ne way i ran 3 runs at the 1/4 mile track. now my car idles rough/shakey. cannot see any blown off vac lines. any ideas? thx. still runs and drives fine but shakes the car at idel and when i press on the gas the shaking goes away.

 

better get it home and check compression.

 

What is your vacum pressure at in relation to where it was before?

 

Check the map sensor make sure the vac line is still on and make sure its not torn at all....

-dj

 

ouch i was just reading your other threads

 

Yeah if you didn't have the car tuned and yet you still went and pounded the drag strip, I'd do two things:
1) Check the MAP hose
2) Do a compression test and pray it's ok.

 

He said that the shaking go's away when he gives it gas. A unhooked map sensor will get worse if you give it gas.


A motor with a broken seal will run better if you give it gas

 

[QUOTE=LUPE]He said that the shaking go's away when he gives it gas. A unhooked map sensor will get worse if you give it gas.


if the motor has a load on it then yes but in nutral it will get better when you give it gas.

 

dude i had the same problem. i hate to break it to u but it may be the motor

 

were you running a midpipe?

if so your motor is gone

 

no stock midpipe. it drives fine it boosts fine, it appears to not have as much vac as it did before. if its at an idle it shakes, but as soon as i raise the rpm's to 1200 it goes away, it drives fine. I drove it home 30 miles from the track. my friend said that it sounds like i fouled a plug. I dont know, this **** is so frustrating.

 

sounds like a cracked/chipped apex seal

 

ok, with all this said, is there ne way to self diagnose this? To think (not saying its not cuz i dont know,) its an apex seal and to have it turn out not to be is still an expensive diagonostic. and might as well rebuilt the motor ne way at that point :smiley_12

 

What rpm does it idle at? Is the idle bouncy(like several hundred rpms)? It is unlikely that you broke a vacuum line by making runs at the track, unfortunately. Bumper to bumper traffic is a more likely cause of a broken vaccum line(underhood heat and idle fluctuation). It sounds like you have broken a seal. Youre firing on 2/3 of your engine(4 of 6 faces). Your plugs can foul but not that easily either.

The best way to see if it is a vacuum line is to get a compression check. This takes a lot of courage for most rotary owners because we know what is coming. My guess is you damaged a seal. If you had truly broken a seal it would not start. I mean really broken it. You probably cracked one. This is not good. It means youll break it soon. But we are all just speculating.

Youre going to need to get an official mazda test done as a piston type tester will probably not reveal the true problem as the pulses are very very quick and hard to discern at 250 rpms(thats if you cracked a seal). You need to go to a place you trust and witness the test.

 

it idles at 800-1000 rpm's. its just rough. it starts just fine, it drives fine, it boosts fine. just idles bad. can pettit do the test?

 

Nope but I bet Cam can tell you at the drop of a hat.

Edit: the jumping idle(hundreds of rpms) is a sign of a large vaccuum leak.

 

Compression tests are around $75, and if you haven't had one done on the motor lately it's always nice info to have.

It's possible you blew out the LIM gasket if idling is your only problem. The 93s have a fiberboard type of gasket that is prone to breaking and leaking - to replace that involves removing the UIM, Intake, turbos, and finally the LIM. These leaks can be kinda hard to find because it's so crowded - if you decide to prod around with carb cleaner be careful that the engine isn't too hot.

Dave

 

+1

I took off my elbow, TB, UIM to poke around under there for plug wires, vacuum hoses, and check valves last night and I must say that even going that far has been one of the un-funnest things I've ever done to my RX7.

On the plus side I found a vacuum hose that has been misrouted for 2years+ and found a broken check valve.

 

AWD-RWD racer, I had the exact same symptoms on my FD, and after doing a compression test, it turned out that the rear rotor of my engine went bad with blown apex seals.

 

and they could tell you that just by doing a comp test? or they had to tear the engine apart first?

 

They can tell which rotor is bad. They can tell how bad it is. The only rebuild option they can not diagnose(but do not need to) is a coolant seal failure.

 

Shell the $75 already and get the comp test done instead of going around it with questions! People can only give you so much info on what to do, but if you give compression numbers then it would be more helpful to diagnose your problem.

 

i have an appt on tuesday for it. I would do it if I didnt work everyday till then.

 

I hate pulling the UIM. It's a PITA and I ususally break something along the way...

 

also not constently but every now and then it does the idle jumping from like 1200-500 does it for like 2-3 min and then goes back to normal. or when i give it some gas.