Recently developed a stalling issue.
84 633csi
85 M106 engine
M1.3 with 179 ECU
Stock? In tank fuel pump
255 External Pump w/less than 1000 miles on it, new fuel hoses in between (but I installed it back in 2013)
Begi RRFPR Rebuilt a few months back
No visible leaks anywhere
After driving for 10-15min last week, this is what happened. Parked car, went to start, started and shut off. Tried again a few more times, same thing Fuel pressure (I have a digital fuel pressure gauge) was reading less than 20psi. A few days later I added 5gal gas just in case. Before I did, I started the car and the pressure read normal-above 40. And would increase when revving. After adding gas, was the same.
Went to test drive this past weekend and it would run fine for the first 2-3 minutes and then start to die. If I apply gas, it will stay running. But the moment I let go, the engine dies right away. Was able to limp it back to my garage with multiple shut offs in between. I changed the fuel filter today, the old one was def clogged up, and even with the new one the issue persisted.
I'm trying to narrow down what part of the system I should diagnose. Any pointers would be appreciated.
Stalling Issue M106 M1.3 - Thinking Fuel Related
Re: Stalling Issue M106 M1.3 - Thinking Fuel Related
A few things come to mind as possibilities, none of them really likely, but worth checking.
The intank pump, did you replace it? Unless you did or have documentation that it was done in oh, the past 100K or less, it's probably dead. They don't last nearly as long as the main pump. Even if you took it out and tested it, they can test good as the brushes reseat, but only work briefly.
Disconnect the return fuel line from the regulator, jumper out the relay or even crank briefly and see if you get fuel coming out. If you do and the pressure reads low it suggests the FPR.
Something that's easy to overlook but would be in conjunction with the intank pump is fuel lines. Cheap fuel lines may not last over 10 years but even if they're good ones loose clamps can bite you. On a couple of different BMWs I had a loose clamp allowing the pump to suck air and either starting very hard or running out of gas with over a quarter of a tank. What was especially puzzling to me is they didn't leak fuel, no drips, no signs of leakage, but they would suck air. So make sure everything is tight on the suction side.
And of course what brand is the new 255 pump, a good one or what? On my E36 I replaced the pump with a known brand, but not like Bosch or VDO and had nothing but troubles. Turned out it wouldn't pump enough pressure. It worked, but IIRC it was a 3.5 Bar system and it wouldn't pump more than 2 or 2.5. That took a while to figure out.
The intank pump, did you replace it? Unless you did or have documentation that it was done in oh, the past 100K or less, it's probably dead. They don't last nearly as long as the main pump. Even if you took it out and tested it, they can test good as the brushes reseat, but only work briefly.
Disconnect the return fuel line from the regulator, jumper out the relay or even crank briefly and see if you get fuel coming out. If you do and the pressure reads low it suggests the FPR.
Something that's easy to overlook but would be in conjunction with the intank pump is fuel lines. Cheap fuel lines may not last over 10 years but even if they're good ones loose clamps can bite you. On a couple of different BMWs I had a loose clamp allowing the pump to suck air and either starting very hard or running out of gas with over a quarter of a tank. What was especially puzzling to me is they didn't leak fuel, no drips, no signs of leakage, but they would suck air. So make sure everything is tight on the suction side.
And of course what brand is the new 255 pump, a good one or what? On my E36 I replaced the pump with a known brand, but not like Bosch or VDO and had nothing but troubles. Turned out it wouldn't pump enough pressure. It worked, but IIRC it was a 3.5 Bar system and it wouldn't pump more than 2 or 2.5. That took a while to figure out.
Re: Stalling Issue M106 M1.3 - Thinking Fuel Related
Thanks for your input Mike, always appreciated.
- Have owned the 6 since 2007, never once changed the in tank pump! I wouldn't be surprised if it's shot, but from what I've researched online, it wouldn't cause this type of issue?
- Forgot to mention that the FPR is brand new.
- When I did the fuel pump I did replace a bunch of them with new Goodyear branded hoses. Seems to have held up great over the years. I also used ABA style hose clamps to prevent severe biting into the hoses themselves. Still something to investigate.
- Walbro GSL392 pump.
I'm taking the car to a shop tomorrow to have some non related fabrication work done. I have asked if they could try to diagnose and troubleshoot this issue. Will mention some of the above items.
Here are some other thoughts I had, to not rule anything out.
1. Anything on the air side that could cause this? The way the engine dies out so abruptly reminds me of trying to run an OBD2 car with the MAF unplugged. Did confirm that all my vacuum lines were still attached and not broken.
2. I recently replaced the water pump gasket. Is there anything in that area that could cause this type of issue?
3. I recently replaced the wastegate diaphragm. Is there anything in that area that could cause this type of issue?
- Have owned the 6 since 2007, never once changed the in tank pump! I wouldn't be surprised if it's shot, but from what I've researched online, it wouldn't cause this type of issue?
- Forgot to mention that the FPR is brand new.
- When I did the fuel pump I did replace a bunch of them with new Goodyear branded hoses. Seems to have held up great over the years. I also used ABA style hose clamps to prevent severe biting into the hoses themselves. Still something to investigate.
- Walbro GSL392 pump.
I'm taking the car to a shop tomorrow to have some non related fabrication work done. I have asked if they could try to diagnose and troubleshoot this issue. Will mention some of the above items.
Here are some other thoughts I had, to not rule anything out.
1. Anything on the air side that could cause this? The way the engine dies out so abruptly reminds me of trying to run an OBD2 car with the MAF unplugged. Did confirm that all my vacuum lines were still attached and not broken.
2. I recently replaced the water pump gasket. Is there anything in that area that could cause this type of issue?
3. I recently replaced the wastegate diaphragm. Is there anything in that area that could cause this type of issue?
Re: Stalling Issue M106 M1.3 - Thinking Fuel Related
The significance of the in tank pump was more that if there is a loose hose clamp it would be more likely to be a visible leak with a working pump. I concur though, a bad in tank should not cause your symptoms, except maybe unless the suction side was sucking air.
Re: Stalling Issue M106 M1.3 - Thinking Fuel Related
Bringing this back from the dead.
Recently brought the car back from the shop-- they were only doing fab-related items. Went for a quick spin before leaving the shop, started was running okay. I did a light throttle boost pull for just a few seconds-- after shifting to neutral the engine died. Tried to restart and while it did once/twice, it would not stay on for more than a few seconds.
Fast forward to this past weekend.
1. I thought it was fuel related, I have a fuel pressure gauge so I could watch in real time. Well, that gauge is shared by an oil pressure gauge and I was looking at the wrong readings!
2. I replaced the in-tank fuel pump because I thought this was fuel related.
3. Went to start yesterday, ran rough, shut off after a few seconds.
4. Pulled plugs, all black and fouled. Cleaned them best I could with a wire brush. Re-installed, car started but rough and died after a few seconds.
5. Thought I might have fuel washed the cylinders. Pulled plugs, dropped oil into the cylinders, re-installed, car started but rough and died after ~5-10 seconds. This was the longest the car had stayed running.
Other things I have checked.
1. Fuel pressure is good. When the car dies, I can hear the fuel pumps turning off.
2. Main relay getting 12V at pin #30. Main relay getting 12V at pin #86 with key on.
3. Fuel pump relay getting 12V at pin #86. (Acc. to HPSI Motronic troubleshooting, pin #30 should be hot?)
4. No vacuum leaks so far. I do have to double check the couplers attached to the intercooler, but highly doubt it!
5. ICV buzzes with key on.
6. New fuel filter (old one was clogged).
7. Confirmed I am getting spark, although did not test all cylinders.
I am starting to think that the fuel side of things are okay, and my issues may lie with the spark side. Looking for any input, thank you. Here is some videos below of the car struggling to run yesterday. Middle gauge -- top = oil pressure, bottom = fuel pressure.
https://photos.app.goo.gl/njp5d2zBrPAagXzk6
After changing fuel pump + wire brushing spark plugs.
https://photos.app.goo.gl/U52R43S8s7VLM4HP9
After adding oil to cylinders.
Recently brought the car back from the shop-- they were only doing fab-related items. Went for a quick spin before leaving the shop, started was running okay. I did a light throttle boost pull for just a few seconds-- after shifting to neutral the engine died. Tried to restart and while it did once/twice, it would not stay on for more than a few seconds.
Fast forward to this past weekend.
1. I thought it was fuel related, I have a fuel pressure gauge so I could watch in real time. Well, that gauge is shared by an oil pressure gauge and I was looking at the wrong readings!
2. I replaced the in-tank fuel pump because I thought this was fuel related.
3. Went to start yesterday, ran rough, shut off after a few seconds.
4. Pulled plugs, all black and fouled. Cleaned them best I could with a wire brush. Re-installed, car started but rough and died after a few seconds.
5. Thought I might have fuel washed the cylinders. Pulled plugs, dropped oil into the cylinders, re-installed, car started but rough and died after ~5-10 seconds. This was the longest the car had stayed running.
Other things I have checked.
1. Fuel pressure is good. When the car dies, I can hear the fuel pumps turning off.
2. Main relay getting 12V at pin #30. Main relay getting 12V at pin #86 with key on.
3. Fuel pump relay getting 12V at pin #86. (Acc. to HPSI Motronic troubleshooting, pin #30 should be hot?)
4. No vacuum leaks so far. I do have to double check the couplers attached to the intercooler, but highly doubt it!
5. ICV buzzes with key on.
6. New fuel filter (old one was clogged).
7. Confirmed I am getting spark, although did not test all cylinders.
I am starting to think that the fuel side of things are okay, and my issues may lie with the spark side. Looking for any input, thank you. Here is some videos below of the car struggling to run yesterday. Middle gauge -- top = oil pressure, bottom = fuel pressure.
https://photos.app.goo.gl/njp5d2zBrPAagXzk6
After changing fuel pump + wire brushing spark plugs.
https://photos.app.goo.gl/U52R43S8s7VLM4HP9
After adding oil to cylinders.
Re: Stalling Issue M106 M1.3 - Thinking Fuel Related
How is the blow off valve configured? This thing is running motronic with an AFM so if the blow off valve isn't being recirculated properly it'll be going super rich every time it opens.
I was blowing through the AFM on the original system, so I placed the valve right before the AFM. If you're drawing through the AFM that's metered air and it must be circulated back into the metered system upstream from the compressor.
I was blowing through the AFM on the original system, so I placed the valve right before the AFM. If you're drawing through the AFM that's metered air and it must be circulated back into the metered system upstream from the compressor.
Re: Stalling Issue M106 M1.3 - Thinking Fuel Related
The setup is:
Filter > AFM > Compressor > Intercooler > Intake > BOV > Throttle Body
I ran it the same way prior to having and intercooler installed and it would idle just fine. But that could be a reason why it would want to stall after a boost pull.
I did get it to run and stay on today. I replaced the plug wires with tested good spares, spark plugs Bosch WR8DC (spares), checked the distributor cap/rotor (both good), added a little oil to each cylinder, tested the resistance on the ICV (3pin, checked okay), and double checked all vacuum hoses.
Car idles like crap and is running very rich. Without throttle, the idle rpm is very low, ~500. Disconnecting the ICV while running did not show any significant change.
https://photos.app.goo.gl/hrSTCy5CGBaH5CFN9
I'm stepping on the throttle at the beginning and end.
https://photos.app.goo.gl/KcbCpC8D5KZjQVQ76
Filter > AFM > Compressor > Intercooler > Intake > BOV > Throttle Body
I ran it the same way prior to having and intercooler installed and it would idle just fine. But that could be a reason why it would want to stall after a boost pull.
I did get it to run and stay on today. I replaced the plug wires with tested good spares, spark plugs Bosch WR8DC (spares), checked the distributor cap/rotor (both good), added a little oil to each cylinder, tested the resistance on the ICV (3pin, checked okay), and double checked all vacuum hoses.
Car idles like crap and is running very rich. Without throttle, the idle rpm is very low, ~500. Disconnecting the ICV while running did not show any significant change.
https://photos.app.goo.gl/hrSTCy5CGBaH5CFN9
I'm stepping on the throttle at the beginning and end.
https://photos.app.goo.gl/KcbCpC8D5KZjQVQ76
Re: Stalling Issue M106 M1.3 - Thinking Fuel Related
Delete - Double Post
Last edited by The Don on Oct 16, 2024 8:08 AM, edited 1 time in total.
Re: Stalling Issue M106 M1.3 - Thinking Fuel Related
Delete-triple post
Last edited by The Don on Oct 16, 2024 8:08 AM, edited 1 time in total.
Re: Stalling Issue M106 M1.3 - Thinking Fuel Related
Is the BOV routed back to the compressor inlet or is it blowing off to atmosphere?
Re: Stalling Issue M106 M1.3 - Thinking Fuel Related
Blowing to atmosphere.
I checked the fuel pressure today, in lets say about 20 hours, the pressure was reading zero. Is there a standard for how much loss is normal?
I checked the fuel pressure today, in lets say about 20 hours, the pressure was reading zero. Is there a standard for how much loss is normal?
Re: Stalling Issue M106 M1.3 - Thinking Fuel Related
It would be nice if the system held pressure but they don't always. This may extend cranking but will have no effect on running if proper pressure is maintained in the rail.
The BOV is a big issue. They often hang open during normal running, any time there is strong enough vacuum in the manifold. It will be lean sometimes and rich other times. It will never run right. What you could try is disconnecting the vacuum line to it, see what difference it makes. Don't spool the turbo up, just drive it moderately and see how it behaves.
Under boost, when it blows off its going to be massively rich. Pouring tons of fuel in with the throttle closed. You can't get away with it running a draw through setup.
The BOV is a big issue. They often hang open during normal running, any time there is strong enough vacuum in the manifold. It will be lean sometimes and rich other times. It will never run right. What you could try is disconnecting the vacuum line to it, see what difference it makes. Don't spool the turbo up, just drive it moderately and see how it behaves.
Under boost, when it blows off its going to be massively rich. Pouring tons of fuel in with the throttle closed. You can't get away with it running a draw through setup.
Re: Stalling Issue M106 M1.3 - Thinking Fuel Related
I am digging into this more, this definitely could be it. I visited a friend who also has a turbo M30 powered 6 with the same BOV (TurboSmart 50mm), and he said 1) It would stay open at idle and cause surging & 2) He had to add a stiffer spring. He is running standalone so unmetered air is not as big of an issue.turbodan wrote: Oct 19, 2024 10:31 AM It would be nice if the system held pressure but they don't always. This may extend cranking but will have no effect on running if proper pressure is maintained in the rail.
The BOV is a big issue. They often hang open during normal running, any time there is strong enough vacuum in the manifold. It will be lean sometimes and rich other times. It will never run right. What you could try is disconnecting the vacuum line to it, see what difference it makes. Don't spool the turbo up, just drive it moderately and see how it behaves.
Under boost, when it blows off its going to be massively rich. Pouring tons of fuel in with the throttle closed. You can't get away with it running a draw through setup.
So then I dug in more and listed on TurboSmart's website is disclaimers that their BOV could potentially be incompatible with cars running an AFM. That it could cause the car to STALL, RUN ROUGH, or RUN RICH.
Will disconnect the vacuum line and see what happens.
Re: Stalling Issue M106 M1.3 - Thinking Fuel Related
With standalone, I'm assuming Megasquirt, anything that makes it into the manifold will be accounted for. Any leaks in the plumbing will have no effect on AFR. Motronic assumes that every single cubic foot of volume it meters through the AFM is going into the engine, and nothing more. Turbos complicate this situation because vacuum leaks within these systems can cause both a lean and a rich mixture, depending on the situation. For the most part it will be rich though.
I really like the plain-jane Bosch diverter valves. I'm running a single one, two is better for redundancy and flow. Just weld a 1" stub onto your compressor outlet plumbing, run as much hose off of it as you need to get the valve where you want it, weld another 1" stub on the compressor inlet plumbing and clamp the outlet of the valve to that. It recirculates the flow back to the compressor inlet and allows the compressor to freewheel without spooling all the way down. More efficient than a blow off to atmosphere configuration, and it is a closed loop downstream of the AFM so Motronic won't see wildly excessive flow readings. No air leaks, no possibility of drawing in unfiltered air.
I really like the plain-jane Bosch diverter valves. I'm running a single one, two is better for redundancy and flow. Just weld a 1" stub onto your compressor outlet plumbing, run as much hose off of it as you need to get the valve where you want it, weld another 1" stub on the compressor inlet plumbing and clamp the outlet of the valve to that. It recirculates the flow back to the compressor inlet and allows the compressor to freewheel without spooling all the way down. More efficient than a blow off to atmosphere configuration, and it is a closed loop downstream of the AFM so Motronic won't see wildly excessive flow readings. No air leaks, no possibility of drawing in unfiltered air.
Re: Stalling Issue M106 M1.3 - Thinking Fuel Related
Haven't had much time to diagnose, but did quickly disconnect the vacuum line while the engine was running to see if there was any change. Nothing changed in the idle. Still ran really rich (tons of smoke) and idle was low/rough. I removed the BOV just to inspect the movement of the piston/spring, and it seems okay.