• Hi Guest! Being a Paying Supporter is NOT a requirement to participate at BCF. However, subscribing will help ensure we can continue to serve the LBC community for years to come. If you enjoy BCF and find our forum a useful resource...Please consider supporting us by **Upgrading**
    (PS: Subscribers don't see this banner)
Tips
Tips

Thoughts...rough running at cruise.

brettL

Freshman Member
Offline
Hey Friendly People, I'm after suggestions,
My 100 4 has had heaps done over the last year, Ive done about 5000mls since engine and carbie rebuild (carbies done by sumidel, so done properly), now it has plenty of power , idle is smooth, mixture is great nice light brown plug tips and grey exhaust.....BUT it will run rough at cruise and after a decelleration downhill seems to starve for fuel and dies. If i pull over and try to start it again away it goes after one turn no problem. Like i said power is great, accelerates beautifully so fuel supply and timing (electronic ignition) is ok , if the road is rising it will cruise under load very well.
I have tried blocking off the vac advance , made no difference to anything.
Increased idle speed to 1000 rpm , no difference.
Removed air cleaners, slight improvement but still roughish and stalled after decel.
The timing at the moment is set at tdc i advanced it a tad coz it should be 5-8 deg adv , awfull very rough but again power was good and idle was fine.
No one I have spoken to has any idea what the problem could be and I am at a loss, what else can I try?
 

Dandare

Jedi Hopeful
Country flag
Offline
Brett, are you saying the internal colour of the tailpipe is grey? This is not normal for unleaded fuel IMO and may mean you are running pretty lean.

Danny
 
OP
B

brettL

Freshman Member
Offline
Hi Guys,
To answer the question ,Rough on flat, and tail pipe is a black grey but not black black so I call it grey.
Anyway as it happens after I posted the above description of the symptoms I thought I'd go over it once more. My thinking was there must be an air leak between the carburettor butterfly and the head...all looks good , inlet manifold is firm on the head as are the carbies on the manifold...however i took a spanner to the manifold/ head nuts anyway and was able to tweak them 1/4 turn.....Problem GONE. Dohhhh. Wish i had done that a few weeks ago.
I know i should have checked them before but honestly they must have been just loose enough to allow air in under major vacuum but not any other time.
Thanks for the responses anyway . Brett.
 
Similar threads
Thread starter Title Forum Replies Date
77MidgetMkIV Rough running at weird intervals-any thoughts? Spridgets 22
D GT6 Rough GT6--your thoughts? Triumph 9
T Powertrain locked up three times whilst driving today - anyone have thoughts? Spridgets 15
C 1960 BT7 Thoughts Austin Healey 14
C TR4/4A TR4 Thoughts Triumph 15
C MGA MGA Thoughts MG 20
AngliaGT Thoughts/advice on Miatas? Other Cars 22
Joe Schlosser Thoughts on a long traffic Light Spridgets 11
Got_All_4 TR6 Cam selection decision time could use your thoughts Triumph 2
D TR2/3/3A Any thoughts on this part? Triumph 6
M Next job[s] on Otto - thoughts? Spridgets 35
G TR4/4A Thoughts on my coolant Triumph 12
Jim_Gruber Thoughts on driving Bugsy with the hardtop installed. Spridgets 32
Jim_Gruber Thoughts on stock '69 1275 manifold vs LCB Headers for street use Spridgets 9
JPSmit DC Power source thoughts Restoration & Tools 11
Rut TR6 Thoughts on this car? Triumph 10
D Thoughts on Paint Removal... Austin Healey 11
AngliaGT Thoughts on Volvo wagon? Other Cars 5
cmacmillan TR6 TR6 grille repair - thoughts? Options? Triumph 6
AngliaGT Thoughts on Miatas? Other Cars 11
J Thoughts on waxing new paint? Austin Healey 14
KVH TR2/3/3A Thoughts on This EBay TR3 Please Triumph 25
Brinkerhoff Thoughts on car lifts ? Restoration & Tools 13
N Spitfire New thoughts on a.c. in Spitfire Triumph 11
Mink TR4/4A Your thoughts/value of this TR4 Triumph 357
HealeyRick Nasty Thoughts - Driving Impressions Austin Healey 15
F Thoughts on aftermarket air cleaners? Austin Healey 12
B Wiring Harness Issues -- Any Thoughts? Spridgets 6
KVH Some Thoughts Entering the New Year Triumph 18
Flash_Harry Any thoughts on these spark plugs? MG 9
richberman Thoughts on canted car? Austin Healey 15
lbc_newbie thoughts on exhaust Spridgets 9
T TR2/3/3A Thoughts on a TR3a Triumph 12
TR4nut TR2/3/3A Any thoughts on TR3A overheating struggle? Triumph 19
M Some random thoughts on a cool, sunny day Triumph 9
John250 TR5/TR250 Thoughts on selling my restored TR250?? Triumph 33
glemon Blasphemy Impure Thoughts Triumph 22
JPSmit Bought a Tool Chest today - thoughts needed. Restoration & Tools 16
bugedd Thoughts on this radiator Spridgets 9
AN5Sprite Tunebug engine diagnosis, thoughts anyone? Spridgets 47
boxfullofyertoys Thoughts on DIY welding/bodywork Spridgets 27
Stick Thoughts on Spridgetech Fiberglass Bonnets? Spridgets 2
T TR6 Thoughts on Superchargers for a TR6 Triumph 25
bugedd Bonnet thoughts... Spridgets 3
John_Mc Mechanic error? Thoughts? Other Cars 19
JPSmit Expansion tank thoughts Spridgets 6
DNK Lift THoughts Restoration & Tools 14
DNK Need Thoughts Triumph 57
drooartz Tunebug vs MGB, initial thoughts Spridgets 67
T Thoughts on Installing Rivergate 5 Speed Kit Spridgets 2

Similar threads

Top