Starts, runs rough for 30 seconds, then it shuts off or just will not start?

2006 VOLVO XC90
191,000 MILES • 5 CYL • 4WD • AUTOMATIC
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HOTSAUCE
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I've owned the vehicle for about 2 years and have probably put 18,000 miles on it. The idle has never been smooth. It progressed to the point that it would sometimes shut off at a stop sign/light unless I applied some gas. Then sometimes when I started it and was in park, it would idle a little rough but didn't shut off. But as soon as I put it in drive or reverse it would die. I'd have to restart it a few times leaving my foot to the floor when in gear, eventually it would 'take' after a 3-5 second delay. I noticed that the problems weren't as bad when I had more gas. Soon after that, it wouldn't start at all. I assumed it was a bad fuel pump. I ordered and installed the new pump, but I wasn't able to get it to start.
Someone from a different site suggested that I replace the fuel filter. The one that I replaced the original with was much smaller but fit. I was able to get it started and drove around the block without it shutting off. I had just enough time to brag to my wife that I'd fixed it, before I went outside, and it wouldn't start.
The battery was low but in good shape. I had it charged. Because of some code, I've replaced a solenoid and MAF. The MAF I replaced looked brand new. I've changed the coils and plugs. New fuel filter and fuel pump. What would you advise that I do next? Fuel pump relay? Fuel pump control module?
Thank you in advance!
Oct 25, 2022 at 11:07 AM
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AL514
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Hello, before replacing any more components, if you are concerned about a fueling issue, and I have personally experienced some issues on Volvo's and the fuel systems. I would do a fuel pressure test to verify that the pressure is staying where it should at all times, meaning under a load when the vehicle is in drive, but you have your foot on the gas, which will put a small load on the engine. With these systems, if I remember correctly, you have to T into the fuel line going to the Fuel Rail where the fuel injectors are. I'll put a diagram showing this.
Another thing is if you want to try to maintain your own vehicles, you will want to buy a scan tool, even a basic one that can read engine computer diagnostic codes and show you live data from the engine while running. This is a huge help to see how the vehicle is reacting. I will post more information here for you in a minute.

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator
Oct 25, 2022 at 1:39 PM
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HOTSAUCE
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I've noticed that the scan tools vary a lot in price. I've seen plugin and Bluetooth varieties. I assume the Bluetooth models send the info to your phone? Any buying advice?

If I am unable to get a fuel pressure test reading while under a load, will it prevent a reliable diagnosis?
Oct 25, 2022 at 1:46 PM
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AL514
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Yes, you can get some Bluetooth type scan tools, but I recommend something like this one from Harbor Freight (4th pic). It is $99.00, but you can find cheaper ones on amazon, just as long as it says "can read live data". You don't want just a code reader. The live data is where you will be able to give us some numbers from the data and we can help you far more, knowing what the engine computer is actually doing. Sorry for this long post, but I wanted to help explain how a few things work.

With a basic scan tool that can give you live engine data; you really don't even need to take a fuel pressure reading at first. There are ways to see if the engine is running lean or rich just by live data. For example, the computer data will have data Pids (Parameter IDs) such as Long Term and Short-Term fuel trim. Or it will give readings from an Oxygen sensor, coolant temperature sensor, intake air temperature sensor, etc. Picture 3 below is an example of a few data Pids. You can see the Short Term B1S1 reading -3.9% there. That is the fuel trim from Bank 1 Sensor 1 oxygen sensor and its reading -3.9. So, the engine computer is reducing fuel from the air fuel mixture by 3.9 percent on Bank 1. This means Bank 1 is running a little rich and the computer is compensating for it.

Now from what I have seen Volvos do, they rely heavily on fueling parameters. I had a Volvo that had its rear Oxygen sensor voltage that was stuck reading full rich. The vehicle would not run at all, it would start and stall, maybe run a little bit then stall, huge lack of power. But this was all because the computer was compensating for a condition that did not exist. It was just a faulty reading. So, you can see how a simple obd2 scan tool can help in a huge way instead of changing a ton of parts. Granted the fuel filter and pump may have been on its way out. A restricted filter will ruin a fuel pump.

Having said all that. I do believe you have a fueling issue. Because of your comment about filling the tank. This has to do with the Evap system, but that is a whole other system to explain.

Another thing, you mentioned you had to charge the battery, if you drive the vehicle every day or other day, you shouldn't have to charge the battery at all. If it was reading low voltage, it is most likely starting to fail. They last about 3 years or so. But checking the battery voltage with the vehicle off and then also when running. The charging system should be 13.7 to 14.3volts. Here are some guides to help. If you have any more questions just ask. Again, Sorry for the long post.


https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

https://www.2carpros.com/articles/car-battery-load-test

https://www.2carpros.com/articles/how-to-check-a-car-alternator
Oct 25, 2022 at 2:15 PM
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HOTSAUCE
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No need to apologize for giving me a thorough, well-reasoned answer! Do you suggest I purchase the scan tool you recommended or do the fuel pressure test first?

You stated the issue may be related to the Evap system?

Lastly, the recharging of the battery was due to it running down while unsuccessfully trying to jump start it.
Oct 25, 2022 at 2:46 PM
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AL514
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Well, since you are wanting to get into repairing your own vehicles, I'd grab a scan tool and take a look at what the engine computer is doing. Collect some data, and that will direct your next test. Some people just keep changing parts until the vehicle runs correctly. But think about how much you can save if you know exactly what part is bad. Plus, a ton of headaches. The fuel pressure test on this vehicle is very difficult, it requires special adapters, and such so save that until you're sure you need to. Let's see what the engine is actually doing first, then we can test.
Oct 25, 2022 at 2:55 PM
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JIS001
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Hello, I just wanted to jump in. Is this a turbo or none turbo engine? If it is turbo, I would inspect the charge air pipe. The black plastic hose that goes over the cam cover. If it popped out at the turbo side or at the charge cooler end, it would cause your symptoms of no start and give it gas to try and keep the engine running. This will also most likely set an engine light.

Another issue I saw at Volvo was the fuel pump modules getting corroded. We hardly saw them here in California, but in areas with snow and lots of rain it was an issue. The fuel pump module, if it has not been updated, is located behind the wheel well on the rear right (passenger) side of the vehicle. If it is still there inspect the connector pins and module pins for corrosion. The updated repair at the time was a new fuel pump control module and splicing in a new harness. The new location to place the module was under the rear seat.

Update us with the information and provide pictures if possible. Hope the extra information helps.
Oct 25, 2022 at 8:28 PM
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Al,
I purchased the scan tool that you recommended. What information should I be relaying? I won't be able to get to it for a few hours.

Jorge,
The vehicle is a turbo. According to the vehicle history it's been in the interior South, so no salt / near the ocean. I'll take a look as soon as I am able and let you know. Thank you, sir.
Oct 26, 2022 at 8:09 AM
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AL514
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Take a look at Jorge's suggestion first, if all is okay, then we can dive into the scan tool data.
Oct 26, 2022 at 8:51 AM
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The black plastic hose is secure on both ends. I'll need to go get some of the pliers that remove the paneling before I can inspect the fuel pump module. That's going to take a couple of hours. Would using the scanning tool save me time and money here?
Oct 26, 2022 at 12:46 PM
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AL514
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Well, the idea behind the fuel pump module is really its location, so he was referring to checking its harness wiring plug on the module. Checking inside the connector for any white or green crusty corrosion. Look deep into the female pins on the connector with a flashlight, and then the pins on the module. I can see by its location how it can get corroded easily. Honestly, I don't know why they always put fuel pump modules in the worst places. That one looks like you just need to pull part of the wheel well back to check it, you shouldn't have to remove the entire wheel well. If the connector and wiring to it looks okay, we will move on. But you can always take a look at the engine data with your scan tool.
It will be good to get used to using it, it will be a very helpful tool in the future. You can scan for diagnostic trouble codes too and see if the engine computer is setting any.
Did you get the one I put up a picture of?

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing
Oct 26, 2022 at 2:38 PM
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HOTSAUCE
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Yes sir.
Oct 26, 2022 at 2:41 PM
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AL514
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I noticed this, on their Harbor Freight site, they have a manual you can download which will help you a lot understanding the tool. And there is also a software update for it, but i haven't checked into it yet, but I will. Looks pretty decent. Make sure the key is off before hooking it up and then key on engine off and it will start communicating with your vehicle but do still check the fuel pump module. Jorge worked for a Volvo dealership, so he will know what issues were seen the most.
Oct 26, 2022 at 2:47 PM
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I'm getting a P0101 (1/1) pending. Mass or Volume Air Flow Circuit Range/Performance.
Oct 26, 2022 at 4:06 PM
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AL514
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Okay, that gives us some direction, since it's a circuit code we can do some testing with a multimeter, and also in live data there should be a data Pid about the mass air flow sensor, such as its grams per second (g/s), its voltage reading at idle and off idle as well as see what the other sensors are doing because of a faulty mass air flow reading. I'm not saying the sensor is bad since you mentioned already replacing it. This is a circuit code, meaning the engine computer (ECM) is seeing either a voltage or frequency discrepancy depending on how this MAF signals the ECM. The first thing to do, when you get time, is to inspect the MAF connector. Make sure there's no corrosion in the connector or loose pins. We can go over this tomorrow when you have time, I'll pull up the wiring diagrams for the MAF and see what it should be getting for a voltage supply and ground. You mentioned a solenoid you replaced; do you remember which one it was?
Also check the throttle body, make sure the throttle plates look clean around the edges where they touch the throttle body, you don't have to move the throttle plates. You should be able see if there is carbon build up by just taking the air intake tube off.

Also, what condition is the air filter in?
Oct 26, 2022 at 6:01 PM
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HOTSAUCE
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The connector to the MAF looks good.
The throttle body is at the opposite end of the MAF, correct? That would put it fairly low behind the center of the engine. If I'm going to inspect that, is it easier to put the vehicle on some jack stands and go from the bottom or disconnect/dismantle things until I'm able to get to it?
Before I took it to one mechanic, I cleaned both solenoids. She replaced one, but I don't remember which. My wife said she may have the receipt at work and will check tomorrow.
The air filter is also new.
Oct 27, 2022 at 6:26 PM
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JIS001
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Yes, the throttle will need to be accessed from the bottom. Warm up the engine to soften the plastic pipe over the throttle. Will make it much easier to remove and install. If you try to install it when cold, the plastic gets very hard and very difficult to install back.

If there is oil/carbon build up the PCV system could be plugged up. Now I wouldn't think that would cause your original concern with the hard start and running rough. A defective Mass Air Flow sensor could do that. Are there any other codes that posted besides the P0101? Maybe fuel trims codes like a P0171 or P0172? Vacuum leaks will also cause that issue with P0101.

Once you get the engine running and have it idle on its own. Look at your live data. I need you to turn off all the accessories. Radio, A/C blower motor inside cabin lights, etc. I need you to give me the long- and short-term fuel trim numbers. Also give us the MAF reading in g/s Look at fuel status and let us know if it says CL or OL or it gives a weird message? We will wait for an update.
Oct 27, 2022 at 8:18 PM
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AL514
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I'm still here too, we're working together on this to help you get it resolved. When you go to look at live data, write down the long term and short-term fuel trims when the engine is cold and when it gets up to temperature. Also monitor what the rear (or sensor number 2) Oxygen sensor is doing. It will be a 0.100 to 0.900mv reading. If it is stuck at either end such as 0.900mv which is almost 1volt or closer to 0.100mv write that down. Also, with the fuel trims since you are most likely just going to be looking at it in the global obd2 side it should just give you a percentage. A positive number or negative, but in case it reads a different fuel strategy, here is the service info on your vehicles Adaptive Functions (page 1).
And pages 2 to 4 are some data PIDs to look at.
Oct 28, 2022 at 9:00 AM
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HOTSAUCE
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I'll do so as soon as I am able. Y'all have no idea how much I appreciate the two of you!
Oct 28, 2022 at 9:19 AM
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In order to get to the throttle body, I thought I should remove the bracket in front of it. I removed 2 of the 4 bolts when something (heavy and over my chest) shifted. I'll probably need to use a jack to get it back into position to put the bolts back. I didn't feel comfortable proceeding with out checking with you two. Also, since I haven't been able to start it I was going to use a heat gun to loosen some of the rubber. Is that cool?

I have been unable to get my vehicle started since I bought the OBD2 scanner. Therefore, I can't give you warm numbers. I was only able to get the following readings that y'all requested.

STFT B1 0.0%
LTFT B1 0.0%
STFT B1 S2 99.2%
MAF 0 (lb/min)

Would the fuel status and rear oxygen be under a different abbreviation?

Lastly, I'm getting an additional code of
U0073 Control module communication Bus "A" off.

Nov 1, 2022 at 4:37 PM
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I believe that the "heavy thing" that shifted was the transaxle. If I can't inspect and clean the throttle body, I may be in over my head.
Nov 1, 2022 at 6:53 PM
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JIS001
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The picture you posted was the turbo? And yes, you may have moved the transaxle mount bolt. I think maybe you should tow it to a shop. If it is not starting, I would recommend that you look at the fuel pump control module as previously recommended.
Nov 1, 2022 at 7:45 PM
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AL514
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In the second picture, are those the two bolt holes that you removed? If so, to the left there looks like an engine mount to me. Here's a picture of the throttle body, if it was part of the transmission/transaxle that moved, I think you may have pulled the wiring harness apart, the code you're getting (U0073) is a network no communications code, it's probably why your scan won't communicate either. If the CANbus network, which is a 2-wire network, either shorted out together or both shorted to ground it would take the whole network down. Try to get things back together first, you may have to put a jack under the transaxle to lift it into position to get the bolts back in. Also check for any wiring harnesses that either got pulled apart or if any connectors were pulled apart. I'm pretty sure you're going to find a damaged harness due to the new issues you're having.
The third diagram is the info on the CANbus A network, and the fourth diagram are the two wires for the network (green and white).
Nov 1, 2022 at 7:48 PM
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HOTSAUCE
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I believe that I can get the bolts back in. The photo was taken while I was on my back looking up.
I'll order a fuel pump control module then. Thank you.
Nov 1, 2022 at 7:49 PM
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HOTSAUCE
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If it's going to require a new harness, I may as well just scrap it, no?
Nov 1, 2022 at 7:52 PM
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JIS001
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That is why you need to inspect it first to verify that is the issue. If you see corrosion on the terminals, then that is your issue with the no start.
Nov 1, 2022 at 8:04 PM
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AL514
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No, its most likely just the harness in the area where things moved around. i wouldn't scrap it unless you had planned on getting rid of it. But if things are too much to handle then I would follow what Jorge said. Just relay everything that happened to the shop you take it to, so they have an idea of what happened.
Nov 1, 2022 at 8:07 PM
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HOTSAUCE
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I put the bolts back in place. I was able to start it briefly. The middle row of seats are removed so I could change the fuel pump. There are quite a few wires / connections that I could have accidentally moved. I did something after the 26th because I only had the one code then.

I don't know what my next move is. There's no telling how much it would cost me to get it fixed. Even if I get it fixed, it has close to 200k miles. Is it worth it?
Nov 1, 2022 at 8:49 PM
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JIS001
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Inspect the fuel pump module before doing the pump. The harness as mentioned earlier is a pigtail and not the body harness. Trust me, I have done a body harness on your vehicle model, and it is not fun.
Nov 1, 2022 at 9:52 PM
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I just want to make sure that I'm understanding the current plan. It's likely that I accidentally disconnected a wire recently, but the rest of the harness is probably okay? So, I need to check connections in the areas that I've been working on. The OBD2 will let me know when I've reconnected the proper wires.

Also, I should replace the fuel pump control module? I installed a new fuel pump 2 weeks ago.
Nov 2, 2022 at 8:17 AM