| Author | Message | ||
     tanluhan Unregistered guest Posted From: 58.96.231.94 |
Hi guys, my shadow has bee acting up recently. When i first got the car, it used to require 10mins or so of running at high rev to warm up, and thereafter, the vehicle will be smooth as silk. However, now it takes longer and longer to warm up, sometimes even 30mins, and in the 30mins, the vehicle will run extremely rough, it will jerk and will stall if not even gas is given. Even if i floor the pedal, i will be jerky to move off, and might stall as well. After this warmup period, the vehicle will run great, no jerks and no stalls. I have changed the sparks, spark cables, adjusted the timing to the best of my ability (any other position would cause the vehicle to run not as smoothly). The ignition coil is a new flamethrower coil as well. My suspect is on the carbs as there is not much left to change on the ignition side. Appreciate any advice, thanks! (Message approved by david_gore) | ||
| David Gore Moderator Username: david_gore Post Number: 2801 Registered: 4-2003 |
Please advise chassis number and country of delivery for original purchaser of your car so our members can provide more specific advice on possible causes and remedies. | ||
| Robert Noel Reddington Grand Master Username: bob_uk Post Number: 1659 Registered: 5-2015 |
Assuming SU carbs Check choke operation. | ||
| Omar M. Shams Grand Master Username: omar Post Number: 1388 Registered: 4-2009 |
David is right. We need to have car details. However, if i were to take a stab at it..... one of your carburettor pistons is getting caught. The pistons need to slide up and down in their chambers smoothly. If one of these stick, you could get what you are experiencing. | ||
| tanluhan Unregistered guest Posted From: 58.96.231.94 |
Hi, to add , its a UK vehicle. By warming up, i do not mean the temperature on the gauge. The car warms up nicely, but takes an even longer time to start running smoothly. Im located in Singapore, hence the weather is always warm, which mean there should be no need for the termostat to kick in/out. (Message approved by david_gore) | ||
| luhan tan Unregistered guest Posted From: 58.96.231.94 |
Hi guys, thanks for the advise. Sorry my vehicle is a SRH32914. For the choke operation, do i have to take apart the carb? When i start it, it revs highly, for some time, i can bring it down by stepping on the gas. But even at idling it will continue to run rough for up to 30mins of driving. The rough running and stalling is only during move off of the vehicle. Once it passes 10kph or so, it will be smooth. The high speeds(110kph) will be smooth as well (Message approved by david_gore) | ||
| tanluhan Unregistered guest Posted From: 58.96.231.94 |
i would also want to add that, if i drive the car everyday, this issue will not happen. The longer it sits in the garage, the more time it takes for the vehicle to 'recover' to its normal driving state. (Message approved by david_gore) | ||
| Paul Yorke Grand Master Username: paul_yorke Post Number: 1989 Registered: 6-2006 |
Hi, you can see if the choke is working ok by viewing the image on the right hand side of the carb intake. It will be down when starting cold and should move upwards as the engine warms. Probably within a few minutes where you are. It may be a weakened problem. Locate the small ish float chamber vent hoses ( the one in front of the left hand carb is easiest ) and disconnect it. Then take for a test drive. | ||
| Alan Dibley Prolific User Username: alsdibley Post Number: 118 Registered: 10-2009 |
Check the level of fluid in the gearbox. If it's low it can give similar symptoms. Check with engine warm and idling. How do I know?....... Note that the choke has nothing to do with the carbs. It works by closing down the intake plenum before the carbs. Regards from Alan D. | ||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 1712 Registered: 9-2004 |
Worth checking the stove pipes for cracking/ holed. If these have failed it can delay the warming up process on automatic choke system.  BTW not used with LPG.  | ||
| Jeff Young Grand Master Username: jeyjey Post Number: 364 Registered: 10-2010 |
I would think this: i would also want to add that, if i drive the car everyday, this issue will not happen. The longer it sits in the garage, the more time it takes for the vehicle to 'recover' to its normal driving state. reinforces Omar's suggestion of a sticky carb piston. | ||
| tanluhan Unregistered guest Posted From: 58.96.231.94 |
Spent the afternoon tinkering with the rolls. The choke is working, took it out and played with it by turning the center portion of the spring left and right. plugged out the weakener, and plugged it with a bolt. no difference between plugged and unplugged. toyed with the timing, already at the optimum mark. opened up distributor cap, looks good. eletronic ignition looks new(lucas). Even when engine is well and warm, it is unable to idle with 100% smoothness, with very slight misfire here and there, which can be easily seen from a sharp drop in the ampmeter everytime a misfire happens. I can conclude that the stall and jerking is the severe symptom of the unsmooth idling, exaggerated by the cold and newly started engine. Hence, to solve this issue, the cause of the unsmooth idling must be found. As of yet, i do not have any other leads, other than rebuilding the carbs or changing out the eletronic ignition. Everything else relating to the firing of the engine seems be in good working order. @alan the gearbox oil is full. dont think it affects match as it is a idling problem (Message approved by david_gore) | ||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 1713 Registered: 9-2004 |
"Even when engine is well and warm, it is unable to idle with 100% smoothness, with very slight misfire here and there." Not the stove pipes in that case. My Shadow 2 had this type of fault for a period before the Opus electronic distributor module packed up. A posting on the system etc has been covered. | ||
| Jeff Young Grand Master Username: jeyjey Post Number: 365 Registered: 10-2010 |
It's worth checking to see if the carb pistons are all gunked up before moving on to other more involved things. https://www.howacarworks.com/fuel-systems/checking-and-cleaning-an-su-carburettor Cheers, Jeff. | ||
| Omar M. Shams Grand Master Username: omar Post Number: 1389 Registered: 4-2009 |
I am with Jeff on this one.It is an easy check and well worth doing. | ||
| ross kowalski Grand Master Username: cdfpw Post Number: 698 Registered: 11-2015 |
tanluhan, If you put a vacuum gauge on the manifold and filmed it while the engine was misfiring, that would be helpful in diagnosing a problem like this from across the internet. I have to add, I do like the sticking carb slide theory. It's only a few minutes to pull the bells and clean and check them. Don't drop the screws. | ||
| tanluhan Unregistered guest Posted From: 58.96.231.94 |
Tomorrow i will check for vac leaks, and take apart the carbs. hopefully i will see something interesting in there! (Message approved by david_gore) | ||
| David Gore Moderator Username: david_gore Post Number: 2808 Registered: 4-2003 |
Tanluhan, Before you do anything. download the Shadow II workshop manual from the Technical Library for free especially Chapter U which should have detailed carburettor disassembly and rebuild information for your car [I cannot be more specific as my experience is confined to pre-emission Shadow I's]: http://rrtechnical.info/SY/TSD4200/tsd4200.htm There is another thread currently active which illustrates the problems that can arise from not having the right information available before starting remedial work. If your car has SU HD8 carburettors, the first thing I would be checking is varnish build-up on the piston and the bore in which it moves as this can cause problems with the air/fuel mixture if the piston does not move freely to allow the variable venturi feature of this carburettor to function as intended to give the right mixture for the operating conditions. | ||
| Mark Aldridge Grand Master Username: mark_aldridge Post Number: 493 Registered: 10-2008 |
I am not familiar with Shadow2 ( chassis 32914 ),but they have a twin tailpipe , and therefore is it not possible to determine if the misfire relates to one cylinder bank ? The Carbs are I believe HIF7 as early Spirits . I have had float problems with these carbs giving rise to occasional flooding , before the float sinks completely ! If the misfire is on one cylinder bank only, then I would go for Distributor cap leads or plugs. Mark | ||
| David Gore Moderator Username: david_gore Post Number: 2811 Registered: 4-2003 |
Mark, Your suggestion is fine if the twin systems are fully independent of each other. All the dual systems I have encountered have included a balance pipe connecting both systems usually just behind the engine under the bell housing. In this scenario, using the individual exhausts may not give a valid indication. | ||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 1716 Registered: 9-2004 |
One bank fed by two carbs as well. BTW I have replaced the floats on the SS2 but have never on the SS1 even though petrol is only used occasionally now, after many years of using just LPG the pumps stopped working needing a sort out to get working again. | ||
| Mark Aldridge Grand Master Username: mark_aldridge Post Number: 494 Registered: 10-2008 |
David, The balance pipe on early Spirits is of small diameter, and a misfire is easily distinguished from the tailpipes.My past 1981 Spirit gave me a lot of practice! Saves a lot of time taking out plugs unnecessarily. Sadly finding a duff plug on my Shadow 1 is not as easy with the single system. Tanluhan, be prepared that even new plugs can fail quickly, I have had this experience in the past. Mark | ||
| Paul Yorke Grand Master Username: paul_yorke Post Number: 1991 Registered: 6-2006 |
Quote "plugged out the weakener, and plugged it with a bolt. no difference between plugged and unplugged." did you try it unplugged? What did you plug? You need the float chambers open to the atmosphere to test it. What spark plugs did you fit? | ||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 1717 Registered: 9-2004 |
The checking of a miss fire on a Shadow 1 cylinder can be carried out with this easy method. First make sure the ht leads are free to remove from the top of the distributor cap. Start engine and when miss fire is present remove distributor ht leads one at time [should have a spark from dist to lead on each one removed] until the faulty cylinder is found by the ht lead making no difference to engine sound. Refer to the distributor timing order to locate the faulty plug, ht lead or whatever. Tip, use insulated pliers. BTW carb weak flat spot, carb rich rough running black smoke! Shadow 2 close air gap to min to see and confirm module failing. | ||
| Robert J. Sprauer Experienced User Username: wraithman Post Number: 14 Registered: 11-2017 |
You may be surprised in what you see in a very dark environment with the engine running. You may notice arcing of the leads in certain areas. | ||
| Chris Browne Prolific User Username: chrisb Post Number: 282 Registered: 2-2010 |
Hello Patrick, I’m always interested in picking up tips about tuning of Shadow 2’s. What is the air gap you refer to in your post? Thanks in anticipation. Kind regards, Chris | ||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 1718 Registered: 9-2004 |
Chris, the air gap is set between 8-14 thou or .20-.35mm. This is adjustment is set between the reluctor tooth and the pickup limb. When I suffered a misfire on the SS2 I closed the gap to minimum and the car was used for two years before it packed up completely on start up from cold. BTW The minimum setting is only ok with a good distributor shaft with little run out, also when setting the gap use non ferrous feeler gauges and check all the reluctor teeth. Hope this helps. Pat. | ||
| h_kelly Prolific User Username: h_kelly Post Number: 244 Registered: 3-2012 |
Tanluhan, had similar problem on Shadow 2 few months back, I thought it might have been the electronic ignition, anyway fitted new plugs distributor cap and rotor arm and thankfully it runs well since. I also bought new coil and ignition but haven't needed to use same just jet, thankfully. I reckon the frost may have affected then dis cap but no obvious evidence of same. Anyway it surprised me how a dis cap, rotor arm and new plugs could gave such radical change in performance |
