EML

[Deleted member 138290]

I haven’t given my car a proper blast for ages as it goes well enough but for ages now ever since a 2nd tweek remap I get EML saying fuel presssure too low.... anyway just took my daughter home and on way back decided to pull over and do a standing start, so foot to floor and away but I’ve discovered the EML light comes up when I get to 3rd gear (5 speed semi) and the black smoke from the back is unmissable.... but I’m sure it’s nothing to do with the remap as the 1st (custom remap) there was never any issues...... 2nd tweek remap was with hybrid turbo and c30amg injectors..... any ideas please ? Must mention that 2nd tweek I drive all the way back from Newquay no problem and, for a few months after so no idea what’s causing it ??

 

[Teego]

Try an Italian tune up. 30 miles above 3000rpm.

 

[Deleted member 138290]

Never heard of that ? I gather 3rd/4th gear constant for 30 miles ?

 

[Deleted member 149005]

Remove the 2nd tweek remap and start again

 

[Teego]

Never heard of that ? I gather 3rd/4th gear constant for 30 miles ?

Yes, it can work. Cleaned ours out a couple of times. Need to get heat into the exhaust system. Always do a mini version of this en route to MoT with our diesel or petrol cars.

 

[markjay]

I would also recommend dropping a bottle of injector cleaner into the tank just before the 'Italian tune-up'. While you're at it.....

 

[Deleted member 138290]

Ok thanks for all the advice !

 

[Deleted member 138290]

So been looking over an annoying clicking from an injector and did the leak spray test and turns out the injector nearest the rad was leaking..... gave another good clean and dropped in a new washer/ seal and issue seems solved but will find out tomorrow am when I go shopping lol.... hopefully no EML !

 

[Deleted member 138290]

So I gave the merc some kick earlier when an f10 m5 decided to have a go.... EML yet again... only this time none of the injectors are leaking ?? Same error code too (fuel pressure too low)

 

[Chugg]

Hi mate. Could it be a bad fuel pressure sensor, or fuel pump becoming lazy? Have you tried getting any live info of the code reader when driving to see if everything in the fuelling system is performing within the correct parameters? Or blockage in fuel line or injector?
Maybe the stock fuel pump even if working fine can’t deliver enough fuel to meet the demand of the new state of tune. This used to be common when tuning to upgrade to higher capacity fuel pump and regulator/accumulator if required.

 

[Deleted member 138290]

Hi, well a mechanic did mention the in tank pump maybe the issue and I have got a spare and a 420 cdi HP pump but that isn’t a straight fit... no I haven’t tried reading the values on the code reader whilst driving but ideally could with a passenger who can understand the figures but then I’m only novice/ mainly self taught... as for a pressure regulator, can you recommend an upgrade ? Cheers

 

[Deleted member 138290]

Actually I might be lucky and have a pressure sensor as I came across a full ml 420 cdi fuel set with rails, pipes, hoses, HP pump and several other parts so I will go and have a look !

 

[Deleted member 138290]

Lol well after finding to sensors I’ve fitted them and now my car won’t start so put the originals back and still won’t start ?? I’ve changed both sensors in the past but never had car not start ?? Seems like there’s no fuel getting pumped thru the system tho the in tank pump buzzes ?? I’ve got a funny feeling car wasn’t going to start today at all but, can’t figure it out ?? Pump Fuse is ok too !

 

[Chugg]

Sounds like bad luck mate! I’ve not done any upgrades to my current car (first merc and a diesel estate so never going to be a sports car!) I’m afraid and not familiar with your model, so not sure of a pump or regulator upgrade. But Wallbro used to be a manufacture of choice for high capacity fuelling stuff. Anyway, yours might be fine, sounds like a case of code reading and tracing power back from pump etc. kind of investigation.
Good luck bud

edit: just read properly you said pump buzzes, so presumably has power and moving, whether at full capacity is another thing. I’d check and recheck what you’ve done with the sensors for now, and check everything around you may have moved or dislodged, or cracked a brittle wire or something. Could be a pain

 

[Chugg]

Could check in fuel rail too if fuels reaching there while cranking.

 

[Deleted member 138290]

Well I’m now not sure if pump is buzzing or not and I decided to remove the injectors to find they were all flooded ?? Wondering if the relay has blown but can’t remember how to check the rear SAM with my multi meter lol... bit of cable from battery to power and see if it fires up

 

[Deleted member 138290]

Putting a wire from batt to relay pin and pump buzzes but still won’t start, just turns over ?? Checked wiring a both sensor plugs and one was split but sorted that and still no start ??

 

[Chugg]

Sounds like you have fuel, so no spark/ignition somehow. Could be lots of things really; the sensors mentioned, crank sensor and the like? There’s a gremlin somewhere. Guessing compression’s good.

 

[Deleted member 138290]

Well not exactly sure what happened but I ended rewiring the pressure sensor on the front end of the fuel rail, putting the original sensors back on and putting the original injectors back in and she’s back up and running..... IF I get EML tomorrow when I nip to town then I will be investigating the in- tank fuel pump next...

 

[Chugg]

That’s good, at least you’re up and running, and if it’s OK now you’ll know it’s one of those things that’s the culprit