Howdy! So I recently picked up an 850 that will not start for $200, aside from that it's in good condition. I've just got started working on trying to track the issue down. So far what I am seeing. The fuel pump is not turning on. I bypassed the relay to no avail. So I went and supplied 12v to the pump and the pump fire's right up with no issues. Using a multimeter with the key on, the pump is receiving less than 1v. I'm also seeing no spark being delivered to the cylinders. The dash lights are not present with the power switched on. Im not seeing any blown fuses. The ECU is not sending any codes, not even a no fault code. Any help would be greatly appreciated!

 

Well my friend, you're in the right place! Might take some time getting the help you need, but these guys know their stuff and they'll get you fixed up, I'm in the same boat with you, limited Volvo knowledge, but somewhat automotive qualified, enough to get into trouble. These cars are sensitive to get started but once they do they are excellent runners. I suggest you read as many posts as there are to self educate, one of the posters has a link to download the Volvo service manual, very helpful, definitely check out the fuel relay above the radiator, you'll read about it in the posts. Seeing as we are in the same boat, welcome aboard! I am still being helped tracking down my mystery too. But I feel confident these are the guys to help, because if you don't know Volvo's, even though your willing, you're little help with them.

 

What year is the car? Is it a turbo? They are easy enough to fix in my opinion. I bought several that wouldn't run, just for fun. The fuel relays are a known issue, it was good to bypass that. Another issue is the plug attached to the "main fuel injection relay" that is usually mounted above the radiator (not on a 97, though). I never bothered to look at what all it powered, but for sure you don't get any spark when it's offline. On the pre-OBDII cars, you don't get any diagnostics and I consider that a "symptom" The problem is not the relay, it's the plug. Another problem I had was the oil seal on the back of the intake cam popped out and oil got in the distributor. The oil caught fire and melted the rotor button. Another problem I had was deterioration of the old rubber in the piping between the MAF and the throttle. On a turbo it's a lot of plumbing. The worst piece of that plumbing, for me, was the rubber elbow right on the throttle body. I've seen a couple of cam sensors go bad.

 

Thanks for the welcome response folks. This is my first time using any forums, so thanks! Agreed Turbo piping can be difficult, especially on a FWD car. I have a Saab 9-3 HOT, piping aside, it's a headache on its own haha. This is my second Volvo, daily drove a 92 740 turbo wagon for a year or so till the transmission crapped out on me. I miss that thing. I've got an understanding of these cars cause I'm always digging around in them at the junk yard. Never thought I'd own a 5 cylinder though, but I'm excited about it. This 1995 850 is NA. I have the manual as well. I'm wondering.. does the ECU control all of these electrical systems I'm having issues with? I'd imagine the fuel delivery would just be a separate system. I mean, besides the ECU controlling the injectors. The ignition I would imagine is directly controlled by the ECU though, right? Is the dash dependant on the ECU as well?

 

1995 cars have separate ECU for ignition and fuel injection. There may be some variety, but I have one that is that way. My car is a manual transmission car so it only has two computers. An automatic would need 3. A 1995 turbo is totally different; they had a modern ECU.

The instrument cluster is an onboard computer itself that talks to the ECU. On a 1995 you can "talk" to the instrument cluster using the obd port under the hood. Since your warning lights aren't lighting up, I have to think you have some stuff on the cluster not getting power. In fact your first post is like nothing is getting power. And honestly that is a simple problem. You know some locations where you are supposed to have 12 volts. Right? And with a wiring diagram you can find more.

 

I counted 3 computers, one for the auto trans, one right next to it for ignition and then near the brake booster one for the ABS. Aside from the obvious computers under the hood, are their any others I'm not aware of? Ok so the cluster is receiving speedo and tach telemetry directly and not through anything else? Sounds like I'm going to be digging around looking for messed up wires for weeks haha.

 

For grins and giggles, take the hose off between the air filter box and the throttle body and shoot a 2 second blast o starting fluid down the throttle body and give it a crank. If it starts and runs for a couple seconds, you have spark, but no fuel, if it doesn't start, you have no spark. It will get ya started in the right dirction at least.

 

Yeah, I tried that the other day, no luck. There's a central electrical issue affecting all systems accept the accessories. All the lights, windows, horn, etc work fine... Well, except the radio, the radio says code. I imagine that has something to do with the battery being unplugged often and the anti theft being reset.

 

Yeah, the code is due to the radio anti-theft. Have you tried removing the ignition computer, checking the pins on it, and then reseating it? I like to start with the simple stuff. Also have you checked all the fuses in the engine bay (including the ones under the fuse cover when you remove it). If I remember correctly, there is a separate fuse that controlspower to the ECU.

 

Yeah I did check both the pins on the ECU and the fuses. I'll check again for the ECU fuse though. Haven't had any time this weekend to root around in it.

 

Are you telling me you don't have a fuel injection computer? That might be your problem. maybe you have enough of them, but let's make sure. Volvo used a bunch of different systems at the same time.

 

It's a Bosch computer so I'm assuming that's the fuel injection ECU.

 

Any update zedd? Still rooting around trying chase it down? You do have all the sensors connected? That last one got me, I didn't think that they were all needed.