W124/M104 stalls in reverse, idle and while driving

[Celicasaur]

Hey folks, so out of nowhere my car has started to play up...first time in 4 years (granted I've only covered around 4k miles in that time also)

It was recently having a slow and progressive misfire that I could hear which was oil-fouled plugs. Something sorted with a new set of rocker cover seals. However out of the blue it one day (2 weeks ago) just started stalling almost immediately when put into reverse. If I let it idle for long enough, it'll cut out also. Worst of all it also cuts out when driving (frequently too).

I replaced the OVP this weekend (and the rocker cover seals/spark plug seals) but it hasn't made any improvement to the symptoms. FYI I replaced the engine harness with a new MB unit 3 years ago (and less than 3k miles at that) so I doubt the loom would be an issue. Oh, I of course re-gapped the plugs and checked the coil packs for cracks etc. Spark/misfires don't appear to be the problem here. It runs smooth when it does decide to run.

Any other suggestions? Dare I say it, I almost 'miss' driving this boring car.

 

[219]

I'd take it for a good run on some fast A roads . Sometimes an 'Italian Tune Up' works wonders - take the car out and give it a thrill , then see if it improves .

Lack of use can cause all sorts of problems , and if the car has sat the lest few months , it may just need a good run . It costs nothing but fuel to try .

 

[Celicasaur]

Ahhh, yeah no, it cuts out while driving and even on the throttle too.....sometimes even bucks back and fourth while coasting at idle rpm in gear...very confused and haven't got a lot of understanding of this engine. Only saw on the weekend that it has VVTi.

 

[Petrol Pete]

Sound's like it needs it's codes reading.

 

[optimusprime]

May need new ht system parts if revs are low it will stop when you select the gear

 

[Will]

Have you checked the fuelling side of things?

 

[Celicasaur]

I'd like to check fuelling, but I've spent hours trying to search for the right thread pitch for the port on the motor so that I can attach a fuel pressure gauge...does anybody know what it is?

 

[Celicasaur]

so i finally pulled my finger out and plugged in my fuel pressure gauge that I bought from eBay.

Before I did that though, i checked the fuse box and #7 was melted....worrying in itself. The fuse metal hadn't broken, but the overall size of the fuse had shrunk, meaning the metal contacts of the fuse box weren't touching it. I replaced the fuse and so far on my drive way moving back and fourth it seems OK now (used to instantly stall before). I'll have to investigate the melting issue another time.

Fuel pressure ....58psi with engine running and 48 psi when I remove the vacuum line to the pressure regulator. Hmmm....any thoughts? For what its worth, I can't smell any fuel in that vacuum line.

So eith the

 

[219]

The issue with continental fuses is well known , they corrode at the ends , this causes a high resistance and burning results .

Change all the fuses periodically for reliability, and when you’re doing it , clean up the contacts in the fuse box .

Here’s a video on the subject

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[Celicasaur]

Thank you Mr Pontoneer.

Ahhh....see i was nervous thinking that something is roasting itself internal, causing the fuse to melt. If it's just a case of general cause, then I won't panic too much just yet.

I've been driving it for a few days since the fuse swap and it's totally fine like before now. Never thought s fuse would cause such havoc. At least it made me check my fuel pressure though. Nice to know the pump and regulator are in good standing.

Now I just need to work out why my heater fan fuse keeps blowing....ahem....i'll never sell the car at this rate

 

[Will]

What does fuse #7 relate to on your model?

 

[219]

Thank you Mr Pontoneer.

Ahhh....see i was nervous thinking that something is roasting itself internal, causing the fuse to melt. If it's just a case of general cause, then I won't panic too much just yet.

I've been driving it for a few days since the fuse swap and it's totally fine like before now. Never thought s fuse would cause such havoc. At least it made me check my fuel pressure though. Nice to know the pump and regulator are in good standing.

Now I just need to work out why my heater fan fuse keeps blowing....ahem....i'll never sell the car at this rate

The heater fan fuse blowing is another known issue .

The fan motor bearings are seizing up and causing the motor to pull too much current .

You need to strip away the plastic covers to get at the motor and use some spray lubricant ( silicone works well ) and spray the motor bearings until it runs free . Sometimes you have to take the motor out to dismantle it , clean and lubricate the bearings. It will be stiff to turn by hand before you start . This is the result of the small amount of water that is drawn in along with fresh air .

A good lube job is normally good for a couple of years before doing again . It is a very common issue .

 

[Celicasaur]

The heater fan fuse blowing is another known issue .

The fan motor bearings are seizing up and causing the motor to pull too much current .

You need to strip away the plastic covers to get at the motor and use some spray lubricant ( silicone works well ) and spray the motor bearings until it runs free . Sometimes you have to take the motor out to dismantle it , clean and lubricate the bearings. It will be stiff to turn by hand before you start . This is the result of the small amount of water that is drawn in along with fresh air .

A good lube job is normally good for a couple of years before doing again . It is a very common issue .

Thank you, that's a lovely reply sir.

My only issue here is that I've taken the blower out and inspected it already and it appears fine. I also tried a couple of blower motors from breakers yards and they also did the same thing - blowing the fuse after about....30 seconds or so of operation. Kinda stumped with that one. I'm not too great with motor electrical systems.

 

[219]

Thank you, that's a lovely reply sir.

My only issue here is that I've taken the blower out and inspected it already and it appears fine. I also tried a couple of blower motors from breakers yards and they also did the same thing - blowing the fuse after about....30 seconds or so of operation. Kinda stumped with that one. I'm not too great with motor electrical systems.

Are all these motors turning freely by hand - there should be no stiffness at all , in fact you should be able to spin them and let them spin freely for a good few seconds , with air resistance against the squirrel cage being the main thing to slow them down . What I've done , when I had them out of the car , was to connect a battery and spray oil right into the bearings while they were running , it's amazing what a difference it makes .

Chances are , used blower motors from breakers yards are little better than your original one and already stiff to turn .

The only other thing that sometimes goes wrong , but rarely , is the resistor pack which gives the different speeds - follow the cable from the motor back and it goes to this box ( metallic box which is full of what look like springs but are actually different resistive elements ) some call it the 'flux capacitor' haha ! These can sometimes fail .