gradedcheese

Can anyone please offer me some troubleshooting suggestions?

My 1973 RX-2 Auromatic will start up fine and run for anywhere from 30 to 60 sec or so and then it dies fiarly quickly. After that it is very difficlut to restart it (but easier the longer you wait between starts) - it will either not start or start but run at near 0 rpm with a WHIIIIRR sound and the car shaking a lot and then die or start and run for very little time and die again.

I've tried:
- spraying carb cleaner in the carb
- using and not using the choke
- replacing the fuel filters
- checking that the fuel pump still runs (it does)
- swapping the coils around (in case one is failing)
- replacing a rotor and a condensor or two based on what spares in the car

What should I try next? A friend suggested that the exhaust may be plugged up and causing too much back pressure for the car to run so he said I should try unbolting the exhaust from the TR manifold and seeing what happens... however the noise, I assume, would be pretty extreme.

mrmasda

I know this sounds too simple but change the plugs and when you take them out see if they are fuel foiled.

gradedcheese

ah, i will try that just in case. i don't think it would produce these symptoms but at least it's easy to do so I may as well give it a shot.

gradedcheese

well, I pulled the spark plugs out, three are fouled and one covered in oil too. the last one was not even hand tight in the thread and the little tab where it sparks was literally bent in. I have some cool photos of it to put up later.

However with new plugs the car still acts the same way Any other ideas?

Darth Linux

float level? after it dies is fuel pouring into the venturi like a flood or what? sounds a lot like when the floats are set to high and more gas is going into the engine than what it can burn. it will run for a short time and then stall out and be impossible to start again until that gas evaporates. the evidence is when you pull the air cleaner off, you can litterally see fuel spewing into the throat even after the engine has died.

gradedcheese

while it may be a carb problem I don't think it's float level... I have had the air cleaner off all this time and after it dies there's nothing to be seen in the carb throats. I can smell a little fuel but I suspect it may be from whatever was left when the car died rather than a flooded carb.

I think it's probably an ignition system problem but I am not sure. Once thing I know is the wire to the solenoid that makes the starter run is in bad shape and sometimes the car won't start unless I wiggle it, however I doubt that would kill the car later (that wire only has 12V when you crank right?) but I need to trace that wire back, cut it, and replace it.

buzz

When the car dies, do it just stop from an idle rpm, or drop rpm, stagger for more than say 5 seconds and then die. What happens if you are holding say 2,000 rpm? Die slow of fast? Smokey exhaust?
I agree with your friends suggestion of backpressure killing it - definate possibility, but with the car running there should be a decent amount of air out the tailpipe - so it shouldn't be too hard to check.

If it dies slowly then its less likely ignition than fuel. If it dies after about 45 sec on idle, but sooner on 2k or 2.5k rpm, then its running out of fuel (crimped line... blocked filter... cruddy pickup... water in fuel?). If you can, try starting it with the air filter off and using a syringe (5-10cc) or similar, hold the throttle part open and when it starts to drop rpm a little, squirt a little more fuel into the primaries. You can keep an engine running with no fuel system supply like this.... (but be careful with it!!!)
The engine might be just running on the float chamber - this process above might prove it. If you use the process above to get it started, then after a while it can idle ok, then blame the carb accel pump.
If the exhaust smells petrol-ly then it could be too much fuel , possibly due to flooding, stuck needle & seat - but holding a higher than idle rpm should make it continue running.
If its idling but dieing on throttle it could be blocked jets. The syringe process above will overcome this.

If NONE of this helps, then start looking at ignition. At least you have isolated on element from the loop.

Wankelguy

See if the fuel filter is emptying out. If it is, it is probably a blocked fuel pickup tube inside the tank. I had that same problem with my '80. I got an old bass guitar string and bent one end of it to form a little hook, then chucked the other end in my drill and roto-rootered it out. I think I used an "A" string IIRC.

gradedcheese

buzz -- it sounds like a fuel issue from what you said but I'll have to try spraying fuel or starting fluid into the carb once I have a second person handy along with the other stuff you mentioned.

Wankelguy -- I don't think that it's emptying but I'll double check. I changed the proper fuel filter and also put a new one under the hood (someone had installed one there) and they look to be getting fuel through them. but I'll have to take another look.

buzz

The accel pump should be enough to get it running - I was playing with the throttle in the engine bay to keep it running and hold it open.

I suppose it was easier for me with a right hand drive car!!!! I can stand at the carb and still be within reach of the keys! :P

Get it idling and then when the engine note drops a touch try spraying in a little more fuel into each of the primaries, the engine note/rpm should pick up.
IF this is the case, then yes, the fuel is running out.

Check the fuel flow to the carb, by pumping the petrol directly into a jerry can or the like and measuring how much output there it.

Again... be careful with the petrol.

gradedcheese

Well I think it's a carb problem...

I took off the top of the carburetor and removed every single jet and air screw and cleaned them thoroughly (they were covered in dirt) and then cleaned things up on the carb, like the fuel bowls, reassembled everything, and fired the car up. It started and ran for at least two minutes before the tach started jumping up and down a little and it finally died (but that could have been a number of things at this point, maybe even timing, mixture, etc). I'm going to start messing with it again this evening and see if I can make it run longer or just run without dying.

That said is there anything else I need to clean that I probably didn't get at from taking the top of the carb off? Also how was I supposed to remove the choke cable from the linkage on the carb top?

dole2000

isn't there a fuel pump in the trunk in that model and a fuse near it? My wife used to have and RX-3 and when it did that it was always either the fuel pump or the fuse back there.

gradedcheese

yeah it has a pump in the trunk somewhere. I think the fuse is in the fusebox in the dash on mine (not blown). I suppose the fuel pump could be bad but it does work for a while and I swear I hear it still running after the car dies. It could just be barely running though. There's still fuel in the filter when the car dies though.

buzz

does your carb have the little port-hole view thing into the float chamber? If so, get the car running and see what happens with the fuel level. It should stay level. If it drops, the needle might be stuck or similar.

gradedcheese

it doesn't. However I should just see if I can get at the needle and see if I can clean and inspect it. Is the needle accessible after I take apart the carb top where the fuel inlet is? I need to find my RX-2 book which I misplaced ASAP.

I keep seeing rebuild kits for RX-2/RX-3 carbs on ebay, I wonder if it's worth it.

yikes, this thing even has a fuel return line on it. still not as scary as one of my BMWs with not one but two Zeniths on it

buzz

sorry... I don't have a rx2 manual handy (its 9.45am here and I'm at work....). I used to have one here in the office... but someone questioned it .
It should be readily accessible - can't think why not - as it should be something that needs to be set pretty much last thing in a carby build / tune activity.
I'm suspecting you will be needing a gasket kit if you start hooking into it in any more depth.

gradedcheese

I didn't get a chance to mess with the car last night hopefully tonight I can fire it upa nd see what I can do, and if it still dies pretty soon I'll start looking into the fuel pump and rebuilding the carb.

I'd rather convert to a Weber but the parts are way over my budget right now and I suppose the Zenith isn't so bad if rebuilt.

buzz

another thought - try opening the fuel cap in case it's a vapour lock issue.

Good luck with it!

A single dizzy weber conversion is easy - (the twin dizzy inlets are a little harder to find)... 6 bolts, connect throttle cable and get the fuel union sorted.

Out of curiousity, How much would a complete weber set-up go for in the US - there was one going locally for $650AUD..... about $430US for the inlet, carb and linkage (and filter I think).

Darth Linux

Graded,

your carb has not one but two glass ports for you to check out the fuel level with. In my experience, the RX-2 carbs get so caked with oil and dirt over the years, it's real easy for you to not see the things. You'll need to get a couple of cans of carb cleaner and an old toothbrush and really clean the outside of the entire carb as well as you can. THen you'll need a flash light and small mirror so you can actuallyl see the fuel through the glass on each side. The firewall side is harder to see than the front side, but the mirror and light will help. At idle the fuel should be in the middle of the glass where the line should be.

Yes definately buy a carb kit of eBay. Just one warning, it's very easy to set the floats incorrectly on these carbs because there are two adjustment points on each float. If your carb literally dumps fuel down the throat after the rebuild then you've set the floats wrong. See my webpage below for a look at my carb before and after the rebuild, it's amazing how much dirt and muck was on that thing.

Dave

gradedcheese

thanks dave I'll try that and I'll look at the photos now.