go to come off until I give it abit more throttle again. Was thinking maybe misfire due to spark plugs? The cars had a lot of money spent on it being built, I've just fixed the oil feed and water leak but now this. Because its ported how it is, normally sounds abit misfirey anyway but now it's a lot worse.

Any help would be appreciated. Thanks josh

 

welcome to the board

you might want to include what EMS you're running and any pertinent supporting parts (injectors, ignition, etc.). it may help the FD guys get you an answer quicker.

have you done a recent compression test?
what plugs and how many miles on them?

 

Apexi management, 1680cc secondary injectors, billet bits fuel rail, engine rebuild and Bridgeport conversion 1000 miles ago. Just had its run in remap.

No I haven't and I don't even know where the plugs are¿

 

The car needs to be tuned.

Not much more to say about it really.

Bridgeports have radically different tuning requirements than stock and it takes a talented tuner to make one run correctly.

If you don't know where the spark plugs are then STOP AND FIND SOMEONE WITH EXPERIENCE!

What are the turbo specs? If you say "stock turbos" we have a problem.

Bridgeports will quickly foul spark plugs unless the tune is decent. Lots of timing down low (I run 18 degrees), a good 1200 - 1500 RPM idle, and 14:1 AFRs.

 

Sorry I didn't state. Obviously the car is tuned, it was built and mapped by rotary motion. Ran fine up until started misfiring the other day, I am a mechanic but haven't worked on a rotary before so didn't know if their we're any common faults.

It's a single turbo conversion using a Holset HX40 Turbolader Turbo.

What spark plugs would be best if I was to buy new?

 

4 NGK 9s are likely the best plug.

However, check to make sure there isn't another problem. Has the AFR reading changed? Fuel pressure? Is the EMS reporting sync errors?

 

I haven't noticed any changes on the handheld commander inside the car. Should all the plugs be the same? I read somewhere about using two different heat rating plugs?

How can I find out if there are any reported errors? There's no engine management light showing on the dash?

Thanks Josh