| Author | Message | ||
     Richard Greene New User Username: benzjag Post Number: 3 Registered: 12-2012 |
Lately, the only way I can get my 78 Shadow to start from cold is to hold down (with my vice-grips) the rod going to the butterfly (think the rod is called the butterfly rod). Pic below is of this rod. I noticed the rod will shake violently unless pressed manually (and the car will cut off). With the rod held constantly down, the car starts immediately. If I remove the "vice-grips" to hold the rod down, the car will idle ok for a few minutes but will eventually stall. From then on, I have to keep pressure on the accelerator to keep the car idling. After the car has reached normal temperature, I have to keep the accelerator pressed for a few minutes to keep it idling and then suddenly it will idle perfectly on its own. After all this sequences, the car idles perfectly. During all this, the car will start perfectly IF I press and hold the accelerator. I feel sure it is choke related? I have not worked on the Shadow choke system. Any pointers sincerely appreciated! Richard   | ||
| Geoff Wootton Grand Master Username: dounraey Post Number: 635 Registered: 5-2012 |
Hi Richard Looks like you have a problem with your choke solenoid. This solenoid does precisely what your vice grips do; it holds the air intake butterfly valve closed during the start and warm up period. When the engine approaches running temperature it switches itself off. Here is a diagram of it taken from the SY2 manual:  Note the solenoid is located on the opposite side of the carburetor and is labelled no. 3 in the diagram. To test the solenoid, first disconnect the two wires and check one of them is supplying 12v when the engine is cold. If the voltage is present, remove the two setscrews and lift the solenoid from it's housing. Applying 12 volts through the two wires should produce quite a strong magnetic field - the solenoid should easily lift a largish wrench off the workbench. A common fault with the solenoid is the connecting wires wear, and even snap off, at the point where they enter through the top plate.  I repaired mine by carefully drilling off the top plate and resoldering the wires. Geoff | ||
| Geoff Wootton Grand Master Username: dounraey Post Number: 636 Registered: 5-2012 |
Richard If the problem does turn out to be the choke solenoid, you may find this thread of interest: http://au.rrforums.net/forum/messages/17001/13329.html?1362957335 Geoff | ||
| gordon le feuvre Frequent User Username: triumph Post Number: 62 Registered: 7-2012 |
THE THEORY IS THAT THE SCINTLLA SWICH WILL CLOSE WHEN IGN. ON AND TEMP IS BELOW?. THIS WILL MAKE CIRCUIT AND GIVE FEED TO CHOKE SOLENOID(ASSUMING IT'S WORKING). THIS "HOLD" CHOKE FLAP TO AVOID THE FLUTTER PROBLEMS WHEN CRANKING (MORE SO IN COLD WEATHER). ONCE ENGINE STARTED ALTERNATOR FEED TELLS SCINTILLA THAT ENGINE IS RUNNING AND RELEASES CHOKE SOLENOID SIGNAL TO ALLOW BI-METAL COIL TO CONTINUE CHOKE OPERATION. ITHERE IS AN ADJUSTMENT SCREW ON SCINTILLA. I HAVE ADJUSTED THESE ON CARS IN PAST TO GET GOOD CHOKE OPERATION.RICHARD, I WILL RESEARCH SHADOW 11 OPERATION AND REPORT BACK WITH MORE ACCURATE INFO. | ||
| gordon le feuvre Frequent User Username: triumph Post Number: 63 Registered: 7-2012 |
UPDATE ON THIS IS THE SCINTILLA SWITCH IS ALSO CALLED THERMAL DELAY UNIT AND THERMAL TIME SWITCH. IN ADDITION TO WHAT I DESCRIBED EARLIER IS THAT THERE IS A RELAY IN THE CIRCUIT THAT PROVIDES AN EARTH PATH WHEN ENERGIZED BY ENGINE BEING CRANKED. THE SWITCH IS SUPPOSED TO OPERATE A 0 DEGREES AMBIENT TEMP. OR BELOW. AS I SAID EARLIER THERE IS AN ADJUSTMENT SCREW ON FACE OF THE SWITCH WHICH CAN BE "TWEEKED" TO MAKE CHOKE SOLENOID OPERATE AT HIGHER AMBIENT TEMP. I HAD CAR THAT WOULD ALWAYS MAKE CHOKE FLAP FLUTTER. IT WAS PRETTY NEW AND HAD CHOKE BI-METAL REPLACED. SORTED BY DOING AS DESCRIBED. THE SCINTILLA/THERMAL TIME SWITCH/THERMAL TIME DELAY IS LOCATED JUST BELOW AND INSIDE OF O/S BLOWER MOTOR ON RH DRIVE CARS SCREWED TO BULKHEAD. CHAPTER M SECTION 3-5 supp.3 OF SHADOW 2 WORKSHOP MANUAL DESCRIBES OPERATION ETC. | ||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 931 Registered: 9-2004 |
IMO I would check and set the rod as per manual first as it looks as though it has been got at as the lock nuts are loose. | ||
| Bob Reynolds Prolific User Username: bobreynolds Post Number: 229 Registered: 8-2012 |
There are two mechanisms at play here: The choke mechanism and the fast idle mechanism; and it seems you might have problems with both of them. The choke solenoid will definately cure your first problem of the fluttering butterfly during starting. It holds the butterfly closed during cranking and possibly for a few seconds afterwards, depending upon the temperature. It does not operate during warm-up, as that would result in a considerably over-rich mixture which would soon cause the engine to flood and stop. After the choke solenoid has released, the choke is gradually turned off by the bi-metallic strip in the big black cylinder on the other side of the choke flap. This also operates the fast-idle mechanism. As the choke flap returns, it gradually raises the rod in the photo, which rotates the fast idle cam underneath. This cam controls the 'stop' position of the throttle linkage, causing the throttle to be held further open than normal as the engine warms up. As has already been advised, check the operation and adjustment of the rod and also check the operation of the fast idle cam underneath it. The cam should rotate as the rod is moved up and down. | ||
| Brian Vogel Grand Master Username: guyslp Post Number: 1197 Registered: 6-2009 |
Richard, There is also a treasure trove of information on the carbs and automatic choke system in chapter U of the workshop manual. That chapter is 664 pages long, and you must be certain to be referring to the "chunk" of the chapter applicable to the original delivery market of the car. At one point I could swear I documented where the various sections & sub-sections started in this chapter by delivery market, but if I did I can't find it on the forums right now. I would not have thought to look in the chapter dedicated to Emissions Control Systems, but there's lots of information there about things that you wouldn't necessarily think were related to the chapter title at all. Brian, who remembers all of this based upon Mr. Reynolds' post and my adventures setting the idle speed on LRK37110 | ||
| Richard Greene New User Username: benzjag Post Number: 4 Registered: 12-2012 |
THANKS for the extremely valuable information. I definitely understand the system better. Hopefully, I will get a chance to get back to the car this coming week. I will update and likely will have more questions! Richard | ||
| Richard Greene New User Username: benzjag Post Number: 5 Registered: 12-2012 |
I bench tested the choke solenoid today. It is working, and I am getting power to the solenoid while cranking. After the car is running, there is no power to the solenoid. Is this normal? I had to use the vice-grips again to get the car started. I removed the grips shortly after it started with high idle (like it should)but after running a few minutes, the idling got slower and finally cut off. It would not restart unless I held the butterfly rod down. Bob mentioned "adjusting the rod"? HELP! Richard | ||
| Bob Reynolds Prolific User Username: bobreynolds Post Number: 231 Registered: 8-2012 |
"I bench tested the choke solenoid today. It is working, and I am getting power to the solenoid while cranking. After the car is running, there is no power to the solenoid. Is this normal?" Yes - unless you are at the North Pole. (see my explanation above). Also, check that the solenoid is working in situ. If it is working properly you should not be seeing the butterfly rod moving up and down violently during cranking, as you mentioned in your first post. The solenoid should be holding the choke firmly closed at this point. "I had to use the vice-grips again to get the car started. I removed the grips shortly after it started with high idle (like it should)but after running a few minutes, the idling got slower and finally cut off. It would not restart unless I held the butterfly rod down. Bob mentioned "adjusting the rod"?" The idle speed is meant to get slower as the engine warms up. It should finish up at about 600-650RPM. You adjust this at the throttle stop screw on the carburettor. Look in the Workshop Manual. It tells you how to make all these adjustments. You say that the car would not restart after running for a few minutes unless you forced the choke back on. This is unusual unless you are in sub-zero temperatures. Once the combustion chambers have got a bit of heat in them, the choke should no longer be required to enrich the mixture for starting. If these symptoms came on suddenly it is possible that you might have an air leak somewhere in the intake system that is playing havoc with the mixture. Check the pipe connections to the weakener system, cruise control, gearbox, etc. | ||
| Paul Yorke Grand Master Username: paul_yorke Post Number: 1366 Registered: 6-2006 |
As another line, try disconnecting the fuel float chamber breather/weakener hose. N.s. is easiest to get to. It may be the anti-diesel valve not operating properly and weakening the mixture right off? Just a thought with an easy test. | ||
| gordon le feuvre Frequent User Username: triumph Post Number: 64 Registered: 7-2012 |
Look at tee one topics no 81 as this explains anti diesel valves etc. I had ss2 that would not start/run and it was this valve causing vacuum pressure to be exerted onto float chamber effectively holding back fuel as Paul Yorke is saying. It's only reading his comments that reminded me! | ||
| Brian Vogel Grand Master Username: guyslp Post Number: 1216 Registered: 6-2009 |
I'll chime in with a "me too" with regard to LRK37110. When I first got her, and until I figured out what was going wrong, I could not get the car to stay running without pressing the accelerator quite a bit. If you let off she'd just sputter out. The anti-dieseling/anti-run-on solenoid was stuck partially open. A good dose of penetrating oil, a day or so of letting it soak, then manually cycling the thing enough times that I was satisfied it was working again cleared that problem right up. Brian | ||
| Richard Greene New User Username: benzjag Post Number: 7 Registered: 12-2012 |
Finally, I got back to the car today. I replaced the Anti-Dieseling/Anti-Run-on solenoid. I have partial success. The car now will NOT cut off when warmed up (and the choke cuts off) and restarts perfectly when hot (after the choke cuts off). I still had to hold the vice-grips on the butterfly rod to keep the rod completely down to get the car started (and to get the car to idle with the choke). After the car started (with the vice-grips), I immediately removed the vice-grips and the choke worked perfectly as did the idling. As mentioned earlier, before replacing the Anti-dieseling solenoid, it would cut off once the choke cut off when the car warmed up. I am thinking the bi-metal spring needs adjusting to keep the butterfly rod down firmly on initial startup. Any ideas? Brian, I read the workshop procedure but I will confused. Any help appreciated on the procedure. Also, as mentioned earlier, I have tested the choke solenoid on the bench and it works (picked up a rather large wrench)! Richard | ||
| Brian Vogel Grand Master Username: guyslp Post Number: 1223 Registered: 6-2009 |
Richard, Did you also read Chapter K5b on the HIF7 SU carb? When you are pulling the butterfly rod down with the vice grips all you're doing is shutting the butterfly, probably completely. It's been a long time since I did any noodling around with the butterfly rod, but as Patrick Lockyer noted it appears that the stop nuts at each end are not in their correct place, which would be right up against the caps into which each end of the rod screws. If memory serves, the ends of the rod are threaded such that if you turn it in one direction it pushes the caps away from each other (and eventually they fall off of the end of the rod) and the other pulls the caps toward each other (which has the effect of "shortening" the rod and closing the butterfly more tightly - I could have the effect backward - you'll figure this out a bit later). Since you can get the car starting normally using your vice grips to hold the choke butterfly closed, I suggest you do the following: 1. Remove the air intake trunk so that you can actually see the butterfly. Put your vice grips on as you do when you are having success starting the car so that you can see just how closed the butterfly is (I suspect completely, but it's worth looking). 2. Get an open-end wrench of the correct size and gently move those stop nuts as far up the rod as they will go toward the unthreaded center on each end. You need to hold the rod in place so that it doesn't rotate when you're moving the nuts. 3. Figure out which direction you need to turn the rod to get the effect you want on the choke butterfly while the choke is not yet set. One direction will cause it to close a bit more while the other will cause it to open a bit more. 4. With the car dead cold, set your choke as though you were going to try to start it, then quickly observe the position of the choke butterfly (I suspect it will be open further than it should be - a "non-choking" choke). 5. Working quickly, turn your rod in the direction necessary to get the choke butterfly closed like it should be when the choke is on. You should know which way to rotate based upon your findings in step 3. 6. Holding the center of the rod so that it cannot turn and undo the adjustment you just made, move the stop nut at each end all the way out from where its resting so that it touches the cap at each end. Once they are firmly against the cap at each end this should prevent the rod from turning on its own from vibration and undoing the adjustment you made in step 5. 7. Making sure that the choke is still setting as you adjusted it, try to start the car. If that works then turn it off and replace your air intake trunk. Brian | ||
| Richard Greene New User Username: benzjag Post Number: 8 Registered: 12-2012 |
Thanks Brian! As always, an excellent explanation. I will hopefully get back to the car next week & will update. Appreciate it! Richard | ||
| Bob Reynolds Prolific User Username: bobreynolds Post Number: 234 Registered: 8-2012 |
That's a very good idea to remove the air trunking so that you can see the choke butterfly. That butterfly rod doesn't actually work the choke flap - it's the other way round! The bi-metallic spring opens and closes the choke flap, which moves the rod up and down, which works the fast idle below. But it is obvious from one of the above photos that the rod needs adjusting and locking into position. It could be that the rod is so out of adjustment that the fast idle mechansm is jamming it and preventing it from travelling its full extent, thereby preventing the choke from closing properly. As Brian says, take the trunking off and examine the position of the choke flap when the engine is stone cold. It should be almost fully closed, but my guess is that something is stopping it from closing fully, which is why you are having to close it with the vice grips. Try pushing the flap closed with your fingers and see if something is jamming it open. If so, I would remove the butterfly rod completely and see if it then closes properly. If not then the bi-metallic spring must be out of adjustment. The workshop manual gives dire warnings about not meddling with the bi-metallic strip adjustment, so I've never done that. I suppose you could mark the position before adjusting it. If the choke is not fully closed when cold, this would also explain why the choke solenoid isn't working properly, as it will be too far away from the magnet to attract it. | ||
| Paul Yorke Grand Master Username: paul_yorke Post Number: 1368 Registered: 6-2006 |
****Opps - see you've had a couple of extra replies since I started this. Apologies for repetition.*** Although the solenoid is strong and may be getting a feed and earth, it needs to be touching the heel on the flap shaft to hold the flap and stop it bouncing. Almost definitely the rod is too long holding the flap open slightly. This will weaken the mixture and stop the solenoid holding the flap. The rod should only affect fast idle settings so check the flap is completely shut. Might be an idea to remove the rod, put the fast idle on the cam and start the car to check the car starts OK with the rod out of the equation. (The Bi-metallic spring is set and marked with a V at the factory. They very rarely need adjusting.) | ||
| Richard Greene New User Username: benzjag Post Number: 9 Registered: 12-2012 |
Update: I removed the trunking & the choke flap is closing completely, but the car did not start. Checking the flap again, it was not closed being slightly open. I manually held the throttle open & the flap again closed tightly with good resistence. Problem is it will not stay closed upon cranking for the car to start. As previously mentioned, the choke solenoid is working. I am not stranded because if I hold down the pedal for about 5 seconds while cranking (and then release the pedal), the choke flap is closed & the car starts perfectly. The choke then continues to work perfectly with the idling speed slowly coming down to normal as the car warms up. I didnt try to adjust the rod because the flap is closing correctly with good resistence. Richard | ||
| Bob Reynolds Prolific User Username: bobreynolds Post Number: 240 Registered: 8-2012 |
You do realise that you are supposed to depress the accelerator before starting the car? This releases the choke and sets the fast idle. Just checking.  | ||
| Bob UK Unregistered guest Posted From: 94.197.120.192 |
Note that once set in factory the choke settings stay set. So don't adjust without careful check of other parts. Put a switch on the choke solenoid rather than grips. Also is the main jet and float level correct. These engines start easy and need little choke time. 700 rpm idle is fine 650 has no advantage and is not cast in stone. mine just bumps into gear at 700. Oil the choke flap spindle. My flap closes with ease. When cold it snaps shut. Except I use lpg only so have wired the flap so it can't shut. The rest of the bits still work but do nothing. The main throttle stop should be adjusted so that the desired idle rpm canbe adjusted in with the bypass about 1 turn out. I like to set up with the carb butterflies gripping a fag paper with main throttle stop slack. If car abrupt on take off allow one carb butterfly to lag a gag paper width. This is done on a lot of twin SU using the lost motion caliper Between the spindles. at idle the carbs are in sync. The throttle moves and the carbs are out of sync. As the throttle opens more the out of sync is very small only so it cant be felt. Unfortunately on emission cars the equipment mucks up the so subtle tweaks to get the engine to sparkle on small throttle openings. It's well written in the manual and like all electro mechanical stuff simple and oiling is a must. Very robust. Gloss black for solenoid. Tatty wiring shrink tube. If the switch have loose terminals wire brush and dress the revit down, small toffee hammer hold switch in hand and gently tap. Note that a lot of the adjustments are for setting up when made and shouldn't ever need service adjustment. But the attractive looking mechanism attracts fiddlers who subtly put things like operating angles out. So Work mechanism and observe carefully the settings. The levers and links are cadmium plate to clean, dot brake oil and green scotch brite. 2BA and 4 BA both have metric and sae a/f very near equivalents. Correct sockets and spanners are cheap and easy to get. Smallest needed is 6BA. Sets available in 1/4 drive £30 for snap on level quality. Halfords tools worth a look. Draper expert do a BA, af and metric set with screw driver hand which also is an extension breaker bar ratchet and deep sockets and wobble bar and spring, uj and the ratchet is drop off release 1998 £40 bargain. Spanner sets £10, I have two sets of elora ones. Ring and open-ended and a set of magneto spanners. All my small nut problems solved. also BA taps and dies are cheap at less than £10 each. 2 3 and 4 does most things. 0BA is rare except Lucas stuff. care ful tweaking these carbs will hold tune for years. Vacuum leaks obviously check for. engine oi. for lubing once a month good, and easy maybe overkill. Very rarely do SU need to be overhauled by professionals and is straight forward easy diy much SU info on other sites. Tough and robust Carbs. It's impossible to assemble wrong and very obvious. except needle position refer to manual anyway. A feature I like is the single bolt fixing, makes cleaning and overhaul very easy and inviting to do. £100 is plenty. Black dash pots look good. Use aerosols Matt black under coat with gloss on top. Lpg has a vaporizer which works the same as an SU carb with no float bowl or throttle plate. The SU carbs are used for throttle only using bypasses for fine setting. Instead of a main jet is a 15mm copper pipe poking in the carb mouth. That's it no clever stuff. No pump no choke no liquids after vaporizer. In very low temp hot water bottle on vaporizer helps. mine starts first or second 5 second crank and is instantly drivable, brakes!!. Within yards I have loads of power and dead smooth idle. As long as the sun rises my car starts. The system only works if an ignition pulse at coil is present. Even if the engine is stopped there's no vacuum to opberate the diaphragm and the valve is gas tight. For the ultimate durability drivability and reliable go lpg. Advert not sponsored. Remove 100 litre tank and fit a box same shape, more boot space. A. One gallon can of petrol will do should you be nervous. Then the gas filler can sit proudly under the flap. flying spares may have a leaky tank cheap. Fuel systems don't get simpler but some installers get over complicated. Resulting in more money and rough running. Closed loop is good to set use voltmeter to tune to 1 less a tad to get nice response. The fitting is cheap and welded at the y exhaust pipe. Another contraption is a waste of money. Because the more you speed the longer payback is. Like a £100 gas plate that looked nice but would not start on gas and spat back when not warmed up. It actually shot a flame out. (Message approved by david_gore) | ||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 934 Registered: 9-2004 |
If all else is ok ie The setting and condition of the bi-metal spring with all other control rods etc. IMO I would be looking to a sticking inlet valve! | ||
| Martin Taylor New User Username: martin_taylor Post Number: 9 Registered: 7-2013 |
If you choke stops working it can be that the hot pipe has rusted through inside the exhaust manifold, the bimetallic spring will still function but it will overheat and deform and possibly jam the pivot bearing from the soot and heat. The way to test this is to remove the pipe from the cold side and blow through it, air should come out at the spring coil end and nowhere else. Soot on the spring is also a bad sign | ||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 935 Registered: 9-2004 |
A flow check that will confirm a leak or blockage in the stove pipe. The restricter in the bi-metal housing can be replaced if the fow is excesive. This will not effect the first part of the cold start with the choke butterfly valve flap fully closed for a perfect startup. |
