The ECU swap made no difference.

I just noticed that my car is one of those that was built during the changeover, and it has both OBDI and OBDII. I'm gonna try and track down a scanner and see if the OBDII port will tell me anything

 

If it is any consolation, I am dealing with a similar problem on my wife's 2007 VW Beetle. No start, no fuel pressure at the fuel rail. Pump works and puts out 40 PSI and no lines are blocked, disconnected, or leaking. About ready to shove it over a cliff!!

 

I have a Eurovan that sometimes gives me fits too. I've noticed that I have the most problems with cars that start with a V.

Makes it easy to swap batteries though

 

Well....no codes through the OBDII port. I'm giving up for now. I've got other projects that need my attention.

Thanks for all the suggestions.

 

An update, just in case somebody is doing a search in the future.

I've got a friend who runs a shop, and he's got all kinds of fancy (expensive) Snap-on scanners and stuff, so I took the car to him. He hooked up his equipment and found all kinds of intermittent signals, but nothing definitive.

He went and talked to a friend of his who is a Volvo specialist, an they got on identifix.com. I'd never heard of it. Maybe some of you have.

Anyway, they found two listed instances of almost the exact same problem in two other 850's. The printout he gave me reads as follows...


Vehicle - 1994 850 2.3

Customer Concern -
Customer put a used engine in the vehicle. Ever since then it will not start. Very intermittently will have one spark and injector pulse. Seems to spark one time after the key is turned off.

Tests/Procedures -
1. With a scope, check output of engine RPM sensor. Check while cranking. If the pattern looks thicker when cranking compare to when not cranking, there is interference.

2. Check ground and voltage drops to the starter when cranking.

3. Check the starter amp draw. It should not exceed 150-160 amps. A bad starter can put interference into the crank sensor signal.

4. Ensure all bolts holding transmission to the engine are present and tight. A loose or missing bolt cause this problem.

5. Remove the transmission and check the mating surface between the engine and transmission. Use a wire brush or wheel to clean the surface.

Tech Tip -
Making a 4 gauge ground wire and bolting it between the engine and transmission will typically NOT fix/verify this concern. The only way to fix it is to remove the transmission. This is very common on all the Volvo aluminum block engines after the transmission has been taken off.

Potential Causes -
+ Dirty engine / transmission mating surface
+ Ground
+ Starter
+ Transmission mounting bolts

Confirmed Fix Summary - Transmission Ground Wiring



He's going to go through the check list, but based on his earlier tests he's pretty sure the only remaining option is to pull the engine or transmission and clean everything real good. Given that the car sat for a couple years with no motor in it, and having found multiple instances of a dirty mating surface between the engine and the transmission being the cause of bad grounding, I suppose that's what I'll do.

This better work....

 

OK then ... and I'm just talking out loud, I'm sorry and I know in the "tech" note that adding a ground wire wouldn't fix it but why in the world not ?? I'm just thinking logically that if you offer electricity a perfectly good path from one part (engine block) to another part (transmission body) through a nice fat copper cable why in the world would the mating surfaces between the two make any difference ??

To me that's like saying you need to replace motor mounts with solid metal ones if your starter doesn't work. Most cars use rubber in their mounts and have a ground cable separate just to get the current from the starter back to the battery.

Has anyone had to pull their engine to clean the mating surface with the transmission to solve a problem ??

ADDED 6-27-13 ,,, someone did pull theirs, cleaned up the surfaces and it did cure their problem. I don't understand, but I believe !!

 

I asked the same questions. My mechanic friend just sorta shook his head and shrugged, and told me he asked the same questions of his Volvo friend. It made no sense to any of us, but like I said, they found two specific instances of that being the problem.

You can bet for sure that I'm going to try multiple additional ground wires before I pull anything apart.

 

Maybe there is something to it but I'm with you, I'd tack a few grounds on that thing before I went through all the trouble to pull the engine and clean the mating surface.

 

I know this is many months old. However, the one thing that drives me crazy most often, on every forum I'm on, is when people post a problem, get all kinds of advice, and then disappear. I wanna know what worked, if anything, right?

To that end, an update...

This project has been on the back burner. The idea of pulling the motor just to clean the bellhousing frustrated me. The whole idea just seemed dumb. I tried bolting a cable between the block and the spot on the transmission where the negative battery cable attaches, and that did nothing. I cleaned the OE ground cables that bolt to the cam cover...no difference.

So last week, finally, out came the motor. I sprayed down the block and transmission with carb cleaner where they bolt together. Then I hit the both with a wire brush on my drill, and sprayed it down again.

Then I hit the spots on the block near the starter where the ground wires attach, and ran a tap through every hole. I sprayed out the holes with carb cleaner, and cleaned the ends of every wire that bolts to the block or transmission.

I put it all back together, turned the key on and off a few times to pressurize the fuel system, hit the starter, and it fired right up.


Yeah. It seems I have.

This is by far the strangest thing I've ever seen. If I hadn't been doing the work myself I never would have believed it if somebody else came up with this ridiculous story.


On a different note, it's running, but not well. It had a misfire, so I put new plugs in it. Still misfired. I drove it a mile to Autozone to check codes, and the plugs were already black...except #5 which was pretty clean. I pulled the codes, and got PO305 (cyl 5 misfire). I'm assuming it's running rich, which is why the plugs are black, except for #5 which isn't firing, and the unburned fuel is washing the plug clean. Maybe?

The other 4 are all evenly black. The cap / rotor is new. Plug wires were recently new on a V70 I had, and it ran well.

Other codes I got are PO245, and P1310. I'll be doing a search, but any thoughts in the meantime would be appreciated. For now, I'm just glad it runs. I bought the car two and a half years ago, not running, so obviously I'm rather thrilled. Besides, I seem to recall mentioning something about wanting to push it off a cliff a few months back

 

I'd toss a bottle of either Lucas fuel injector cleaner or Chevron with techron. I lean toward the Lucas, I've had good luck with it producing noticeable difference on badly neglected engines. Not that yours is badly neglected but it might make a difference if the injectors are starting to clog a bit.

With running rich and no obvious cause I tend to point to the coolant temperature sensor. It can drive the injectors rich or lean depending on how they start to fail. The problem with the sensor is that it can start to be off from actual temperature and mess up fuel mixture but still be giving the computer a reading it can believe so no code Just a thought.

 

Just out of curiosity, if the injectors are clogging, wouldn't it be running lean? I assumed soot on the plugs means it's running rich. I was thinking vacuum leak maybe, but haven't had time to mess with it.

I've also noticed my temp gauge isn't working, so you may be right about that sensor. That's on tomorrows list of things to do.

 

They can get dirt, grit something in the pintle end and not close fully so they leak or drip constantly. That condition could cause them to go rich but it's pretty rare.

If your gauge is dead that sensor should be bad enough to set the check engine light off but ya never know. Just be careful when you go to pull the thermostat housing torx bolts out. Some people like to replace them with hex head bolt as the torx can be a bit tricky.

 

Wow! That is really nuts about the mating surface.

Do a compression test on #5 to make sure you don't have a burnt/chipped valve or something.

 

Wow! That is really nuts about the mating surface.

Do a compression test on #5 to make sure you don't have a burnt/chipped valve or something.

 

Ok, the car's running awesome now. As I mentioned earlier, I like when people post the ultimate solutions to whatever problems they had, so....

The black plugs were fouled by a vacuum hose that I missed when I put the motor in. I plugged the vacuum line in, and that problem was solved. The misfire on #5 was an injector that I'm guessing wouldn't close completely. I swapped in another injector, and it's good to go.

It's always nice when something that's been sitting in your yard for 2 years is running again.

I appreciate all the suggestions during the process.

On the downside, in the category of "fate is cruel"...

For the two years I was looking for a decent motor to put in this car, I was also looking for a 5 speed. I couldn't find one. About a week after I finally got the car running, having obviously had to pull the motor, my local pick-a-part yard got a 5 speed car in, which I jumped on immediately. The transmission is sitting in my garage, with an assorted pile of parts, but now I've got to decide if I want to I pull the motor again. I'm thinking about saving it for a Volvo powered 5 speed....something...don't know what. Remember the ford ShoGun?

Anyway, thanks again for all the help.

 

Thanks for posting an ending to the story. I hear you about the long threads with no resolution. This might have been just another urban legend!