Hey there,
I've got a Volvo 850 from 96 and it cranks like it could tik over at any point but never starts,
Tried replacing the cam sensor and ignition coil but the car refuses to get spark, ignition coil is getting power and works but the car just isn't producing spark,
The fuel line works fine and it's delivering it fine,
I'm honestly stumped,
Any insight would be brilliant,

Many thanks.

 

These things have a systemic problem that the "main fuel injection relay" becomes unplugged. It has a plug that has some clear vinyl parts inside. These parts rot away and at some point, you'll unplug. On a 96 this relay is right on top of the radiator fan. No spark is a symptom. The relay powers all the fuel injectors but it also powers a few pins on the engine computer which causes no spark. I think another symptom is that the OBDII diagnostic plug doesn't communicate, but don't quote me.

Keep in mind here this is not a "buy an auto part" situation. figure out if you're unplugged here first. If it turns out you are unplugged, you can make something, or you can find the guts of that plug on davebarton.com and fix the plug back like it was.

Here is the right style, but I never knew whether he offers the exact plug. The guts certainly look right:
Volvo Harness Parts

 

Yeah funnily enough the OBD II port doesn't communicate at all,
Will definitely give that repay and plug a check and see,
Any other ideas aside from this just so I can get a list of some sort and just go through a further checklist,

Many thanks!

 

I'm going to assume I figured it out in one shot, ha ha.

 

It's a strange one, the relay in question is so hard to replace because I don't know who had it before but the relay on it doesn't have the probes coming out of the relay they are on the wiring,

Every other one I've seen has the probes coming out of the relay so I'm quite stumped,

Any ideas ?

 

Replaced the relay that we spoke about and the car almost started but not quite,

I'm thinking possibly the crankshaft position sensor next ?
That or possible the ECU but i really hope it's not an ECU problem

 

ECU issues are rare. Start with the basics - fuel, spark, compression. If you pop out an injector and crank do you see fuel spritz out? How old are the plug wires (look for a date code on the wire). If they are over 5 years, replace. Consider doing a stage 0 tune up - wires, plugs, cap rotor. Use OEM or good old copper core plugs and gap at .028". You can also use a noid light to see if you are getting spark. Dunno if the crank sensor is even in play on a 96 but here's a link on how to test:

https://www.matthewsvolvosite.com/fo...ic.php?t=58548

Last is to test fuel pressure. use the shrader valve on the end of the fuel rail for a gauge. Should be 39 PSI give or take. RobertDIY has as vid for this. If you don't get over 25, try jumpering the fuel pump relay (worn pumps can draw too much current which kills the relay or slow down). Also consider replacing the fuel filter....

post up how you make out,

 

Update,

So cleaned up some of the manifolds and grounds and the OBDII started working, not got an Autel on it yet however replaced the distributor cap and the rotor arm and the cars getting spark,

My father came round and while we were playing around with it we popped out the injectors to look at them and none of the Injectors are opening up, checked the power prongs that go onto them and they are sending power to the Injectors so the fault is with the injectors,

An injector popped off when cranking the car and as soon as a drop of fuel went into a cylinder the car fired straight away without an issue,

Any ideas on how to free up the injectors or repair them ?

Many thanks.

 

Sounds like you are making progress, but it seems unlikely that all of the injectors would fail at the same time. Have you been able to test the fuel pressure yet?

 

Hi there,

Haven't tested the fuel pressure yet but can say for certain it's at least 35 PSI,

The car has been of the road and not started for 6 years so for me anything is entirely possible,

The only thing is I don't know much with injectors so any advice on cleaning them out or so would be amazing,

I've been thinking that with the car sitting for as long as it has that the old stale fuel that was in it could have clogged the Injectors, thoughts ?

Cheers

 

I have never tried it (or needed to), but I see several tutorials on cleaning the fuel injectors after removing them. I agree with you that it's possible all of them are gunked up after sitting for six years. Here's a link to one: . It's not for a Volvo, but the process should be similar. There's a tutorial on SwedeSpeed that might work: Fuel injector diy cleaning | SwedeSpeed - Volvo Performance Forum.

Let us know what you find. You could try it on just one and see if you get a good squirt of fuel.

 

Update,

So I got all 5 injectors off and got cleaner for them, hooked and old speaker cable up to open them while spraying the cleaner through them and at first it was going through them like a tap and then it slowly turned into a nice spray,

Got them all back on and hooked the speaker cable up and get the tick to open them up when the speaker cable goes on them but when I hook them back to the car they don't tik to open so I'm thinking maybe a dirty or bad ground somewhere that's stopping the ECU from sending the signal to open them in that pulse that it's supposed to do ?

Started cleaning the easy to access grounds and then cranked it and it fired and then cut out so it's not opening all of the Injectors so need to get to the other grounds,

Started taking the intake manifold off but need to see what else I need to get it off and then get the grounds there.

 

Kirikier, I'm impressed with how methodical you are! Taking off the intake manifold is quite easy, but you should probably buy a new gasket before putting everything back together. If memory serves me correctly, you just need to loosen the bottom set of bolts, and the manifold comes up and off.

Thank you for keeping us up to date.

 

Just in case - I have a set of used Bosch orange injectors from an 850 I can send you (free to a good home lol), PM me your address if interested and I'll mail them over.

 

Kirikier, did you ever resolve your problems? I would be great if you could post your solution.

 

Hi there sorry I've been busy but here you go,

UPDATE

I managed to get a lend of two working ecus from a car I know worked, it was the same model and year and it changed nothing so I put the old ones back in,

Kept cleaning up the grounds and might I say no one talks about how difficult the grounds are to find using only the schematics for them but anyhow,

I tried jumping the alarm system relay 210-211 and the jump itself was successful but it did not change anything either so the relay there still functions as it should,

I pulled the dipstick and had a good ol' sniff at the oil on it and it stinks of petrol on the dipstick so someone suggested it could be lawnmower syndrome and so I tried the resolution for that,

Took all the spark plugs out put a little oil down each cylinder head let the plugs dry out and then cranked the car for two minutes and it didn't start just a massive white cloud out of the back of the car lol,

I need to get a lend of a compressor tester and go from there but I'm running out of ideas

 

Oh and side note the front electric windows weren't working but I tested the motors on them and they functioned so got the centre console taken apart below the handbrake and it turned out the previous mechanic had unplugged the plug for them so plugged that back in and replaced the fuse and the windows started working,

Small victories lol

 

Glad to hear you're still working on it. If you had a cloud of smoke after putting oil in each cylinder, the plugs must be firing. Have you looked at the plugs after cranking a bit to see if they are wet with gas? After all of your testing and cranking, IF you are getting gas into the cylinders, you could have easily fouled the oil with unburnt gas (and washed down the cylinder walls). If and when you do get it started and running consistently, make sure you change the oil promptly. Good luck!

 

UPDATE:

So I got the car on ramps and got under it to try and find some of them nasty grounds and found one under the intake manifold so got that cleaned up,

Drained the oil and replaced the oil filter then oil as well as replaced the fuel filter,

I can't seem to find some of the grounds and I'm still getting no injector pulse,

Not really sure what else could prevent the injectors from getting pulse but as of now it's still a non starter,

Thinking about checking the timing and seeing if that's all in order as it's starting to sound like a missfire,

I would upload videos to display what I'm talking about but the website doesn't allow me to upload videos from my own device, I apologise in that regard.

 

Just in case - I have a set of used Bosch orange injectors from an 850 I can send you (free to a good home lol), PM me your address if interested and I'll mail them over.