97 850R wagon no idle after PCV replacement

jjc1 · Post by **jjc1** » 15 Mar 2014, 15:14

So things started with a failed emission inspection for NOx. This car does not have a EGR or air pump and I think the cat is OK. It has 88K original miles on it. My IAC, TPS, MAF have been recently changed (bosch parts from FCP), and I've also cleaned the throttle body so I suspected the injectors and fuel pressure regulator. So I pulled the injectors to have them rebuilt and ordered a new fuel regulator and filter. It ran smoother and with a bit more power after the injectors were done as two weren't at 100% when tested prior to rebuild. I also changed the thermostat and engine temp sensor although my scanner didn't indicate any issues with them.

After the injector work, I noticed smoke from the oil dipstick so I ordered a PCV kit, new hose with the sensor at the turbo and since I was going to pull the intake, the knock sensors. All this was obtained from FCP and Bosch parts or volvo parts used.

After getting it back together today, I fired it up and it immediately starts but does not idle at all. If I try to feather the gas pedal, it will sputter and pop/backfire a bit. I've re-checked my work and although I didn't pull the manifold, I know the hoses are connected and plumbed correctly and clamped tightly. The manifold gasket is fine, all sensors are plugged tight. No loose vacuum hoses. No codes. This is disappointing.

Since this is a car that my daughter takes to college, within the last 20K miles, I've replaced the timing belt, plugs/wires/cap/rotor, cooling hoses, front O2 sensor, IAC, and TPS and MAF, all filters are fresh, fuel relay has been replaced.

Any suggestions before I pull the manifold again to double-check everything? I'm stumpted!

Post by **rspi** » 15 Mar 2014, 19:18

jjc1 wrote:...and although I didn't pull the manifold, I know the hoses are connected and plumbed correctly and clamped tightly. The manifold gasket is fine, all sensors are plugged tight.

...Any suggestions before I pull the manifold again to double-check everything? I'm stumped!

I'm confused... did you pull the manifold to do the job or not?

If you DID pull the manifold to do the job, I would look real close at the corner of the manifold closest to the drivers front tire to make sure you did NOT put the hose clamp between the manifold and head.

Post by **misha** » 15 Mar 2014, 19:30

jjc1 wrote:After getting it back together today, I fired it up and it immediately starts but does not idle at all. If I try to feather the gas pedal, it will sputter and pop/backfire a bit.

The only thing which will prevent the car from idling is IAC valve and it's hoses.

Intake manifold gasket,like Rspi suggested,shouldn't keep the car from idling and running.According to members experience here on the forum...it would run like a crap but it should run.

What about throttle position sensor...is it connected?

Post by **cn90** » 15 Mar 2014, 20:13

1+,

Happened to me after the PCV job too!
The hose feeding the Idle Valve became disconnected.
Re-installed it with clamps, all is well.

Post by **rspi** » 15 Mar 2014, 20:29

That actually happened to me on my first PCV job as well, '98 S70.

IAC lower tube was loose.

jjc1 · Post by **jjc1** » 15 Mar 2014, 20:59

I will double-check the IAC hoses but I did check them earlier.. will double-check it's tight. TPS is connected as well as all the other sensors including the IAC. The only thing I can think of, is perhaps the manifold gasket is defective... I was pretty careful not to crimp it but you never know. Perhaps that hose clamp at the end where the plumbing turns towards the turbo slipped on install. The intake looks like its flush but again, it's hard to really see to be sure. For earlier post, yes I pulled the manifold to get to the breather box, plumbing and knock sensors. I do have a spare new gasket and will install it tomorrow, weather permitting. After a 60+ degree day today, we're supposed to get 6-12 inches of snow starting tomorrow eve.

Again, no codes. I tried disconnecting the MAF, IAC, and TPS in turn, without affect. Codes were generated but I cleared them after each of these attempts. The result was the same.... car fires right up and the idle spikes up as it should, then the engine dies immediately. Feathering the gas will prolong the run for a second but it does run like crap and dies. .... thinking/hoping its the manifold gasket. Thought this would go smoothly as I've done it a couple of times before on another car.

jjc1 · Post by **jjc1** » 16 Mar 2014, 09:06

Tried to fire it up this morning after it sat all night and was cold. Car cranks fine, immediately fires and revs for about a second then dies. No codes. I've checked the IAC hoses... all tight.. MAF and air intake filter box all tight. I double-checked that hose clamp holding the PCV plumbing around the turn at the intake (last bolt on driver side) and was hoping that I would see it out of place (thinking it may have slid between the manifold and head, causing a space/leak) but it's fine. So I don't think the intake gasket/alignment is the problem. The logical thing to suspect is that I've missed a major intake hose or something like that, given I had the manifold off but I can't find it. It's acting as if it's not getting fuel so my next step will be to put a gauge on the fuel rail to see if I'm getting fuel pressure. I can't really imagine the FPR is defective (new FCP, 200 miles on it) but perhaps the fuel pump has coincidentally failed. I was going to pull the intake off again but will chase the fuel pressure first.

BTW. I double checked the TPS, IAC and MAF but they seem fine. I tried pulling the connectors to each of these in turn and then tried to fire it up with no difference (cranks, fires, RPM spikes up, dies immediately). It did generate a code with the TPS connector off and I re-set that - - then put it back on to re-try with another sensor. It behaved the same... cranks, fires right up, idle spikes for a second then dies. ....thinking fuel at this point...... fuel relay was changed about 10K miles ago as preventative measure... I kept the old one any may try swapping if the pressure is low.

beigg · Post by **beigg** » 16 Mar 2014, 10:55

stock intercooler? Check for a split ic hose or busted core in the ic.

jjc1 · Post by **jjc1** » 16 Mar 2014, 11:06

Intercooler is stock - - were no issues prior to the PCV work yesterday but I'll get under there to check this weekend. The hoses look OK from up top but will check underneath.

Update: Fuel pressure is OK. I attached the gauge and when I put key on, it pressured up to at least 45 lbs and when I cranked it, the pressure stayed steady. No change on symptoms. When the weather clears (probably next weekend), I'll pull the manifold to check the gasket - - unless anyone has other suggestions!

Post by **rspi** » 16 Mar 2014, 12:17

Check the wires at the injector relay on the scrod. I would unplug it then plug it back in.