hey my names lee and i just bought an 86 rx7 N/A. the car only has 63,000 original miles on it. i bought it without an exhaust, i recently put one on which is single pipe. the car was running really rough as it had been sitting for quite some time, i think bout 3-4 years before i bought it. i had my mechanic take a look at it and he said that my injectors were really shitty and that they might be leaking. he also said that whenever i had to start the car, i had to put the gas pedal to the floor. it started up most of the time without it however. then a few days ago, i brought it to a shop to get a tune up. it drove to the shop fine and everything, although when i started it up it reaked of gas. so i back it up into the parking space, wait about 30 mins for my car to be taken in, and the guy cant start the car. i thought he had done something to make my car not start but apparently the motor was flooded. we pulled the plugs and cleaned them off, tried to crank it, wouldnt start. put the car on the lift, theres gas leaking out of my exhaust pipe! im just wondering what may be the problem cuz i was really excited to get this car going but now it looks like im gonna be set back a few hundred dollars to get it fixed!

 

Dirty injectors are common in 25 year old cars. Places like witchhunter performance, as well as local shops can service injectors for around $15-20 a piece. Hot start problems are almost always related to injector condition, so starting getting them taken care of is not a bad idea.

 

i have a straight pipe on there now and the mechanics who "fixed" my car said that because i dnt have all 3 cats on there, theres not enough back pressure to support the start up. every time i try and start it, it wont because it is flooded. i have to crank it first without the EFI fuse in then crank it again with it back in. funny thing is, the last time i tried doing this, it flooded a lot. i dnt understand this problem and i currently have my car on cl for sale because i do not want to deal with another huge problem car like i did with my s13. if any one has any solutions please let me know. thank you

 

have the injectors cleand and balanced or replace them (all 4). but a rx7 is a great car to own, keep it and work out the small probs.

 

that mechanic is a moron. Most likely your injector are dirty not properly spraying. Might be dripping gas. Liquid gas in an engine does not burn correctly and that why you're finding it in your exhaust. It needs to be sprayed as a fine mist.

 

It looks like you didn't bother to read my post. Any yes, that mechanic is a moron. Engines don't need back pressure to start.

 

Correction= Rotary Engines don't need back pressure to start.

back pressure does play a large part in the performance of many engines, the rotary is not one of them.

 

Backpressure != velocity.

 

ok so how does you guys suggest the best way to clean the fuel injectors would be? i was told never to put fuel injector cleaner into my gas because it could potentially ruin the motor...

 

Have them serviced. The injectors are pulled individually and flushed so they will open fully, close fully, and spray correctly. If they are gunked up they will leak and spray streams of gas instead of the fine mist needed for compression with air to combust. You can simply take them out and use seafoam on them if you want.

 

There's also this trick for adjusting the amount of startup fuel: https://www.rx7club.com/2nd-generation-specific-1986-1992-17/looking-car-has-hot-start-problems-499744/.


Backpressure plays a role in the performance of ALL engines, including rotaries. An exhaust that is overly restrictive (and creates extreme backpressure) will kill power. That doesn't mean having an unrestricted exhaust will also kill power. And it certainly doesn't mean that an engine won't start with an open exhaust.

Modern cars are tuned with a specific volumetric efficiency in mind (how much air the engine can take in divided by the theoretical volume based on displacement). When you change the exhaust system, the volumetric efficiency also changes. When the airflow changes, and the amount of fuel does not, the mixture goes too rich or too lean. This is where the myth comes from. A modern car with a stock ECU and a big 'ol free flowing exhaust can run lean and actually LOSE power (or even detonate).

 

get your injectors cleaned here:
http://www.witchhunter.com/
>get new spark plugs>tell your mechanic he's ******* stupid>drive>enjoy

 

seafoam is a bad idea, IDK about rotaries but on pistons it will strip the Cyl walls of oil, and cause some damage... Seafoam is a very strong solvent. if you're going for a decarbonizing use techron. Rebulding the injectors might do you good.

 

Also, BG is a really good system if you can find someone who does it.

 

Do you have any evidence to support this or are you just spouting what some idiot said because he waited 10k miles to change his oil and used seafoam?

 

thanks guys for all your help. i think im going to have them cleaned like you guys said. but lets say theyre too far gone, what size injectors do i get on a stock n/a motor and how much do they run? and is it true that there are different sized injectors that go together? i know there's a primary rotor and a secondary one, do they play a role in the injector size???

 

Yes, they are different. 460cc Primaries and 550cc secondaries. I don't know prices off hand. You can go to www.mazdatrix.com or a similar store to find them though. They have them listed for $229.72.

 

Wrong.

There are four 460cc low impedance injectors.

I strongly suggest getting a picture before you buy and just buy them on this website. After you get them send them to witchhunter for a rebuild because they will almost surely need it while you have them out. Make sure you get low impedance. They have a square plug with a center notch on the outside of the plug.



Far left is low impedance.

 

Please don't give information that you don't know. If you don't know for sure, don't answer. As said above the N/A has 4x460 and the Turbo has 4x550. And being you have an 86 you would want low impedence.

 

I got that from the book Street Rotary. Sorry if it is incorrect.

 

I agree with the guys that are giving you the right info these cars are great dont sell.Just a little about my 88' GTU my last motor had 217,000 miles and ran like a top when i pulled it so they are great not to mention so much fun.New injectors or having them serviced is really great info thats probably a huge prob since the car sat for so long and that mechanic must not know rotarys cause ive got racing beat downpipe and pre silencer on mine into two and a half all the way out the back and well my car runs great so lust give it some love cause thats what these cars take and ENJOY cause thats what will come i promise