Alright, here's the story...I just got back from the UK D1 Drift Competition, and a good time. I'd say it took about two hours worth of driving to get there, with my british mates, one who has an RX-7 also. The car ran great, and had no problems besides an accidental jamming of 3rd gear (damn notchy tranny!). Anyways, halfway home, we pull up to a roundabout, and my car just feels horrible jumpy...feels like the engine is about to jump outta the car. Sorry, of course, I freak out. I'm watching all my gauges, checking my heat, boost, water pressure, all that rot..and nothing is amiss.

I'm boosting normal...10PSI at WOT, and there's no power loss of any kind. I mean the car hauls azz the way it was supposed to, and I'm very careful with how hard I run it. It was what I would call a spirited drive to and from.

There's no smoke, no problems with loss of boost, and it's smooth as a baby's butt on the highway or just cruising through town. What I am hearing though is a ton of exhaust burbling..kinda popping. I've always had a little bit, because it's ported, and every once in awhile I'd get a pop, espescially on a shift, but that's it. It's been tuned VERY well by a proper tuning shop.

So..here's the problem, at idle, it idles extremely low, say about 200-400, the engine looks like it's about to jump off the mount, there's no fumes, no smoke, no smell...everything looks fine. What the heck could it be?
Don't tell me it's an Apex seal...this thing was rebuilt, everything was, practically, plus it was tuned really well!! I haven't even driven it hard in about 8 months (mostly cuz I was in the hospital recovering from a botched appendectomy.)

I didn't have my data commander hooked up at the time..I'm gonna have to go take a look at it, but it's too dark tonight. I put some better gas in it, drove it home, and it did great on the highway, it's just whenever it goes in to neutral or idles, it just starts to croak and have a really bad, lumpy idle.

I haven't even put 3K miles on the engine yet!!!

 

Sounds like the motor. Apex seal damage. Time for a compression test.

 

Yeah sounds like a cracked seal or something.

 

yeah when my friends fd cracked a seal it would do the same thing, as yours is doing. (shake and shutter hard while at idle)

 

prehaps your idle just went to crap cuz something fell off (i have seen it a lot of times)

try putting your foot on the gas and idling her at about 800rpm-1krpm in netural and come back and tell us what the vaccum is. if its about 16in/hg or above, you probally just gotta raise your idle. because somethign is malfunctioning

perhaps one of the following is fked...

dashpot
ISC
AWS
Wax rod assembly
fast idle screw
possibly the airpump solenoid

disconnect these one at a time to see if you get your idle back.

 

What Apex seals and size are you currently using

 

2mm Apex Seals...standard OEM Mazda seals.

Alright, I went out to the car, and guess what? It idled perfectly right at 1000rpms, then dropped down to it's usual 700..but with a slight lumpiness, more than it used to. It's like the car has a slight shake to it, now. Even after rev'ing it, it dropped back to it's normal RPM. But then, I put it in gear, went forward just a bit, and dammit, the damn thing started to die a bit.

So, I hooked up my PFC, and got the readings off of it...plus checked my vacum, etc. At 1000rpms at my boost was sitting at about 11-12, when it started to fluctuate really badly with the idle and almost die, it would almost drop below 10. At 2000K my idle was 16-18 for vacum. 700RPMs idle was sitting at 10 also.

My boost is set for 10PSI through the PFC, and this is the information from it:
IgnCD 7 Dg
IgnTR 6 Dg
Air Temp 55C
Boost - 420-430 at idle
Knock - None (small sliver)
Water Temp -66C
Bat Volt 13.9

The other readings were:
PIM 1.96-2.00 at idle
VTA1 - .41V
VTA2 - .94V
VMOP - 1.34
WTRT - .48V
AIRT - 1.01V
Fuel -3.55
O2S - .50V

The car still idles hard, it seems. My engine has about 3K on it, it's STILL underneath the engine warranty, because I got the 5Y/60K mileage deal from Pineapple Racing. This really ticks me off, because this car HAS BARELY BEEN DRIVEN...AND it's been tuned, with NO changes to the PFC, NOR ANY MISUSE, ABUSE...not even DRAG RACING. Maybe some spirited sprints on the highway, but since my accident involved my leg, I have NOT gotten on it, not the way you'd expect an FD to be run.

This really ticks me off...everything was perfectly fine..and now this. Crap. I'm gonna see if the Base Auto Center has a compression tester, tomorrow.

 

Gah...I guess all the helpful people went home for the day. I can't get a compression test till tomorrow...so I guess we'll find out then.

Thanks to whoever helped.

 

good luck telling pineapple that a drift comp wasent abuse... i have yet to hear a story where they covered a motor under warrenty.

 

that vaccum seems very very very low. your suppose to have about 16-18 at 800-850rpm when idling after warming up... (i have seen a 40k stock engine pull 20in/hg at a 800rpm idle which would be very good) well unless you have a huge port on your engine. if your engine was just rebuilt to stock specs and your pulling 10in/hg at 700 and/or 11-12 at 1krpm, im sorry to inform you that you might/probally need a new rebuild very soon.

 

Skunks, even a normal street ported engine will have a lower vacuum than a stock port motor.

I don't think its a popped motor. Could be anything from plugs, to a bad censor. CJ

 

I DIDN'T DRIFT at the competition. I simply went as a spectator. Sorry for not making that clear. We went to go watch it, we weren't competitors.

The motor has a small street port, and like I said, I haven't been running it ragged...not even close.

 

good luck, sorry to hear about this

hopefully it's something small and stupid

just so you know, if you decide to pull the motor and send it to pineapple, based on RX794's experience, if there is nothing wrong with the motor, you'll be charged for shipping/reassembly (about $600 if i remember correctly)

so make SURE it's not the motor

 

If I have to make a guess.. I say its not blown and its something simple as vacuum or pressure line popping off..

You'll know if you cracked or blown your apexi seal..

I say take your UIM and start checking all your lines.. also, adjust your idle.

 

Yes...thanks everyone, I'll know for sure tomorrow...I certainly hope it isn't blown, but rather just something popping off. I'll have to print out that vacum lines chart again.

 

My 1993 R-1 used to do the same thing, especially on a warm day after running pretty hard. Found the vacuum line that goest to the boost sensor (firewall near wiper motor) came off. Put it back on - everything OK. I finally wired the filter up to the bracket to keep it from pulling the line off.

Mick
San Diego

 

Vacuum leak or other sensor issue. Not a blown motor.

 

well if you want to to figure out if it is a blown engine or not, bite the bullet and take it to mazda for a real compression test.
(cost in hawaii for this is 170 dollars...)

perhaps you can find someone near you which has a true rotary compression tester

 

well if you want to to figure out if it is a blown engine or not, bite the bullet and take it to mazda for a real compression test.
(cost in hawaii for this is 170 dollars...)

perhaps you can find someone near you which has a true rotary compression tester

 

MAP sensor hose? Located by TB on firewall.

 

im betting map sensor as well. . .

paul

 

i was wondering why no one said map sensor sooner, most of the time that is thrown out at the same time that a blown motor is

 

this symptom sounds like a chipped apex seal from what i read in rx7 magazine awhile back...

U can fix this if the chip' is not large by driving on the free way for about 15min at 3000rmp-4000rpm in a constant speed.

 

i highly doubt that...

 

Well..here's the deal. I went to the Auto Hobby Shop, today, to use a compression tester, and dangit it, it was broke, so it was a no-go.

The car is perfect in gear and on the go, no loss in power, and today, it wasn't that bad. It's almost like it's getting flooded with fuel and dying or something at low revs.

For some reason, I just have this feeling it's NOT a blown motor, and that it's something else. My leg is killing me right now, so I'm just going to research it until I find out a little bit more about what to check, and then go take a look, then.

I'm also going to see if there's a proper rotary tuner based in the UK somewhere, that can take a look at my car. I want to make sure it's tuned properly...and I fear I'm too amateur'ish as yet to make a proper determination.

I'll fill in everyone with pics and info as I find it. I like to document stuff like this...