850r wont start help please

[oubalie]

Morning to everyone
please can some one help me my 97 850r has cut out with me yesterday after driving through water which happened early hours of the morning in rainy wheather. car was spluttering abit but came right after a few kms then drove it about 5kms and cut out .the following day i dried all the electrical connectors ,distributor and still no start ,battery was going flat rather quickly so removed it and charged it up fully overnight then went onto internet to see how to check cranshaft and camshaft sensors to find out that i never had 12volts on pin 3 on the camshaft sensor and that is why i dont have spark on lug leads .now is this the ecu that could be damaged and can i hotwire from 12v+ to pin 3 on camshaft sensor please?.i have fuel pressure aswel just no spark from coil to plug leads .
THANKS ANY HELP APPRECIATED
Anthony

[LeeT5]

You drove through water!! So it must be something to do with water ingress.

Check all plugs and connections for water ingress and clean and dry them. Check your airfilter is not wet too. If it is, replace and dry out the MAF.

[Dangerous Dave]

How deep did the water get?

[oubalie]

hi thanks for replies water was more of a splash and id say about chassis height ,i did remove all the wire connection and sprayed wurth electrical cleaner on them and then blew it with compressed air same with all sensors and filterbox which was dry
thanks anthony

[MoleT-5R]

hi thanks for replies water was more of a splash and id say about chassis height ,i did remove all the wire connection and sprayed wurth electrical cleaner on them and then blew it with compressed air same with all sensors and filterbox which was dry
thanks anthony

did it start, after treatment..??

[LeeT5]

did it start, after treatment..??

This is going to be painful! :doh:


If the Air box and filter was dry, then the cause of your problem is unlikely to be water. Most likely just a coincidence.
Sounds to me like your just going to have to start your diagnosis 'methodically' to acertain the cause. Although, your symptoms do sounds like Fuel pressure sensor failure!

First of all, if the engine cranks but you have no spark at the plugs/HT you need to work back and check that you have 12v and switching live at the coil. If you have 12v but no switching signal, then suspect the crank sensor.
You also need to check for 12v AND 5v at the MAF. If you have 5v then your ECU or ECM (Engine Control Unit / Engine Control Module) is powered up and live or working! If you do not have 5v then you need to check ALL the fuses and the integrity of the ECM and it's fixing. Make sure it's not come dislodged.

It's a good idea to check all the fuses anyway but try and do it without pulling them all out one by one. This is not good practise.
Use a multi-meter and have the ignition ON and check for 12v across each side of a fuse. It should be either 12v across both sides of the fuse if circuit is live or Earth across both sides of fuse if circuit is not live. Obviously, 12v on one side and earth the other, means the fuse has blown ;)

Also, when your ignition is on you can also check fuel pressure, or at least, that the fuel pump is running. Depress the shraeder valve and see if you have good fule pressure continuously running.

See how you get on :wave23d:

[Dangerous Dave]

This is going to be painful! :doh:


If the Air box and filter was dry, then the cause of your problem is unlikely to be water. Most likely just a coincidence.
Sounds to me like your just going to have to start your diagnosis 'methodically' to acertain the cause. Although, your symptoms do sounds like Fuel pressure sensor failure!

First of all, if the engine cranks but you have no spark at the plugs/HT you need to work back and check that you have 12v and switching live at the coil. If you have 12v but no switching signal, then suspect the crank sensor.
You also need to check for 12v AND 5v at the MAF. If you have 5v then your ECU or ECM (Engine Control Unit / Engine Control Module) is powered up and live or working! If you do not have 5v then you need to check ALL the fuses and the integrity of the ECM and it's fixing. Make sure it's not come dislodged.

It's a good idea to check all the fuses anyway but try and do it without pulling them all out one by one. This is not good practise.
Use a multi-meter and have the ignition ON and check for 12v across each side of a fuse. It should be either 12v across both sides of the fuse if circuit is live or Earth across both sides of fuse if circuit is not live. Obviously, 12v on one side and earth the other, means the fuse has blown ;)

Also, when your ignition is on you can also check fuel pressure, or at least, that the fuel pump is running. Depress the shraeder valve and see if you have good fule pressure continuously running.

See how you get on :wave23d:

Sound advice as always Lee :D

Though I didn't think there was a fuel pressure sensor on the 850R?

[LeeT5]

Me neither, but one look at the fuel rail will confirm that!

[oubalie]

Hi all sorry for late reply but with work and all with rain and cold weather i started from scratch and eventually found a wire had burnt off in the harness after repairing it i found 4 earth wires that had 12v on them repaired that problem under the dash aswell. Now i think that my ecu might of blowen also so will take it in to ecu repairers and let them check it out .i was on ebay looking for a ecu for a 850r but no luck and i read on this forum that theirs is a specific parts no mine has a motronic 4.3 module fitted ,i found one that has been modified to 4.4 but dont know if it will work the seller says that it will but that it has to be remapped to my car .i dont know so will leave it alone can i fit a dastek chip to it without a ecu ?(im not to clued up on that side of electronics

[oubalie]

well after almost a month at volvo agent they found 1short in harness in engine bay and 3 shorts under dashboard also the ecu has blown .Now to find a ecu in south africa will be fitting a t5r ecu in the mean time .will get car back tomorrow .thanks for all the advise and help will keep you informed