1600M Mis-firing
Discussion
Can anyone sugest a solution?
My 1600M with the standard 1600 Ford lump and 32/36 DGV carb has started to mis fire so badly that it can hardly climb the slightest incline.
The following have been changed: New distributor,Plugs,coil, plug leads, rotor arm, points, distributor cap. The mechanical petrol pump has been changed to a solid state electric type. The carb has been stripped and cleaned. All earths have been removed and cleaned. The coil has been powered directly from the battery to eliminate possible faulty ignition switch etc. The cylinder compressions have been checked cold and hot and all 4 pots read 140 psi.
The car starts first time and while stationery revs freely only when the engine has a load does the missing start and progressively gets worse. I have even mounted a small can under the bonnet filled with fresh petrol and reverted back to the mechanical petrol pump to eliminate possible poor fuel problems or the electric pump causing the fault.
Running out of ideas!
Cheers
Old timer
My 1600M with the standard 1600 Ford lump and 32/36 DGV carb has started to mis fire so badly that it can hardly climb the slightest incline.
The following have been changed: New distributor,Plugs,coil, plug leads, rotor arm, points, distributor cap. The mechanical petrol pump has been changed to a solid state electric type. The carb has been stripped and cleaned. All earths have been removed and cleaned. The coil has been powered directly from the battery to eliminate possible faulty ignition switch etc. The cylinder compressions have been checked cold and hot and all 4 pots read 140 psi.
The car starts first time and while stationery revs freely only when the engine has a load does the missing start and progressively gets worse. I have even mounted a small can under the bonnet filled with fresh petrol and reverted back to the mechanical petrol pump to eliminate possible poor fuel problems or the electric pump causing the fault.
Running out of ideas!
Cheers
Old timer
Have you cleaned out the carb and float chamber yet? Under heavy driving load more fuel is required and this extra flow can move rust and dirt to block filters and jets or even to hold open the float chamber valve. On my Seven which had the same engine and carb I had a small globual of braze which occasionally caused either overfilling or blocked the float valve. Seems unlikely this could reproduce all your symptoms though. Did you change all the ignition bits after this problem started or did it happen when you changed everything?
Thanks for your replies.
Yes carb completely cleaned including all jets etc. Reset float level as well. There is also an inline filter besides the one on the carb inlet. The distributor was brand new including cap, rotor, condenser points etc but all these have been changed again. Must admit it seems like a fuel problem. The plugs when removed have normal fawn coloured insulators within the plug but the metal tips are black suggesting an over rich mixture.
Yes carb completely cleaned including all jets etc. Reset float level as well. There is also an inline filter besides the one on the carb inlet. The distributor was brand new including cap, rotor, condenser points etc but all these have been changed again. Must admit it seems like a fuel problem. The plugs when removed have normal fawn coloured insulators within the plug but the metal tips are black suggesting an over rich mixture.
Thanks again fellows.
Condenser has been changed, 12volt coils (both) resistor scrapped many years ago.
The vacuum advance was checked on the bench and seemed to be OK. Will check again though and maybe replace the old distributor.
Last time the 1600 gave any trouble was about 20 years ago, similar problem in that the car started but when warm mis fired and then stopped. When cool would start again OK. That turned out to be a faulty coil breaking down under load.
This time very frustrating as it always starts first time from cold or hot, it seems to be loading the engine that causes the problem. Will press on and try the suggestions, not ready to sell quite yet!
Condenser has been changed, 12volt coils (both) resistor scrapped many years ago.
The vacuum advance was checked on the bench and seemed to be OK. Will check again though and maybe replace the old distributor.
Last time the 1600 gave any trouble was about 20 years ago, similar problem in that the car started but when warm mis fired and then stopped. When cool would start again OK. That turned out to be a faulty coil breaking down under load.
This time very frustrating as it always starts first time from cold or hot, it seems to be loading the engine that causes the problem. Will press on and try the suggestions, not ready to sell quite yet!
...Wayne I have been known to be wrong, and I am sitting in my office..but, more on the wrong cap..... it is rotationally different on the contacts within the cap, this allows you to start the car but then the mechanical/vac advance rotates and takes the rotor arm away from the cap contacts and the engine fails until it is slow enough for the rotor arm to make contact again and send sparks to the plugs (which have fouled up due to no spark and then struggle to fire as they are wet)
Adrian@
Adrian@
Edited by Adrian@ on Thursday 9th April 08:22
Adrian@ said:
...Wayne I have been known to be wrong, and I am sitting in my office..but, more on the wrong cap..... it is rotationally different on the contacts within the cap, this allows you to start the car but then the mechanical/vac advance rotates and takes the rotor arm away from the cap contacts and the engine fails until it is slow enough for the rotor arm to make contact again and send sparks to the plugs (which have fouled up due to no spark and then struggle to fire as they are wet)
Adrian@
Like I said this is the man to listen to and absorb some knowledge from a hands on type of guy. Where would some of us guys be without TVR wizards like Adrian / John in Canada / Marshall Moore in the U.S.A. and others??????Adrian@
Edited by Adrian@ on Thursday 9th April 08:22
Terminator said:
V8TVR1978 said:
Where would some of us guys be without TVR wizards like Adrian / John in Canada / Marshall Moore in the U.S.A. and others??????
Driving a better make of car? 
With guys like these, we ARE driving a better car.
V8TVR1978 said:
Terminator said:
V8TVR1978 said:
Where would some of us guys be without TVR wizards like Adrian / John in Canada / Marshall Moore in the U.S.A. and others??????
Driving a better make of car? With guys like these, we ARE driving a better car.
Adrians comments re the distributor cap made me look closer. All the caps are identical but the symptoms were similar to a problem cap he described with the rotor shifting too far when the Auto advance comes in.
Problem identified as finger trouble in replacing the new distributor. Lined up the rotor on dis cap plug one segment but this was based on my estimate for the initial timing setting for the dis. After timing with a strobe the dis was rotated several degrees, forgot to re check position of rotor arm in relation to plug 1 segment. Resulting in the spark from the rotor just reaching the segments on idle but as soon as the revs increase the bob weights advance the rotor position so that the spark cannot then bridge the gap. Presumably as the engine warms up the spark from the coil gets weaker and the problem is compounded. Also found an almost imperceptible slit in the carb accelerator diaphragm causing petrol to drip. Assume that before the carb was cleaned etc. the slit was at the top and I have moved it to the bottom on reassembly that was why it was not noticed before.
Thanks to all for your help.
Problem identified as finger trouble in replacing the new distributor. Lined up the rotor on dis cap plug one segment but this was based on my estimate for the initial timing setting for the dis. After timing with a strobe the dis was rotated several degrees, forgot to re check position of rotor arm in relation to plug 1 segment. Resulting in the spark from the rotor just reaching the segments on idle but as soon as the revs increase the bob weights advance the rotor position so that the spark cannot then bridge the gap. Presumably as the engine warms up the spark from the coil gets weaker and the problem is compounded. Also found an almost imperceptible slit in the carb accelerator diaphragm causing petrol to drip. Assume that before the carb was cleaned etc. the slit was at the top and I have moved it to the bottom on reassembly that was why it was not noticed before.
Thanks to all for your help.
Edited by Loubaruch on Friday 10th April 22:36
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