Yesterday morning I went to the car, started it up and moved it about 10-feet to get it out of the way for my brother. It started fine. However, when I went to start the car around 5:00 that evening, nothing, wouldn't start at all. The engine would spin, but wouldn't catch at all. I checked the fuel pump and that was doing its thing, it was getting gas (checked at Schrader valve) and pulled the plugs to check spark - oh, no codes thrown either. The plugs had this hard black stuff caked on ALL of them, so I figured that the plugs were fouled and the car was running REAL rich thus flooding it (I smelled a faint whisp of gas when trying to start it). The plugs are 1.5 year old NGK's... With the closest parts place a 10-mile drive, I grabbed a brass "toothbrush" and cleaned the plugs off the best I could and reinstalled. After cranking for a good 30-seconds, the engine started to catch and when I tried again, it started and ran REAL rough for about a 1/2 minute blowing whitish exhaust that smelled of gas. After the engine warmed up, the white exhaust went away and the engine idled normally - in fact, I just got back from a 80-mile drive home. Oh, I wasn't home when this happend

Other facts:
- I've noticed a slight drop in fuel milage, but I figured that the AC may be running harder as it's been very hot the past week or so.
- There seems to be a lack of power in passing gear between 3k & 4k rpm. However, when it gets over 4k, it takes off.
- I seem to be going out of overdrive going up hills a lot more lately. Again, I thought that may be the AC working harder.

That's the story, here are questions....

1. Would a fouled up MAF sensor cause this to happen? I replaced it 2 years ago with new one I got from FCP Groton..
2. What about the timing belt? I was told it was replaced when I bought it (25k miles ago).
3. What about PCV? I don't know if that's ever been done or not.

Any other thoughts? My mechanic friend said that he would bet that it's the MAF, but I really don't want to throw $175 at a question mark. Know what I mean?

 

First thing I would do is replace plugs with OEM, new wires, dist cap and rotor. The fact that is started means it has nothing to do with the timing belt. The fact that is runs and runs rough leads me to believe it just needs a tune up and possibly the MAF.

 

Ditributor cap and rotor (OEM) were replaced last April/May, wires (Bougicord) replaced last fall. I know that I'll need to replace the plugs as they are fouled, but being so new, will I need to really replace the cap, rotor and wires?

 

I wouldn't think so. From what people have said though they have had problems using plugs other than OEM or Bosch. I just use OEM only, but I have the Turbo models.

 

I've heard nothing but good things about the NGK's though. Eh, whatever. I'll probably just get the regular OEM instead and if I notice a big difference, I'll put in NGK's at a later time.

What about the MAF? Would there be any signs that it's going? Like I said, I'm really apprehensive about throwing that kind of money on something that I'm not 100% convinced is the problem. I used to get around 27mpg, now it's around 25mpg average, the slight lack of power at mid-rpm's... Related maybe?

 

Hi,

I too, am doubting the MAF sensor, or clogged air filter (did you use MANN/K&N? I wouldn't go with other brands, but you probably did replace it with OEM, assuming from the fact that the ignition components were replaced with OEM). MAF sensor may be reading incorrect air flow and commanding the EEC to supply more fuel than is necessary, thus creating rich A/F as you noted, and causing the plugs to foul up with carbon deposit. It may/may not be a faulty sensor, but could be the sharp turn on the wiring that seems to affect the sensor performance: (http://volvospeed.com/Repair/maf_secure.php).

Also, if you have a digital multimeter you can test the ignition coil Ω, or see if it arcs at night.

>Other facts:
- I've noticed a slight drop in fuel mileage, but I figured that the AC may be running harder as it's been very hot the past week or so.

Yes the A/C always affects fuel consumption.

>There seems to be a lack of power in passing gear between 3k & 4k rpm. However, when it gets over 4k, it takes off.

If turbo, it may just be the turbo lag. If N/A (turbo as well), the engine may need to reach the power (torque) band to produce enough punch. Did the performance change, after you noticed the hard-start problem?

>I seem to be going out of overdrive going up hills a lot more lately. Again, I thought that may be the AC working harder.

Indeed. Or, due to fouled plugs, the engine may be trying to work harder...

>1. Would a fouled up MAF sensor cause this to happen? I replaced it 2 years ago with new one I got from FCP Groton..

I wonder why the diagnostic doesn't catch this and store any code...


2. What about the timing belt? I was told it was replaced when I bought it (25k miles ago).
As long as the timing belt is in one piece, it should not have anything to do with the problem. BTW, if your 850 is '93, I believe the replacement interval is 60,000 miles, not 70,000 miles. This is due to narrower widthbelt.

3. What about PCV? I don't know if that's ever been done or not.
If it has never been serviced, I would just replace/clean everything within the system. If you do, the intake manifold may have to come off and you need a new intake manifold gasket.

>Any other thoughts? My mechanic friend said that he would bet that it's the MAF, but I really don't want to throw $175 at a question mark. Know what I mean?

Yes, I do understand what you mean. Again, try wiggling or unplugging the sensor harness (wiring) while at idle (be sure to set the shifter in "P", apply P-brake fully and chock the wheels if possible) and see if the engine responds.

I hope this gets you started. Also, it wouldn't hurt to double check on the coolant & transmission fluid levels.

Will wait for your finding.


JPN

 

Well, lets see...

- Didn't test the coil, but it did cross my mind at one point. Will so that. What value should I see?
- It's a N/A. Wish it was a turbo though. Performance hasn't changed since the starting problem.
- When the MAF went before, there were no codes thrown then either. That's why I'm not confident of the solution.
- I didn't try to unpled the MAF while running, but did check the wires and harness as I knew that's an issue with these cars.
- Coolant is fine, tranny fluid is good. Both serviced recently.

 

Just as an added thing... To me, it's almost like it's flooding. If it was a carborated engine, I would be checking everything that would cause an engine to flood, especially at start. Having said that, I was reading in another thread (https://volvoforums.com/m_22877/tm.htm) that the coolant temp sender may cause the engine to flood and mine has in fact been flaky recently. It never read hot, but about 30/35% of the time, the gauge doesn't register at all.

 

That's something that is fairly cheap and easy to replace. Might as well do the thermostat at the same time, if it hasn't been done for a while.

 

Ok, but will that cause the engine to flood, foul the plugs and cause the non-start issue as I mentioned above? I'm still throwing money at a question mark at this point. I realize that it's only 30 bucks and a thermostat is $10 (which one, 87º or 92º?), but throw a $180 MAF and shipping and now were pushing $250.

 

OK, I hope this post gives you more specific picture as to the problem.

Coolant temp sensor could flood the engine, though it depends on the situation. If the coolant temp sensor is faulty and keeps feeding the ECU with low coolant temp input, the ECU thinks the engine is still cold and tries to supply more fuel.

To test the coolant temp sensor, a digital multimeter is imperative. If you don't have one yet, why not get one for $20-$30 at Sears (Kmart has some too) Craftsman meter.

IAW the factory manual, the correct resistance range should be:

32F: 7,300 Ohms
68F: 2,800 Ohms
176F: 300 Ohms
212F: 150 Ohms

Immerse the sensor (the "bulb" portion only) in a hot pot and start heating to see if the sensor reads close to the above figures to determine its condition.

I hope you can get some progress as to eliminating the headache.


JPN

 

2nd post; Hard Starting indeed....


JPN

 

Done and done

With your second post, I'm seeing the coolant temp sender as a common issue between starting and poor drivability. This seems that it COULD very well be the problem here. Now I have to figure out if it's a bad connection or a bad sender... Either way, I'll pull it and test it as per the sheet you attached.

Where can I get my hands on a factory manual? That thing seems to put my Haynes to shame...

 

The manuals are available on Earth.....[8D].

(I hope you saved them; let me know if you need the URL again)

They are in PDF format. Note, however, that the manuals are only "partial" and they do not contain everything. If you need to know everything, you either have to go VADIS (software-version of the manual?) or get the genuine factory manual retail at:

https://www.volvotechinfo.com/index....m.serviceparts

Good day!


JPN

 

PLUGS,

1.5 years old on any car is pretty old. I would replace with OEM. I was fortunate enough to come across a supply of Autolite XP plugs (about 200 of them) my father had worked for an equipment supplier to Autolite and obtained them free! These happen to fit my VW and the Volvo. I have used them in both and found them to be EXCELLENT. Since these are an Iridium Plug and cost upwards of $10.00 a piece I can reccomend them but they are pricey.

Your wires cap & rotor sound like they are new enough to not have caused the problem. MAF will usually cause a much more serious issue than you are experiencing. You can clean it though, I know many people are afraid of this but I have cleaned about a dozen MAFs using the following method with only positive results.

Remove the Intake hose and disconnect the MAF wiring.
Unbolt the MAF housing and all from the Air cleaner box.
Place the whole MAF into a ZIPLOC bag (large size)
Pour in a whole bottle of Rubbing Alcohol. (clear not green 91% you can get at Wal-Mart)
Zip the bag shut and shake like "Shake & Bake" do this a few times a minute for a few minutes.
Then drain off the alcohol and place the MAF somewhere warm to dry COMPLETELY.(2 hours)
Don't use compressed air or anything to dry it faster.
Place the MAF back in and enjoy.