Hey all, I've been lurking around the forums for a while but this is my first post. I've got a '97 850 T5 with ~180k mile that sometimes is really slow to start and recently had to be serviced because it would stall immediately. First, some background:

Back in about November my car started running a slow coolant leak. At first it was manageable- I would fill up the reservoir and that would last a week or 2 at a time and since it was a mild winter I didn't consider it too serious (dumb, I know). Eventually it started to leak really bad and then I got an intermittent Check Engine Light and the car started struggling to start, so I went hunting for the leak. Found a leaking top radiator hose, replaced it. Still leaking bad from behind the fan so I replaced the radiator about 2 weeks ago, along with the oil cooling o-rings/seals/clamps from the auto transmission and turbo, flushed the coolant, changed the oil and filter thanks to the great walkthroughs here and Bay13. No more coolant leak. Still trouble cold starting. The power has been very soft (weak acceleration almost like the turbo isn't kicking in) since I first noticed the leak in November, and in stop-and-go city driving I could feel it really struggling to get moving from low RPM. I'm pretty sure I tightened up all the clamps for the turbo intercooler hoses and everything else.

Within a week the car would not start at all, so I had it taken to a garage for service. They ran the CEL: P0172 System too rich Bank 1. They replaced the MAF sensor and air filter, cleaned the throttle body and intake manifold as well as the induction system. Car started great at first for a few days but then the CEL came back and it's been struggling to cold start in warm weather again.

So my question is: how do I go about diagnosing the cause of the persistent struggle to cold start? I'm going to replace the thermostat and ECT sensor and replace the vacuum line connectors since those seem to be common enough and cheap to do. The mileage is about average in mixed driving (21-22 mpg), the engine temp gauge always starts cold and rises to the 3 o'clock position after a few minutes and stays there. The only other thing I can think is related is this:

For the longest time I've had an odd symptom- when stuck in stop and go traffic, particularly on a hot day but even sometimes in cooler weather, the outside temperature indicator (on the trip computer) would start to creep up by 10-20 degrees F relative to ambient. After getting back up to speed the temperature would go back to about normal. The engine temp gauge would always read normal at the 3 o'clock position whenever this happens. The only thing that could really make it go away was to turn the heat on, put the windows down, and pray the engine temp stayed normal (which it always has according to the gauge on the dash) while I sweat my *** off in misery. This happened today when I was stuck in traffic on 95 for the umpteenth time, so I mention it on the off chance it might help. I would guess something is dumping heat near the sensor and that driving at speed provides enough wind to cool it down.

Sorry for the long post, but I'm trying to give you guys all the information I can think of that might be pertinent. I really want a way to narrow down the cause without spending hundreds more on wild guesses.

 

The OBDII code of P0172 corresponds to 2-3-1 or 2-3-2 OBDI code; following from '95 Turbo Manual:
================================================== =======
Code 2-3-1 (Long Term Fuel Trim Partial Load) Or
Code 2-3-2 (Long Term Fuel Trim Idling)
1) Check for other codes. If Code 3-1-5 is stored, perform
testing on that code first. If Code 3-1-5 is not stored, go to next
step.
2) Check status message on Volvo Scan Tool (998-8686). If
status message reads LOWER LIMIT, go to step 8). If status message
reads UPPER LIMIT, go to next step.
3) Turn ignition on. Connect voltmeter between MAF sensor
connector terminals No. 2 and 4. If voltmeter reads .1-.2 volt, go to
next step. If voltmeter does not read .1-.2 volt, test using new MAF
sensor.
4) Check for air leakage in intake system. Repair as
necessary. If air leakage in intake system is not present, go to next
step.
5) Check for air leakage in exhaust system. If there is no
air leakage, go to next step. If there is air leakage, repair as
necessary.
6) Check fuel and residual pressure. If fuel and residual
pressure are okay, go to next step. If fuel and residual pressure are
not okay, repair as necessary.
7) Connect breakout box to ECM and check ground connections.
See COMPUTERIZED ENGINE CONTROLS in I - SYSTEM/COMPONENT TESTS
article. Reconnect ECM. Repair as necessary.
8) If status message reads LOWER LIMIT, turn ignition on.
Connect voltmeter between MAF sensor connectors terminals No. 2 and 4.
If voltmeter reads .1-.2 volt, go to next step. If voltmeter does not
read .1-.2 volt, test using new MAF sensor.
9) Check for air leakage in intake and exhaust system. Repair
as necessary. Check fuel and residual pressure. Repair as necessary.
If no air leakage and fuel and residual pressure are okay, go to next
step.
10) Remove hose leading to intake manifold from EVAP valve.
Connect vacuum pump to EVAP valve coupling. If vacuum gauge does not
show stable vacuum, repair as necessary. If vacuum gauge does show
stable vacuum, go to next step. Check engine oil and fill as
necessary.
11) Start engine and run at idle a few minutes. Using Volvo
Scan Tool (998-8686), read off value on SHORT TERM FUEL TRIM and note
value. Disconnect and plug crankcase ventilation. Read off value of
short term fuel trim once again. If value is more or less unchanged,
go to next step. If value rises, engine oil is diluted with fuel.
Repair as necessary.
12) Connect breakout box to ECM connector and check grounds.
Connect ECM. Check all signals to and from ECM. Repair as necessary.
================================================== ===

If it were me, would ck:

1. compression; just to know it's OK
2. ck for vacuum leaks
3. ck fuel pressure
4. other than those, see other items above to ck. Also can't rule out the MAF sensor they sold you went bad..

Good luck!

 

Wow, lots of useful information there. Looks like I have what I need to figure this one out- thanks so much!

 

One thing i forgot; after replacing the MAF you may need to reset all the ECM learned settings by unplugging the Batt for awhile (hour should do it for sure), then reconnect (make sure you have radio code). The ECM will eventually relearn on its own, but could take days.

This thread reminded me (see post #4)...
https://volvoforums.com/forum/showth...675#post214675

 

Interesting- I wasn't aware that the ECM learns settings over time- thanks for that bit of advice.

I'm posting an update in case someone comes along with the same problem.

So far I've replaced the thermostat and ECT sensor, MAF sensor, radiator and associated oil cooling line connectors to turbo/auto transmission, flushed coolant, replaced radiator hoses.

Leaving the negative battery lead unplugged for ~1hr successfully reset the check engine light and restored acceleration to normal. Car starts normally so far although it has only been a few days since I tried the ECM reset trick and replaced the thermostat and ECT sensor. Mileage is normal as before (about 20-22mpg in mixed driving, 30+ highway on long tips ~450 miles).

The check engine light does come back, same code as before (too rich). I don't have a Volvo scan tool but I do have a multimeter so I will be checking voltage readings from the MAF sensor terminal and checking for air/exhaust/vacuum leaks, then checking fuel pressure and compression.

I will post another update if/when I figure out the cause.

 

Hi hoping somebody can help me here,

Have a 97 S70 t5, which has started to run like a sack of S#@*T,
A orange light that is an Triangle with another green shape inside has been on now for a month or so, i have been told it is something to to with the emmissions ??

I have noticed that when i want to put my foot down she wont want to go anywhere just really sluggish and only until i bake off it will go.

Have changed plugs,tested 5 leads 2 came back faulty so replaced the 2.
Recently took it to the garage to get a OBD scann however the guy who connected the computer had no clue how to use it, the only code that cam up was dtc:232 which i beleive is the same as P0172 code,

Any help would be great

 

What country are you in? They did not sell S70's in the USA in 97.

 

Yes i know that, i am in NZ

 

Well, this is not the S70 section but you may get help here. Have you checked all of your vacuum lines? Is your turbo still working? What does the owners manual say about the symbol on your dash?

 

Final update:

Bad fuel pump. Replaced it, now it runs just like new.

So the '97 models don't have the OBDI diagnostic system. After having the car looked at by the dealer's system, they figured out it was a bad fuel pump.

The year before I got stranded at work when my car refused to start, so I had it taken to the closest repair shop (I didn't have a spare car to drive all the way back home and out to work again, so I needed a place that was metro-accessible from a friend's place in the city). Big mistake. They put in a ****ty fuel pump that couldn't handle the load and slowly died, giving me awful acceleration on the highway until it began refusing to start up.

Long story short- really wish there was an alternative to a $x00 fee just to get a decent diagnosis from the OBDII. Check if your state is considering "Right to Repair" legislation and push for it. Also, sometimes it's more convenient in the long run to take the car to people who know what they're doing. Not that the dealer is a guarantee on that, but that's life. For what it's worth I did get really great advice eventually from my local dealer. Next up will probably be the PCV (hoping I can get past 200k miles before then).

Thanks to everyone who posted. Hope this helps someone else out.