RX7Club.com


Go Back   RX7Club.com > Tech and Performance > General Rotary Tech Support
Sign in using an external account
Register Forgot Password?
Register Photos FAQ Members Search Today's Posts Mark Forums Read VendorsUsed Cars TSB & Recalls Garage
Welcome to RX7Club.com

Reply
 
 
 
 
LinkBack Thread Tools Search this Thread Display Modes
Old 04-13-12, 07:09 PM   #1
Exhaust Leak
5 Year Member
 
Trader Score: (0)

Join Date: Nov 2007
Location: Shaw AFB, SC
Posts: 23
I need HELP!!!

Here's my little story... I got this 91 FC n/a only 110k miles 5 speed that hasn't been running for 5 years... just sitting collecting dust... Picked it up from this old lady... I got it running and started driving it daily... I noticed it started doing this idle surge thing... I didn't mind too much for it thinking it was just cause it was sitting for so long might've been flooding issues or what not... Anyhow two weeks ago I take it for a drive to the dmv and it sat for about an hour when i get back in it and it won't start... It'll crank but not start... after some time of working on it and charging battery I finally get it running... Only problem she won't wold an idle and will die out if i let go of the gas... being the brave soul that I am I just decide to drive back home while keeping it revved up... As I'm driving it back home this thing could barely make it 50 mph and I get to 3rd gear and can't go past 4500 rpms with pedal to the metal... I barely get it home after having to pop clutch 3 times after stalling on the way... I start working on it and this thing will start but won't idle and dies out after I let go of gas. I could get it revved up good in neutral no problems, some popping coming from exhaust ... I started searching on the forums and figured it could be ignition problems... I went changed spark plug wires after noticing the old ones were pretty beat up... put the new ones in and started the car. idles perfect no problem until i decided to rev it up a bit, and it straight dies again after letting go the gas... I get cranked again and placed something to hold the gas steady... I noticed my reverse lights were on. I was impressed because 1) the car was in neutral and 2) the reverse lights weren't working before when it was running fine. I then notice smoke getting in the car so I shut it off... I looked under the car and noticed the main cat was blazing bright red and then I looked under the hood and I can't tell if smoke is coming from clutch or tranny... I need help... don't know where to start troubleshooting...
pm0369 is offline   Reply With Quote
Old 04-13-12, 10:18 PM   #2
HeyHeyHey..Its the Goose
 
Qingdao's Avatar
 
Trader Score: (2)

Join Date: Apr 2012
Location: Charleston
Posts: 877
Dude you've got bad gasoline.

Pluck the high pressure fuel line out and sit it in a gas can. Turn the key and let her go! Dig a hole dump it and repeat with fresh gasoline.


EDIT: it may take a few flushing runs to get it all out, but I see you're located around goosecreek... Go to the drag strip and get the race gasoline. Using stupid high octane fuel will expidite the proccess. ;-)


EDIT 2: Also a can of seafoam will help your beat up injectors. :-P
__________________
1979 S model 13B N/A (for sale)
1984 GS 13BT
1979 12A 90% factory stock WIP

Last edited by Qingdao; 04-13-12 at 10:23 PM. Reason: Forgot the foam
Qingdao is offline   Reply With Quote
Old 04-14-12, 07:55 AM   #3
Exhaust Leak
5 Year Member
 
Trader Score: (0)

Join Date: Nov 2007
Location: Shaw AFB, SC
Posts: 23
Bad gas? Never crossed my mind but I'll give it a shot... Thanks will post back!
pm0369 is offline   Reply With Quote
Old 04-20-12, 08:24 PM   #4
Exhaust Leak
5 Year Member
 
Trader Score: (0)

Join Date: Nov 2007
Location: Shaw AFB, SC
Posts: 23
I have to ask...what makes you think its bad gas that I'm dealing with? Not that I'm doubting your knowledge but it doesn't explain why my reverse lights are working in neutral... I just changed the fuel filter and it sure was disgusting... the car seems to start up a lot smoother however I still get popping and no idle just dies as soon as i let go of gas, and the cat still gets blazing red within seconds of the car on... My question is how did you know I have bad gas, and what does it have to do with my reverse lights being on in nuetral?
pm0369 is offline   Reply With Quote
Old 04-20-12, 08:39 PM   #5
oi oi oi
5 Year Member
 
john ward's Avatar
 
Trader Score: (7)

Join Date: Jan 2006
Location: wilmot,oh
Posts: 611
Clogged cat, incorrect timing, incorrect air fuel mixture. Possibly the excessive heat messed with your reverse switch??
john ward is offline   Reply With Quote
Old 04-20-12, 08:46 PM   #6
Exhaust Leak
5 Year Member
 
Trader Score: (0)

Join Date: Nov 2007
Location: Shaw AFB, SC
Posts: 23
Now that makes better sense to me... so the reason I didn't believe my cat was clogged was because the exhaust blows strong... so should I go ahead and continue to drain my fuel or replace the cat?
pm0369 is offline   Reply With Quote
Old 04-20-12, 09:30 PM   #7
oi oi oi
5 Year Member
 
john ward's Avatar
 
Trader Score: (7)

Join Date: Jan 2006
Location: wilmot,oh
Posts: 611
You can do a backpressure or temperature test on the cat. Confirm timing is correct and check fuel pressure for starters
john ward is offline   Reply With Quote
Old 04-20-12, 09:31 PM   #8
HeyHeyHey..Its the Goose
 
Qingdao's Avatar
 
Trader Score: (2)

Join Date: Apr 2012
Location: Charleston
Posts: 877
Lean means hot. When your hella lean it means REALLY hot. The old gas has probably guuyed up your injectors. Thats why I would sugest seafoam. Lean is the cause of the heat and heat is MOST likly the cause of a tail light malfunction... Although your tail light wires run down the left side so it might just be bad luck they went out.

Gasoline turns into water eventually. This will lower the octane rating of the fuel you are pushing through your injectors. The lower rating will retard the detonation in the combustion chamber.

At idle your machine will fire at TDC or rotor equivilent (OK I am not 100% down with the lingo of rotors, but I know my machines). The engine will run on the lower octane because it can fire at an acceptable time. When you throttle up your ignition circet (or spark advancer) will move the ignition timing to a more advanced location. The gasoline will not combust at the right time. Hence you get a boging.



If your catalitic converter is messed up kick it. Yup just kick it. When cats go bad they genrally make a rattleing sound when you kick them. What has happened is the porceline honey comb has broken loose. I DO NOT think this is your issue. A bad catalitic converter would cause you to foul the O2 bung and run rich, not lean.
Qingdao is offline   Reply With Quote
Old 04-20-12, 10:13 PM   #9
HeyHeyHey..Its the Goose
 
Qingdao's Avatar
 
Trader Score: (2)

Join Date: Apr 2012
Location: Charleston
Posts: 877
If you're wondering HOW exactly I know....

Years of pulling engines out of the trash and engines out of a junkyard and messing with just about every Honda motorcycle ever made will teach you the tell tale signs of what an engine is trying to comunicate to you.

Also, you clearly stated the signs of your problem.

As for the reverse lights... man thats just coincidence. The exhaust does run kinda close to the shifter were the pickup is but not that close. Besides you should have a heat shield in place to protect wires from that kind of thing.
Qingdao is offline   Reply With Quote
Old 04-20-12, 11:05 PM   #10
Forum Vendor
5 Year Member
 
RotaryEvolution's Avatar
 
Trader Score: (30)

Join Date: Oct 2003
Location: Las Vegas, 1 mile from the strip
Posts: 2,354
jesus guys just tell him and stop making him run around in ******* circles...

do a compression test, do it properly and cross your fingers. your description is one of 2 things, you lost a rotor or you hopefully just lost a primary injector due to it sticking from sitting for 5 years, which is rather unlikely since it was working which is odd for an old injector to work and then seize up later.

in 25 years of being an automotive technician i have only seen one case of "bad gas", which had water in it due to a ruptured holding tank at a local gas station which filled with sediment and ground water. only other remotely similar case was an idiot who pumped gasoline into his diesel chevy.

if a rotary is popping from the exhaust and the cat is glowing you can pretty much bet it's still pumping fuel from a dead rotor into the exhaust which is what is cooking the exhaust, so unfortunately i can almost guarantee you have a toasted motor.

you can try a decarb and hope it is just a few seals stuck from carbon that may free up, but free revving it to redline if they don't free up on their own you're SOL and the seals are probably fractured.


anyone who is still running an uncracked original block i will tell you now what i tell everyone who walks in the front door: "you're running on borrowed time." plain and simple, i am also not looking for a buck from anyone. original 2nd gen 13B engines are dropping like flies.

Last edited by RotaryEvolution; 04-20-12 at 11:16 PM.
RotaryEvolution is offline   Reply With Quote
Old 04-21-12, 08:18 PM   #11
HeyHeyHey..Its the Goose
 
Qingdao's Avatar
 
Trader Score: (2)

Join Date: Apr 2012
Location: Charleston
Posts: 877
Quote:
Originally Posted by Karack View Post
...snip...in 25 years of being an automotive technician i have only seen one case of "bad gas", which had water in it due to a ruptured holding tank at a local gas station which filled with sediment and ground water. only other remotely similar case was an idiot who pumped gasoline into his diesel chevy....snip...
Seriously? Well I guess cage mechanics don't see as much bad gas as motorcycles and boats...

I've got you beat though... I've seen diesel in a two stroke scooter. How he got the nozzle in there beats the heck out of me.
__________________
1979 S model 13B N/A (for sale)
1984 GS 13BT
1979 12A 90% factory stock WIP
Qingdao is offline   Reply With Quote
Old 04-21-12, 09:10 PM   #12
Forum Vendor
5 Year Member
 
RotaryEvolution's Avatar
 
Trader Score: (30)

Join Date: Oct 2003
Location: Las Vegas, 1 mile from the strip
Posts: 2,354
lol, maybe he thought he was being green by using the green pump!

point is, i see many people try to do every test except a compression test. threads may drag on for weeks and the car torn half way apart in an effort to find a phantom issue. a compression test takes 5 minutes and only requires 1 fuse be removed and 2 spark plugs, nothing that isn't easily reversible.

it could be a bad spark plug or cable i suppose also(rare occurrence unless they have something rediculous like 40k miles on the plugs), but it never hurts to know the condition of the engine internals. with these engines it should almost be a mandatory starting point before diagnosing anything else because compression issues will cause all sorts of different things to result.

sometimes i think people purposefully avoid testing compression.. heh

Last edited by RotaryEvolution; 04-21-12 at 09:15 PM.
RotaryEvolution is offline   Reply With Quote
Old 04-21-12, 11:36 PM   #13
HeyHeyHey..Its the Goose
 
Qingdao's Avatar
 
Trader Score: (2)

Join Date: Apr 2012
Location: Charleston
Posts: 877
Yeah, could be bad ignition... 5 yo gas just brought it to mind first.

Speaking of compression testing (Warning vering off topic). Can you use a normal compression tester on a 7? I know Mazda made a special one to test each of the chambers but if I just slap a regular one on my 7 i'd just get the greatest compression of all of the chambers not idividual ones, right?

EDIT: I guess what I'm saying is should I be on the hunt for a good compression tester for a wankel?

Last edited by Qingdao; 04-21-12 at 11:39 PM.
Qingdao is offline   Reply With Quote
Old 04-22-12, 11:37 AM   #14
Forum Vendor
5 Year Member
 
RotaryEvolution's Avatar
 
Trader Score: (30)

Join Date: Oct 2003
Location: Las Vegas, 1 mile from the strip
Posts: 2,354
you can use a conventional piston engine compression tester, you just have to remove the schraeder valve from the hose where it would thread into the spark plug hole.
RotaryEvolution is offline   Reply With Quote
Old 04-22-12, 05:14 PM   #15
Exhaust Leak
5 Year Member
 
Trader Score: (0)

Join Date: Nov 2007
Location: Shaw AFB, SC
Posts: 23
well the reason I don't think it could be bad gas is because I've cycled two tanks through it before it stop running. I put gas in both my vehicles the same day by the same gas station. Now Karack... I am very afraid of checking my compression just for the fact that I'm terrified to know that I need to rebuild this beast...
pm0369 is offline   Reply With Quote
Old 04-22-12, 06:48 PM   #16
Forum Vendor
5 Year Member
 
RotaryEvolution's Avatar
 
Trader Score: (30)

Join Date: Oct 2003
Location: Las Vegas, 1 mile from the strip
Posts: 2,354
and that's why no one wants to bite the bullet, even though it is a quick and simple test.
RotaryEvolution is offline   Reply With Quote
Old 04-22-12, 08:23 PM   #17
HeyHeyHey..Its the Goose
 
Qingdao's Avatar
 
Trader Score: (2)

Join Date: Apr 2012
Location: Charleston
Posts: 877
Quote:
Originally Posted by pm0369 View Post
well the reason I don't think it could be bad gas is because I've cycled two tanks through it before it stop running. I put gas in both my vehicles the same day by the same gas station. Now Karack... I am very afraid of checking my compression just for the fact that I'm terrified to know that I need to rebuild this beast...
Completly dumped all fuel and started a fresh tank?

STORY TIME :P I used to own a GEO metro. When I bought it, it ran PERFECT like a kitten. Then after a few days the thing started doing EXACTLY what you discribed (cept for the reverse light thing). HOT and studdering at high RPMs then shutting off. I changed the plugs and plug wires and the distributer... NOTTA. My buddy took a wiff of the exhaust and we deside to dump the tank and clean the hell out of it. Sure enough after washing out the tank with acetone she fired right up and continued purring like a kitten till she rusted through.



EDIT: Now a GEO metro is a piston powered TBI engine. So it is a different beast, but the theory remains.
Compression test would rull out a lot of stuff. I'll help you check it if you need help.
__________________
1979 S model 13B N/A (for sale)
1984 GS 13BT
1979 12A 90% factory stock WIP
Qingdao is offline   Reply With Quote
Old 04-27-12, 03:59 PM   #18
Exhaust Leak
5 Year Member
 
Trader Score: (0)

Join Date: Nov 2007
Location: Shaw AFB, SC
Posts: 23
ok I'm thinking something's up with the fuel pump cause I disco the hi pressure fuel line by the fuel filter and I turn the key to on and nothing is coming out... am i missing something?
pm0369 is offline   Reply With Quote
Old 04-27-12, 08:35 PM   #19
Exhaust Leak
5 Year Member
 
Trader Score: (0)

Join Date: Nov 2007
Location: Shaw AFB, SC
Posts: 23
pulled the fuel pump out... and this thing is filthy... filled with all kinds of sludge and rust... I placed a light and mirror in the tank and didn't find any rust in the tank... anyhow... what's a good fuel pump to throw in... should I go ahead and change the pressure regulator as well... or any other components.
pm0369 is offline   Reply With Quote
Old 04-28-12, 06:32 PM   #20
Forum Vendor
5 Year Member
 
RotaryEvolution's Avatar
 
Trader Score: (30)

Join Date: Oct 2003
Location: Las Vegas, 1 mile from the strip
Posts: 2,354
stock fuel pump is best.
RotaryEvolution is offline   Reply With Quote
Old 05-12-12, 12:10 PM   #21
Lousy Crew Chief
 
Trader Score: (0)

Join Date: Feb 2010
Location: Shaw AFB, SC
Posts: 390
pm0369 happens to live down the street from me. I swung by and took a look at it. From a couple quick glances I noticed his MAP sensor had a nice melted area. It would start right up but it was running rich as I could smell it pretty good. The plugs HAVE NOT been changed in god knows how long so I suggested changing the plugs. The claim of the cat getting hot is a huge sign of a clogged cat. Rotaries tend to do that eventually and with the addition of old plugs I can imagine the cat clogging right up. I suggested unbolting his cat and trying again after he swaps the plugs. I've never experienced a blown rotary but a lot of times I hear they they don't even like to start, which leads me to think that it MAY have good compression. If all else fails we will definitely do a compression test.
Mrmatt3465 is offline   Reply With Quote
Old 05-12-12, 11:20 PM   #22
GateKeeper MOD.
5 Year Member
 
misterstyx69's Avatar
 
Trader Score: (130)

Join Date: Sep 2005
Location: Smiths Falls.(near Ottawa!.Mapquest IT!)
Posts: 19,517
if you just do the compression test First,you will save all the hassle of Screwin with **** that you think it is.
IF you have a good engine,then you can go from there..BUT if you don't and you keep on guessing,then you'd just be doing all that work for..Nothing.
misterstyx69 is offline   Reply With Quote
Old 05-15-12, 07:51 PM   #23
Exhaust Leak
5 Year Member
 
Trader Score: (0)

Join Date: Nov 2007
Location: Shaw AFB, SC
Posts: 23
Removed the cat... it looked pretty nasty and seemed pretty clogged... All it did was make the popping extremely loud, and I can see the cool flames coming out from the precats now... It starts alot easier and faster now but still dies and won't idle... battery is completely dead now but once I get it charged I'll be doing a compression test next...
pm0369 is offline   Reply With Quote
Old 07-01-12, 09:52 AM   #24
Exhaust Leak
5 Year Member
 
Trader Score: (0)

Join Date: Nov 2007
Location: Shaw AFB, SC
Posts: 23
alight i know its been a while... But today I'm doing my compression test... Crossing fingers...
pm0369 is offline   Reply With Quote
Old 07-01-12, 02:28 PM   #25
Exhaust Leak
5 Year Member
 
Trader Score: (0)

Join Date: Nov 2007
Location: Shaw AFB, SC
Posts: 23
So I'm done with compression testing... and let me tell you guys... I got about 75 to 80 psi on the rear rotor... and for the front... nothing... not even a budge... So I'm assuming its time for a rebuild.
pm0369 is offline   Reply With Quote
Old 07-01-12, 02:28 PM
RX7Club
Mazda RX7




Paid Advertisement


 
 
 
Reply

Tags
guuyed, high, map, rpm, rx7club, sensor, studdering

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


All times are GMT -5. The time now is 04:14 AM.
All content Copyright 2007 by Internet Brands, Inc.

Contacts

SEO by vBSEO ©2010, Crawlability, Inc.