Please Assist. W638 108CDI Cannot restart engine when hot or warm.

[mushr00m]

I have checked through the forum but I am not seeing the W638 vans.

Changed the Thermostat 3 weeks ago. Low temp forced me to change thermo. Cured that problem. Now, everythime the van engine gets to 80 -90 and of occassion 100. The van stops completely. Leave for 1.5 hours and sometimes restarts. If not wait till morning and all is fine. We did have a flash of EDC on the dash. But never returned. I dont have a MBSD. So cant check. Noone around within 200 miles has one. Changed fuel filter 1 week ago and no difference. Removed Feed pipe to the fuel filter, cranked engine over to check for fuel. Nothing. Tried sucking on fuel pipe to draw fuel, Nothing or just very very small amounts. Do I assume fuel pump is shafted HP or just the feed pump.???? or can it be at most the CPS which I am unable to find and images at not helping on duckduckgo. If you have possible answers could you help with images please. Its -10 where I am and the 2 hour trek home was not pleasant. Thank you.

 

[mushr00m]

Forgot to mention. It only break down when I have come to t a stop and waiting for anywhere from 30 seconds to 5 mins, then it stalls.

 

[AMGeed]

It does sound as though you have the symptoms of a failing CPS sensor. It will get progressively worse if it is.
Ideally it needs to be diagnosed by Mercedes Star equipment.
On UK vehicles, the CPS sensor is normally located on the nearside right at the back by the bulkhead and on top of the gearbox.

I'm not familiar with your Vito, but this website will help you locate the sensor. Just check you have the correct engine which you can check from the data card.

Mercedes FG 638 > Mercedes EPC Online > nemigaparts.com

Parts catalogs. Spare parts catalog Mercedes EPC Online. Mercedes. Van. FG 638.

nemigaparts.com

This site will give you your engine code and full data card if you input your full 17 digit Vin#

Mercedes VIN Decoder | Decode Your Mercedes-Benz VIN

Want to know the specifications of your Mercedes? No problem! Our free Mercedes VIN decoder retrieves detailed information about your Mercedes-Benz vehicle.

www.lastvin.com

 

[mushr00m]

on top of the gearbox is the reverse switch. this was replaced many years ago. Tomorrow I will check this area. behind the engine around the gearbox area. Wife went back to the van and did not start 2 hours later. Yes it is getting worse.

 

[mushr00m]

It does sound as though you have the symptoms of a failing CPS sensor. It will get progressively worse if it is.
Ideally it needs to be diagnosed by Mercedes Star equipment.
On UK vehicles, the CPS sensor is normally located on the nearside right at the back by the bulkhead and on top of the gearbox.

I'm not familiar with your Vito, but this website will help you locate the sensor. Just check you have the correct engine which you can check from the data card.

Mercedes FG 638 > Mercedes EPC Online > nemigaparts.com

Parts catalogs. Spare parts catalog Mercedes EPC Online. Mercedes. Van. FG 638.

nemigaparts.com

This site will give you your engine code and full data card if you input your full 17 digit Vin#

Mercedes VIN Decoder | Decode Your Mercedes-Benz VIN

Want to know the specifications of your Mercedes? No problem! Our free Mercedes VIN decoder retrieves detailed information about your Mercedes-Benz vehicle.

www.lastvin.com

Okay, went to the van today. Refuses to start. I can suck the fuel to the filter. When trying to start teh van, the rev needle bounces slightly. I get no bounce on the speedo. Tomorrow, I will order both Cam and crank sensors. Van is 20 years old. If still no joy, then I will pull apart the injector wires and see if theres any damages. Thank you bud.

 

[AMGeed]

Okay, went to the van today. Refuses to start. I can suck the fuel to the filter. When trying to start teh van, the rev needle bounces slightly. I get no bounce on the speedo. Tomorrow, I will order both Cam and crank sensors. Van is 20 years old. If still no joy, then I will pull apart the injector wires and see if theres any damages. Thank you bud.

I would have the problem diagnosed before ordering parts for it. You may be spending money unnecessarily,
It's only my opinion that the CPS could be at fault due to it previously restarting when cooled down but really needs investigation before changing parts.

 

[mushr00m]

well i had to tow the van for 1/2 mile before it caught a rolling start. I sucked fuel upto the filter tried starting it for 2 mins and nothing. The drag bump start worked. Got it home. removed the CPS and the oring is fairly hard and feels old. So repping the sensor regardless along with crank version. However the crank version will not come out at all. Pliers fails, flat head screw driver fails. Pliers and flat head twisting gently fails. Think someone has been digging on this sensor before. Check all pipes. Full of diesel. No sign of leaks at all. New filter. so walking to shop to get part that is on order. Will let you know later. However pls comment on that crank sensor. Seems alittle iffy to me. Curious, sweet black merc you have. How much are they nowadays.???

 

[mushr00m]

I would have the problem diagnosed before ordering parts for it. You may be spending money unnecessarily,
It's only my opinion that the CPS could be at fault due to it previously restarting when cooled down but really needs investigation before changing parts.

Okay changed the Cam sensor. I a m not gonna say its fixed yet. However if you do not hear from me. Assume its fixed. However, we did tow start the car but that was a long pull to get it going. I cannot change the crank sensor as it seems completely wedged tight. Not sure how to remove it without breaking it.

 

[mushr00m]

thank you for your assistance, i will keep you updated if someone else fails. However, do you know of anyone selling a MBSD...????

 

[mushr00m]

Okay it stalled on tick over after 10 mins. I can say I hear what sounds like bearing grinding. It is rather loud but then dies away after 5 mins. I cannot pin point where its coming from. Either Water pump, Fuel pump, tensioner or steering pump. Jesus the van is giving me a battering without a diagnostics system.

 

[mushr00m]

I can also say and i forgot to mention. Upon inspecting the crank sensor. I used a flat head scred driver and slowly wedged it underneath. I can see it is cracked where the BOLT TAB joins the main sensor. Yet I cannot pull it out at all. However I do have a new one ready to fit but cant ge the old one out. Do you have any ideas.? please.

 

[Stratman]

Just a wild guess, but perhaps a previous owner broke the mounting tab and glued it in place. In which case, good luck removing it.

 

[grober]

T1N 901 903 Sprinter reference material

diysprinter.co.uk

 

[grober]

TRY USING PLUS GAS RELEASING AGENT OVERNIGHT THEN TAPPING OR VIBRATING THE SENSOR AND TRY ROTATING IT AT THE SAME TIME RATHER THAN PULLING OR LEVERING IT OUT- GETTING IT ROTATING IN THE HOLE AND IT WILL COME OUT

Dismantling Lubricant Spray- 400ml 07660704894 PLUS GAS

Lubricant to aid screw and bolt assembly Cleans grease build-up and leaves protective film Reduces squeaks and rattles on machinery Helps prevent re-seizing of treated parts

www.diycarserviceparts.co.uk

OR THERES THIS HOME MADE 50/50 ATF/ACETONE MIX ----MAY MELT THE PLASTIC MIND

Releasing agent better than WD40 etc... - Mustang Owners Club of Great Britain

I just copied this off of one of the American forums I am a member of. I know a lot of the products mentioned aren't available here but it does sound like useful info all the same... Machinist's Workshop Mag published some information on various penetrating oils that I found very interesting...

www.mocgb.net

 

[mushr00m]

I have tried to twist it off and that is impossble. The holder twists so hard I have broken a very small part of the upper plastic where the clip joins on. However does not impacts it operation. Just how it clips together. I have acetone somewhere, this i can try. However, I may try turning it again. Remove the tab then i should have a thick piece of plastic to bite on to.

 

[mushr00m]

Keeping you all updated. Replacedx CAM sensor, finally removed the barsteward of a crank sensor. After 6 hour operation in -7. Found my fuel pipe from Filter to fuel feed assembly unit has failed. Ordered a new one. Broken clip on the pipe but oring is still good.

 

[AMGeed]

Looks like you found the source of your problem

 

[mushr00m]

No its not the main issue. The crank sensor had been glued into the cylinder block, which was original broken by the look of things. I found the magnet inside to be broken into three pieces. However, yes as it stands, the van runs just fine on tick over for 20+ mins. This has been tested 3 times now and I am yet to still replace the broken fuel line. Once i replace the fuel line then i can test drive the van.

I have to ask, is it common for the fuel pumps to fail on the vans or are they mostly bullet proof.??? Getting some really weird noises. Last about 5 - 10 mins and sounds like marbles.

 

[BlackC55]

They do wear out. You are going to be throwing parts at it if you cant get it plugged in. It sounds like the fuel pressure is dropping off. Can you do a leak off check of the injectors?

 

[mushr00m]

They do wear out. You are going to be throwing parts at it if you cant get it plugged in. It sounds like the fuel pressure is dropping off. Can you do a leak off check of the injectors?

okay. after 6 hours torture with the fuel line. Everything went back together.

Notices of visual inspection. Pulled of the delivery pump where the main pipe had to be replaced. Notice that the drive assembly is very very sloppy. major movements in and out by push and pull and major side to side movement. is this natural..??? picture enclosed. Anyways, cleaned all around the main pump and cleaned the pictured unit too. Put everything back together along with new fuel pipe leading to filter.

All is good. Started van and start very well. Ran it for 1 hour last night and went shopping and no major issues all but the Performance. Seems to have dropped a few ponys. Just lost a little of its get and up go factor. Maybe its just me. 0 air bubbles, All pipes connected. Lost 24 hours due to investigations and in this lost time was working hours of 12 hours replacing the dam crank sensor and CAM sensor also the fuel pipe.
Mercedes knows how to annoy there mechanics for dam sure.

I will do a leak off test soon but its - 15 now and covered in snow. So will have to wait for a while. On this subject, I know i need a rebuilt turbo, just wondering for now BUT!!! has anyone upgraded their intercooler on this said version of van...?