Car Won't Start When Warm

LoveX1/9s

LoveX1/9s

True Classic
My 85 X 1/9 used to stall out while driving.

Now it does not start after driving. I can drive it a block or miles but once I turn it off, it won’t start for hours. It feels a little rough but its almost perfect. That said, I always feel like I’ll be stranded. Sometimes, it will start right up after a drive it - It’s a mystery.

I’ve replaced, the fuel pressure regulator, the fuel filter, fuel pump, coil (it fried) which lead me to replace the fuel injection brain and the car ran fine for about a year – no more stalling at speed. About 3 weeks ago, it stranded me upon start. So, I replaced the fuel pressure regulator and it ran great until yesterday – when it wouldn’t start for hours after driving it 30 miles.

Is there an easy way to check for vacuum leaks without using flammables? Should I just replace all the vacuum lines and while I’m at it the fuel lines? I have the book but I figure, if it’s rubber, just replace it.

I’m guessing I can use a fuel line as a vacuum line. Is that right?

Or is there anything else I should check?

Thanks in advance.
 
Use the Xweb Google search to look for "warm starting problem" and other variations of that phrase. Lots of threads on similar issues. One takeaway is to check your voltages. Hot starting can take more power and if your starter circuit is pulling too much power the ignition voltage can be too low to function properly.

Is you battery newish?
Do you have a hard start relay installed?
 
A little different than yours, but my current problem is driving fine for about a half hour, and then I'll die at a traffic light and need to wait at least 15 minutes or so to restart. The obvious answer is go to the fuel injector troubleshooting manual, but to save you a little time searching I found this thread which eyes the engine temperature sensor as a possible target for hot restart issues.

Hot stalling (and hard to restart)

Hi Gang- It's been a long time since I've dropped in to say hello! Hope everyone is well. Life has a way of taking over, and with a couple of little kids, I don't have nearly as much time to spend with my cars as I used to... but I have run into a problem with my X1/9 that I want to take care...
xwebforums.com
 
LoveX1/9s said:
My 85 X 1/9 used to stall out while driving.

Now it does not start after driving. I can drive it a block or miles but once I turn it off, it won’t start for hours. It feels a little rough but its almost perfect. That said, I always feel like I’ll be stranded. Sometimes, it will start right up after a drive it - It’s a mystery.

I’ve replaced, the fuel pressure regulator, the fuel filter, fuel pump, coil (it fried) which lead me to replace the fuel injection brain and the car ran fine for about a year – no more stalling at speed. About 3 weeks ago, it stranded me upon start. So, I replaced the fuel pressure regulator and it ran great until yesterday – when it wouldn’t start for hours after driving it 30 miles.

Is there an easy way to check for vacuum leaks without using flammables? Should I just replace all the vacuum lines and while I’m at it the fuel lines? I have the book but I figure, if it’s rubber, just replace it.

I’m guessing I can use a fuel line as a vacuum line. Is that right?

Or is there anything else I should check?

Thanks in advance.
Click to expand...
Have you tried flooring the accelerator when it does this?

If it will start then, the cold start injector may be enabled on hot start, flooding the engine. If it starts when you do this, chasing that line of thought may pay off.

Just a thought.
 
kmead said:
Have you tried flooring the accelerator when it does this?

If it will start then, the cold start injector may be enabled on hot start, flooding the engine. If it starts when you do this, chasing that line of thought may pay off.

Just a thought.
Click to expand...
Thanks Karl. I will give it a try.
 
JimD said:
Use the Xweb Google search to look for "warm starting problem" and other variations of that phrase. Lots of threads on similar issues. One takeaway is to check your voltages. Hot starting can take more power and if your starter circuit is pulling too much power the ignition voltage can be too low to function properly.

Is you battery newish?
Do you have a hard start relay installed?
Click to expand...
The battery is new enough. Not sure if I have a hard start relay installed.
 
Michael Oxman said:
A little different than yours, but my current problem is driving fine for about a half hour, and then I'll die at a traffic light and need to wait at least 15 minutes or so to restart. The obvious answer is go to the fuel injector troubleshooting manual, but to save you a little time searching I found this thread which eyes the engine temperature sensor as a possible target for hot restart issues.

Hot stalling (and hard to restart)

Hi Gang- It's been a long time since I've dropped in to say hello! Hope everyone is well. Life has a way of taking over, and with a couple of little kids, I don't have nearly as much time to spend with my cars as I used to... but I have run into a problem with my X1/9 that I want to take care...
xwebforums.com
Click to expand...
WIll look at all of that. Thanks.
 
More info. The battery isn't that old but I'm charging it. If the battery was low, would it start sometime? It would seem like it wouldn't start at all if that was the case. However, my car won't start sometime after driving it.
 
My mechanic (now retired) said when the gas sensor and oil light come on when it's time for a tune up. Do they always come on together when it's just tune up time? Other dashboard lights are included. The alternator light or battery light looks OK to me. The RPMs are when at iddel and the car is off. He may have turned it up before when the car was stalling so not sure if the idle is high or not.
 

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It's hard to tell but maybe I have selective hearing and hear a hiss. Perhaps comming from the vacume hose. Will look into that further. It' also hard to tell but I think I see fuel in the junction on the 1st picture - at least something appears wet.
 

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So, I wasn't thinking but the guy at the automotive shop said I could use oil and a UV light to find a vacuum leak. Ummm, not in this case but I hear it works in oil, coolant and fuel. I hear it’ safe for oil but is it ok to put it in the fuel tank??? Seems risky to me.
 
LoveX1/9s said:
My mechanic (now retired) said when the gas sensor and oil light come on when it's time for a tune up. Do they always come on together when it's just tune up time? Other dashboard lights are included. The alternator light or battery light looks OK to me. The RPMs are when at iddel and the car is off. He may have turned it up before when the car was stalling so not sure if the idle is high or not.
Click to expand...
The Ox Sensor light comes on whenever the oil pressure light is on (but not the other way around). When the engine is running they should both turn off. There is a milage counter mounted inside the center stack, and this counter turns on the Ox Sensor light every 30,000 miles. If the Ox Sensor light is on while the engine is running (and thus the oil pressure light is out) it means only that it has been at least 30,000 miles since last time the counter box was reset.
 
LoveX1/9s said:
My mechanic (now retired) said when the gas sensor and oil light come on when it's time for a tune up. Do they always come on together when it's just tune up time? Other dashboard lights are included. The alternator light or battery light looks OK to me. The RPMs are when at iddel and the car is off. He may have turned it up before when the car was stalling so not sure if the idle is high or not.
Click to expand...
The gas sensor light comes on every 30,000 miles. Depending on which plugs you are running, you should be changing them at 30k along with the distributor cap and rotor. Tune up is complete. Personally I would change the O2 sensor every 60k.
 
LoveX1/9s said:
It's hard to tell but maybe I have selective hearing and hear a hiss. Perhaps comming from the vacume hose. Will look into that further. It' also hard to tell but I think I see fuel in the junction on the 1st picture - at least something appears wet.
Click to expand...
Not likely to be fuel in the first picture. This is part of the crankcase ventilation system, so any wetness is likely to be oil. There should of course not be any oil either, so check the plastic tee for cracks etc.
 
LoveX1/9s said:
So, I wasn't thinking but the guy at the automotive shop said I could use oil and a UV light to find a vacuum leak. Ummm, not in this case but I hear it works in oil, coolant and fuel. I hear it’ safe for oil but is it ok to put it in the fuel tank??? Seems risky to me.
Click to expand...
That’s not how vacuum leaks work. You can find vacuum leaks with the engine running by spraying carb cleaner towards each connection, when the carb cleaner hits the leak it seals it momentarily and the engine burns the carb cleaner, you will see the rpm rise when that happens.
 
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kmead said:
That’s not how vacuum leaks work. You can find vacuum leaks with the engine running by spraying carb cleaner towards each connection, when the carb cleaner hits the leak it seals it momentarily and burns the carb cleaner, you will see the rpm rise when that happens.
Click to expand...
Agreed. I’m going to try the home made smoke machine method. With my luck, flammables won’t end well. 😔
 
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My 84 does this randomly after driving and shutting it off. After letting it "cool down" for 30mins to an hour, it starts right up. Interested to hear any solutions you find....
 
ng_randolph said:
The Ox Sensor light comes on whenever the oil pressure light is on (but not the other way around). When the engine is running they should both turn off. There is a milage counter mounted inside the center stack, and this counter turns on the Ox Sensor light every 30,000 miles. If the Ox Sensor light is on while the engine is running (and thus the oil pressure light is out) it means only that it has been at least 30,000 miles since last time the counter box was reset.
Click to expand...
So do I have a problem because both lights stay on at the same time?
 
LoveX1/9s said:
So do I have a problem because both lights stay on at the same time
Click to expand...
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.
 
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