Volvo Penta Stalling and alarm location

[alldodge]

Fuel pressure is still about 15lbs

So long as the pressure stays at only 15 psi, it will not run right.

 

[Tohonda]

I understand the fuel pressure should be higher. It was low so I put on a new pump. It stayed the same. The regulator was changed and it stayed the same. I removed the VST and rebuilt it. I checked all the fuel lines. I ran it on a remote tank. What else will cause low fuel pressure?

 

[alldodge]

Disconnect the fuel line going into the TB and connect the fuel pressure gauge directly. If your unable to get at least 60 psi then the new fuel pump is bad or the incorrect one, If you get at least 60 psi, then your back to the TB and the regulator

 

[Tohonda]

When we rebuilt the TBI we used the new spring in the kit...14lb regulator spring...going to put in the 30lb spring...thx

 

[Tohonda]

Replaced the regulator spring. It now has 32psi of fuel pressure. Now the motor floods. I can not give it throttle quickly. If I give it throttle slowly it will run up to 4k rpms. The motor will die when I come back down to below 2k rpms and is hard starting.

 

[alldodge]

When the ignition is turned ON without starting, do the injectors drip fuel?

 

[Tohonda]

No.

 

[alldodge]

At first

It starts and runs very well at idle up to about 1300rpms under load then back fires thru the TBI.

It immediately cleans up and runs very well up to 4000rpms for approximately 30 seconds. The motor then dies. The fuel pressure and voltage appear good throughout the rpm range under load.

We were not getting enough fuel (backfire) then it would clear up as rpm increases, 30 sec later it would die (no fuel)

Current

Now the motor floods. I can not give it throttle quickly. If I give it throttle slowly it will run up to 4k rpms. The motor will die when I come back down to below 2k rpms and is hard starting.

Now its flooding

If your getting a nice looking spray pattern from the injectors while the motor is running (fine mist and no drips), then I would assume the injectors are usable. The ECM controls the open/close times of the injectors and this is controlled by the MAP. The MAP provides vacuum readings which the ECM increases or decreases on times.

I also am finding the older SBC TBI (automotive) were running 11 to 13 psi so I may have misinformed, also say this is the 89 and early models, and as you mentioned previous. The later vortec models are up to 30 psi. So either is a typo, and may be on my chart, right now I don't know. Will add, I don't see any TBI on boats until after the introduction of vortec heads which happened in 95

Hey Fun Times happen to have any thoughts?

 

[Tohonda]

Replaced the MAP sensor. Vacuum was good. Set the base timing after doing the regulator 30psi. I plan on retesting the vacuum, TPS and coolant sensor but have not tested yet, motor performs the same with coolant sensor disconnected.

 

[Fun Times]

Do you recall what fuel PSI spring was in the TB originally? And did it look like someone may have been into the TB before you?
What kit did the 13 or 30 psi springs come from? I recall depending on engine models in question, 'Most past members mention when buying most aftermarket auto type kits, never seemed to receive the correct spring and the original spring should be reused at all possibilities.

Sometimes finding the correct trustworthy fuel pressure specifications for the TBI's can be seriously confusing as the engine manufacturers tend to use 'Either" "OR" psi rating depending on ECM type, engine year, engine model design/type such as Gen+/GM Vortec or non Vortec, Injector brand, size, etc. etc.. On the earlier years for the mercruiser side it was 12 psi before bumping up to 30 psi on some engines, etc...And of course all hoping for no misprints along the way.

Here's an example from 1994 that might also help tell if there's a color code on your injectors too?, REQUIRED FUEL INJECTOR “POD” AND ECM REPLACEMENT

A. REQUIRED FUEL INJECTOR “POD” AND ECM REPLACEMENT
Model
MIE 350 Magnum EFI Tournament Ski Engines Only
Serial Number: 0F215555 to 0F225894
Problem
Under certain operating conditions, early production engines may experience a “flat spot” or a “stumble” in the mid range.
Correction
Before ordering the Fuel Pressure Conversion Kit, take the flame arrestor off and look at the color code on the top of the injectors. If the injectors have Pink/Purple color code on them and the ECM has the number 9958 on it, these are the 30 psi injectors and the repair has already been done.
If the injectors have Blue/Black color code on them and the ECM has the number 998B on it, these are the 12 psi injectors and the kit has to be installed. Order the kit listed. This kit contains a new “pod”, that has 30 psi injectors, an ECM and other miscellaneous parts to make the repair. The ECM has to be changed to match the higher injector pressure. Follow the instructions that are packaged with the kit for replacing the parts.

All that mentioned it "would" seem you'll need the 13 psi spring even though it seems to low especially since your low PSI booster pump is only at the correct 8 psi...It was just more common to see/be used to seeing a higher psi to the high pump side for most engines...But not all.

http://flyingfishcarburetors.com/Y45-2RochesterTBI.htm

http://www.batterypete.com/batterie...-tbi-fuel-injector-kit-for-5-0l-5-7l-engines/ ,

[h=2]Description[/h] [h=1]New Mercruiser Volvo Penta TBI Fuel Injector kit for 5.0L, 5.7L engines[/h] This listing is for NEW – not re-manufactured standard fuel injectors and gaskets that will fit your Volvo Penta, OMC or Mercruiser 5.0L v8, 5.7L v8 engine.
For use with 220-260hp rated Volvo Penta, OMC or Mercruiser and Indmar 5.0L v8, 5.7L v8 engines. These Fuel Injectors are rated 55lbs@13psi

Have you had a chance to put the engine on a diagnostic scanner? Checked for codes yet, https://www.youtube.com/watch?v=fSEwwa6D2jM

Keep an eye on the TBI injector spray pattern...https://www.youtube.com/watch?v=7XMYQPY0pYQ

 

[Lubak572]

Try SPR Perfomance for TBI info/parts.

 

[Tohonda]

The original spring was 15lbs based on the fuel pressure. We put in a 14lb spring from a GM TBI rebuild kit. The fuel pressure remained at 15lbs. We replaced the fuel pumps believing the fuel pressure was low. The fuel pressure remained at 15. The run-ability problems persisted. The motor acted lean so we put in a 30lb regulator spring. Now it seems to have too much fuel. I will check the color code on the injectors and look for codes and test the vacuum.

 

[ddbyrd3]

So I don't want to muddy the waters here, However, my brother in law, had similar issues as you are having, did all the same checks. He took his ECU in after exhausting EVERYTHING else, had it tested, and found the ECU was bad. He replaced it, and his problems have been solved. He has a Larson, 2002, 5.0 VP, Fuel injected motor.

 

[Tohonda]

Where did he take the ECU to be tested?

 

[ddbyrd3]

A place called OBD Diagnostics in Redondo Beach Calif. Bob and Ken are the owners. They specialize in GM Marine electronics. From what I hear, it is a common failure. They can test it onsite as well.

 

[Tohonda]

TBI was dirty when I started. Rebuilt it. Replaced regulator spring to make 30psi. Injectors have no color code. Injector part number 17084304. Borg Warner TBI. When I cross it to GM it fits a 7.4l. Not sure if a 7,4l injector takes 14 or 30lbs of fuel pressure.

Tested the vacuum at idle. 13lbs. Climbs to 18 at 3000rpm...Vacuum seems good.
Ran codes. Code 33 found. MAP is new. Code 33 remains even after clearing it. Looks like I need to test voltages at ECM

 

[Tohonda]

A place called OBD Diagnostics in Redondo Beach Calif. Bob and Ken are the owners. They specialize in GM Marine electronics. From what I hear, it is a common failure. They can test it onsite as well.

thx, looks u may be correct.

 

[alldodge]

Code 33 can be there is an open circuit

 

[SD2600]

I have used bob. Stand up guy. Answered my phone call even on Sunday afternoon, quick turn around time. Def worth the $$ to have your ecm checked

 

[Tohonda]

Code 33 can be there is an open circuit

There is a troubleshooting procedure in the manual. Ill run thru it today and share the results