96 850 NA misfires, hard start, stalls

eriscentro · Post by **eriscentro** » 25 Jan 2017, 09:49

Hey guys,

I posted about a year and a half ago that one morning my 850 was running rough, stalled out and barely started again (only started up after about 20 minutes), Once that problem occurred, I hadn't had an issue since. On occasion, maybe every couple of months, it'll run rough for a few minutes but the problem resolves itself after a few minutes. Having said that...

Last week I had driven to the store with no issues. When I went to leave, the car started, but ran like crap. It clearly felt like it was misfiring, and ultimately when I put it into drive or reverse, it would completely stall. Although the codes didn't pop up immediately, I ultimately had a P0300 and codes for misfires on 2 or 3 cylinders. That day, it was incredibly difficult to get the car started, in that I'd have to let it crank for 10-15 seconds, although each time I put the car into gear, it would stall out. After about 20 minutes, of sitting in the parking lot (directly blocking everyone, mind you), it started up and ran fine.

Today, I went to start the car, and although it started up with no issues, I could feel that it was running rough at idle. After a few minutes, another P0300 appeared with 2 other misfire codes. I disconnected the MAF sensor while running, which caused the car to stall. Afterwards, it refused to start. About 15 minutes later, after letting the car sit, it started up once again, requiring 10 or so seconds of cranking, and continued to run awfully. Although it didn't stall when in gear, it was buckling and sounded as if it wanted to.

In both cases, when in park or neutral, revving the car is OK, and doesn't trigger a stall. When I first attempt to accelerate from idle, there's a slight buckling where the engine drops below normal idle for half a second or so.

Having said all that, the fuel pump was replaced in August due to a leak at the top of the tank (annoyingly, that didn't appear to solve the problem, but that's a different story). I'm not sure when the wires, plugs, cap, and rotor were last changed, although the plug wires are dated "11 04". My best guess is that the plugs have 30K on them, but the rest of the parts are unknown. Anyone have recommendations? I have basic tools with me (I'm at school, so the car is sitting in a parking lot at the moment), so I don't have a ton of flexibility in what I can work on.

Edit: Having the MAF sensor connected or disconnected didn't have an impact. Also, I have a P0442 (or 0445) that pops up every few hundred/thousand miles, but no other codes. As an interesting aside, the evap code always tends to come on when I pass through one particular section of a town.
Double edit: I'll check the distributor cap ASAP since I noticed some oil-ish fluid on the top of the block immediately to the left of the cap.

Post by **rspi** » 25 Jan 2017, 11:20

Sounds like a MAF or ECT issue.

eriscentro · Post by **eriscentro** » 25 Jan 2017, 19:23

I went out to take a look at the car this evening, and sure enough, it started right up with no problems and ran fine. I let it heat up to temp, drove around the block, and had no misfire or hesitation/buckling issues. Furthermore, I was able to restart the car when hot with no issues either. MAF readings were about .55lb/s, coolant temp was 190.4F. But...

What I did notice is that after running the car for a few minutes, there was a loud, distinct ticking that could be heard with the hood open. I searched all over to try to find it, and the noise appears to be coming from the injector relay, right above the radiator fan on the right side (by right side, I mean from the viewpoint of looking at the car head-on). Presumably this ticking shouldn't be heard, correct?

Post by **rspi** » 25 Jan 2017, 19:57

Correct.

Post by **erikv11** » 25 Jan 2017, 21:57

PM me if pick-n-pull isn't easy for you - I could send you an injector relay from my 97 850 parts car if you pay postage.

I would peek under the distributor cap and make sure you are'n dealing with a blown rear cam seal, which would spray oil and/or moisture in there and cause misfires.

eriscentro · Post by **eriscentro** » 31 Jan 2017, 16:38

Update to this. Last week, I drove for 10-20 miles with no issues whatsoever. This evening, I started the car for the first time in about a week with no issues. Started on the first crank. I let the car warm up and drove around the block, only to have it enter another state of misfiring and hesitation. I also noticed that the injector relay was ticking quite loudly once again (I'll look into getting a replacement ASAP). When I went to restart it, the car took 10+ cranks to finally get going.

It possibly appears that the issue is related to the engine temperature.

I popped open the hood to take a look, and I noticed two things (it's dark and raining, so I only had a few minutes).
- After pulling the snorkel leading into the air box, I noticed that directly to the back and left of the box there's a white-topped hose that appears to be disconnected. Do anyone have an idea? The picture is attached. The white piece feels to be rubbery.

- I noticed that around the PCV flame trap area and below, there's clear markings of some kind of leak. Once the weather clears up, I'll remove the throttle cover, airbox, and distributor cap to take a look.

- Lastly, on the top of the engine, on the driver's side, the crevice that's circled (that's on old picture) always appears to be slightly wet. Any ideas?

Post by **sleddriver** » 31 Jan 2017, 19:18

All of that oil on top of the motor in your last photo isn't good. Start by replacing the oil cap gasket as it's probably hard-as-a-rock. Next pull the plug wires and look into the wells for signs of oil, which can cause the problems you describe. If you do find oil down there, you need to clean it up very well, and clean your spark plugs free of all signs of it. Else the film can bleed charge straight to ground (engine block).

If the rear camshaft seal behind the distributer is leaking, oil can foul the dist. cap leading to misfiring. It'll also make a mess downstream. Fortunately rear cam seals are easy to replace. Doing so will also give you the opportunity to inspect both the camshaft & crankshaft position sensor wiring for missing insulation. Any shorts can also lead to misfiring, poor running.

Post by **rspi** » 31 Jan 2017, 19:31

I would not try to unplug the spark plug wires unless you get some replacements. After market wires often break when you try to pull them off. Get good Volvo or Bougie Cord wires.

eriscentro · Post by **eriscentro** » 31 Jan 2017, 19:37

That photo is probably a year or two old - the oil has been since cleaned up (PCV and new cap seal). Its purpose was to note that corner that is mysteriously wet quite frequently.

I checked the plug cavities a couple weeks ago, and noticed that one of the plug wires, within the cavity, was clearly stained in dried up oil. Fortunately, the well itself was clear. I had noticed that several years ago but didn't think much of it. The cords are made by Bougicord, and I believe are dated 11/04 or 04/11.

Once the precipitation dies down I'll check the distributor-cap area and see what I can find. That oil stain on the lower side of the block is mysterious; my oil levels are fine. The randomness of the issue is the strange part. One day/minute the car is fine, and out of nowhere it starts to become problematic.

Post by **erikv11** » 31 Jan 2017, 20:02

If that photo is of OP's engine, then he definitely has Bougicord wires not aftermarket. So it would be fine to pull them.