Volvo Penta Stalling and alarm location

[Tohonda]

I have a 1997 Volvo Penta it is TBI

5.7GIPLKDCE, SERIAL NUMBER 4110144111, PRODUCT NUMBER 3868623

This is a recent purchase. It sat for 2 years.

I cannot locate the warning horn/alarm anywhere and it never sounds. It is not under the dash, on the engine or in the controls. Any ideas?

I removed the fuel and cleaned the fuel tank.

I put new gas in and tested the motor.

It ran poorly. Backfired through the TBI and exhaust and stalled under load.

I replaced plugs, wires, cap rotor and water pump based on condition, age and symptoms.

Compression is 180 to 195 in all cylinders.

Spark test shows good spark.

Fuel pressure test [HP] shows 15lbs.

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.

The engine will restart but immediately stalls. If I wait 5 to 10 minutes it will restart and run at idle up to 1200rpms, under load. It will run this way without incident.

The temperature is good both on the gauge and at the thermostat.

What should the temp on the exhaust manifolds be?

I am going to pull codes tomorrow.

Any ideas about what else I should be looking for?

 

[alldodge]

Fuel pressure test [HP] shows 15lbs.

This is your first problem, it should be higher
GI-A should 30 psi
GI-B/C/D/E should be 50-60 psi

 

[Tohonda]

I thought the same thing but the manual says 11lbs.....

High Pressure System Checks

The single most important diagnostic tool is a

fuel pressure gauge. Attach it to the high pres-

sure pump test valve and crank or run the engine.

Look for the pressures specified.

̄ 39 -+ 3 PSi (MFI)

a 11 +-- 2 PSi (TBI)

 

[alldodge]

Wouldn't be the first time there was a typo in a manual. I have a chart which indicates the pressures for different models, but did go look at the LK manual at boatinfo and it does show the 11 psi. The issue I'll present is the TB is of GM design and all GM TB are at least 30 psi

 

[alldodge]

Your Alarm should be under the helm.

 

[Tohonda]

When I look up a 1989 GM 5.7 TBI the fuel pressure, high side, says 15psi. I am right at that.

 

[alldodge]

When I look up a 1989 GM 5.7 TBI the fuel pressure, high side, says 15psi. I am right at that.

There is another poster which asked the same question, so I will answer it this way. The LK series manual does show 13 +/- 2 psi for TBI. That said, it would not be the first time that there was a typo in a manual. The TBI is a GM designed unit which was used by Merc and VP. All the GM and Merc TB's are listed as at least 30 psi.

I also have this chart (but it to could also be a typo)

 

[Tohonda]

I replaced the fuel pump today. The pressure is still 15lbs...is it possible both pumps are bad or another problem is causing low pressure?

 

[Tohonda]

The only code was the map sensor. Code 33. I went through the troubleshooting procedure and it indicated the map sensor was bad. Replaced it. Same problem exists.

 

[Tohonda]

Fuel pressure remained steady under load. Stays at 15 even when it dies.

 

[alldodge]

I think your measuring pressure at the low pressure pump. You should also have a Vapor Separation Tank (VST) which contains the high pressure pump. To read the HP pump, you need a fitting to place in line at the TB

http://www.marinepartseurope.com/en/volvo-penta-explodedview-7797410-23-10770.aspx

The fitting is part number 01800001320



https://actron.com/content/gm-tbi-adapter-716

 

[Tohonda]

I have a fuel pressure test kit with that fitting I used it...it is 15lbs. The VST sits just under the high pressure pump. There is a schrader valve on the HP line and on the VST. When I test the low pressure pump it reads 8.

 

[Tohonda]

Im thinking about removing the VST to check for debris and running the motor on a remote fuel tank...

 

[alldodge]

In that case I would suspect the fuel pressure regulator which is part of the TB

 

[Tohonda]

I was thinking the same thing but it seems to be non-serviceable. I cleaned and rebuilt the TBI not realizing it had a regulator built into it....it looks to be just an empty chamber. I would guess that I need to get a new TBI top half since it is built into it.

 

[Tohonda]

Now that I think about it I did replace the diaphragm when i rebuilt it....

 

[Tohonda]

Maybe I made an error...Ill check it.

 

[Tohonda]

I was reading these forums and see that there is a volvo service bulletin from 1999 that says to remove the exhaust flappers....I did notice that my port exhaust runs 15 degrees hotter than the starboard side...do you think this could be a problem?

 

[alldodge]

Member hnt found GP Sorensen part # 97-724 at autozone a couple years ago (for $26) which is a rebuild kit for the regulator. You can also find the whole TB pressure regulator by searching for "GM throttle body fuel pressure regulator"

https://forums.iboats.com/forum/eng...replacement-fuel-pressure-regulator-5-7lx-efi

 

[Tohonda]

OK, checked regulator. Looks good. Fuel pressure is still about 15lbs. Pulled VST. Found one of cooling lines plugged. Fixed it. Replaced float needle and gasket. Tested vacuum, map sensor, fuel pressure and spark...all looks good. Plugs looked lean. Still backfires and stalls...