Riddick_941991

Ok so i recently purchased this really beautiful 86 mazda rx7 with only 82,000 miles on the odmeter. the body is in perfect shape its got a custom exhaust and an original 13b. I only payed 2000 dollars for the car, and from stepping up from a little honda civic i thought this was a great buy. So before buying the car i checked the important things we checked the compression it tested great so i was determined to get the car, the only problem was it doesnt like to crank im not to sure how the guy i bought it from got it to crank but he was able to drive it out of his two storie garage. well after we trailered it home we didnt feel like pushing it up the drive way so we got my 4x4 pick up and pulled it down the street until it fired up. But as soon as he got it started it was putting alot of white smoke out really bad, i asked him what it was he told me its just the bad smoke from sitting for 2 years sense 2006. so i thought it was no problem. so i got to work on the car the next day. First thing i did was i drained all the gas, and yes of course the gas smelt like cat ****. So after completing that i imidetly drained the oil. but when i was draining the oil i got some clumpy **** out with the oil and i couldn't figure out wat the hell it was. So After draining it i put some fresh 20w-50 in it and put a new oil filter on. I just bought some new gas to put in the car 93 octane and put maybe 1 gallon in. And because my battery was dead i went and borrowed my moms mustangs battery and tried to fire it up, the only problem is it would turn over put it wouldnt start up so can any one please help me and lead me in the right direction?

Go48

iTrader: (7)

A proper compression test is the first thing you should do to verify that the engine is basically healthy. If the engine passes the compression test you can look elsewhere for the problem(s). Unless you do such a test first, you may be chasing your tail for a long time looking for non-existent causes of the problem.

How did you do the compression test? Since you appear to be new to rotary's, I would suggest that you investigate how to do a proper compression test. There are special testers that are used to conduct proper compression tests on rotary engines. Unfortunately, most people don't have such a tool, but there are other ways to get a general idea of the level of engine compression. Read on.

BACKGROUND: Problem is, each rotor has 3 compression faces and you need to know the compression reading for each face in order to evaluate engine health. A conventional compression tester can be used for a ghetto test, but you need to know how to use such a tester. If you use a conventional tester incorrectly, you could still have a failed apex seal and the tester can show good compression based on the one good compression face.

To use such a tester, remove the EGI fuse from the engine compartment fuse box. Remove one of the leading (lower) spark plugs. Then remove the shraeder valve from the tester (or press the button on the side of the tester if it has one) so that the pressure does not build up in the gauge. Screw the tester hose into the spark plug hole and have someone crank the engine with the gas pedal depressed while you watch for 3 even bounces of the gauge needle.

You can also do a "puff" test which can reveal low compression on one or more rotor face. To do such a test, remove one of the leading spark plugs, remove the EGI fuse, crank the engine with the gas pedal depressed and listen for three strong puffs--like PUFF-PUFF-PUFF. What you don't want to hear is PUFF-puff-puff or puff-puff-puff or silence-silence-silence--or any combination of those. Now do the other rotor. You can also search the forum for more information on doing such tests.

Also, take a look at the spark plugs while you have them out. If the center insulator is anything other than a tan color, replace them.

Riddick_941991

See i bought the car from Jose zeda also Jose Rottary we checked the compression with some compression tool of his he said it came out good its a healthy engine. and so far for the longest time i have know him he has been honest about his work.

greener_dude

I have an 87 rx7. car starts beautifully with a little mod that was done. these cars love to flood. So to get it to fire up there was a fuel pump switch installed under my steering wheel on the flat plastic panel. Basically with fuel on, I crank until i hear the engine puff or try to catch. I flip off the switch off while cranking and as soon as it revs up i flick the fuel pump switch back on (or else it will die within a few seconds). end of story... works EVERY time!

It would not surprise me one bit if your car was flooding. Have you ever poped the spark plugs out and noticed there wet?!?!? If so, its a good indicator of flooding.

also to note my motor is weak on one rotor, without that mod it would not start (easily).

What a lot of guys do instead is pop the fuse under the hood or dry off the plugs but thats annoying especially if you stall the car or you need to do it a lot. The switch was just the easiest solution. It also doubles up as an anti-theft device... my brother tried to start the car when i wasn't around and he thought the switch was for my fog lights and left it off lol.

JonnyK

"I just bought some new gas to put in the car 93 octane and put maybe 1 gallon in. "


Great advice so far from everyone. Just one point to add though, these cars don't like high octane gas. The rotary engine is a very low compression engine (compared to other high performance piston engines) and will not run well on 93 octane.
The higher the octane rating, the [I]more[I] the gas resists detonation. In high compression engines you need this to prevent premature detonation (explosion before the spark plug fires) but in lower compression engines this will lead to poor performance and faster carbon build up.
It's actually a good thing these cars run better on lower octane (assuming the engine is still stock and not turbocharged) because they suck down the fuel faster than any other car their size.

thatguy85

My 88 rx7 does the exact same thing. It will crank but it will not start. No amount of plugging and un-plugging the egi fuse has thus far worked. I think it may be the fuel pump... I unhooked both the lines that go to the fuel pump and just cranked it to see if any fuel spilled out, and did not.

I know that's kind of a ghetto way to test your fuel pump, but I think that pinpoints the issue right there.

MazdaMike02

iTrader: (4)

How is 9.4-1 and 9.7-1 low compression? (Both series N/As)

Do a proper compression test, 100+ total is great, 90-100 Decent, but not the best, 80-90 is on its way out, under that and its pretty much toast.
At about 85 maybe a bit more you'll experience hard starting, it'll flood easy due to low compression.

At 80000 miles you shouldn't have to worry about compression. The motor in my car lasted 240 000 kms, so iduno 180000 or 190000 miles.

misterstyx69

iTrader: (142)

I hate to be an ***,But Instead of Posting,I would be on the phone to the Guy that you Bought it off of,and see if he would at least Take some Time to Look at the car..If he is as Honest as you say he is,he will come over Start the car up and tell you a little about it..Truthfully,I have sold ONE Rotary Car,and I Fully Disclosed EVERYTHING about the car,the Good and the bad.And I made sure the Guy that Bought it,knew about the Car's mechanics,and how they worked..I Refused to sell it to Someone that didn't know Squat about RX7's..anyhow,It sounds like the car is Flooded..and they Like to do that,If the car was run for say.a minute,or Started moved and shut down,Quickly..anyhow,my .02 cents..

drifter_xs

remember ... rx7 like too flood .... pull the fuel pump fuse and crank a lil... like 3 times... then put it back... also check the starter and battery...nice and simple...

JonnyK

9.4:1 and 9.7:1 are relatively low compression compared to other high performance engines (in my experience). Unless the temperature is really hot out (95 deg. or higher) I wouldn't consider running anything higher than 89 octane unless its in an engine with compression at 10:1 or higher.

Compression isn't the only thing to consider when choosing fuel (sometimes manufacturers design lower compression engines to run on premium with hotter plugs, different timing, etc.) but it is a good indicator of where to start. I think especially in a rotary engine, where you've already got a wide combustion chamber and difficulties with efficiently combusting fuel, you'll want to run a lower octane fuel, and it cheaper to boot!

MazdaMike02

iTrader: (4)

IMO thats high compression, I usually deal with 8.0-1 or lower with v8s. Nascar teams run around 14-1 or somethin close to that, keep in mind those are meant to run one race and they're rebuilt.

JonnyK

Just coming from diffent backgrounds. I come out of working on motorcycles where 9:1 is normal and most true performance bikes are aroune 12:1 or 13:1. I've read that the rule of thumb was that 9.4:1 and lower only should only burn 89 and anything over that depends on the ambient temperature and manufactureres recomendations (though usually 91 or 93). I have a Honda Superhawk (90 degree V-twin with 9.4:1 compression) and I never put anything other than 89 octane in it. 30K on the odometer and still going strong, never any sign of knocking.