whiteclipse16

First off, what I have is a 79 Rx7. Not sure as to which motor because its my grandpa's car, I'm just trying to help him.
Secondly, I've read through the First Gen FAQ pages trying to solve the problem on my own, but haven't had any luck.
Now, my problem is that the car will start and run nicely, I think it has some slight hesitation when accelerating or starting out. Once the car is warm, it will not start on its own. If you prime it by pouring a little bit of gas in the carb it will fire right up and run fine again. We've installed a new accelerator pump and put a carb rebuild kit in it and its still no good.
Last summer the car started giving him problems. It would just up and quit out on the road. He replaced the fuel pump and cleaned the gas tank out throughly. Now the car will at least start and run, but just won't start when hot.
Any ideas are greatly appriciated.

Also, I found multiple links to a downloadable carb. manual, but they all take me to "Internet Explorer cannot display the page" even the one thats posted on here. Does anybody have this downloaded that I could get it from.
Thanks Much

RotaryRocket88

iTrader: (7)

I'll let one of the 1st gen guys give you advice on the carb'd engine, but I can direct you to a very good link for manuals for rotary powered vehicles: http://foxed.ca/foxed/index.php?page=rx7manual. I think the '80 workshop manual will be what you need, as I don't see a '79 specific one listed.

whiteclipse16

Thanks Rotary, I'll check it out.
Bump, any ideas guys?

installer67

iTrader: (18)

I'm not terribly familiar with the SA's, I have an FB. But it sounds to me to be choke/emissions related since the car will actually start, but then dies when warmed up.

rxtasy3

iTrader: (2)

i had a hot start issue on an engine i built. i reused all seals and springs in the build. it would start just fine when cold but after driving it around and stopped somewhere, it was a bitch to restart. on the second build i found that the apex seals were way out of tolerance along with weak springs. needless to say i went back with all new stuff and haven't had one single problem with it starting and currently has 40 some thousand miles on it. have u tried using the choke to start it when it's warmed up or when trying to start it does it sound like it wants to start but doesn't catch? i know that last part sounds weird but that's how i describe it. others probably know what i'm talking about.

whiteclipse16

My grandpa seems to thinks its something with the hot start system on the carb. I've been reading this morning from the manual that Rotary linked me to.
When you talk about the apex seals being out of tolerance. Thats internal correct? Sorry but I really don't know much about these engines, just some second-hand knowledge.
As far as starting when its hot, I haven't been around when he's tried, but the way I understand it won't even start pulling the choke out. You have to dump a little bit of gas in the carb for it to start, Only When its Warm though. It fires right up when cold.
I understand what you mean by the last part, but as I said, I haven't been around when he was tinkering.
Thanks for the responses, anymore ideas let me know. Might try to check out that hot start system sometime.

rxtasy3

iTrader: (2)

yeah apex in internal. actually outside the carb and ignition, everything else that has to do with making it run is internal.

RotaryRocket88

iTrader: (7)

Yes, the apex seals are on the tips of the rotors and allow the engine to make compression by sealing against the housing. Seals that are out of tolerance would likely cause a reduction in compression, which makes starting the engine much more difficult.

whiteclipse16

:/ Dang, I was really hoping this would just be a carb. adjustment problem. When he first bought the car and got it running it ran great. Then it got to the point where you'd just be driving and it would quit. You could crank and crank, choke it, prime it, everything and it wouldn't start, and then it would just all of a sudden start. No pattern or anything.
Thats when he put a new fuel pump in and cleaned the tank. Now it will start good, but just not when its up to temp.
Not sure about road driving as he hasn't taken it out since the fuel system work.

Are these Apex seals difficult to change? What about cost?
He keeps wanting to just do a chevy V8 swap, but thats going to be probably $1,000 to do.

Just curious, would anyone be interested in buying it. He does want to sell it.

rxtasy3

iTrader: (2)

a stock rebuild will more than likely cost more than 1k. u can save alot by doing the tear down, cleaning, and assembly urself. the biggest cost is all the internal metal seals and springs. and it would be best also to have a machine shop resurface the 3 intermediate housings. then there's the extra cost with porting if u choose to have that done. reading back thru this i noticed something that hadn't been suggested. do a compression check. if it was possible to get it running so u could get it up to temp so u could see if there's any difference in compression between cold and hot. a regular tester will work, u just have to remove the needle valve in it. pull the leading plugs out and have someone spin the engine over while u watch the needle bounces.

whiteclipse16

Thanks rxtasy3. I did mention that to my grandpa to try to determine if the problem is in the motor or carb. Are the compression specs/tolerances in the FSM.

RotaryRocket88

iTrader: (7)

Minimum compression spec is ~82psi in the 2nd gen FSM, but that's a low number really. Ideally, you would like to see 90-100+ psi on each rotor face. I don't think the 1st gen FSM will list it any differently.

bryceRXer

I think your grandpa is right. Look into the hot start assist. Have someone watch it as you try to start it hot, or even activate it manually. Do a search in 1st gen section on "Hot start assist" and see what you can learn before doing a rebuild.

whiteclipse16

Thanks for all the help so far guys. I printed off the carb manual and am going to try to do some testing this weekend. Wish me luck.
One thing I haven't heard mentioned is about all the vacuum lines. I know theres a ton of them and I imagine that if one is bad it will effect the carb operation. Do you think it could be contributing to my problem though?

Pele

iTrader: (28)

It is possible, but it would more likely show itself at all times if teh problem was a vacuum leak.

Still, there are odd circumstances where a metal line has broken open and when it heats up and expands, it opens far enough to make the vacuum leak bad enough to stall the engine.


I'd still look into the hot start system. (There should be a motor on the driver's side shock tower with a cable that goes to the carb.)

Also, check compression. Where abouts do you live? There are many members with compression testers that may help you out.

Also, what's the mileage on the engine?

whiteclipse16

It does sound like its somewhat of a long shot for it to be a vacuum line but its something to check I guess.
Just to clarify because I think some misunderstood somewhat. As of right now, if the car is just idling when its warm it will still idle fine. It doesn't stall, it just won't restart if you shut it off and try to restart when its warm.
However a prob. close to 2 years ago now, what led to all the issues was the fact that the car would just die going down the road. Sometimes it would start right back up and sometimes it wouldn't. Some people that thought they were mechanics messed with adjustments on the carb, hence why we believe the carb needs properly adjusted.

Also, I'm located in Steubenville, Ohio. Its on the eastern edge of Ohio. Near Weirton, WV and about 45min. from Pitts., PA.
Will a regular compression tester work with the needle removed, or do I need a special one. I've heard conflicting reports about this.

And to answer your other question. I believe the car has around 80,000 mi. Don't quote me on that. Original miles too, the motor has never been redone or anything, so it could be the Apex seals? :/

Thanks for all the help guys.