SwedeSpeed - Volvo Performance Forum banner

1 - 17 of 17 Posts

·
Registered
Joined
·
5,317 Posts
Discussion Starter · #1 ·
Been having random hard starts today, mostly when warm after sitting for a bit, but has happened cold, so I plugged in VIDA and monitored fuel pressure. Normally when the key is switched to II the FP will prime to 480-500kpa (nominal is 480kpa at startup). My FP will goto 480kpa, but will slowly fall. I pull fuse 21 for the fuel pump, come back a half hour later and it drops to ~330kpa and still dropping (VIDA states residual pressure should be 375-395kpa). So I switch to 0, pop the fuse back in, switch to II, FP reads 440kpa, try to start, and hard start but runs fine. Try the same procedure agian, except after waiting a half hour I switch the key back and forth a few time between 0 and II and it will start no problem.

I do not smell any fuel smells outside of the vehicle. I've just had the injectors serviced and they checked out, but it's possible one of them is leaking, it does smell quite rich once it starts. I do have my stock injectors and will try swapping them in to see if they hold pressure. If not, am I looking at a possible fuel pump replacement or is there a check valve or regulator that needs to be replaced?

Thanks
 

·
Registered
Joined
·
2,778 Posts
just replaced my fuel pressure regulator for the diaphragm leaking/split and it fixed my long crank/slow start problem. may be it for you too.

good luck
 

·
Registered
Joined
·
5,317 Posts
Discussion Starter · #3 ·
just replaced my fuel pressure regulator for the diaphragm leaking/split and it fixed my long crank/slow start problem. may be it for you too.

good luck
Ok, can't really look this up now. What year is your Volvo? Does 2005 have a regulator (I don't recall if it does)? If so, where is it?

Thank You.
 

·
Registered
Joined
·
63,543 Posts
External C/V works for 99-2000s. I've never heard of a failure of the check valve on P2s
 

·
Registered
Joined
·
5,317 Posts
Discussion Starter · #9 ·
Maybe this isn't my issue.

This morning 80-90kpa before primed, 450kpa when primed and starts no problem. Let it sit for 10 mins and hard start. Looked into it a bit more and residual fuel pressure drop is within acceptable.

Any other thoughts? Maybe a sensor issue? ETC, CPS, IAT... come on XC, give me a CEL! :D
 

·
Registered
Joined
·
5,317 Posts
Discussion Starter · #10 · (Edited)
It's the injectors. Removed them and 4/5 were wet. O-Rings were holding pressure just fine. The pintle on the injector and injector seat on the manifold was wet. Pintle was leaking fuel when closed.
Installed the stock injectors and so far three hot starts and not a problem. Looks like I'll be looking for new injectors. I'm going to contact the shop that cleaned them and ask them what solution did they used to clean them.

Looks like I'll also be going for an oil change.
 

·
Registered
Joined
·
5,317 Posts
Discussion Starter · #11 · (Edited)
Just to clarify on my symptoms/observation on this hot start issue for future reference for others:
- Cold starts: OK
- Quick on/off hot starts: OK
- Hot starts after +10min: Hard, approx 10-20 strokes.
- No running issues. Injectors fueling like normal.
- Fuel pressure will gradually drop after shutdown.
- Injector pintles wet upon removal on hot engine. *Alway disconnect the battery and relieve fuel system pressure safely before servicing.
 

·
Registered
Joined
·
5,317 Posts
Discussion Starter · #13 · (Edited)
2.5

Fuel pressure sensor is new. Crank sensor possibly, but the symptom was quite repeatable and only happened when warm after sitting. I just went back out and the engine still registered warm, started without an issue with the stock injectors.

The Pintle was leaking fuel when closed into the manifold and I assume onto the valve and into the cylinders and ultimately into the crankcase, this is why I think I should change the oil. The fuel could have also just evaporated in the manifold and caused a highly rich condition that the engine needed to pump out before starting.
 

·
Registered
Joined
·
2,871 Posts
I've seen a couple cars where the fuel pump controller goes bad, but in those cases it caused a full no start condition. It didn't set codes, it just randomly wouldn't start.

There is a technical service bulletin somewhere about some fuel pump controllers being mounted outside of the cabin under the car and susceptible to environmental damage. The fix is to replace the controller and move it into the cabin with a modified harness. I don't know the vin range of effected cars.

The first time I encountered this fault it took weeks to sort out because it was so intermittent.

With similar complaints I've run into a couple cars where the fuel pump's were installed incorrectly and lines were kinked and even more obscure, I have encountered a couple cars with trash in the fuel tank that was restricting fuel flow. I'm doubtful either of those would apply to you, but I thought I would throw it out there.

Sent from my SM-G900R4 using Tapatalk
 

·
Registered
Joined
·
2,871 Posts
Again, this doesn't really fit your symptoms, but if you are getting cam sensor fault codes look at the fly wheel if you can. These things are very sensitive to interference so much so that when someone used to much never seize on the bolts in the bell housing it slung some some around inside when the bolts were tightened with an impact wrench and that caused issue.

I've seen rusty flywheels cause a no start or slow start too.

I can't remember what conditions the technical service bulletin was for, but there is a "spacer" thing to move the crank sensor a little further away from the flywheel that I've had to use a couple times.

Sent from my SM-G900R4 using Tapatalk
 

·
Registered
Joined
·
11 Posts
Antherzoll, did you ever sort this problem?

I am having intermittent start problems on a 2007 V50 2.4i. Sometimes engine cranks 6-7 seconds whilst other times starts straight away. Hot, cold, makes no difference, nor if it is overnight or just 10 minutes. It can start first go after sitting overnight so this makes me think it is not a cracked pump body or similar.
 
1 - 17 of 17 Posts
Top