rancherprice

Went out after school to go home and my 2002 ML-320 cracked over but would not start. I have checked out the spark, fuel pressure, injectors, timing and compression. All good. Replaced the crankshaft position sensor, pulled the valve covers and checked the timing chain, all good. Any ideas?

Maj. Dundee

If the CEL is not illuminated, then it is a fuel issue, probably the pump.

rancherprice

i checked the fuel pressure at the connection on the engine and it was ~30 psi.

Maj. Dundee

And what is the pressure while cranking the engine?

rancherprice

The engine won't crank because I think I have too much disconnected. But when I turn the key on the pressure comes up to 48 psi. After 30 min with the key off it came down to 32 psi. The starting pressure is high enough that it should atleat try to start isn't it?

Maj. Dundee

Are you getting a message in the odometer window saying, START ERROR?

rancherprice

No START ERROR.

Maj. Dundee

I don't know what you have removed, as you said earlier, but with a fully charged battery, crank the eng. and at the same time look at the Tachometer and see if the needle bounces to approx. 200 RPMs.

If it doesn't then it is a faulty Crank. Position Sensor.

rancherprice

CPS is OK. Tach comes up to 200 while cranking.

Maj. Dundee

Turn the key to pos. #2 and check for 12v on both contacts at fuse #19.

Maj. Dundee

Is the Check Eng. Light on?

Turn the key to pos. #2, and do all the Telltale Lights illuminate, especially the CEL?

Then wait about 5 secs., is the CEL on?

rancherprice

All of the tell tale lights come on including the CEL. Only the air bag and SRS lights go of after 5 sec.

rancherprice

When I pull the fuse, I get 3.8 V on the front leg and 12.4 V on the rear leg.

Maj. Dundee

The fuse is blown. Replace it, but understand that fuses blow because of an existing problem.

rancherprice

the fuse is ok. Those readings were with the fuse pulled out. With the fuse in I get 12 V on both sides.

Maj. Dundee

Does the eng. still turn over?

Is everything back in place?

If so, turn the key to pos. #2 and while doing so watch the RED LED light. Does it quickly blink once?

rancherprice

YES, it blinks one time.

Maj. Dundee

I should of thought of this earlier. Turn the key to pos. #2 & check fuse #26 for 12v.

rancherprice

Fuse is good. 12V both sides.

Maj. Dundee

Does the eng. still turn over? Hopefully you didn't run the battery down.

rancherprice

Engine does still turn over. Do you have instructions for how to check the timing chain? I have the valve covers off and need to know what marks I am checking on the crank and cams.

Maj. Dundee

You are barking up the wrong tree with the timing chain. Are you absolutely positive you are getting enough fuel pressure?

rancherprice

I just put the fuel pressure tester on again and it came right up to 50 psi when I turned the key on. Bounced around right there while I cranked it.

Maj. Dundee

Remove both top covers to the fuse relay box, turn the key to pos. #2 and probe the cir. #15 stud for 12v.

Also do the same to the cir. 15 stud at the right side fuse panel.