SwedeSpeed - Volvo Performance Forum banner
1 - 20 of 25 Posts

·
Registered
Joined
·
1,199 Posts
Discussion Starter · #1 ·
We have a t5 s40 with 34k on it and sometimes it won't start. It cranks strong, but just doesn't start. I replaced the fuel pressure sensor and the problem went away for a month and now it's back. It only happens on cold starts, and eventually it'll start.

There was no pem recall because it's installed under the back seat already, that's what Volvo told me and it is there. There are no codes, pending or otherwise now. But before I did the fps, it was showing a pending fault for low fuel pressure at start and the new fps seemed to have fixed it.

Anyone know where I should look next?
 

·
Registered
Joined
·
1,591 Posts
already replaced the battery right?
 

·
Registered
Joined
·
1,199 Posts
Discussion Starter · #3 ·
No but I had it tested and they said it's like brand new. It's a Volvo battery but I don't know if it's original. The car runs great once its running. This only happens on cold starts.
 

·
Registered
Joined
·
1,280 Posts
Load test the battery! How old is yours?
 

·
Registered
Joined
·
1,280 Posts
I'm going to load test it tonight and see what it does. But I don't know its age
It should have a date code, but load test it and then check back. Then we can start to narrow it down. These P1s are just very particular with batteries.
 

·
Registered
Joined
·
1,199 Posts
Discussion Starter · #7 ·
We bought the car a few months ago, and I don't have a detailed history of what was done except the basic maintenance on carfax that Volvo reported. Just oil changes and some other stuff. I'll post back when I do a load test. She doesn't get back from work until 7pm
 

·
Registered
Joined
·
1,280 Posts
That's fine. I meant like on the top of the battery there is normally a series of digits that resemble a date. That's normally when the battery was made in the factory.

Napa or such load tests for free btw.
 

·
Registered
Joined
·
1,199 Posts
Discussion Starter · #9 ·
I had advanced auto do it last month and the guy said it was like new, but I don't have the numbers.
 

·
Registered
Joined
·
3,412 Posts
As part of the deductive process, do a tuneup (plugs + air filter) and then check your fuel pressure at the rail. If there's a delayed start, sometimes it's a loss of fuel pressure thanks to the check valve on the fuel pump losing pressure over time
 

·
Registered
Joined
·
1,199 Posts
Discussion Starter · #11 ·
I did the air filter when we got it, and pulled the plugs and they looked fine. It has no issues running through. I don't have a fuel pressure gauge, I guess I should invest in one. My obd is reporting 44psi pressure, and it doesn't fluctuate with load. This is before and after changing the fps.
 

·
Registered
Joined
·
1,280 Posts
Alright. So you can rule that out. Your FP is good while starting?
 

·
Registered
Joined
·
1,199 Posts
Discussion Starter · #14 ·
That's what it's telling me. It's strange because it's not every day, and it's only when it's cold.
 

·
Registered
Joined
·
4,373 Posts
You need to check the fuel pressure. Throw a gauge on & watch the pressure after you shut the car off. I suspect it's going to zero pretty rapidly. It should hold pressure for several hours. A rare problem but your symptoms sure sound like it. Pressure should spike close to 90psi when you are cranking on a cold start.
 

·
Registered
Joined
·
1,199 Posts
Discussion Starter · #16 ·
I'll see if I can borrow a fuel pressure gauge tomorrow if not I'll go buy one.

At 34k it's hard to believe that something is broken. The car didn't sit for long periods of time, it just was driven only a few thousand miles a year. That's what the oil change intervals suggest. If the fps fixed the problem for a month, why would the problem come back? I'm leaning towards replacing the pem because I can always return it if it doesn't solve the problem. It's just strange that it has zero issues besides starting.
 

·
Registered
Joined
·
1,280 Posts
I'll see if I can borrow a fuel pressure gauge tomorrow if not I'll go buy one.

At 34k it's hard to believe that something is broken. The car didn't sit for long periods of time, it just was driven only a few thousand miles a year. That's what the oil change intervals suggest. If the fps fixed the problem for a month, why would the problem come back? I'm leaning towards replacing the pem because I can always return it if it doesn't solve the problem. It's just strange that it has zero issues besides starting.
Very very rare to be the PEM. Especially if it's under your seat. It just gives signals about fuel. Not a lot to go wrong in that, the ECM or TCM. It's normally ancillary devices connected to them.

Your car doesn't have a lot of miles, but it is 10 years old. I'm not sure why it is occurring. But start with fuel pressure. That's the basically. Like PCZ said, it should hold. If the PEM was bad, I don't think the issue would be intermittent.
 

·
Registered
Joined
·
4,373 Posts
I agree, either failure is rare. PEM exceeding so & would give other symptoms.

Low fuel pressure code... This supports the draining back theory. Gauge will tell the story once you get it installed. Real bummer if that's the issue as it will require you to drop the tank & replace the fuel pump.
 

·
Registered
Joined
·
1,199 Posts
Discussion Starter · #20 ·
Of course I have to drop the tank... I had to do that on my audi in the snow. At least it's not snowing. I'll grab a gauge tomorrow and see if that helps me narrow it down. Maybe I can cut a hole in the trunk haha.. Seriously, is that an option?
 
1 - 20 of 25 Posts
Top