Blowndakrt

Hello all. I do not own an RX7. My buddy does. He does not have interent access at this time, so I told him I would try to help him out. He is having some trouble with his car. It has been taken to several shops, but to no avail.

He has a 93 FDS3 R1. He getting a miss at idle. He is not sure if it does it while driving, he says he cannot tell. He has a high idle as well, around 1500 rpms. If he turns on the A/C, it will bump the idle up and it doesn't miss. I forgot to ask how much it jumps up to.

He has replaced the ignitor, leading coil, plugs, and plug wires. He also had the wire from the ignitor to the coils replaced, although the shop that did it for him, replaced the wire with one that is about 12" longer than the old one. Not sure if that would affect timing at all.

Also, when the engine is warm, it does not want to start easily. It mainly cranks and will feel like it is starting, then when you let off the key, it dies.

My thoughts were possible vacuum leaks, but I have no clue about the rotary engines. Not sure how much different they are from a normal engine, so not sure if the same principles hold true. I also thought about timing, but once again, I have no clue how to check timing, or adjust it if needed.

Any advice or things to check out would be a big help.

Thanks in advance.


Shawn

rynberg

vacuum leak, bad fuel pressure regulator, etc. Could be a few things.

He needs to go through the troubleshooting portion of Section F of the factory service manual.

SpeedKing

iTrader: (4)

What's the mileage, and does the car have any mods?

The high idle sounds like a vacuum leak, and difficult hot starting is a sign of low compression. Might want to check your lines and have a rotary specialist perform a compression check.

Ohnigiri

I have the same exact problems and here is what I have done:
new plugs and wires....no help
Metered every imput device on the engine that would effect cold idle. The nuetral switch was shorted out with the 1-2 switch. I cheated the signal to the ECU....no help.

Get a compression check and prepare for a rebuild. Money is on a busted rotor seal.

After your friend drives for a while does the idle "sound" like the car is going to die even though the RPM's look OK? When he restarts his car hot it takes a long time to get the engine to kick over on it's own? I gotta floor the gas to get mine started after it gets warm.

MR_Rick

iTrader: (7)

Could be fuel also. Poor fuel presure will cause problem starting or injector (s) going bad also. There is a lot of thing but I agree with the above high RPM sound like a vacuum leak. The only thing that deals with timing is the crank angle sensors.
BTW rotary engines are the normal ones

Blowndakrt

I am not sure if he even has the factory service manual. I would bet he does not. Do they offer a hanyes type manual for the RX7?


Thanks

Shawn

Blowndakrt

I am not sure on the mileage, I can check tomorrow. As far as I know, he is stock.

The biggest problem seems to be the lack of decent shops around here. Closest Mazda dealer that is willing to look at it is over 2 hours away.

Are there some key areas to check for vacuum leaks that are common on these motors?

Thanks

Shawn

Blowndakrt

I will ask him about the "sound" you are referring to. I do know when the engine is warmed up, not necesarrily hot, he has trouble starting it. A round trip of 20 miles or so, requires about a half hour of cool down time before it starts up fine.

Thanks

Shawn

Blowndakrt

So fuel and vacuum seem like the two biggest things to check. Is there a port to hook up a fuel pressure guage?

The part that was leading me towards timing, was the fact that when he turns on the A/C the idle jumps up to compensate the extra load, it idles fine. I will have to check with him to see what the idle jumps up to.

And the normal commment, didn't mean anything by that. LOL. But the concept behind the rotary engine has always baffled and amazed me. I guess when you break it all down, it makes sense, but still takes a bit to soak it all in. And it is not your typical piston, crank, valve type motor. To me that is normal. Haha.

Thanks

Shawn

Ohnigiri

How is the gas mileage? Getting worse?

I have opted to buy a used engine w/ similar mileage as mine. I am rebuliding it in my shed. I refuse to nickle and dime this kind of problem. (nickel and dime= $200-$400 per troubleshooting step) I figure after about 3 months the engine will **** and I will have an upgraded one to drop in with minimal down time involved. Let me know if your friend ever figures out for sure what the problem is.

SpeedKing

iTrader: (4)

The notorious "rat's nest". You'll have to go over these lines to make sure none are split or loose.

http://www.robrobinette.com/hoses.htm

Blowndakrt

I am guessing he doesn't really check gas mileage, so can't help ya there. For his sake, I am hoping its not time for a rebuild or a new motor. I know I can't do it. LOL.

I will let you know if we find anything out, but with both mine and his limited knowledge of these motors, I am guessing we won't find anything you haven't already tried.


Shawn

Blowndakrt

You have got to be kidding me? What have I gotten myself into? LOL. I know for a fact I am gonna be the one helping him on this. Hahaha.

Do they sell kits that replace all those lines, like a pre-cut and labeled kit, or do you just go buy 8 miles of vacuum line, cut it yourself, and do it one at time sort of process?


Really starting to question how good a friend he is. LMAO


Thanks

Shawn

SpeedKing

iTrader: (4)

Yep.

http://www.rx7store.net/index.asp?Pa...ROD&ProdID=633

But I wouldn't put all my stock into this. It could be one of the lines or it could very well be something else. Try checking all your couplers too.

Blowndakrt

Well I figure I would start with some carb cleaner. Spray it on the hoses, to determine if its the hoses that are leaking. But then again, its not my money. LOL I might just tell him order replacements, so we have that part covered and can move on to the next step.


Shawn

dgeesaman

iTrader: (7)

You can get a kit with all new check valves for $170 (www.mazdaformance.com I think) but that's OEM and they are the same hoses that hardened on in the first place.

Otherwise, buy silicone hose or viton. It's a time consuming installation (https://www.rx7club.com/showthread.p...light=hose+job), but without it you'll be dealing with vacuum leaks till the day the car dies.

Dave

Blowndakrt

Very good writeup. Almost looks easy, just very time consuming.

Is this something that could be done in a day, or would we be better off shooting for a weekend? His is currently his daily driver.


Thanks

Shawn

MR_Rick

iTrader: (7)

well sometimes when you get that deep into a project it might take you more than a weekend because you never know what you will find. I went from putting a simple downpipe to redoing my wire harness and a bunch of stuff that let the car sit for a month.

before you get into doing this I will do a compression test. If that's good then that's a relive. But I recommend if you are going to do the hoses job to take the injectors out and send them to get clean.

Ohnigiri

Buy a multimeter and check your solenoids and sensors while you are in there also. While you have it apart. It's just easier.

Blowndakrt

Is there a way to do a compression test without taking it to a rotary specialist? I talked to him today about it. The car has 60K miles. He took it to a dealer that is 2 hours away last year for the same problem. They did a compression test on it and said it was fine. Now a year is a long time, I know, so gotta convince him into getting another one done. The only thing the dealer could find wrong with it was the ignitor. That was replaced along with all the other stuff mentioned in the first post at that time.

Also, who does injector cleaning? Is it a simple task that a normal shop could do, or would you recommend a specialist for them?

I guess its time for him to pony up and buy a beater before we start to tear into this thing.



Thanks

Shawn

Blowndakrt

I have a multimeter. Is there anywhere to get the proper numbers for what sensors and solenoids should read?


Thanks

Shawn

Ohnigiri

I have the mazda manuals on my computer. PM me and we can figure out how to get them to you. They are to big to email. Sorry it took so long to get back with you.

Ookpik

You can download the manuals at:

http://www.iluvmyrx7.com/3rd_gen_manuals.htm