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No acceleration when applying gas

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No acceleration when applying gas
#1
grandpa Ashburn Thomas Cianni
raleigh, NC, USA   USA
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Hello all,

1955 TF 1500 (supercharged)

I have had some issues recently with acceleration (or lack there of) when i put my foot down i feel acceleration in small "spurts" Almost like gasps of acceleration, the sounds from the engine are a little muted as well. Doesn't matter what gear i'm in but happens consistently over 2K RPM and doesnt matter how high the revs go. It has no issues starting or idling.

I have been told it is running rich so i thought maybe the plugs were all gunked up so i replaced those and no change. I stopped using the choke as well but havent seen a difference. Do i need to remove the carb and clean it?

Any other suggestions would be appreciated.

Cheers

Thomas

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Re: No acceleration when applying gas
#2
TD4834 Avatar
TD4834 Bill Chasser
Sacramento, CA, USA   USA
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1950 MG TD
1951 MG TD
1951 MG TD MkII
1952 MG TD MkII    & more
Well first it's better to have a blown motor run a bit rich rather than lean. Is the blower belt intact and the idler tensioned properly? What did the plugs look like when you took them out? Have you checked your filter screen? Had you done any tuning or changed immediately prior to the poor performance? Recent fuel purchase? Have you checked your point gap lately. Just throwing stuff out there to see if it sticks.

Bill Chasser
TD-4834


Bill Chasser
TD-4834
TD-5779
TD/c-8151
TD/c-16920
TD-19408
TD-24060

TF-8200

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Re: No acceleration when applying gas
#3
grandpa Ashburn Thomas Cianni
raleigh, NC, USA   USA
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Bill,

Thanks for the reply, the spark plugs were pretty grimy when i pulled them out but i have no idea how long they were in there.

The belts looks normal and i unfortunately wouldn't know how to check the idler tensinor.

Haven't made any changes except installing new tach and speedo cables.

I did not check the point gap on the plugs before i installed them, forgot about that.

My friend mentioned fuel as well, and i wonder if it is because i am using 87 octane? Should i be using 93? The floater in my tank is gone so i never really know how much gas i have in there so i fill it up usually after a long drive.


Cheers

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Re: No acceleration when applying gas
#4
LaVerne Avatar
LaVerne LaVerne Downey
Fruita, CO, USA   USA
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1954 MG TF "Green Hornet"
1969 MG MGB "The Beater"
1979 Triumph TR8 "Turd 8"
Do you have a boost/vac gauge? If so what happens to the gauge when you put your foot down? Doing on diagnosis sucks.. I've tried many times...sometimes it's good....sometimes not so much. It helps to know any events that led up to where you are now. Did this happen over time or just all of a sudden? Any accompaning noises? I'd start with the distributor....inspect the plug wires at both ends and the cap and coil for corrosion and any other wires. I'd crank the car over without the cap and make sure I was getting a good fat spark. Check the timing and if all looked good there I would do a compression check on all of the cylinders and then move on to the carb. You haven't said what type of supercharger is on the car and what carb. As a general rule any supercharged car should only use the highest octane fuel you can find.

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Re: No acceleration when applying gas
#5
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Hawkmonster Joe Policastro
Flagstaff, AZ, USA   USA
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Tom I am going to follow up on LaVerne comment but since you have a 1500 perhaps it is like the MGA and my spark plug wire comment may not be applicable.

I do have a supercharger on my TD but before installing it I had a similar issue to what you described. I found my issue was plug wires so I went to NAPA and they sold me the pieces to build my own. See picture below. Those new wires solved the issue. Cost was around $ 8.00.

I also got the impression in reading your post when you had "no idea" of the spark plugs that perhaps this TF was relatively new to you. If that is the case before I went to carbs I would replace points, condenser, wires and adjust timing. Suggestion 15 to 20 degrees BTDC at 800 to 1000 rpm and total advance of around 30 to 32 BTDC at 3000 rpm.

You do need to run high octane. How old is that gas? May want to drain it and put in a couple of gallons of new.


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Re: No acceleration when applying gas
#6
plus4moggie Tom Lange
Bar Harbor, ME, USA   USA
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I agree with LaVerne - you need a complete tune-up first of all. In doing so I would also change the condenser on the points plate, as that frequently goes bad, and cuts down on power. You certainly need no more than 87 octane if everything is adjusted right.

Do you have the NEMGT Register Handbook, which goes through all the necessary steps for tuning - it's very good, although it may not talk about using a dial-type timing light, necessary to get the timing spot on?

I doubt it is anything with the supercharger; even if you have lost the belt, it should still run well. You can pull the carb dashpot and clean it and the piston circumference with carb cleaner, but don't touch (or knock) the needle.

Tom Lange
MGT Repair

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Re: No acceleration when applying gas
#7
plus4moggie Tom Lange
Bar Harbor, ME, USA   USA
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OOPS! Major error on my part. I forgot your car is supercharged. No, do NOT use 87 Use mid-grade certainly, and probably premium.

What supercharger do you have?

Tom Lange

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Re: No acceleration when applying gas
#8
grandpa Ashburn Thomas Cianni
raleigh, NC, USA   USA
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Thanks for all the advice everyone, i appreciate it.

I have a Judson supercharger that i believe was installed when my grandfather bought it back in the 50s

I do not have the NEMGT Register Handbook, but if it is recommended i will look into picking it up.

I could swear my MG mechanic told me 87 would be fine so i am surprised to hear that everyone is recommending 91 or 93. I got the car running and have been taking it out at least once a week for the past two summers. Only really started to experience the issue the last 4 trips of this past summer. The gas is not really old as i would pump a few gallons into the tank after every trip. Maybe i can start her up tonight and just try to burn through the rest of the 87 i have in the tank.

My mechanic told me i might be using the choke too much and that could be causing the rich mixture.

Cheers

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Re: No acceleration when applying gas
#9
Hawkmonster Avatar
Hawkmonster Joe Policastro
Flagstaff, AZ, USA   USA
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Tom in regards to choke. Use to start, not while running. Superchargers do need to run rich. If lean you can really hurt the internals of the engine.

Tom or others maybe able to give you some advice on that specific supercharger. How to service it, etc.

Back to LaVerne's comment have you done a compression check, adjusted the valves?

That book can be bought new for $50 from the New England register. That and a manual are worth their worth in gold. It has been around for years. You rarely see it used because people consider it to be invaluable.

Joe

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Re: No acceleration when applying gas
#10
grandpa Ashburn Thomas Cianni
raleigh, NC, USA   USA
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Joe,

Thanks for the information, i will see if i can pick up that documentation.

I think that must be what happened, i would pull open the choke to start the engine and never pushed it back in. I was told it should go back in itself but i dont think it ever did.

If that is what happened, as long as i keep the choke closed will the car recover? Or do will i need some work done? It obivously depends on how much damage was done from the extra fuel, is there something i can look at to see if damage has been done?

Cheers

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Re: No acceleration when applying gas
#11
grandpa Ashburn Thomas Cianni
raleigh, NC, USA   USA
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I also have not done a compression check or adjusted the valves, dont have the knowledge to do something like that.

Cheers

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Re: No acceleration when applying gas
#12
Hawkmonster Avatar
Hawkmonster Joe Policastro
Flagstaff, AZ, USA   USA
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Tom no need to panic or worry about the fuel. Just drain it and put in high octane. Put the gas in your DD. No harm done at this point. If you run low grade gas you will get pinging and also if it is too lean you can blow up the bottom of the engine. Just correct it and move on after you do the tune up.

Funny you mention a MG mechanic. It has been my experience that these older cars are not like "modern" MGs and supercharged ones are really different. For example, the distributors should be professionally curved for a supercharger and not for a normal carb setup. Not sure how picky you are about the performance of your cars but every little point needs to be done to really enjoy the performance of these cars with a supercharger.

In regards to choke question. Do the tune up first and see what happens you may in fact need to adjust the choke cable as part of the tuneup. But first things first.

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Re: No acceleration when applying gas
#13
Hawkmonster Avatar
Hawkmonster Joe Policastro
Flagstaff, AZ, USA   USA
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Tom look into a local club that has T members. If you are going to own this car you need to learn the basics. I am confident one of those old guys will be willing to teach you and guide you. It will only take some reading before and some hands on experience with a tutor. Like all of us, you can do it. It is not rocket science and easy to learn.

Please post some pictures of that supercharger. Having one on a TF is not a everyday experience. It would be a real treat for us. How about some of the car while you are at it.

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Re: No acceleration when applying gas
#14
grandpa Ashburn Thomas Cianni
raleigh, NC, USA   USA
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Joe,

Completely agree, i could swear my mother was a member of that NEMGT and will look into that.

I'll grab some pictures when i get home for sure.

Cheers

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Re: No acceleration when applying gas
#15
bobs77vet Avatar
bobs77vet bob K.
northern Va, VA, USA   USA
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It sounds like a fuel delivery problem to me. How do you know you are getting adequate fuel delivery?

Perhaps measure the fuel pump flow into a container using a stop watch and compare to fuel pump specs

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