Car Won't Start When Warm

With ignition on, but engine not running, both lights should be on.

With ignition on, engine running, both lights should be off. If the oil pressure light is on when the engine is running, you have a problem, regardless of the state of the Ox sensor light. You should get this sorted out before doing anything else; you could actually have low oil pressure (bad), or it could be a problem with the oil pressure sender or associated wiring (much less bad).

The Ox Sensor light being on while the engine is running does not indicate a problem. It is just a reminder that it has been 30k miles since the counter box was reset.
 
Will try a few things given the oil level is correct. I suspect the last thing I do is replace the oil pump after the easier fixes are done and the light most likely will remain on.
 
Yet more problems. I'm going to say I don't have a vacume leak (I checked). I found small fuel leak (problem solved) and while fishing arround,

I found an issue with the fuel vapor lines. The hose that’s supposed to be connected to the Y connector is gone and everything from there to the charcoal canister is missing - so no 2 way valve either.

Not sure is this affecting my start issue but the system isn’t closed because there’s an open end on the charcoal canaster and as you can see, the other end that looks like it’s coming out of the fuel filter (It’s not thank GOD 😊) is also un connected.

What are your thoughts?
 

Attachments

  • 10.jpg
    10.jpg
    281 KB · Views: 62
  • 11.jpg
    11.jpg
    279.3 KB · Views: 65
Yet more problems. I'm going to say I don't have a vacume leak (I checked). I found small fuel leak (problem solved) and while fishing arround,

I found an issue with the fuel vapor lines. The hose that’s supposed to be connected to the Y connector is gone and everything from there to the charcoal canister is missing - so no 2 way valve either.

Not sure is this affecting my start issue but the system isn’t closed because there’s an open end on the charcoal canaster and as you can see, the other end that looks like it’s coming out of the fuel filter (It’s not thank GOD 😊) is also un connected.

What are your thoughts?
Although you are contributing to the general haze of hydrocarbons in the atmosphere, it has nothing to do with your engine running problems…

There are a few threads which deal with this system, Hussien redid his and documented the process as I recall. The diagrams in the Fiat manual are complete and the parts diagrams are pretty helpful as well.

A good thing to fix but not the end of the world. Just try not to smoke while you are leaning into the engine bay…
 
Although you are contributing to the general haze of hydrocarbons in the atmosphere, it has nothing to do with your engine running problems…

There are a few threads which deal with this system, Hussien redid his and documented the process as I recall. The diagrams in the Fiat manual are complete and the parts diagrams are pretty helpful as well.

A good thing to fix but not the end of the world. Just try not to smoke while you are leaning into the engine bay…
Lol on the smoking. Not so much on the hydrocarbons. It's always passed emissions I don't know how many times in this manner. Someone plugged the hose I showed with a bolt I took it out for now. I thought it could have been it because the charcoal canister does have a line to the air intake and I'm 2 hoses and two-way valve short of completing the loop.
 
Hi Steve, Why does it start when hot sometimes?
As things wear out, you enter a land of luck... I am not saying that knackered rings is the root cause - I am saying that lower compression makes everything harder. It is clear your car has been mucked around by good ole previous owner so you need to assume that everything is wrong unless you have checked it yourself.

For me, the oil light on with engine running is highest priority. No need to worry about hot start if that light is telling the truth - you shouldn't be driving it at all!
 
Lol on the smoking. Not so much on the hydrocarbons. It's always passed emissions I don't know how many times in this manner. Someone plugged the hose I showed with a bolt I took it out for now. I thought it could have been it because the charcoal canister does have a line to the air intake and I'm 2 hoses and two-way valve short of completing the loop.
This isn’t part of the emissions test though it can cause the car to fail the visual.

The biggest concern with plugging it is actually collapsing the tank as the fuel pump can suck the steel in if it doesn’t get makeup air…

The parts are available and its really just some common fuel hose.
 
Very early in my ownership (driving it home) my car illuminated both the oil pressure light and Ex gas sensor light. Long story short, the oil pressure warning light switch was bad; removing the boot on the switch showed oil oozing out. Installing a replacement did the trick.

If you suspect the cold start injector of activating when it is not supposed to and dumping excessive fuel into a hot engine and causing hard starting, it's easy to eliminate that possibility.

1. You can just unplug the cold start injector's electrical lead and if that makes a difference, then your issue is the thermo-time switch, which is what activates the cold start injector.

2. If unplugging the electrical lead does not make a difference, try a pair of pinch-off pliers or equivalent to pinch off the fuel supply hose going to the cold start injector. If that does make a difference yet #1 did not, then the issue is the cold start injector not properly sealing itself off, in which case you'd need a new cold start injector.

Leaking injectors dumping fuel into an engine can lead to thinned out oil which can lead to loss of compression. Does your engine oil smell gassy or look thin? Smoking gun!


A fuel pressure reading is always helpful in these cases. An easy but dangerous way to connect a temporary gauge is the feed hose to the cold start injector. It's dangerous because the Cold start injector fuel line nipple is old and brittle and identical cold start injectors are crazy expensive if you break that nipple off while trying to remove the hose. Depending upon what your fuel pressure gauge kit has for fittings, it might be better to T into the fuel hose right after the pump or right after the main fuel filter.


During hot no start events, check the electronic ignition box located in the right engine compartment scuttle. These are generally warm to the touch, but if yours is really hot, that might be an indicator of an ignition issue creating the hot no start.


Hopefully a worn engine is not your ultimate issue, but if you suspect low compression as the hot no start culprit, compression tests that compare cold and hot values will tell you everything you need to know.

Chain parts stores have loaner programs for common test equipment like fuel pressure gauges and compression testers. While you have the fuel pressure gauge kit, check to see if it is also a vacuum gauge. Knowing how to read a vacuum gauge is a lost art but those who know what they are looking for attest that they are valuable tools, even for engines that won't start.
 
Last edited:
Very early in my ownership (driving it home) my car illuminated both the oil pressure light and Ex gas sensor light. Long story short, the oil pressure warning light switch was bad; removing the boot on the switch showed oil oozing out. Installing a replacement did the trick.

If you suspect the cold start injector of activating when it is not supposed to and dumping excessive fuel into a hot engine and causing hard starting, it's easy to eliminate that possibility.

1. You can just unplug the cold start injector's electrical lead and if that makes a difference, then your issue is the thermo-time switch, which is what activates the cold start injector.

2. If unplugging the electrical lead does not make a difference, try a pair of pinch-off pliers or equivalent to pinch off the fuel supply hose going to the cold start injector. If that does make a difference yet #1 did not, then the issue is the cold start injector not properly sealing itself off, in which case you'd need a new cold start injector.

Leaking injectors dumping fuel into an engine can lead to thinned out oil which can lead to loss of compression. Does your engine oil smell gassy or look thin? Smoking gun!


A fuel pressure reading is always helpful in these cases. An easy but dangerous way to connect a temporary gauge is the feed hose to the cold start injector. It's dangerous because the Cold start injector fuel line nipple is old and brittle and identical cold start injectors are crazy expensive if you break that nipple off while trying to remove the hose. Depending upon what your fuel pressure gauge kit has for fittings, it might be better to T into the fuel hose right after the pump or right after the main fuel filter.


During hot no start events, check the electronic ignition box located in the right engine compartment scuttle. These are generally warm to the touch, but if yours is really hot, that might be an indicator of an ignition issue creating the hot no start.


Hopefully a worn engine is not your ultimate issue, but if you suspect low compression as the hot no start culprit, compression tests that compare cold and hot values will tell you everything you need to know.

Chain parts stores have loaner programs for common test equipment like fuel pressure gauges and compression testers. While you have the fuel pressure gauge kit, check to see if it is also a vacuum gauge. Knowing how to read a vacuum gauge is a lost art but those who know what they are looking for attest that they are valuable tools, even for engines that won't start.
Thanks Dan. All of this is very helpful and when it happens again, I'll give it a go. As for the oil light, It went off when resetting the O2 senser light. Car was telling me it's time. Will still do the pressure tests. I did a smoke test on the vacuum and found no leaks.
 
As things wear out, you enter a land of luck... I am not saying that knackered rings is the root cause - I am saying that lower compression makes everything harder. It is clear your car has been mucked around by good ole previous owner so you need to assume that everything is wrong unless you have checked it yourself.

For me, the oil light on with engine running is highest priority. No need to worry about hot start if that light is telling the truth - you shouldn't be driving it at all!
Lucked out. Resetting the O2 also turned off the oil light.
 
Agreed. I’m going to try the home made smoke machine method. With my luck, flammables won’t end well. 😔
I want to know more about this home made smoke machine method. I am that terrible combination of extremely chemically sensitive, clumsy, and desperate to get my cars going.
 
I want to know more about this home made smoke machine method. I am that terrible combination of extremely chemically sensitive, clumsy, and desperate to get my cars going.
You’ll need a hand pump with hoses. You can get it at Home Depot. A soldering iron and a glass jar. Drill three holes in the jar top one for each hose and one in the middle soldering iron. Insert items a seal. Out rags and baby oil in the jar. Plug in the iron. You should get a lot of smoke once it builds up and you pump. Take off the air flow meter. Put a rubber glove on it and clamp it down with the clamp. Cut a hole in one finger of the glove, insert tube and clamp. If everything is air tight, you’re good to go. If not, you’ll see smoke where there’s a leak. Including your home made smoke machine so make sure there’s no leaked there.
 
Very early in my ownership (driving it home) my car illuminated both the oil pressure light and Ex gas sensor light. Long story short, the oil pressure warning light switch was bad; removing the boot on the switch showed oil oozing out. Installing a replacement did the trick.

If you suspect the cold start injector of activating when it is not supposed to and dumping excessive fuel into a hot engine and causing hard starting, it's easy to eliminate that possibility.

1. You can just unplug the cold start injector's electrical lead and if that makes a difference, then your issue is the thermo-time switch, which is what activates the cold start injector.

2. If unplugging the electrical lead does not make a difference, try a pair of pinch-off pliers or equivalent to pinch off the fuel supply hose going to the cold start injector. If that does make a difference yet #1 did not, then the issue is the cold start injector not properly sealing itself off, in which case you'd need a new cold start injector.

Leaking injectors dumping fuel into an engine can lead to thinned out oil which can lead to loss of compression. Does your engine oil smell gassy or look thin? Smoking gun!


A fuel pressure reading is always helpful in these cases. An easy but dangerous way to connect a temporary gauge is the feed hose to the cold start injector. It's dangerous because the Cold start injector fuel line nipple is old and brittle and identical cold start injectors are crazy expensive if you break that nipple off while trying to remove the hose. Depending upon what your fuel pressure gauge kit has for fittings, it might be better to T into the fuel hose right after the pump or right after the main fuel filter.


During hot no start events, check the electronic ignition box located in the right engine compartment scuttle. These are generally warm to the touch, but if yours is really hot, that might be an indicator of an ignition issue creating the hot no start.


Hopefully a worn engine is not your ultimate issue, but if you suspect low compression as the hot no start culprit, compression tests that compare cold and hot values will tell you everything you need to know.

Chain parts stores have loaner programs for common test equipment like fuel pressure gauges and compression testers. While you have the fuel pressure gauge kit, check to see if it is also a vacuum gauge. Knowing how to read a vacuum gauge is a lost art but those who know what they are looking for attest that they are valuable tools, even for engines that won't start.
 
Hi Paul,

I thought it was all sorted out but it is not.

The car starts when it feels like it. For a while, it would not start when hot and after it cooled off, it would start.

Lately, it will not start when cold. I drove the car around for miles and it started every time. After I got it home, it started every 15 to 30 mins no problem. Then after it was cold – nothing. So, I disconnected the air flow meter for fun and it worked although there was no reason why it should of. In fact, it would not start unless it was disconnected. Much later that night, with the air flow meter connected it started again.

I called a supplier and he told me the real problem was the spark box (the part you mentioned on the passenger side). I drove for hours and it started every time. After I got home, it started every 15 to 30 minutes. I ran an errand with a friend, left my car at home and when we returned – nothing. The spark box was cold and I disconnected the air flow meter but that did not work. I would not expect either to work because cooling off the spark box (which was not hot so I didn’t need to) or disconnecting the air flow meter when cold should not have started the car either way.

In the past it appeared as if the car had to cool off to start but that is no longer the case.

It is 35 F now, the car is cold, has not been driven for hours and it will not start in my drive way. I do not know the next time it will start or why at this point ☹
 
Well, you know the old saying, when all else fails, read the instructions.

Begin with the FI troubleshooting manual, which itself begins with words to the effect: "Make damn well sure your ignition system is functioning perfectly before messing with the FI!"

Other than trying to start it and reporting results, what about TESTING? What tests have you done?
 
car is cold,
hmm. I am thinking cold start injector issues. If cold start injector not functional, won't cold start [it is the "choke" on injected cars]. If cold start was failing for a while - perhaps it was operating when it should not = flooding when hot and hot start problems. I would check electrical and fluid connections to cold start injector and after that, the box of smoke.
 
Well, you know the old saying, when all else fails, read the instructions.

Begin with the FI troubleshooting manual, which itself begins with words to the effect: "Make damn well sure your ignition system is functioning perfectly before messing with the FI!"

Other than trying to start it and reporting results, what about TESTING? What tests have you done?
A smoke test to assure there were no leaks in the vacuum system.
 
Back
Top