Stalls while driving Topic is solved

[99TurboBrick]

Background:
1999 S70 T5 Manual
151k miles

Hello all, I’ve had 3 stalls now in the last 6 weeks. The first I thought might be a fluke (gas tank 1/8 full, driving on hill, maybe pump just wasn’t getting fuel for a moment?). After the second stall, I decided to act.

1. Replaced battery. Old battery was 5.5 yrs old, had only 12.1 volt charge. Bought Foxwell battery tester, SOH (State of Health) was 48%. Replaced with new Odyssey battery. New battery has full charge. Battery tester says alternator charge is fine.
2. Replaced original Volvo Fuel Pump Relay with new Volvo OEM relay.
3. Tested Evap Purge Valve near radiator. Disconnected, blew into it, and valve was shut, as it should be. (when they fail, they get stuck open)
4. Test fuel pressure at the rail, was good at about 50 lbs.

Note:
• No Check Engine Light on any of the stalls. No codes in OBD II.

Other symptoms:
1. Stalls happen when engine is cold (at least 1 hr since engine last ran).
2. Stalls occurs within about 5 mins of driving.
3. Stalls occurs when slowing down to approach intersection.
4. After stalls, engine will start up again, maybe not the first time, but probably like the second time, within a minute of the stall.

Related Issue?
• I have a choppy, rough idle when the engine is cold. The idle fluctuates between 900-1100 RPMs for about 2-3 mins, then smooths out. Engine shakes a bit.
• When I approach an intersection, if I pop it into neutral, the RPMs drop to about 500 for a couple seconds, then rebound to 900, but maybe that’s normal.

Possible causes?
• Fuel filter – Last fuel filter change was 11 years ago and 54,000 miles ago. I am definitely due.
• Fuel pump – I have the original in it. 23 years old, and 151,000 miles total on the car.

Other stuff to consider:
• Clean throttle body?
• Clean Idle air control?
• Vacuum or Evap leak?
• Fuel pressure regulator?

Thank you!

[duke1]

hi id clean the idle control first there easy to remove and clean with a good can of aerosol injector/carb cleaner and might fix the issue,it did help with my old girl a 94 855 na ,good luck

[scot850]

Does a 99 P80 have an IAC? If so, where is it fitted?

Thanks,

Neil.

[99TurboBrick]

Yes, but they call it a "Control slide"

https://usparts.volvocars.com/p/42879695/9454745.html

Somehow connects to the throttle module that's under the intake manifold. And there's a couple other hoses attached to it also. Haven't found a really good diagram yet, and it's tough to see down there.

[99TurboBrick]

Thanks for the tip about cleaning the idle control. I am suspecting it's some kind of idle issue.

Just now I was driving, same circumstances (cold engine, short trip), and when I popped it into neutral to coast to an intersection, I could see the tach drop almost all the way to zero. The battery light kicked on, and I was able to see it and hit the gas and prevent the stall. So, something is going on with that idle.

[abscate]

You’ve got a vacuum leak or loose induction hose. Check the small ones under the intake manifold and the left side of engine for the evap purge. You can’t see them to check, they have to be removed.

Your T5 1999 doesn’t have an idle valve. It’s all in the throttle body.

[99TurboBrick]

Aha.

So no codes would show for a vacuum leak or induction hose leak?

The vacuum lines that you're referring to, I believe you mean the Evap lines, correct? I replaced that set last year. So I *should* be good. (photo below)

Thanks for the heads up on the idle control. These bastards have so many variations, it's hard to know what the heck you have.

So, any chance this could just be a dirty throttle module? I have a Xemodex that was installed 10yrs and 50k miles ago.

Finally, I was thinking of just removing the Xemodex, cleaning it, and installing a RIP kit. I think that would eliminate any possible induction pipe issues if they exist. Let me know if my thinking is wrong. And thank you for the response!

[99TurboBrick]

Yep, abscate was 100% correct. The IPD silicone turbo inlet hose that I installed over a year ago had come loose at the turbo.

Well, that would also explain the rough idle I was getting for the first 2-3 minutes after a cold start.

I suspect it would also explain the odd sound I was hearing when the turbo was spooling, almost like a light metal scraping sound (I'm just guessing, but I wonder if this is the sound of the metal impeller inside the turbo?).

[scot850]

You can check the impeller by removing the turbo inlet pipe from the airbox at the turbo end. Stick a finger in the turbo you will feel the end of the impeller. try to move it with your finger side-to-side. If you can it nay be the reason for the noise you were hearing. If it barely moves then if you can access the inlet with a phone and take a picture of a mirror on a stick you may be able to see if there is any damage to that tend of the impeller.

Neil.