Good day
I parked my car and the next day it does not wanted to start. My timing belt is intact and the tension looks ok. A local mechanic assumes that the timing belt jumped one teeth which is very unlikely. If it is the case what would be the symptoms? The engine is turning around freely. I m driving a 2002 S40,2.0L. No turbo. What can i check before I take drastic measures.
Thanks
Car wont start but cranking
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emtor
- Posts: 30
- Joined: 23 January 2017
- Year and Model: 2002 V40
- Location: Norway
- Been thanked: 1 time
Read my post "Cranks but no start".
Try starting with the throttle slightly depressed.
If the Idle Air Control Valve is stuck, depressing the throttle will make the engine not dependant upon the IACV.
If it starts but stalls as soon as you let go of the throttle it's probably the IACV.
Either it's stuck or leaking through the gasket or the electric motor driving the valve is shot.
The IACV-motor can be checked with an ohm-meter on the pins. Should read few ohms.
Timing belt ? -Not very likely unless you've just done a timing belt change or the cam hubs have spewed oil on the belt or the tensioner/idle pulley is faulty.
A timing belt with correct tension and all teeth intact and teeth not worn down a lot simply does NOT slip.
If that was the case timing belts would slip ten times a day.
If the engine won't start despite giving it some throttle, do this:
Turn the ignition key. Can you hear the fuel pump priming below the back seat?
It should run for two seconds and then stop.
If you can't hear it check the fuel pump fuse and the fuel pump relay.
If OK, look at the fuel rail and find the schrader-valve. Same kind of valve found on car tires with a little plastic cap on it.
Unscrew the cap and push down the valve needle. It should squirt gasoline, not only drip.
If squirt, then you have fuel pressure, perhaps not the correct pressure value but pressure none the less.
Find the fuel pressure regulator on the right side of the fuel rail. Remove the plastic cover and remove the little vacuum hose.
There should be NO gas running out from this tube. With the tube off turn the ignition on to let the fuel pump prime the fuel rail.
If you see gas then the diaphragm inside the regulator has ruptured.
If the schrader valve squirts and there's no gas from the vacuum hose you disconnected then you know you've got gas all the way from the tank to the injectors. Check injectors as a last resort after continuing with the list below.
Remove one of the spark plugs. Push it down onto the engine with a screwdriver and let someone crank the engine for you.
If you've got spark on at least one plug, the engine should at least attempt to fire although not perhaps start or run.
Since you've got spark, the crank sensor and cam sensors are both OK.
Get a wine cork or a ball made from crumbled paper and place it on top of the spark plug hole. Crank the engine. The cork/paper ball should shoot out or at least move.
Now you know that you have gas, spark and at least some compression.
Still dead? Check for vacuum leaks. If no leaks,-check timing belt for missing or worn teeth and check cam timing marks against crankshaft timing mark.
If marks are OK, check MAF sensor and IAT-sensor. Then check coolant temp sensor. Also check harnesses to all sensors and IACV and make sure all these have correct voltages on their respective pins. Also check for broken or shorted wires.
Try starting with the throttle slightly depressed.
If the Idle Air Control Valve is stuck, depressing the throttle will make the engine not dependant upon the IACV.
If it starts but stalls as soon as you let go of the throttle it's probably the IACV.
Either it's stuck or leaking through the gasket or the electric motor driving the valve is shot.
The IACV-motor can be checked with an ohm-meter on the pins. Should read few ohms.
Timing belt ? -Not very likely unless you've just done a timing belt change or the cam hubs have spewed oil on the belt or the tensioner/idle pulley is faulty.
A timing belt with correct tension and all teeth intact and teeth not worn down a lot simply does NOT slip.
If that was the case timing belts would slip ten times a day.
If the engine won't start despite giving it some throttle, do this:
Turn the ignition key. Can you hear the fuel pump priming below the back seat?
It should run for two seconds and then stop.
If you can't hear it check the fuel pump fuse and the fuel pump relay.
If OK, look at the fuel rail and find the schrader-valve. Same kind of valve found on car tires with a little plastic cap on it.
Unscrew the cap and push down the valve needle. It should squirt gasoline, not only drip.
If squirt, then you have fuel pressure, perhaps not the correct pressure value but pressure none the less.
Find the fuel pressure regulator on the right side of the fuel rail. Remove the plastic cover and remove the little vacuum hose.
There should be NO gas running out from this tube. With the tube off turn the ignition on to let the fuel pump prime the fuel rail.
If you see gas then the diaphragm inside the regulator has ruptured.
If the schrader valve squirts and there's no gas from the vacuum hose you disconnected then you know you've got gas all the way from the tank to the injectors. Check injectors as a last resort after continuing with the list below.
Remove one of the spark plugs. Push it down onto the engine with a screwdriver and let someone crank the engine for you.
If you've got spark on at least one plug, the engine should at least attempt to fire although not perhaps start or run.
Since you've got spark, the crank sensor and cam sensors are both OK.
Get a wine cork or a ball made from crumbled paper and place it on top of the spark plug hole. Crank the engine. The cork/paper ball should shoot out or at least move.
Now you know that you have gas, spark and at least some compression.
Still dead? Check for vacuum leaks. If no leaks,-check timing belt for missing or worn teeth and check cam timing marks against crankshaft timing mark.
If marks are OK, check MAF sensor and IAT-sensor. Then check coolant temp sensor. Also check harnesses to all sensors and IACV and make sure all these have correct voltages on their respective pins. Also check for broken or shorted wires.
Last edited by emtor on 01 May 2017, 16:03, edited 1 time in total.
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emtor
- Posts: 30
- Joined: 23 January 2017
- Year and Model: 2002 V40
- Location: Norway
- Been thanked: 1 time
One more thing:
The idle air control sensor kicks in when the throtltle position sensor tells it to, either by a separate switch or when the signal from the throttle position sensor itself indicates a closed TPS. If for some reason the TPS or switch or whatever acts up, the IACV may be in perfectly good order but is never told to do it's job.
This will cause your engine to not start.
The idle air control sensor kicks in when the throtltle position sensor tells it to, either by a separate switch or when the signal from the throttle position sensor itself indicates a closed TPS. If for some reason the TPS or switch or whatever acts up, the IACV may be in perfectly good order but is never told to do it's job.
This will cause your engine to not start.
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