1998 V-70 T-5 Cranks but no-start after running OK

[scot850]

Can you post another picture of the hose and this time taken from a little further back. I think Abscate is correct in his view it is the turbo TCV valve you are showing although there is another valve that looks similar. However I think that has only an in and an out on it.

If it is the TCV (Turbo control valve) it has 3 outlets like the picture which I missed earlier.

There are pictures out there of the TCV and this on IPD website may help:

https://www.matthewsvolvosite.com/how-d ... -tcv-work/

Happy Christmas!

Neil.

[reluctantmechanic]

With respect to the problem of crank but no start, I believe the problem has been solved. I waited a while before posting this because I wanted to be sure.
These were the symptoms:
1. At first, of the course of two years, the car would crank but not start on the fist cranking, but eventually it would seem to catch, then fire up. The problem would not present itself for perhaps another six months or so. Usually it occurred during a winter month, during the coldest day or after a snow fall. The car would show no code.
2. If the car would not start but was in the sun, by mid day, the car would start; usually by this time I would have interpreted the failure to start as water in the fuel line, but in retrospect, I believe it to have been the cold weather affecting the sensor. (Because the car is a dark color, the surface delivered enough radiational warmth to the engine bay, warming its components. like the CPS after awhile.) This only happened once a year for about 3 years.

3. After about 2-3 years, the car would have the same intermittent non-starting problem, but not only on cold days, still it wouldn't show a code. This happened for about 1 year and the temperature seemed to be less of a factor. ( It happened maybe twice, the second time prompted towing to a garage.)

4. Eventually, it would start, but only when it was warm outside (55- 70F and occasionally give the same symptoms described above, where the car seems to want to catch during cranking, but won't or eventually does.

I brought my car to a mechanic who couldn't diagnose the fault because no code was ever showing. ("I'm not throwin' parts at the car.") Eventually, I had it towed home, put a new battery in it after the winter and like magic it started, I drove it around for a few weeks. Sure enough, it gave the code for the CPS. I changed it out and have had not problems starting the car since, over a year ago. (Of course I had to replace the starter because of all that cranking : -)

While comparing the new part and the old part, to verify it was the correct replacement, I noticed that the old part had a phenolic material that had deteriorated and the sensor, a small magnetic winding fell out. I suspect that slight temperature changes caused the damaged part to contract in cold weather at first, eventually not conducting at all. Whether it was damage to the winding or the substrate holding it, I cannot be certain, but the fact that it was cracked probably means that the tolerances changed based on temperature.

The replacement part was of Italian manufacture, having the same shaped aluminum alloy casting as the original. The parts supplier I used is the same used by garages, and it cost about $130 US. If I had it to do over again, I'd replace it when the symptoms first manifest themselves.

Thanks everyone for your help with this problem and with the others I've encountered in t he past.

[scot850]

Appreciate you taking the time to get back and give us this valuable update. Much appreciated.

Neil.

[RickHaleParker]

4. Eventually, it would start, but only when it was warm outside (55- 70F and occasionally give the same symptoms described above, where the car seems to want to catch during cranking, but won't or eventually does.

These P80s do have a fuel pump controller. It is a electromechanical device that looks like a relay.
The most common symptom of a faulty P80 pump controller is ... will not start or hard to start when cold.

The P80 Fuel Pump Controller is located in the engine compartment fuse box, under the second top plate and is marked 102.

The P80 Fuel Pump Controller is an easy fix. Pop the top off and replace the two electrolytic capacitors. Fixes the problem like 99% of the time.

[reluctantmechanic]

Thanks for the info. Initially, I thought it wasa fueling problem; I even told the mechanic it was. I changed out the pump, because the symptoms were similar to those of my 850 when its pump failed, but when that didn't solve the problem, I figured it might be the fuel filter in front of the rear wheel. Nothing solved the problem (obviously), jumping over the fuel pump relay, etc. The fuel rail pressure was OK and the fuel pressure control valve was OK. After the CPS replacement, I noticed that the throttle body spring was a bit sticky after not being used for a few months....... It could use some lubrication which I applied, but I don't know what would be the best.

Many thanks to you and the other guys that helped me with this problem. I was almost convinced that the car was going to be unrepairable, having an intermittent that would be unidentifiable, but at great cost. What is amazing is that the databases consulted by non-Volvo mechanics really don't point them properly through the diagnoses for these problems with these cars. I first noticed this with the 98 850 I have (off road, now). Except for consulting MV, I would never have found the disconnected vacuum house hiding in the rightside of the intage manifold.

[abscate]

Our Quirky Swedes respond well to that gal or guy who knows Volvo ( and often Saab)

Seek out those good independents and the closer you are to Robert in Cincinnati , the better.