Car Won't Start When Warm

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.
Box of smoke?
 
A smoke test to assure there were no leaks in the vacuum system.
A vacuum leak is not what is keeping your car from starting. The components which rely on the vacuum are minor and would have no effect on the car starting or not.

If your intake snorkel hose from the AFM to the intake manifold is in good shape (which means taking it off and verifying it isn’t cracked). This hose being cracked could keep the car from running properly, the engine should start regardless of the quality of the hose (running properly would be another matter).

Dan is speaking of printing out the test procedures from here: https://xwebforums.com/wiki/index.php?title=FuelInjectionTroubleshooting
You can also download a cleaned up version at MiraFiori.com where you will need to make an account to access the file in their Library: https://mirafiori.com/forum/download/file.php?id=13098 the file is too big to attach to this post.
 
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A vacuum leak is not what is keeping your car from starting. The components which rely on the vacuum are minor and would have no effect on the car starting or not.

If your intake snorkel hose from the AFM to the intake manifold is in good shape (which means taking it off and verifying it isn’t cracked). This hose being cracked could keep the car from running properly, the engine should start regardless of the quality of the hose (running properly would be another matter).

Dan is speaking of printing out the test procedures from here: https://xwebforums.com/wiki/index.php?title=FuelInjectionTroubleshooting
You can also download a cleaned up version at MiraFiori.com where you will need to make an account to access the file in their Library: https://mirafiori.com/forum/download/file.php?id=13098 the file is too big to attach to this post.
Thanks... One owner stated that his car started he fixed the vacuum leak but I can see how it would have to be major for that to happen.
I have pulled a ton of grounds off the car that previous owners have installed. It could be a separate problem but lately my clock has to be reset every time I start the car.

But now I have a plan of attack. I’ll be busy for a while but you’ve provided the best way to sort things out… Much appreciated.
 
So, I started with the spark test and after replacing the typical electrical stuff, the car has started every time. In addition, my clock also no longer needs to be reset an the dash board lights have brightened up for the first time in a while. I got the car with dim lights 10 years ago. Previous owners have been creative with ground wires - since removed so someting is drawing on the electrical system. That said the line to number 4 was cooked and lots of dust came out after I disconnected the plug. I am going to continue down the list. Will get to the oil pressure test but I have oil on the spark plug threads so I suspect I will do a before and after test after that's addressed. I will get the UV oil to see where the leak is coming from.
 

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So, I started with the spark test and after replacing the typical electrical stuff, the car has started every time. In addition, my clock also no longer needs to be reset a the dash board lights have brightened up for the first time in a while. I got the car with dim lights 10 years ago. Previous owners have been creative with ground wires - since removed so someting is drawing on the electrical system. That said the line to number 4 was cooked and lots of dust came out after I disconnected the plug. I am going to continue down the list. Will get to the oil pressure test but I have oil on the spark plug threads so I suspect I will do a before and after test after that's addressed. I will get the UV oil to see where the leak is coming from.
Great plug wires available from RX1900 I have them on both my X’s

High quality and the right lengths.
 
So, my fuel pump isn’t getting current. When I disconnect my air flow meter and hold the door open, the car wants to start and spudders out (probably because I created a massive vacuum leak given that the system is open). Should I get a new airflow meter or is there something I can do to fix mine? My guess is that the opening the door in the meter is mechanical in nature. Is there anything I can check?

Thanks in advance for your help.
 
There is a circuit in the AFM that controls the fuel pump to a degree. With early FI systems like the Bosch L-Jetronic on the X, most manufacturers used either an oil pressure switch or contacts in the AFM to determine whether or not the engine was running as part of the safety logic.

Specifically for the X, this task is handled by a pair of contacts in the AFM. With the ig switch in Run (as opposed to Start), if the engine is running there should be air flow thru the AFM. If there is no airflow, then the safety circuit contacts cut power to the fuel pump. This prevents the fuel pump from running and keeping the fuel system pressurized in an emergency situation such as a collision, etc.

When the ig switch is in Start, OTOH, the fuel pump is always energized. The "changeover" between behavior in Start the behavior in Run is one of the tasks handled by the FI system's double relay.

So if you suspect that the fuel pump is not being properly energized, you would need to proof it for both Start condition and Run condition.

To check for proper behavior in Run condition, detach the air ducting from the air cleaner to the AFM, put the ig switch in Run position, and use for example the eraser end of a pencil inserted into the AFM from the air cleaner side to slightly displace the flapper door in the AFM. If everything is right, just the slightest movement of the flapper door should energize the pump which of course will be easily heard as you are right there with the engine off.

Checking for pump operation in Start condition is a little harder as the noise of the engine keeps you from hearing the pump. You could try feeling for operation while a helper turns the ig key to Start, or you could use a simple test light to check for current to the pump.

If your tests indicate that there is something wrong with the contacts in the AFM, the black plastic top of the AFM can be removed with some effort to inspect the circuitry inside. There have been some posts that show what the inside of the AFM looks like and which thingies are the fuel pump contacts. The one below is just what Google came up with from a Jaguar forum, but the accompanying post says the red arrow points to the fuel pump contacts.

AFMboschljetronic.jpg
 
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There is a circuit in the AFM that controls the fuel pump to a degree. With early FI systems like the Bosch L-Jetronic on the X, most manufacturers used either an oil pressure switch or contacts in the AFM to determine whether or not the engine was running as part of the safety logic.

Specifically for the X, this task is handled by a pair of contacts in the AFM. With the ig switch in Run (as opposed to Start), if the engine is running there should be air flow thru the AFM. If there is no airflow, then the safety circuit contacts cut power to the fuel pump. This prevents the fuel pump from running and keeping the fuel system pressurized in an emergency situation such as a collision, etc.

When the ig switch is in Start, OTOH, the fuel pump is always energized. The "changeover" between behavior in Start the behavior in Run is one of the tasks handled by the FI system's double relay.

So if you suspect that the fuel pump is not being properly energized, you would need to proof it for both Start condition and Run condition.

To check for proper behavior in Run condition, detach the air ducting from the air cleaner to the AFM, put the ig switch in Run position, and use for example the eraser end of a pencil inserted into the AFM from the air cleaner side to slightly displace the flapper door in the AFM. If everything is right, just the slightest movement of the flapper door should energize the pump which of course will be easily heard as you are right there with the engine off.

Checking for pump operation in Start condition is a little harder as the noise of the engine keeps you from hearing the pump. You could try feeling for operation while a helper turns the ig key to Start, or you could use a simple test light to check for current to the pump.

If your tests indicate that there is something wrong with the contacts in the AFM, the black plastic top of the AFM can be removed with some effort to inspect the circuitry inside. There have been some posts that show what the inside of the AFM looks like and which thingies are the fuel pump contacts. The one below is just what Google came up with from a Jaguar forum, but the accompanying post says the red arrow points to the fuel pump contacts.

AFMboschljetronic.jpg
Thank you kindly Dan. I'll run through those.
 
There were a lot of lengthy responses so I'll admit I didn't read through all the previous messages, (just skimmed) but just throwing this out there as it was a hot start problem on the my128.. Could it be as simple as vapor lock? Fuel lines too close to a heat source?...
 
There were a lot of lengthy responses so I'll admit I didn't read through all the previous messages, (just skimmed) but just throwing this out there as it was a hot start problem on the my128.. Could it be as simple as vapor lock? Fuel lines too close to a heat source?...
Vapor lock has been rulled out.
 
Mine looks like this. Don't have a helper handy today to test it but if I turn the mechanism, I hear the fuel pump engages. Not sure why it’s not moving on it’s own to start the process. Also, not sure where the contact points are. Although, if I turn the pivot point where the silver arm is connected, just slightly, a connection is made on the left side of the system and you can hear the fuel pump engage.

Not sure what will happen if someone tries to start the car to start the car while I rotate the mechanism. Getting jolted would suck.

I also hear that the fuel system is supposed to be 36 psi but I have to test that too.
 

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Mine looks like this. Don't have a helper handy today to test it but if I turn the mechanism, I hear the fuel pump engages. Not sure why it’s not moving on it’s own to start the process. Also, not sure where the contact points are. Although, if I turn the pivot point where the silver arm is connected, just slightly, a connection is made on the left side of the system and you can hear the fuel pump engage.

Not sure what will happen if someone tries to start the car to start the car while I rotate the mechanism. Getting jolted would suck.

I also hear that the fuel system is supposed to be 36 psi but I have to test that too.
The "mechanism" you see is attached to a "flapper door" inside of the AFM. It's the air being drawn into the engine that would pass thru the AFM and move the flapper and therefore the mechanism visible with the black top off.

Based on the behavior you described, the fuel contacts would seem to be working as intended, so you can put the black top back onto the AFM.
 
The "mechanism" you see is attached to a "flapper door" inside of the AFM. It's the air being drawn into the engine that would pass thru the AFM and move the flapper and therefore the mechanism visible with the black top off.

Based on the behavior you described, the fuel contacts would seem to be working as intended, so you can put the black top back onto the AFM.
Cool. Now I did notice that I hear click when I move the system. Fel pump is getting current but only when I move it my self. When I put the key in run, I hear the multi relay kick in but noting to the fuel pump. I don't hear it hum but I do hear it click with the key in run and I cause the air flow meter door to move? Perhaps a bad fuel pump?
 
Cool. Now I did notice that I hear click when I move the system. Fel pump is getting current but only when I move it my self. When I put the key in run, I hear the multi relay kick in but noting to the fuel pump. I don't hear it hum but I do hear it click with the key in run and I cause the air flow meter door to move? Perhaps a bad fuel pump?
The switch will be actuated by the flap moving as air is drawn into the engine.

The fuel pump doesn’t run if the engine isn’t being cranked by the starter or there is airflow through the intake.

There are two ways power is supplied to the electric fuel pump, in both cases power to the pump comes from the double relay.

The first method has a trigger current coming from the starter solenoid to the one side of the double relay, this current closes the relay and provides power to the pump. This ensures the pump runs and provides pressure when the engine is being cranked. This trigger current is delivered by a wire which is crimped to the wire coming from the ignition switch and is only hot when the ignition switch is in the start position.

The second control path for power to the fuel pump is by way of the Air Fuel Meter (AFM). When the engine starts there is enough airflow through the AFM to move the flap inside and this then closes the little switch inside the AFM to deliver current to the same coil in the double relay to provide power to the pump.

To test that the pump is being supplied with power you can have someone crank the engine while you hold your hand on the pump. While the starter is running the pump should run. It should stop when the starter stops (presuming the engine didn’t start). The second approach to testing that the fuel pump is provided power properly is to remove the elbow going from the air filter to the AFM, then turn the ignition to the “On” position. You will then reach into the AFM throat and push the flap open with either your finger or a screw driver, once the flap moves open the fuel pump should start running and will stop when you let the flap close again.

The image below depicts the double relay and you can see the paths of power to the right side coil for power to close the relay and provide power to the pump.

Power to the relay electromagnetic coil arrives from the starter to the 86a terminal and the second way power comes to the relay electromagnetic coil is from the switch in the AFM which arrives on 86b.

1683082831894.jpeg
 
So when you try to start the car, is the needle on the air flow meter suppose to swing back and forth? It moves about an inch and 1/2 then goes goes back to the start position and keeps swinging back and forth until you stop trying.
 
gas sensor and oil light come on when it's time for a tune up.

Actually - yes and no. You most likely have the Lambda Sensor Switch Unit connected in your car (it's a box just behind the ash tray). If you pull that connector out, the lights will turn off.

My guess is that your oil light was on very "weak", right? Either way, yes - your O2 sensor might be due for replacement - AND for all the people who have original catalytic converters, they're most likely plugged! A local X1/9 friend here had a totally plugged cat and after changing it, the car ran fantastic!

Anyway, a tune up won't make the light go out on its own. It's on for other reasons. My guess is that the diode boxed in blue doesn't block the ground path completely when the sensor switch is turned ON. The Oil pressure light gets a ground path and will light up somewhat - but usually quite dim.


1683248594259.png
 
So when you try to start the car, is the needle on the air flow meter suppose to swing back and forth? It moves about an inch and 1/2 then goes goes back to the start position and keeps swinging back and forth until you stop trying.
Thats what my uno turbo engine does (very similar FI system)
 
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