im working on a 95 850 that quit and wont start.
has spark
has fuel at the rail
turns over smooth
took off the timing cover, belt looks good, tension good.

it seems to me like the injectors arent firing. theres a constant 12v at the injectors, nothing chanages while cranking. im not familiar with these engines but it seem like there should be a pulse at the injector not a constant. im scratching my head here, any help is appreciated guys.

thanks
jamie

 

if you get fuel at the rail, do you check for the pressure?it could be low pressure,who knows. you might also want to check the fuel pump relay.

 

i couldnt find any relays, where are they located?

 

it is located right next to the fuse box.here is a link to show you the location.

http://www.matthewsvolvosite.com/for...pic.php?t=9681

also a video of it.gives you more insight



check for fuel pressure too.make sure you have the right pressure at the fuel rail

 

Another thing to check would be the crank position sensor.

 

i didnt have a fuel pressure gauge with me. i checked for fuel at the shrader while cranking and got a good spray. i pulled the rail off the head and cranked it again, no fuel came out the injectors. this seemed weird to me. it built enough pressure to push the injectors out of the rail but nothing ever came out of them. like i said before there is a constant 12v at the injectors. so i guess im looking for what actuates the injectors??

 

I don't speak perfect Volvo but on most cars the injectors are grounded through drivers inside the ECM. You would have power to the injectors similar to the way you have power to the horn but the horn button closes the circuit to ground. The injectors have the voltage hanging there but until the ECM closes the circuit and provides the ground the injector stays open. It's the current flow that energizes the electromagnet inside the injector to get it to open/pulse so the fuel squirts.
To see if you're getting a pulse you should try getting some "noid" lights at one of the auto parts stores (autozone, oreilly ....). It's a loan so you don't have to keep them. You buy them to take them home and get a refund when you return them. Just make sure you ask for the loaner tool set and don't just grab a retail box off the floor on your own. You use those, you own them You plug the noid light into the injectors harness and it will pulse if the ECM is pulsing the injectors.

Does sound like a crank or camshaft position sensor failed though.

 

so i went back to the farm last night to look at it again. brought my scan tool.
P0137 02 low voltage
P0133 02 slow response
P0400 EGR flow
P0118 coolant temp circuit high
i read another thread about a weak coil so i tried starting it on ether, didnt work. so ive got spark, ive physically seen it but it wouldnt start on ether. coil firing but too weak to ignite???
i couldnt find any troubleshooting procedures for the crank sensor.

 

oh and i cleared those codes, none came back while cranking.

 

It should start and try to run on starting fluid. If it does not, you have a spark problem. I would carefully try to get it to start with starting fluid (when I say carefully I mean spray a couple quick shots and try to start it) If it does not start let it sit for a few minutes to let the starting fluid evaporate and try again. You do NOT want a lot of starting fluid fumes built up and suddenly get a spark and it try to start. If it does not start, check to make sure you have a good 12V to the coil and check the coil wiring. If the 12V and wiring is good, try a new coil and coil wire to the distributor. Please keep us posted!

 

12v to blue wire on coil. doesnt seem to be a ground or voltage to the red wire. i have spark at the coil, coil wire and plugs. i definitely gave it enough ether to start. i put the battery charger on it just to make sure im working with full amperage, ill head back down tonight. still seems funny to me that fuel didnt spray from the injectors when i had them out or that it didnt start on ether. we'll see though, maybe once the battery is fully charged itll run up with a few sprays and i can go back to chasing a fuel issue.

 

i went back to look at it last night. battery was fully charged. i pulled the plugs and wire brushed them, every one was wet w/ fuel. i cranked it over with #1 plug in my hand, had good spark (enough to give me a good bite). i hit it with starting fluid again. nothing! didnt even race up. im gonna recheck the timing tonight. ive got fuel at the rail, plugs are wet, i can here the pump coming on, theres spark. soooo? why wont it start?

 

It seems like it has to have jumped the timing belt.
Starting fluid, spark you should of had it do something. Pop, sputter ... something.

 

ok guys, this thing is killing me. rechecked the timing, all the marks line up. so ive got spark, fuel and good timing but it wont even run up on starting fluid. what am i missing??? could it actually be just a weak coil? i have enough spark that it hurt when i got bit. i dont know, im getting frustrated.
the current owner bought it not running and the previous owner said it made a pop/bang immediately before it died. i dont know how accurate that is.

 

is it possible for only the distributor to be out of time? has anyone seen that? is there a pin or anything that could shear changing the position of the rotor?

 

It is possible to get it 180 degrees out of time, and that would definitely cause a no start issue. When you replaced the timing belt did you use one of the DIY's, or did you use a "mark it and Pray" method? Here is a link to a good timing belt change DIY. http://volvospeed.com/volvo_repairs_...lt_change.html Might want to check it over and see if it helps. Other than that, I'm down to either a bad coil, or a bad ECM module causing a no-start issue. Like I have always said, you need fuel, air, spark, and proper timing for an engine to run. Sounds like you definitely have the fuel, air, and some spark (may or may not be strong enough) BTW, when you get spark, is it a nice blue white spark that makes a crackling sound, or a weak yellowish orange spark?

 

brother did you check if you are getting the right fuel pressure at the rail?one more question does it even crank when you try starting it? when was the last time a tune up was done?

 

psaboic,
i didnt change the timing belt, i was called for a no start issue, it died while driving. pretty sure it has a blue spark.
slimflex2,
it cranks fine. didnt bother to check fuel pressure because it wont even run up on ether.

 

Sorry about that......for some reason I thought you changed the timing belt. I guess I got it confused with another thread I am trying to help on.

Here is a crazy thought that worked for me once when I had a no start issue. Disconnect both battery cables. Then go to the big square black plastic box on the left front on the engine bay and remove the cover. Inside you will find two silver computer modules. One is for the engine and one is for the transmission. Carefully remove both noting which one went in which slot. With both modules removed, short both disconnected battery cables for about a minute.

Now carefully re-install the modules. Attach the battery cables and try to start.

It is a longshot but it worked for me once. For some reason my ECM needed to be reset and once that was done, all was well.

Another thing you can do while the ECM is removed is take off the distributor cap, hand crank the engine and see if the distributor is turning or if the distributor shaft is snapped. Rare, but it has happened.

 

ill try disconnecting everything tonight. although i dont think its an electrical issue considering ive got fuel and spark. i know that the distributor shaft is turning, i pulled the cap and cranked it a few days ago. it did seem to be turning slow though. it really acts like its out of time but the marks are lined up. thats why i was asking if something could happen to throw just the distributor out of time.

if i pull the front cam cover can i see the distributor shaft for a visual inspection?