Martin Adams

Ok... so forgive my ignorance of Wankel engines as I've never actually owned one before.. First off I had no hand in picking this car out AT ALL. It was a surprise wedding gift from my folks. Needless to say I was quite proud to get it condition be damned. From the outside the car seems totally fine aside from a holy in the convertible top. Inside is worn a bit but otherwise clean.. this is where the ok stops.. It idles fine... drives down the road kinda.. but NONE of the gauge cluster is working, when it's hot you basically can't start it, it's gutless.. and I mean REALLY slow. I didn't expect it to be some flashy race car when i took it for a spin but I noticed some pretty obvious signs right off the bat. Above about 3500 RPM the car seems to fall on its face. It goes from pulling pretty ok to just nothing... It will rev all the way to redline, but there isn't really a point as it's just not making ANY power. Also, it smells strongly like it's running rich. REALLY rich. Again, forgive my newbishness to the Rotary car world as I am a Diesel guy.. so this small no piston car thing is all new ground for me. Any help appreciated. Open to emails aswell. Thanks in advance.

littlebit421

Good Luck with your new project. Grab a Beer (if you drink) and start researching on the forum. Maybe Start with A Throttle Position Sensor (TPS for the drivability issue, make sure it is adjusted properly. as far as the cluster and interior issues that may be another story. This is not a guarantee, just a starting point.

WondrousBread

Hard starting or dying once warm *can* indicate low compression. However, there are other things that can cause this.

First, I would warm up the car to operating temperature. Once it is warmed up, shut it off and do a compression test (you can use a piston engine compression tester with the valve removed). Make sure to crank without the EGI fuse installed so the car doesn't actually try to start. To do it properly you will need a tachometer to correct for cranking RPM, but even without one you should be able to get a very general idea of the internal conditions of the engine.

You are looking for 3 even bounces above ~90PSI, on each rotor (front and rear). This will tell you that compression is good, and then you can investigate your other symptoms.

If the bounces are not even, irregular, or provide "low" compression, you will have to evaluate the results to decide if you want to spring for a rebuild.

Do keep in mind that if the oil injection system is not working properly, your compression may appear lower than it really is as the oil boosts compression slightly. However, if your car does not consume any oil or you see oil leaking from the front cover, stop immediately and address the problem.

If you report back with good compression, that eliminates it as a problem and then we can try and address the other symptoms.

Martin Adams

Appreciate the feed back. The TPI is good, checked that just now. The MOP is apparently bad... so that's a thing, also it is leaking a little oil from the front of the motor. Not a lot but there is a leak. The compression test showed really odd bouncing between 74 and 98 psi on the front rotor and the rear was 80 to 90. So just based on what you've told me here I assume I need an engine. Because it's hard to start cold, nay impossible to start hot. and above 3800 rpm it is totally gutless.s Falls flat of it's face.

misterstyx69

iTrader: (142)

Your OMP is mechanical and rarely does it go bad.
BUT the flimsy lines that attach to it can break and leak oil.
You do not necessarily need an engine as you haven't fully diagnosed it.
You need to delve further into it and that would require either research or asking more Detailed questions.
The more details the better your answers will get from others.

Martin Adams

My biggest issue is my pure ignorance of the Rotary engine. I'm not totally sure what questions to ask so I can't properly diag the car it seems... I can say the car is rough starting. I can say it has basically no power. I can tell you it has less power past 4000 rpm. If It was my mustang losing power like that'd I'd blame fuel cut or say the timing is off. The plugs on the injectors are nice and clean. The injectors themselves appear to be pretty new. I have the paperwork from the previous owners showing parts that have been replaced and fuel pump is on the list so I assume someone has had this issue already and was trying to fix it. One good thing about the car is everything appears to have been kept stock standard. Even the new exhaust on the car was put back original. when i did the compression test it gave really wonky results and if I had seen that kinda compression on a small black I'd say it needs rings, that's apparently not how you deal with a rotary engine. I'll give the correct information I have to the best of my ability, but please forgive my newbishness to these cars as I've never actually owned one.

littlebit421

post a video of you trying to crank start the car. you will probably have to upload it to you tube then post the link here.
Also running the car. will it free rev in neutral without load on the engine, or is it just with load that it falls on its face.

Martin Adams

https://www.youtube.com/watch?v=XPJWzrmIriU

littlebit421

Thank you for the video, Ok guys lets help this guy out, this is a little beyond me. As far as all those connectors dont worry about them, you fill find many that dead end. And yes that is very clean, congrats and it will be alot of fun once you get it going good. Just remember this isnt the fastest thing on the street and being a heavy convertible doesn't help. Its fun to put the top down and cruise.
one last thing is the ac on during all this.? Should have any thing to do with your problem but just asking, I had a vert that with the ac on it would surge and almost stall at idle.

Martin Adams

I dont want it to be fast or anything, I just want it to run correctly. I'm ticky like that. As for the AC, the compressor works, but it seems to need a recharge, and as best I can tell, thats R12. So i'll be converting apparently.

Martin Adams

Also, thanks for everyone's time and effort to reply to this thread. I appreciate any feedback at all.

Martin Adams

Ok, so I found a place that will sell me a motor and 5 speed trans with a harness and ECU out of a RX8 for 1200 bucks. Is that a good option for fixing these issues?

littlebit421

I am posting this from my cell phone so please excuse if there is no punctuation. You cannot put an engine out of an RX-8 into an RX7. Well anything is possible if you have the time and money your best bet is if you're set on replacing or rebuilding the engine is going back with what's in it. I recommend trying to figure out what the issue is now then worrying so much about replacing the engine or rebuilding. I'm sure if someone will try again before too long with some more ideas on what to do to try to figure out what's going on just be patient before you go jumping the gun thinking you need a new engine.

littlebit421

I COPIED THIS FROM SOME QUICK SEARCHES I DID. MAYBE IT WILL HELP

I ALSO SENT YOU PRIVATE MESSAGE.

DOES YOUR CAR STILL HAVE FACTORY CATS


This has been answered in the FAQ.
3,500 - 4,000 RPM Hesitation.


I have this hesitation whenever I accelerate right around 3500-4000 RPM
The dreaded 3800 RPM hesitation is cause 90% of the time by poor ground connections between the engine, the battery, and the car. Clean or replace all the under hood ground connections. On 86 model year cars , replacing/regrounding the pressure sensor's ground wire has helped (do not re-ground a 87 or later model year). If there is still a problem after that, look at cleaning the fuel injectors and (on a N/A) that your 5th/6th ports are operating correctly. – Icemark

Go to the two secondary injector connectors and pull 'em off. Key to ON. See if one wire in each connector has batt voltage or not. Should. Sounds like one of the two is off the injector.

Or driver the car using little pedal until you reach 5000rpm. Should. Then stomp the pedal at 5000 and see what happens. IF the engine starts acting crummy with light throttle and reaching appox 3500-3800 rpm.........then suspect the boost sensor is not seeing vacuum from the engine.

And or go to the ECU small plug and make sure each of the four light green wires have batt voltage with the key to ON. Check at the plug, not the jack on the ECU. If you get batt voltage at each light green wire on the small ECU plug, the wiring is intact for each of the injectors.

Then go to pin 2B and make sure it has 3.5-4.5vdc with the key to ON, engine off. 2B is the middle ECU plug and the counting is from looking into the wire side of the plug in a up/down fashion. 2B would then be on the lower row......far right. Brown/red wire.

Martin Adams

Ok.. after several hours now of chasing wires I have concluded most of the engines electronic parts have been replaced by the previous owner. It has new new connections everywhere and new injectors as well. Also, it doesn't have a hesitation the car runs really smooth. It never misses or shudders. It just stops pulling above 380p rpm like it just gives up. You can clearly feel where the power cuts out. It never has a shutter or miss though.

lduley

iTrader: (1)

It sounds like your secondary injectors are not kicking in. Are the top of the injectors the same color on all 4? Does it look like the pigtails have been replaced?

Your compression isn't bad, but its not great either, but its not bad enough to where it should feel gutless after 4K (mine has 70 psi and it still pulls hard to 8k)

I would be making sure there isn't mismatched hi/low impendance injectors, and check your fuel pressure

Martin Adams

Alrighty. Will go out and try that right now. What fuel psi should I be getting?

lduley

iTrader: (1)

www.foxed.ca

this will be your new best friend for anything


also, do you know ANY history on the car? a slipping clutch can make a car feel gutless too