evaluex

I have a rebuild 5,0 TBI (VOLVO PENTA) which won't run as it should be.

TBI on Volvo Penta or Mercruiser seems to be the same

Engine fires up right away and idles more or less correctly (little bit too rough) when accelerating engine revs up but after 2 or 3 times right injector doesn't squirt anymore until at idle again, then injector works again
@ 2000 rpm right injector just stops squirting until back at idle

Have already switched electrical wires from injectors which also switches the problem meaning injectors (which have been ultrasonic cleaned) are GOOD.
When switching injector wires the left injector will go intermittend squirting or not and vice versa.
I did measure +- 6V at idle on the injector wire increasing to +- 12V at 2000 RPM then shutting current down (no more voltage until back on idle)

Fuel pressure was initially fluctuating so I replaced both pumps (low and high pressure)Now perfect at +- 8 psi (low side) and 42 psi (pressure side)
VTS has been complete cleaned also all fuel lines, filter etc etc

Made a video of this intermittend problemfeel free to take a look at

I

already replaced complete ignition (EST) and coil (spare parts not 100% sure) intermittend problem still exist.

Diacom doesn't show any error codes... Intake manifold air temp is -40F... but there is NO IAT sensor on this engine... a lot of black soot in the cooling water meaning too rich? Fuel consumption + 1,5 GPH (diacom) which is too high... meaning engine continues to run in “COLD” mode??When decelerating left injector keeps squirting, right doesn't... Is this normal that injector keeps squirting during decelerating??Ignition can be a couple of degrees error because when putting ignition on base setting mode (diacom) engine stalls and needs to adjusted but this won't cause the intermittend squirting problem I might believe

Can someone help me out with this problem?

If wanted I can send video of diacom running test

BUP

iTrader: (9)

Possible internal injector driver in the ecm and or the ground ? I am able to test that and fix those in MEFI 's. If not possible J connector to the ecm or the pins on the ecm. Possible wiring harness issue and or grounds of the engine. What is your voltage when the injector(s) quits and 5 V Ref.??

. Also what is MAP readings ??? Map is one of the inputs for Injector / pulse widths / commands. What is your operating temps from the coolant sensor ? That sensor is another input for the ECM to command the injectors.

Did the injector service test the injectors / run the injectors at different RPMs and pulse widths for testing ??? I have seen TBI injectors do well at idle but past 2 to 3 k rpms act up. Actually seen MPI injectors do the same as well. Just saying.

What is your ignition timing ? Have you tested the ignition module ?

evaluex

Thank ou for the info... Can I send you the diacom video so you can see yourself all the values?

BUP

iTrader: (9)

I am heading out for work as we speak. You are not in the USA correct. ? How do u want to send that video ??? And thats fine sending it .

evaluex

Send you PM

If the engine would go on S.L.O.W. mode, will this throw a fault code on the ECM
or can this be seen on the diacom?
SLOW mode will cut 1 injector according VP manual... overheating or oil pressure too low...

BUP

iTrader: (9)

For one these TBI s fuel pressure is 29 to 30 psi and not any higher. So you are way high with 42 or 43 psi. , sorry I missed that at first but see it now for what you posted for Fuel pressure. . The service manuals has mistakes and the dealers get the corrections in SB formats about the correct info. The same goes for MERC, They all make mistakes in their writings. Also things get straighten out in OEM class rooms as well about the mistakes that were printed for what ever format.

Next is look for a general warning fault code when scanning and next is what coolant temps are you running. In 2000 or 2001 Volvo guardian temps at 140 and below because it needs to be 160 T stat installed in their EFI apps. Also make sure your T stat is not stuck open -- like I said they have a guardian for low water temps.

Many OEM marine manus Guardian low temps for their EFI engines, with that said one of the reasons why you do not lower the degrees of the T stat for these OEM apps and or make sure your T stat is working correctly. Many do not know this about guardian the low temp readings. FYI