Hi all, first time poster, I've found lots of good info here via google. Got some kind of fuel/air problem with my 96 850 (non-turbo). I've had a lot of trouble finding a trustworthy mechanic in my area so I've started doing some work on this car myself. I'm pretty competent at most minor-medium stuff and I know when I'm getting in over my head

Apologies for the long post, but there's a lot of background on this car that I want to get out there

We had a hard start and dying issue in January/Feb. CEL code pointed to MAF (can't recall the exact code) so we changed that, and things improved for a couple months.

Starting in late April, the car would refuse to accelerate and then surge away from a stop in hot weather. Fuel pump died after this started while my wife was driving it about 1 hour out of town, had a small town mechanic replace fuel pumps and filter (saw old parts when I picked up the car).

That seemed to fix things, but a couple weeks later, the same thing started happening, again mostly on hot afternoons.

We ran a couple bottles of Lucas injector cleaner through it without any noticable change. I replaced the Fuel Pump Relay and there was no change. I went ahead and checked the air filter, and pulled the intake hose off the throttle body and looked for buildup/blockage.... nothing.

I pulled the CEL codes, and I'm getting misfires in cyls 1,2 and 3, codes for too lean/too rich fuel mixtures, and a catalytic converter efficiency code.

Mostly because of the misfire codes, I pulled and checked all 5 plugs. They looked OK, but while I was there I replaced them and the wires as well. Car started right up, accelerates OK from stops, but seems to have lost power and now has a very rough idle. CEL is still on, but I have not pulled codes since then - I need to buy a code reader I guess

First question is, per a few google results, the appropriate gap for this model is .028. The old plugs were gapped a little wider, to around .030 (I didn't install those), so I wanted to double-check that I have the correct gap.

I finally gave up and called my brother who is a helicopter mechanic by trade, and also a competent "shade tree" guy, but is about 2 hours away. He says one or more of the injectors are clogged, pretty badly given that the Lucas didn't seem to help. He's trying to explain to me how I can check the injectors by sticking a long drill bit or something into them and feeling for the pulse, but I'm having a hard time visualizing and he's not ever worked on a volvo before so is having a hard time explaining...

So, question two is, is there a "procedure" for doing this that someone could walk me through, or is this something I really shouldn't mess with?

EDIT: One other thing worth mentioning is that this car does have a rattle coming from the exhaust at idle, and has had one since I bought it back in 2008. Had two mechanics tell me it was something loose inside the cat. I'm aware of the possibility that this could be causing a blockage, but I'm discounting it at this point because 1) it's driven fine like this for almost 2 years, and 2) there's correlation between outside temperature and the problems it's having.

Having said that, I'm open to the possibility that I'm working this from the wrong end so to speak

 

OK, you've got a lot of different symptoms; lets take one at a time..

1. Original issue; runs like crap when hot; first ck the basics: do a compression ck to make sure we're not dealing with some basic engine issue. You have a N/A engine which has 10.5:1 compression ratio so you should see pressures in the 175-195 psi range. BTW: when doing a compression ck, make sure you either use a remote starter button or disable the ignition system by disconnecting the primary coil wires. If that's good, i would ck the fuel pressure; suspect you may have fuel pressure regulator that's due for replacement (just a guess at this point).
2. You changed the plugs and wires but didn't see where you changed the cap/rotor; do it if you haven't recently. Also the car has rough idle and lost pwr after you replaced plugs and wires; did you get two wires mixed up?
3. Don't stick anything into the fuel injectors!! After you have ckd the fuel pressure (and it's correct) then you could pull the fuel rail, point the injectors into a container (or lots of rags), then crank the engine for a moment (get a helper) and observe the spray patterns of the injectors. Should be nice cone shaped spray pattern with little or no dripping. NOTE: this is dangerous; have a fire extinquisher handy!!
4. And yes, you probably need a cat too. What's the mileage on this pup?

 

Hey gdog, thanks for the reply.

First, I have not done a compression check. I don't have the equipment to do it here, but I'm trying to find someone local who can for free or for some amount of beer

I changed the plugs and wires just as a matter of thoroughness, and because I knew they were about 2.5 years old. Doing so took me from a hot stall at idle to a rough idle, which I do consider to be an improvement.

Yeah, I installed the new wires one at a time to make sure I didn't screw anything up, and then double-checked it against a plug wire diagram I found online. I'm 100% sure that's correct. I also pulled and checked the plug gaps about 4 times now lol.

Haven't touched the distributor, but that's been considered. Been approaching this as a fuel system problem based on symptoms rather than an ignition problem. Plus the distributor was changed when the plugs were last changed, about 2.5 years ago. Might still swap the thing out, but see below for weirdness.

Took it over to a buddy's house today and removed the fuel rail with injectors still attached. The cylinders that were reporting misfires looked to have two of four holes visibly clogged. We soaked all 5 injectors in some carb cleaner fluid and also had a go at the throttle body once again. We then tested the injectors (didn't test them before cleaning which I now realize was a flaw in the plan ) by turning over the engine. They all gave a nice cone pattern, no dribbling or anything.

This is where things turn odd. After putting things back together, I started the car. The CEL was still lit, the RPM's gunned to 2000 immediately before settling back down to a very rough, coughing idle. We decided to drive the car over to Autozone to check the CEL codes (about a 20 minute drive), and wanted to reset them before we left, so we disconnected the battery for about 30 minutes.

After reconnecting the battery, the car started right up, did NOT gun to 2000 RPM, and settled into a smooth, quiet idle. Driving to autozone and back, it ran flawlessly, power had returned and CEL stayed off for the whole trip, and the cat didn't rattle at all.

When I got back into the driveway, the rough idle returned, and we noticed a fair amount of grey smoke coming out of the exhaust, which increased as we gave it throttle. Still no CEL.

We let the car sit until it cooled, and started it again. Still a rough idle, but no smoke. Still no CEL either. I backed the car out to drive it home, and when I hit the brakes at the end of his driveway, the ABS and Trac Off lights lit. From that point on, it idled and drove flawlessly.

So... here's what I'm guessing at this point. Correct me if I go wrong, please .

1. As a matter of pride, we did SOMETHING to help the situation today.

2. The help was hidden by the fact that the car had gone into some kind of "limp home" mode, which it took a battery disconnect to clear.

3. There is some kind of vacuum or electrical problem associated with the braking system which is causing the bad idle unless those systems are faulted (I'm assuming here that the ABS and Trac Off lights mean the computer has disabled those systems).

4. Given that the car is seeping oil around the oil fill cap (yeah, I didn't mention that before, just verified the oil on the valve cover wasn't from a spill today) this could be a symptom of a PCV problem.

So, any thoughts?

 

Wow dude, this is like weaving through a bowl of old shaghetti...

OK, sounds like it stills run like crap when hot. You disconnected the battery for 30 minutes (BTW; as far as I know that won't clear any DTCs) which would have cleared out any learned fuel trims the ECU had accumulated.

Then it starts running good again which you correlate to the ABS/TRACs light coming on. So does your ABS light come on regularly?

And, oh yeah, the PCV system is clogged too. And we still don't know the mileage on this car...

At this point, my suggestion would be to find a good (preferably indy) tech and see if he can unravel this mess; you have a lot of stuff on this car that needs fixing, some of it may, or may not, be directly related to the driveability issue you're currently experiencing. Needless to say he will give you laundry list of stuff to get fixed; you will have to pick which is highest priority.

From the symptoms you've described so far, one thing it could be are bad O2 sensors, but then it could be a dozen other things too... You need someone who has a compression gauge, a fuel pressure gauge, lots of other diagnostic tools, and the know-how to use them in figuring out what the problem is.

If you can find a good tech who knows how to diagnose cars, he should be able to figure this out. Then you are only replacing the part(s) that are causing the problems. But that costs $$, since his labor is expensive, but you're paying for his expertise. The alternative is to throw parts at it, doing your best to guess correctly... you might get lucky, but the odds aren't good.

Sorry if this sounds like I'm going off on you here; don't mean to, and I am trying to be helpful. But IMO you've too many things going on at the same time for someone with limited automotive experience to figure out. Now if you were seriously thinking about becoming an auto DIYer, willing to invest in the tools and learn the knowledge needed to know what you're doing, then they're are lots of good folks here willing to help you out and shorten that learning curve a bit. Best of luck and let us know what else you find! If you give us more feedback/info, who knows, maybe we'll get lucky.

 

Few thoughts:

The brakes aren't connected to any vacuum system, so they are not associated with the idle issue. The ABS module will cause both ABS and TRACS lights to light up. You can do a search for sending it out or repairing it yourself – much cheaper than buying a new one.

Yes, the appropriate gap is .028. You can stick with copper plugs, no need for iridium or platinum.

Hold off on swapping the distributor cap – 2.5 years is not a (huge) problem. Check other things first.

Check the gasket on your oil cap. They tend to dry out and become brittle. 5 bucks from FCP took care of the oil buildup on my engine. Your PCV may be ok. One way to check is to put a balloon on the dipstick tube – if it inflates, it needs fixing.

I bought a code reader on sale at AutoZone for 35 bucks, regularly 50 bucks. Grab one up! It’ll help you diagnose specific codes to see how many things are FUBAR.

Yeah, sounds like you may need O2 sensors and maybe a cat. It would be a good thing to start running through a Stage Zero. If they’re still from the factory, I’ll guess a lot of your hoses (especially vacuum hoses) are weak.

Here’s a fuel injector cleaning guide: http://www.fordfuelinjection.com/?p=82 – you know, for next time J

My Miata had a clogged cat and it drove like crap on and off, mostly when I gunned it. Stuck in rush-hour traffic heading up a hill drove me nuts!

Some problems will throw error codes but not light-up the CEL. Get the reader, reset the light, drive for a bit and check for codes.

Pulling the battery for that length of time probably reset the ECU, which would account for the idle difference.

Question; where are you located? You mentioned winter and summer so I wonder how cold it was (hint: update your profile with location, year and model details. It saves you from repeating yourself a lot!)

 

Answers to a couple saved-up questions... Mileage is about 150k, and I'm in KY. "Hot" here is 90F with high humidity, "Cold" here is 28F... also with high humidity

I've been driving the car to and from work this week. That first start up in the morning is a little rough, but overall the car has run wonderfully.

The "Service," "ABS" and "Trac Off" lights seem to go on and off randomly while driving though. From talking to my wife, the car has apparently been showing those lights with no real pattern for some time now. Guess she decided it wasn't important to mention those to me... would those conceivably trip a code?

Will try the balloon over dipstick test.

 

The Service light is just a reminder to spend money at the Stealership , so it doesn't throw any codes. It's only on for the first 5 minutes of a drive and is designed to go on every 5K or 8K miles - until its reset, of course...

The ABS & TRACS usually indicate a problem with the ABS module, but don't think it throws any codes. My lights have been lit up for years and I don't have any codes - of course, I have a '97 which doesn't have the diag/break-out box/thingly by the ECU box, so there may be codes from that on earlier models.