Engine can crank but cannot start

[Refik_rookie]

Hi all, recently i had trouble woth my '89 w124. In the morning, it could start like normal. After running the engine for some time, i cannot immediately start the engine. Like if i were to refuel, off engine, refuel, start engine. But cannot start. Can crank but cannot start. I will leave the car for an hour or 2 then can start.

Any reason y? Or any solution?

[keltanky]

Starter replace?? Battery new?

[keltanky]

Wait wait fuel pump??

[Ricebandit]

Sounds like you have a hot start issue, a result of fuel vaporising in the lines after the car has warmed up for a while and then shut down.

 

The cause is likely one of a couple of items related to maintaining fuel system pressure after shut down. 

 

Assuming that in the morning, the car starts normally, fast idles (around 1000rpm) then after warming up drops to around 700rpm, and that your idle is smooth as well as your acceleration (especially when overtaking), the fault is most likely the fuel pressure accumulator.

 

To test:

1) when car is cold, turn ignition key till all the warning lights on the instrument cluster illuminate, but do NOT start the car. You should also hear a light buzz coming from the rear of the car on the driver's side for about 1sec. (this is the fuel pump priming the system)

 

2) turn the ignition key off, and pop the bonnet.

 

3) look for the fuel pressure regulator it looks like this (the brass coloured cylinder with the curved pipe coming out the top)  grab a 17mm spanner.

 

4) Wait 15 mins, then loosen the fuel line leading to the fuel pressure regulator. Make sure you have a rag around it to catch the fuel spill. 

 

5) If fuel sprays out after loosening the line slightly, then the accumulator is OK. if it just dribbles out, then you need a new accumulator. You shouldn't lose more than a few ml of petrol. Make sure that you retighten the line properly and wipe the area dry. 

 

6) Start the car, and check for leaks from the fuel line that you just tested. If no leak, you can close up and drive to get the accumulator replaced. 

 

happy driving!

[keltanky]

Bro, he needs to remove the Air Filter set lei.. not easy to access

[Refik_rookie]

Yah. Need to remove. I will give it a try later once i getback from work. Battery is still live. Cause can still crank mah. Fuel pump need to check. How to go about it?

[Phang]

I bet my money on a failing crankshaft position sensor

[Ricebandit]

Bro, he needs to remove the Air Filter set lei.. not easy to access

i think its 4 10mm nuts, then just pull the breather hose off, and the whole air filter assembly can pop off. 

 

 

Yah. Need to remove. I will give it a try later once i getback from work. Battery is still live. Cause can still crank mah. Fuel pump need to check. How to go about it?

Turn the key to ignition on, you should hear a buzz for about 1 second. Usually it's pretty faint sounding, keep the door open, and you'll hear it from the rear right wheel area. If no sound, then the pump is shot.

[Refik_rookie]

Got it repaired. The pump is gone. Had to replace it. The rest was fine. Thanks for the help.

The soft buzzing sound is often heard. Will it not buzz as time goes by?

[Ricebandit]

The system turns the pumps on for 1 second when the key is turned to the on position. This pressurises the fuel system in preparation for start. After the engine has start, the fuel pump will run continuously.