so here goes.... i was driving my car after 15 days and the last few times that i have driven it it makes big misfires from the exhuast under boost mozt of the times... but sometimes it drives ok...

this time when i took the car out i noticed that my mmhgs were a little less than usual.... usually threy are at 415 at idle but they were at 390 now... so i floored the car and no misfires... but in the 2nd run there were big misfires and tge car died... so i stoppef in the corner and after a min it started... i brought it home... on the way it 2 more times but then started after trying a little... so i parked it but then it would not start... the next day i checked and thre comprression is good at 95 and 100 psi but there is no spark... so we changed the coils and the ignitor and the car started but my mmhg were now 250... so i took it iut for a drive... it drives ok but no power.... after driving for 20 mins the mmhg came up to 350 but still not much power...

what should i look at now... the compression is good what i should look at now... there are much more frequent misfires....

 

1. The last thing u want to do is to floor pedal and boost your car when u know there are issues, so stop driving it.
2. Give us more details on the car. Stock? Sequential or non sequential, single turbo, mods?

 

Does it sound different when running?

Injector problems?

Black smoke coming from exhaust?

Did you check the leading plugs?

 

+1

Replace the plugs and Ohm test the wires. I have seen 2 new NGK plugs not fire right out of the box. Ensure the coil wiring harness is intact and continuity is there. Check each pin for connectivity while moving it around. They see a lot of heat like the coils in the OEM location. There could be a disconnect or a rubbed spot of the harness that is grounding out.

If you have a PFC then you could look at your timing and sensor voltage to ensure things are in check. With a stock computer, check for codes.

 

just sounds like you need new plugs. Although MOBEONER is right... the last thing you want to do is put a full load on something that you know isn't runnig correctly = Time Bomb

 

I would suggest a little more Cowbell.

 

I know guys i should not be flooring it but i think it was out of frustration... its running non sequential right now... i haveg got new set of plugs now that i will be installing on monday... will update you guys... hope they fix the problem...

 

Think of how frustrated you'll be if it blows up while releasing your frustration.

 

Sadly I have been there.... this is my second time with the fd blew the motor twice on the first one... but just the sheer beauty of the car brought me back to it....

Thanks for the advise I will try my best not to let frustration take over....

 

Yeah bro, when the wife pisses you off, you don't slap her..... You make her *** twice as hard to show her who the man is...

Hope the plugs fix it. We shall see...

 

Thanks for the advise... this is one wicked wife...

Changed the plugs the car started and had 410+ mmhg so all was good... but 20 seconds down they fell to 250mmhg... The car idles very smoothly even at 250mmhg and does not vibrate as much as I would have expected at such low mmhgs and runs ok but has no power and does misfire...

I have noticed that the leading plugs are getting a little wet... what should I look at??

Thanks guys...

 

primary injector may be spraying wrong, running rich will drop the idle lower and cause the vacuum issue.

The backfiring tells me theres fuel being dumped.

Someone had played with my staging on my microtech and my car sounding like it was two stepping on WOT.

 

And we still need specs on the car...

 

boosted car not running well? mash on the accelerator!

take the car to a shop, you shouldn't be touching it until it's fixed.


backfiring tells me you have faulty plug wires/coils or you have intermittent sticking apex seals. that is about the only 2 reasons these cars backfire.

 

Ok guys an update...

If i advance the timing 7 degrees from the power fc the mmhgs go to 430 at the same 850rpms... and the car sounds better too...

 

still doesn't explain the root issue.

 

why would you even touch the timing? maybe you should just take the car to a shop before you destroy your motor... if it isn't already toast

 

did you ever before retard the timing? .. you say the car isn't making any power..

what are your boost readings? are you making any boost? do you have a downpipe? catback? test pipe?

do you have a ported waste gate?

 

Guys this is already at a shop.... where i live there are no rotary shops... as we have only 2-3 rx7s in all....
The shop did not drive the car at 7 degrees advance... they just tried it at idle to reconfirm that it is ignition related as the ignitor and the coils went bad after the bangs and have all been already changed which did start the car from its dead state....but still we feel the spark is not strong enough which is resulting in the low mmhgs... car was only taken out once as i stated above and since then we are just trying to find out the issue...

Any help would be greatly appreciated.... no shops... no rotary experts... you guys are the only lead i have....

 

Never retarded timing...
Boost hits 10psi and drops down to 8 but it is much less power than the car usually made at these boost levels...

Never ported the wastegate....

Thanks...

 

did you also replace the plug wires?

like i said it sounds like an ignition issue so keep ruling anything out in the ignition system.

 

as Karack had stated. Sounds ignition related. I would've gone straight down the line.

Replace plugs......if it didn't fix it... move onto the next.
Replace plug wires......if it didn't fix it move onto next.
Replace Coils....if it didn't fix it......move on to next.
Replace igniter...... I'm pretty sure you'll have it fixed with one of those. I wouldn't touch the tune though

 

Thanks Karrack and manny killer

I did all the above but in a different order:

Car was dead

Changed Coils (Used)
Still would not start

Changed Ignitor (Used)
It started up but with low mmhgs around 280mmhg. Took it for a drive the mmhgs build upto 330 at idle for 10 mins then went down to 280mmhgs

Changed Plugs (New set)
mmhgs went up to 410 for about 20 secs and then back to the low mmhgs

Changed Plug wires (Used)
no difference same low mmhgs

Could it be a weak ignitor or coils?

 

check all of your grounds. Also.. is your car lowered at all? reason I ask is a couple years ago my tired ate through my harness and there was an arc... blew my igniter. But something may not be grounded correctly.

 

Ok an update... We are checking all the wiring and grounds... On the power fc we tried advancing the leading timing a little and it had no effect whatsoever on the car but if we advance the trailing timing the mmhgs start going up. The electrician says that the leading coils are not getting a signal from the ECU maybe... Could that be it??

Thanks...