[Tigers] Tiger won't idle after a bout of hard acceleration

[R Flynn]

Finally got a couple of hours with the Tiger today (which will probably be
it until next weekend sadly) - a few updates:

- It wil begrudgingy idle on about 1/2 choke (I have a manual choke)

- Found the TDC & timing marks under a bit of rust (see photo)
- Could someone tell me the scale of the marks - 3 degrees each (can't see
any numbers there)?

- At lowest idle (on choke) the timing light has the pointer just about the
4th mark (photo attached)

- Plugs look ok'ish (photo of no 2 plug attached)

- dizzy vac advance line itself doesn't leak, each end appears fit snugly

- distributor seems tight, does not seem to have shifted





On Tue, 5 Sep 2017 at 10:39, Larry Mayfield <drmayf at mayfco.com> wrote:

> Folks, there are a few reasons why cars misbehave as they do. With
> running, it is embedded in one of these; Fuel, Air, Spark.  I have not yet
> seen the plan to check all the potential faults that can cause the issue
> being discussed and resolve it. SO, lets develop a plan, eh?
>
> 1.     Is it spark? How to tell, well, put the timing light on it and
> check for the timing. This is about as basic as it gets.  If the timing
> mark at idle is ok then raise speed and check it at some intermediate level
> and determine if that is ok.  When the problem happens, turn the engine off
> in mid issue and pull plugs and check their conditions. Black, too rich and
> maybe not firing. Too white and maybe too lean (ie large vacuum or air
> leak).  One other problem can also cause this as well. Very high mileage
> cam timing chain. Had a Falcon sprint in the shop one day and it would
> barely run. Turned out that the timing chain was so loose that it had
> jumped a few teeth on the crank sprocket. The timing light will tell that
> if that has happened.  If the spark plugs were too white, then find the air
> leak.  If too black or dirty, find the fuel issue. The dizzy timing advance
> diaphragm might also have been damaged, so use you might vac brake bleeder
> and hook it onto the dizzy vac advance . remove the cap and pull a vacuum
> on the diaphragm. Do the internals move of the dizzy move? If not, pull the
> points plate and check under if for a screw or something that is preventing
> advance from happening.
>
>
>
> 2.     Air leaks. Vacuum actually does not leak. Air leaks into areas
> supposed to be under vacuum. So for sure if the brake booster hose has come
> off, then fix that. But check it for cracks and splits as well even if it
> is on. And remember this happened, as I recall, suddenly. So, it is not
> something that has been failing slowly, it happened in a hurry. Did the car
> backfire? If so and it has a power valve, then it may have damaged that.
> That would be letting in way too much fuel for the amount of air coming in
> normally and would require keeping the throttle open to run even a bit.
> There are only three places for air to enter: power brake connection to the
> manifold, the throttle throat on the carb and the dizzy vac advance line.
> Check each in sequence.
>
>
>
> 3.     Fuel, now here is a problem that drove me absolutely crazy on my
> wife’s Mercury Capri. The gas cap vent hole plugged and that caused a small
> vacuum in the fuel tank. But it was enough to prevent fuel from flowing as
> it should. I took that pesky car to a number of fix it places and not one
> single one could give me a cause.  Car would start and run kinda normally
> but under load it was not getting enough fuel for the amount of air and
> would die.  My fix was to drill a hole completely through the fuel cap into
> the fuel side so that it had an unobstructed air flow into the fuel tank.
> End of problem. New cap fixed it ultimately.  If the cross over vent line
> is plugged on one side and the fuel is not balancing out then that can
> cause a fuel issue. One of the issues we all –potentially have is gunk in
> the fuel lines from old cars and bad gas and crap coming loose from inside
> the tank.  I have seen one aftermarket fuel pump so crapped up that fuel
> could not flow through the pump. Holley blue pump.  Fuel should flow
> through the system like a low pressure fire hose. A 5/16 line can deliver a
> lot of fuel. So, add a bit of hose to the end of the fuel line at the carb
> end, find a clean bucket or coffee can. Weigh it before starting and then
> put the end of the hose in the can and turn on the pump and catch fuel for
> say 30 seconds. Then weigh it again. Need to find out if the pump is
> delivering the flow needed. If it comes out ok and if it is dirty also.
> And then if you have a fuel pressure gauge, then put it in line near the
>  carb and check the fuel pressure when the pump has filled the bowl. Just
> look and see I the pump is putting out the necessary pressure. If the flow
> is good and pressure is good then everything back to the tank is good.
> Issue is in the carb. There are only a few things that can prevent fuel
> from being delivered. Gunk is the jets, broken power valve if it has one,
> and a bad accelerator pump. The metering system is dirt simple on ford
> carbs of that era, so remove it and remove the main jets and well, take the
> sucker apart. If you don’t already have it, get a can of carb cleaner, the
> gallon size can and take the parts and dump them into the can. Wait a good
> long while and then remove the parts an hose them off with water. Yeah the
> stuff is generally biodegradable, so no issues. Then use some spray brake
> cleaner and dry everything off. Put it all back together with new kit of
> repair pieces.  One final thought, it can be vapor lock as well. Make sure
> that the fuel lines are not lying on the headers or exhaust somewhere along
> the way. And look under the car when things are pumping. Maybe the single
> rubber fuel line connection up by the tranny tunny has sh*t the bed. And is
> reducing the pressure.
>
>
>
> I put these in the list from easiest to hardest. Easiest first because
> this happened suddenly, ie a short time vs  over winter.  Take notes and
> record data. Sometimes there is synergy involved and having real data to
> look at and compare to spot multi issue at once can be very helpful.
>
>
>
> On my car I put in a  Summit Fuel canister type filter before the pump and
> an inline one just before the carb.  And a shut off valve before the
> canister filter under the car. Nice to be able to shut everything off the
> mess with it without draining the freaking tan every time.
>
>
>
> I am guessing you are going to find shit in the fuel somewhere.
>
>
>
> You now have a plan and some things to check to gather data. None of this
> should take very long to sort out. Sunbeams are 1940’s  technology, lol.
>
>
>
> Good luck and keep me/us all posted on the actual solution!
>
> Mayf
>
>
>
> _________________________
> drmayf
> Worlds Fastest Sunbeam, period.
> 204.913 mph flying mile average speed
> 210.779 mph exit (not top)  speed
>
>
>
>
>
>
>
> *From:* Tigers [mailto:tigers-bounces at autox.team.net] *On Behalf Of *R
> Flynn via Tigers
> *Sent:* Monday, September 4, 2017 3:43 PM
>
>
> *To:* Andy Walker <awtiger at cox.net>; Ron Fraser <rfraser at bluefrog.com>
>
> *Cc:* tigers at autox.team.net
>
>
> *Subject:* Re: [Tigers] Tiger won't idle after a bout of hard acceleration
>
>
>
> I too am deeply suspicious of a vacuum leak somewhere (did a which check
> on the distributor line earlier and that is fine at least and all other
> hoses are at least connected).
>
> In any event, I am travelling for a while hence progress in diagnosing
> will slow down somewhat. In the meantime, helpful bits will be procured so
> I can make some progress in a few weeks when I return.
>
> Thanks to all for the comments, I'll keep you posted on progress.
>
> On Mon, 4 Sep 2017 at 18:27, Andy Walker <awtiger at cox.net> wrote:
>
> Rick:
>
>
>
> Two words…”vacuum leak.”
>
>
>
> Background…I had this very problem before on my old Tiger (B9470058) back
> in 1982.  I was running the open track event at the Mid-America Shelby Meet
> in Tulsa, OK, and having a great time.  All of a sudden, I came into the
> pits after a session and the car wouldn’t idle at all; it would die once
> you let off the throttle.  We jumped on the problem immediately, even
> rebuilding the Holley at the track, but to no avail.  I ended up towing the
> car home, fearing that I’d really done something terrible to it.
>
>
>
> Once I got it home and started looking closely at it, I discovered that
> the brake booster vacuum line had slipped off the nipple on the intake.
> Yep…a direct, rather large vacuum leak.  Plugged the line back onto the
> fitting and, voila…the car idled just fine.
>
>
>
> Moral of the story...check all your vacuum connections before getting into
> anything else.  I’d be willing to bet that a vacuum leak will be your
> culprit.
>
>
>
> Best of luck and keep us posted,
>
> Andy Walker
>
> Edmond, OK
>
> *From:* Tigers [mailto:tigers-bounces at autox.team.net] *On Behalf Of *R
> Flynn via Tigers
> *Sent:* Monday, September 4, 2017 12:38 PM
>
>
> *To:* Ron Fraser <rfraser at bluefrog.com>; tigers at autox.team.net
> *Subject:* Re: [Tigers] Tiger won't idle after a bout of hard acceleration
>
>
>
> Forgot to add the additional info Mayf suggested
>
> - 1965 289, rebuilt sometime in the 1990s, installed in my MK1 sometime
> before that
>
> - Offenhauser dual port 360 intake manifold
>
> - Edelbrock Performer 500cfm w/manual choke
>
> - Engine has been running fine until this happened a few days ago
>
>
>
> On Mon, 4 Sep 2017 at 12:29, Ron Fraser <rfraser at bluefrog.com> wrote:
>
> Rick
>
>                 I would take the top of the carb off, assuming stock
> Autolite;
>
> Check fuel level
>
> Check float operation
>
> Check for debris in the fuel bowl and in the jets
>
> Fix any problems you find
>
>
>
> If there were problems start engine to see if it is running better.
>
>
>
> Check the position of the idle jets
>
> Count the turns in for each – then put them back to original position
>
> Start engine
>
> If no idle – turn idle jets out a ¼ to ½ turn
>
> Start engine
>
>
>
> Ron Fraser
>
>
>
> *From:* R Flynn [mailto:flynnr2 at gmail.com]
> *Sent:* Monday, September 04, 2017 10:17 AM
> *To:* Ron Fraser <rfraser at bluefrog.com>; tigers at autox.team.net
> *Subject:* Re: [Tigers] Tiger won't idle after a bout of hard acceleration
>
>
>
> All,
>
> Thanks for the replies - quick update.
>
> Still showing same behaviour starting cold - starts, runs if given gas,
> just shuts down if left to idle (no surges, running doesn't seem rough if
> given gas). Certainly feels like fuel isn't getting to where it needs to go.
> - Everything appears to be where it ought to be on the carb, no springs or
> screws missing, etc.
> - Fuel is pumping fine & clear up & through the fuel filter
>
> Will try to do some more poking around later today, but need to do some
> other chores first!
>
> Rick
>
> On Sat, 2 Sep 2017 at 10:06, Ron Fraser <rfraser at bluefrog.com> wrote:
>
> Rick
>
>                 There is an old adage – any time you think you have a carb
> problem, check the advance curve 1st.
>
> Your case sounds like there is a problem in the carb; it may need a
> rebuild.  Check the advance curve 2nd.
>
>
>
> Last time I had a problem like this was with a mid-70’s Weber progressive
> 2 bbl. – a chunk of RTV got into the primary jet and I had to floor it to
> keep it running.
>
>
>
> Ron Fraser
>
>
>
> *From:* Tigers [mailto:tigers-bounces at autox.team.net] *On Behalf Of *R
> Flynn via Tigers
>
> *Sent:* Friday, September 01, 2017 6:53 PM
>
>
> *To:* <tigers at Autox.Team.Net> <tigers at autox.team.net>
> *Subject:* [Tigers] Tiger won't idle after a bout of hard acceleration
>
>
>
> All,
>
>
>
> Would appreiciate any thoughts on my latest conundrum ...
>
>
>
> Accelerated hard away from a stop light earlier today and now my Tiger
> won't idle - just dies out, including while shifting if I take my foot off
> the gas (once the transmission engages, it starts running again).   Starts
> up fine, but need to stay on the gas to keep it going.
>
>
>
> Was too hot to start investigating but will need to look into it tomorrow
> - thinking perhaps something popped off the carburettor?
>
>
>
> Cheers in advance,
>
>
>
> Rick
>
>
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