WELCOME TO RIVER DAVES PLACE

Need help with a no start volvo penta 5.7

allblowdup

Well-Known Member
Joined
Jul 20, 2011
Messages
916
Reaction score
850
I have a 2008 5.7 volvo penta that was running fine. shut it off one day and now it will not start. we have diagnosed it so far without a manual. It has spark and fuel pressure. if you pour some fuel down the TB it fires right up but quits once it runs out of fuel. It has 12 v on the pos side of the injectors but the ecm will not fire the injectors. I have pin testes the grounds for the ecm and the ground side for the injectors and are good. I have looked online for an EFI manual for this and cannot find one.
 

redone76

Well-Known Member
Joined
Jan 18, 2013
Messages
2,165
Reaction score
2,212
Did you check the kill switch? I about had my fuel system torn apart before I thought to check the switch. Gave it a little wiggle and she fired right up.
I have read a few articles where Volvo has had problems with the high and low fuel pressure pumps though. Iboats.com has links to service manuals for reference
 

Racey

Maxwell Smart-Ass
Joined
Sep 18, 2007
Messages
14,815
Reaction score
18,797
I have a 2008 5.7 volvo penta that was running fine. shut it off one day and now it will not start. we have diagnosed it so far without a manual. It has spark and fuel pressure. if you pour some fuel down the TB it fires right up but quits once it runs out of fuel. It has 12 v on the pos side of the injectors but the ecm will not fire the injectors. I have pin testes the grounds for the ecm and the ground side for the injectors and are good. I have looked online for an EFI manual for this and cannot find one.
Did you hook a noid light up to an injector lead and see if it strobed?
 

racered

Well-Known Member
Joined
Dec 15, 2008
Messages
484
Reaction score
205
62534629 TBI schematic.jpg Determine whether the ECM is able to switch the ground pin of the injector with a test light, volt meter,,, or with ignition switch on momentarily apply a ground to the ground pin of the injector(s) to hear if they click, with fuel pressure they should spray fuel.
Do you have fuel pressure at the throttle body or fuel filter?
 

allblowdup

Well-Known Member
Joined
Jul 20, 2011
Messages
916
Reaction score
850
I have a 2008 5.7 volvo penta that was running fine. shut it off one day and now it will not start. we have diagnosed it so far without a manual. It has spark and fuel pressure. if you pour some fuel down the TB it fires right up but quits once it runs out of fuel. It has 12 v on the pos side of the injectors but the ecm will not fire the injectors. I have pin testes the grounds for the ecm and the ground side for the injectors and are good. I have looked online for an EFI manual for this and cannot find one.
Yes we didi fuel pumps run with it plugged in but not with it unplugged.
 

allblowdup

Well-Known Member
Joined
Jul 20, 2011
Messages
916
Reaction score
850
View attachment 490039 Determine whether the ECM is able to switch the ground pin of the injector with a test light, volt meter,,, or with ignition switch on momentarily apply a ground to the ground pin of the injector(s) to hear if they click, with fuel pressure they should spray fuel.
Do you have fuel pressure at the throttle body or fuel filter?
Thanks. this one is actually port injected, checked fuel pressure is ok
This is an5.7 sx-a engine
 

Racey

Maxwell Smart-Ass
Joined
Sep 18, 2007
Messages
14,815
Reaction score
18,797
Yes we checked it with a noid light no flash but we have 12v on the positive side.
The ecu works by sinking ground to the injectors for the desired pulse width and timing, the 12v on the other side of the injector is constant. Is this multi-coil or distributor? How many injectors?

Do you have a scope that you can run on the injector leads? How many injectors? it may be possible that one went bad and is dead shorting, path of least resistance, and the others won't work. If this happened it may (or may not) have burned up the drivers inside the ECU.

I would unplug all injectors and then run the noid light.
 

namba860

Well-Known Member
Joined
Jul 15, 2010
Messages
4,274
Reaction score
3,733
I would try the noid light on each injector as well.
 

allblowdup

Well-Known Member
Joined
Jul 20, 2011
Messages
916
Reaction score
850
The ecu works by sinking ground to the injectors for the desired pulse width and timing, the 12v on the other side of the injector is constant. Is this multi-coil or distributor? How many injectors?

Do you have a scope that you can run on the injector leads? How many injectors? it may be possible that one went bad and is dead shorting, path of least resistance, and the others won't work. If this happened it may (or may not) have burned up the drivers inside the ECU.

I would unplug all injectors and then run the noid light.
T
This is a dist system 8 injectors.
If the ecu sinks the injectors to ground similar to the GM MEFI system they use two injector drivers,one for each bank of injectors. I can try unplugging all the injectors and using the noid light but i find it unlikely that two injectors have shorted in the same way at the same time
 

namba860

Well-Known Member
Joined
Jul 15, 2010
Messages
4,274
Reaction score
3,733
Process of elimination we have replaced several ecm on the Volvo product mefi 4
 

allblowdup

Well-Known Member
Joined
Jul 20, 2011
Messages
916
Reaction score
850
ecm.jpg
Process of elimination we have replaced several ecm on the Volvo product mefi 4
this is not a mefi 4 as far as I know. not sure what make,model it is. That is part of my problem
 

namba860

Well-Known Member
Joined
Jul 15, 2010
Messages
4,274
Reaction score
3,733
Ok you have a newer version that is not mefi 4. I have not seen a problem with that particular ecm.
 

Racey

Maxwell Smart-Ass
Joined
Sep 18, 2007
Messages
14,815
Reaction score
18,797
This is why owning one of these is worth every penny :p

 

allblowdup

Well-Known Member
Joined
Jul 20, 2011
Messages
916
Reaction score
850
Ok you have a newer version that is not mefi 4. I have not seen a problem with that particular ecm.
Ya thats why I am really tryng to make sure that the ecm is the problem before I spend $ replacing it. I can't even seem to find a manual for it specifically. they all show pictures of the MEFI stuff. I'll have to grab the sn from the block and see if I can find anything.
 

Outdrive1

Well-Known Member
Joined
Dec 19, 2007
Messages
27,497
Reaction score
14,239
Have you checked fuel pressure? Those pumps on the front of the motor are a known problem. The ethanol eats the paint of them inside and clogs the pump. You need 38 psi for it to run.
 

allblowdup

Well-Known Member
Joined
Jul 20, 2011
Messages
916
Reaction score
850
Have you checked fuel pressure? Those pumps on the front of the motor are a known problem. The ethanol eats the paint of them inside and clogs the pump. You need 38 psi for it to run.
Pumps run and I have fuel pressure.
 

SBMech

Fixes Broken Stuff
Joined
Jul 25, 2012
Messages
7,723
Reaction score
10,148
Injectors not firing can be caused by only a few things.

A bad ground.

A faulty crank sensor and or cam sensor depending on the system.

A bad driver in the ECU, but since you said it's a MEFI then 4 out of 8 would still fire, unless you actually killed the ECU.

Get a wiring diagram and hook the ecu back up, check the 12v and grounds while it's hooked up, make sure you are not loosing a ground when it is under load, IE the noid will flash once then stop.

I suspect a bad ECU or crank sensor. If it picks up the signal inside the distributor, same principle, make sure it's telling the ECU to fire.

In the automotive world it's pretty rare to replace an ECU, usually other problems.

As mentioned, occasionally have seen a shorted injector keep the entire bank from firing, but you said it runs on fuel sprayed into the intake, leaning towards a crank sensor myself.

Obviously if it's getting the trigger signal, you got a bad ECU.
 

Racey

Maxwell Smart-Ass
Joined
Sep 18, 2007
Messages
14,815
Reaction score
18,797
Injectors not firing can be caused by only a few things.

A bad ground.

A faulty crank sensor and or cam sensor depending on the system.

A bad driver in the ECU, but since you said it's a MEFI then 4 out of 8 would still fire, unless you actually killed the ECU.

Get a wiring diagram and hook the ecu back up, check the 12v and grounds while it's hooked up, make sure you are not loosing a ground when it is under load, IE the noid will flash once then stop.

I suspect a bad ECU or crank sensor. If it picks up the signal inside the distributor, same principle, make sure it's telling the ECU to fire.

In the automotive world it's pretty rare to replace an ECU, usually other problems.

As mentioned, occasionally have seen a shorted injector keep the entire bank from firing, but you said it runs on fuel sprayed into the intake, leaning towards a crank sensor myself.

Obviously if it's getting the trigger signal, you got a bad ECU.
It's not a mefi, and i believe he said it has spark, which rules out crank/cam sensor.

I would go along with BDMar and say start checking some grounds, this is really dependant on the ECU, some have a single ground, some have multiple grounds, If the ground path from the injector driver circuit back to it's source isn't good enough to flow the current needed for the injectors they won't fire either. It may be possible that that ground does not affect the main processor and allows it to keep processing data even though it won't fire the injectors.
 

SBMech

Fixes Broken Stuff
Joined
Jul 25, 2012
Messages
7,723
Reaction score
10,148
It's not a mefi, and i believe he said it has spark, which rules out crank/cam sensor.

I would go along with BDMar and say start checking some grounds, this is really dependant on the ECU, some have a single ground, some have multiple grounds, If the ground path from the injector driver circuit back to it's source isn't good enough to flow the current needed for the injectors they won't fire either. It may be possible that that ground does not affect the main processor and allows it to keep processing data even though it won't fire the injectors.
Yea, well it would not be the first time I traced a circuit out because I knew something only to find a broken splice that prevented the signal from firing the injectors, even though it had spark :D

A good multi meter can show you everything you need to know, since you don't have Raceys fancy pants labscope :)

Remember tracing out a circuit via an ohm check is not totally accurate, it can only have one strand of wire left attached and still ohm check out.

Voltage drops tell a much better story, gotta see that amperage flow baby! :thumbsup

I have not seen a ECU not have multiple grounds in 15 years, and then it was a hack job who tied them all together. There should be at least 3 ground circuits and 2 12v feeds minimum.
 

allblowdup

Well-Known Member
Joined
Jul 20, 2011
Messages
916
Reaction score
850
Well here is an update that may surprise anyone who has ever tried diagnosing shit like this. I finally got the adapter for the scan tool and a bit of time to actually use it. Find out it has a map/mat sensor code BP pressure low. I am like ok well that will not disable the engine but what the hell I will chase it down anyhow. Now I have 6 yrs as a tune up and electrical guy with GM but from a few years ago 1990's and my budy has 25 years of the same thing but more current. We both say that a map sensor cannot disable the engine. So anyhow I go through the checks and all the wiring checks out just like it did before the scan tool. The 5 volt reference is good so the manual tells me to jump the 5 v reference to the signal wire that goes back to the ecu. I get 5v on the signal wire according to the ecu so it says replace the sensor. Ok but I think just for shits and giggles Ill crank it with the jumper wire hooked up and son of a bitch it fires right up. plug the sensor back in and nothing. The manual, a certified Volvo mechanic, or anything online will NOT tell you that the map sensor can disable the fuel injection on this engine with EGC.

So if this info helps anyone with a prob like this it is not in the manual.

so cranks but does not start
Have fuel pressure
have spark
have 12 v from ecu to injectors
 

LargeOrangeFont

Steers With Throttle
Joined
Sep 4, 2015
Messages
20,792
Reaction score
25,075
Well here is an update that may surprise anyone who has ever tried diagnosing shit like this. I finally got the adapter for the scan tool and a bit of time to actually use it. Find out it has a map/mat sensor code BP pressure low. I am like ok well that will not disable the engine but what the hell I will chase it down anyhow. Now I have 6 yrs as a tune up and electrical guy with GM but from a few years ago 1990's and my budy has 25 years of the same thing but more current. We both say that a map sensor cannot disable the engine. So anyhow I go through the checks and all the wiring checks out just like it did before the scan tool. The 5 volt reference is good so the manual tells me to jump the 5 v reference to the signal wire that goes back to the ecu. I get 5v on the signal wire according to the ecu so it says replace the sensor. Ok but I think just for shits and giggles Ill crank it with the jumper wire hooked up and son of a bitch it fires right up. plug the sensor back in and nothing. The manual, a certified Volvo mechanic, or anything online will NOT tell you that the map sensor can disable the fuel injection on this engine with EGC.

So if this info helps anyone with a prob like this it is not in the manual.

so cranks but does not start
Have fuel pressure
have spark
have 12 v from ecu to injectors
So effectively there is no "limp mode" in the ECU that will just bypass the MAP sensor and start the engine on some predetermined fueling map to get you home.
 

Racey

Maxwell Smart-Ass
Joined
Sep 18, 2007
Messages
14,815
Reaction score
18,797
Well here is an update that may surprise anyone who has ever tried diagnosing shit like this. I finally got the adapter for the scan tool and a bit of time to actually use it. Find out it has a map/mat sensor code BP pressure low. I am like ok well that will not disable the engine but what the hell I will chase it down anyhow. Now I have 6 yrs as a tune up and electrical guy with GM but from a few years ago 1990's and my budy has 25 years of the same thing but more current. We both say that a map sensor cannot disable the engine. So anyhow I go through the checks and all the wiring checks out just like it did before the scan tool. The 5 volt reference is good so the manual tells me to jump the 5 v reference to the signal wire that goes back to the ecu. I get 5v on the signal wire according to the ecu so it says replace the sensor. Ok but I think just for shits and giggles Ill crank it with the jumper wire hooked up and son of a bitch it fires right up. plug the sensor back in and nothing. The manual, a certified Volvo mechanic, or anything online will NOT tell you that the map sensor can disable the fuel injection on this engine with EGC.

So if this info helps anyone with a prob like this it is not in the manual.

so cranks but does not start
Have fuel pressure
have spark
have 12 v from ecu to injectors
If the MAP sensor was reading full low voltage IE very close to 0v, then there is a very good chance that the fuel map rows/columns that low have such little fueling the motor won't even attempt to run. In most NA pushrod motors the engine is never capable of pulling more vacuum than about 20KPA absolute pressure. So rows/columns below that may not even exist, or could be set to what is effectively 0msec injector pulse. To the contrary the rows/columns at full manifold pressure (high load) are always populated, as you can reach them at any point by snapping the throttle open. So it would run but probably on the very rich side, but run none the less.


Glad you found your problem :thumbsup
 

Bigbore500r

Well-Known Member
Joined
Apr 28, 2014
Messages
12,891
Reaction score
20,211
If the MAP sensor was reading full low voltage IE very close to 0v, then there is a very good chance that the fuel map rows/columns that low have such little fueling the motor won't even attempt to run. In most NA pushrod motors the engine is never capable of pulling more vacuum than about 20KPA absolute pressure. So rows/columns below that may not even exist, or could be set to what is effectively 0msec injector pulse. To the contrary the rows/columns at full manifold pressure (high load) are always populated, as you can reach them at any point by snapping the throttle open. So it would run but probably on the very rich side, but run none the less.


Glad you found your problem :thumbsup
Right - could be as simple as that portion of the table was never numerically populated because it was never intended to run on that part of the table, even when cranking to start. A human still populates those tables....and humans are pretty unreliable :D
 

Bigbore500r

Well-Known Member
Joined
Apr 28, 2014
Messages
12,891
Reaction score
20,211
So effectively there is no "limp mode" in the ECU that will just bypass the MAP sensor and start the engine on some predetermined fueling map to get you home.
Right, or like Racey noted, the faulty sensor causes the ecm to look at a portion of the table that isn't even populated with values. hence "zero commanded injector pulse"
 

SBMech

Fixes Broken Stuff
Joined
Jul 25, 2012
Messages
7,723
Reaction score
10,148
Logic circuit of the ECU preventing start from clear flood mode if it was shorted to postive internally. From what I have read it's a boost sensor as well, possible some internal damage caused it to prevent spark from that (overboost) as well.

The map sensor is the major fuel calculation measurement, lots of vehicles I have worked on that supposedly had "limp home" for a failed map sensor or AFM or crank sensor, do NOT.

Glad you found the problem ABU, thanks for letting us know the result! :thumbsup
 

allblowdup

Well-Known Member
Joined
Jul 20, 2011
Messages
916
Reaction score
850
Alot of ecu's have a baro sensor incorporated into them. It always compares the reading with the baro sensor reading of the sensor. If they are to far off it will set a code. It keeps running but alerts the driver. In this case it does not and yes I suspect that the blocks or lines just don't have any numbers in them. Yup should have a limp mode for that code, it does for other codes. Especially on a boat.
 

Steven Christy

New Member
Joined
May 28, 2018
Messages
1
Reaction score
0
Well here is an update that may surprise anyone who has ever tried diagnosing shit like this. I finally got the adapter for the scan tool and a bit of time to actually use it. Find out it has a map/mat sensor code BP pressure low. I am like ok well that will not disable the engine but what the hell I will chase it down anyhow. Now I have 6 yrs as a tune up and electrical guy with GM but from a few years ago 1990's and my budy has 25 years of the same thing but more current. We both say that a map sensor cannot disable the engine. So anyhow I go through the checks and all the wiring checks out just like it did before the scan tool. The 5 volt reference is good so the manual tells me to jump the 5 v reference to the signal wire that goes back to the ecu. I get 5v on the signal wire according to the ecu so it says replace the sensor. Ok but I think just for shits and giggles Ill crank it with the jumper wire hooked up and son of a bitch it fires right up. plug the sensor back in and nothing. The manual, a certified Volvo mechanic, or anything online will NOT tell you that the map sensor can disable the fuel injection on this engine with EGC.

So if this info helps anyone with a prob like this it is not in the manual.

so cranks but does not start
Have fuel pressure
have spark
have 12 v from ecu to injectors
Thanks so much for posting this update nearly 2 years ago. I have a 2007 5.7 Gi-G with the same symptoms. Have spark, have compression, have fuel - but injectors wont open. Can run on fuel straight down the intake. - Swapped the Ignition Module with same result, about to swap Crank Sensor when I came upon your post. I checked the TMAP, and
jumped 5V to return and it works. Super rich, but fired right up. Thanks for sharing, I've been chasing this for nearly 2 weeks! New TMAP to be delivered on Wednesday.
 

Dalton

Well-Known Member
Joined
Apr 15, 2011
Messages
1,297
Reaction score
788
Thanks so much for posting this update nearly 2 years ago. I have a 2007 5.7 Gi-G with the same symptoms. Have spark, have compression, have fuel - but injectors wont open. Can run on fuel straight down the intake. - Swapped the Ignition Module with same result, about to swap Crank Sensor when I came upon your post. I checked the TMAP, and
jumped 5V to return and it works. Super rich, but fired right up. Thanks for sharing, I've been chasing this for nearly 2 weeks! New TMAP to be delivered on Wednesday.
awesome....that's why this site is great
 
Top