Triumph Repair: Hard start, fuel pressure gauge, psi pressure

Question
QUESTION: Hi I have a 1979 spitfire and when the car sits for 2-3 hours its hard to get it running again but once it starts and warms up its good to go and it will turn on and off easily I've read that it could be because of an empty bowl but I can't find any answers thank you in advance.

ANSWER: Hi Anthony,

This is an easy test to see if it is fuel related. Get the car into the position that you know it is going to be hard to start. If it is not consistant you may have to repeat the test several times.

Get a spray can of starting fluid (available from any auto parts store) and when you are sure it is going to be difficult to start just spray starting fluid into the intake and try to start it. If it starts instantly even if it does not keep running it for sure is fuel related and a good chance an empty float chamber due to heat soak if you are in an area where it is warm.

If the car is hard to start after sitting all night then that is a different problem. In that case you need to put a "T" connection in the fuel line just before the carburetor and connect a fuel pressure gauge to the extra line. (be sure to use clamps on every hose connection)

Most vacuum gauges have a section to measure fuel pressure and they are not expensive. That and the "T" fitting and clamps and a short piece of hose are necessary tools to do the test.

Spinning the engine should get you form 1.5 to 3 PSI pressure.

If the car is also hard to start in the morning then it could also be a problem with the auto choke as they are notorious for failures.

If it is hard to start in the morning then use the starting fluid again. If at any time it don't fire off with starting fluid you need to run a compression test on the engine and test the ignition system. Let me know if you need to do that and I will gove you the test procedures for that.

Howard

---------- FOLLOW-UP ----------

QUESTION: I haven't checked the fuel pressure but it does start with starter fluid and this happens when the car sits over night or cooled off for about 2-3 hours

Answer
Ok, then you have narrowed the problem down to sufficient fuel needed to cold start. Now you still don't know if it is an empty float chamber or a failed choke system so here is the next test.

It is a pain where you sit to pull the float chamber to look at fuel so you can test the choke. (which is not a true choke but an enrichening device) The only thing you want to know is there any fuel in the float chamber at the time of a cold start.

This test is done with no spray, just have someone start the engine cold while you put your hand over the opening of the air filter or remove the air filter and put you hand over the carburetor so as to choke off all air going in while someone tries to start it. As soon as it fires off (if it does) remove your hand and see if they can keep it running. If it stumbles and dies after trying to start put you hand over the intake again and try again but this time when it tries to fire off open your fingers a little to let in a little air and see if you can control the engine speed with your hand by allowing just a little air in.

If there is any fuel in the float chamber, it will run.

There were two different types of auto chokes used on the Stromberg carburetors so if this is the problem you may have to take a picture of yours with the air filter box off so I can tell you how to fix it.

You can attach the picture to this program.

Let me know,

Howard