1998 s70 will not run

Post by **mercuric** » 11 Apr 2013, 17:50

Diagnostic thoughts on the ECT sensor, in hopes of saving you some time/money, or quickly identifying the problem:
1) It's just a simple temperature sensor that changes resistance with temperature. You can test it with a multimeter, correlating the displayed value to the temperature. Graph attached.
2) Any resistor between 1k and 3kohm could be substituted for the sensor for a quick diagnostic if you don't have a meter handy -- That'd tell the ECU the temperature is 20-40c, in the ballpark of what the actual temperature would be.. 3k would be right around room temp.
3) The ECU will promptly set DTC 1-2-3 and use substituted value 20c if the ECT is disconnected or is way out of range (resistance correlating to less than -45c or more than 150c). It's very willing to set this code -- So willing it's the first code you get (and only one immediately set) when you power up an ECU on the bench by applying 12v to the right pins without connecting anything else to it.
4) Actual value can be read off using a cheap ELM327 OBD-II adapter and many compatible applications (ie: torque for android, ScanXL for windows, etc etc)

boballen · Post by **boballen** » 12 Apr 2013, 18:28

I checked out the TPS. The multimeter read 0.47 with the throttle closed and 4.17 full open. From what I read from the posts, that is within the parameters. I then move on to the temp sensor. I found a wire that was connected with only 1 strand of copper. Appeared to be chewed. I spend hours looking for broked or chewed wires. I gusess I missed that one. At any rate, temperarily spliced it back in. The car started on idled and stayed running. However, it still a little rough and the cataylic converter had orange spots on it. Could this be from all the excess gas that might have been in it ? I' ll take it for a ride tommarow to see if things smooth out. That is if this winter storm goes away. Winter just does not want to end. I sure learned a lot form all of you and I sincerely appreaciate it. If it was up to me I would give you all another red star. BOB

boballen · Post by **boballen** » 13 Apr 2013, 15:17

I guess I spoke to soon. This morning I started the Volvo (still running rough, but runnng) , pulled out of the garage the car stalled. I was unable to get it started again. However, I was able to get some codes out of the computer, They are as follows:
A. PO131- O2 circuit low voltage Bank 1 sensor 1
B. PO117- engine coolant temp circuit low imput
C. PO102- mass or volume air flow circuit low imput
D. PO120 - throttle position sensor A circuit

Does this information pinpoint any particular component, or does all need to be replaced. I can' see all of them going bad all at once.
BOB

Post by **precopster** » 13 Apr 2013, 15:49

Your TPS is wildly out of range compared to mine. I would replace it sooner than later. Mine was from a 850 '96 NA.

Why not try the 3K resistor across the temp sensor wire instead of replacing it as well?. This would keep the cost down.

The O2 semsor will be dirty due to the rich mixtures the car has been producing. The cat converter will also be soaked in fuel.

s70fanman · Post by **s70fanman** » 13 Apr 2013, 18:42

If and or when you find the problem please post it!!! My 98 t-5 acted really unVolvo-like and slowly quit I replaced the fuel pump relay and still will not start. By the way does the fuel pump have voltage going to it when the key is no the "run" position??

boballen · Post by **boballen** » 14 Apr 2013, 15:45

HI, guys. Bob here again. When testing the ETC, I get a reading of 5.07 on the sensor end and 5.4 on the other end. This is with the meter set on ohms. With the meter set on DCV I get no reading at all on the sensor end. On the other end I get a reading of 5.41. Does this tell us anything ? I hope I'm doing this right. My wife is a science teacher and she had some resistors in that 1-3kohms. I tried what was suggested in a previous post to no avail. The car does start, but dies in about 15 -20 seconds unless I keep the RPM's up around 5000. It runs longer (still rough), but eventually dies. I'd love some more expert guidance please. BOB

boballen · Post by **boballen** » 11 May 2013, 12:27

I don't know if anyone is still following this thread. My last post was 4-13-2013 I believe. I haven't had any time since ten to work on it. At any rate, I was rechecking everything from the beginning and discovered my timing was off by a fraction. It was set to the a mark on top of the crank gear and not between the 2 teeth with marks. I don't know if this is enough to matter, but resetting it I was not able to turn the crank by hand all the way around. The same is true for the intake and exhaust cam pulleys. It seems to me this is a very serious problem!!!! Please share what you think.

Boballen

Post by **erikv11** » 11 May 2013, 14:05

I certainly do not know the contents of the whole post but I'm sort of following.

So how far off is the timing, in terms of teeth? Did you remove the belt yet, to try and reset timing?

If you can't get the engine to turn over by hand while the belt is still on, try removing the spark plugs first.

jdmack · Post by **jdmack** » 11 May 2013, 14:34

Hi Bob I stumbled upon this thread as was very interested in seeing what the final culprit was. My question was that you had stated the car ran great when you parked it and after sitting for 10 days now the cam timing is off , how can that happen?? I am sure there is a logical explanation but it just seems hard to imagine that if nothing was done to the vehicle while it sat that now the timing is off a tooth. Please keep us posted of any further developments.

boballen · Post by **boballen** » 11 May 2013, 16:38

The timing was off by 1 tooth. Apparently I unknowingly set it that way my self. I don' think the belt could have slipped. I have removed the timing belt and the spark plugs and still can't turn it over at the crank pulley. It turns a little more than 3/4 and then stops dead. If the timing was off by one tooth, could this be enough to cause some internal engine damage? The compression was good all the way around. Was going to do a leak down test but there is nowhere in town that has a tester. I have read where I can make my own from my compression tester. I will give that a try. There were so many things I have done so far All trial and error. I still can't understand how it could be running great one day and 10 days latter not running at all or starting once and a while and then dies. I promised myself it will be fixed and I will do it myself, along with this Volvo forum, of course.