1999 Volvo penta 5.7 GSI stuttering/cutting out - temp gage

[spomey]

I have two issues that I need help with.
1. A few trips ago after sitting on the lake for an hour or so I started the engine (easily) and throttled up. I get about 5 seconds into taking off and the the engine surges badly almost dying, then taking of again and again. Like the choke is on and off, but its EFI....throttle back and then idle for a few second accelerate slowly and it doesnt do it. Choke Related?
2. Additionally my temp gage is full overhot (pegged) but that is some wiring thing that I have had for over a year with no issues. I have heard it is a tan or brown wire, I replaced the temp sensor (i think) on the t=-stat housing with no change. I cannot find any tan/brown wire on the block. there are two wires going to what i believe is the temp sensor. A black and a white with a blue stripe. is there a way to check the gage?

 

[dypcdiver]

Full scale deflection on the gauge, usually means a short to earth somewhere.
Might be a good time to buy an infra red temp gun.

 

[Scott Danforth]

the switch with the two wires is for the alarm.

check the IAC actuator and the IAC muffler

 

[spomey]

the switch with the two wires is for the alarm.

check the IAC actuator and the IAC muffler

I cant figure out IAC.

 

[spomey]

the switch with the two wires is for the alarm.

check the IAC actuator and the IAC muffler

is the IAC the Idle Air Control? is this comment for the gage pegged or the surging at takeoff

 

[Scott Danforth]

IAC is idle air control

 

[ESGWheel]

Spomey,
Best to separate out the two issues. Focus on the bad running as that impacts the ability to have fun with the boat and as you said, the temp issue has been going on for a year+ and is considered an electrical fault vs. actual overheating.

This does assume that you are not experiencing actual overheating as it is one of the fastest ways to ruin a motor. So as a precaution, get an IR gun as dypcdiver suggests. Here is a link to one. They are cheap and a good diogenitic tool. Start a new post with the IR results including your issue with the temp gage.

But back to the funky running. This is a new issues unrelated to the temp gage that has been more than a year?. Correct?

If so, suggest use this thread to focus on that only to preclude getting wires crossed

While I am not familiar with these TBI systems and thus cannot help further, at least this will get the focus on the running issue. Good luck and keep at it > it is 100% fixable!

 

[spomey]

so i took the boat out and the "take off was great all but one time during the day so say 1 out of 8 stuttered. this time the engine actually died. it restarted and ran great. then at home I was checking thigs over and when I turnedthe key the fuel pumps presurized the system but it sounded weak for lack of better wording, then I did it again and it sounded sloshy like maybe there was air and fuel being pumped then the third time it ounded strong and solid. can the fuel pumps push air somehow? no leaks or anything that I could find.

 

[alldodge]

The temp gauge is a single Tan wire to sensor on Stat housing. Remove the wire and see if gauge goes to cold

Check your fuel pressure on the high side of the pump, should be 29 +/- 2 psi

 

[ESGWheel]

These pumps do not like to pump air. And only if you have a ‘leak’ on the suction side could you be pulling in air. While possible, I suspect you are hearing cavitation (weak, sloshy) (link). This can result from a partially blocked line (from the tank pick up tube to the inlet of the fuel pump). Here are the typical causes:

• Your fuel pickup (in the tank) may have a screen on the bottom of it that is clogging up. A lot of older pickups have this screen.
• There is an anti-siphon valve at the top of the tank prior to hooking onto the fuel hose. This one-way check valve prevents the fuel line from draining back into the tank (if it did you would have a hard time starting each time and eventually burn out the pump). These siphon valves can also get ‘sticky’ and block flow intermittently, starving the fuel pump.
• The fuel line itself can deteriorate over time and the inside lining starts to degrade to the point where it collapses (internally) causing a blockage (with no external signs of an issue).
• And there may be a kink or pinch in the fuel line that is not obvious.

All the above can cause intermittent fuel starvation which seems to be your issue. And all of these can cause the pump to cavitate.

And of course, it simply could be a failing fuel pump.

This is the reason for the pressure test. Do you know how? If not, we can guide you.

Also, the pressure it may be intermittent > good runs = good pressure, bad run = low pressure. If low when tested at the dock, all the above are possible. But if within spec, the above may still be possible. While I have never done it, it seems to me that you could hook up the pressure gauge and cruise around with someone monitoring it. When it starts to studder, what is the pressure? Note: this does require some preplanning and precautions. If others have done this or think a bad idea, please chime in.

 

[spomey]

The temp gauge is a single Tan wire to sensor on Stat housing. Remove the wire and see if gauge goes to cold

Check your fuel pressure on the high side of the pump, should be 29 +/- 2 psi

I have two wires to my T stat housing they are black, and white/blue. I cannot find a tan wire anywhere, the only tan one goes to the back of the alternator. I have swapped the temp sensor and the gage both with new, the wires on the back of the gage is tan though.

I also have a single wire White/black with a blage type connector that I cannot find a point to connect to. I searchec for a few hours with lights and mirrors I decided it was just extra,

I have two fuel pumps it seems one pulls the fuel from the tank (I think) and the other pressureizes the fuel rail. I will check them both, I will change the fuel filter and make sure I have the fuel tank full

 

[spomey]

These pumps do not like to pump air. And only if you have a ‘leak’ on the suction side could you be pulling in air. While possible, I suspect you are hearing cavitation (weak, sloshy) (link). This can result from a partially blocked line (from the tank pick up tube to the inlet of the fuel pump). Here are the typical causes:

• Your fuel pickup (in the tank) may have a screen on the bottom of it that is clogging up. A lot of older pickups have this screen.
• There is an anti-siphon valve at the top of the tank prior to hooking onto the fuel hose. This one-way check valve prevents the fuel line from draining back into the tank (if it did you would have a hard time starting each time and eventually burn out the pump). These siphon valves can also get ‘sticky’ and block flow intermittently, starving the fuel pump.
• The fuel line itself can deteriorate over time and the inside lining starts to degrade to the point where it collapses (internally) causing a blockage (with no external signs of an issue).
• And there may be a kink or pinch in the fuel line that is not obvious.

All the above can cause intermittent fuel starvation which seems to be your issue. And all of these can cause the pump to cavitate.

And of course, it simply could be a failing fuel pump.

This is the reason for the pressure test. Do you know how? If not, we can guide you.

Also, the pressure it may be intermittent > good runs = good pressure, bad run = low pressure. If low when tested at the dock, all the above are possible. But if within spec, the above may still be possible. While I have never done it, it seems to me that you could hook up the pressure gauge and cruise around with someone monitoring it. When it starts to studder, what is the pressure? Note: this does require some preplanning and precautions. If others have done this or think a bad idea, please chime in.

great ideas! I will get a fuel pressure test kit and check all of the areas today and let you know!

 

[ESGWheel]

As you observed, there are two pumps to this assembly: a low pressure that pulls from the tank and feeds the high pressure that supplies the fuel rail.

If this pump is same as on my 5.0 GXi there are 2 Schrader valves that you can tap into one for each pump. But as Scott pointed out the key is the pressure on the high side > that is the ticket. If not achieved, then it’s a matter of troubleshooting and finding the cause which is when the low pressure side test will come into play. If not familiar with these gauges here is a link to the one I have: link.

 

[shortbus offroad]

Take your distributor cap off. Grab the rotor and move it back and forth, letting it move up or down at the same time. If it moves more than just the smallest amount the distributor is bad and needs to be replaced. This happened to me withe the same engine. Apparently this is a common problem on gm vehicles that use the same distributor. It took years for me to figure this out.

 

[Scott Danforth]

For $13 you can get new distributor bushings from NAPA

 

[spomey]

Take your distributor cap off. Grab the rotor and move it back and forth, letting it move up or down at the same time. If it moves more than just the smallest amount the distributor is bad and needs to be replaced. This happened to me withe the same engine. Apparently this is a common problem on gm vehicles that use the same distributor. It took years for me to figure this out.

is this for the round distributor? or the funky one?

 

[shortbus offroad]

The round one. I attached a picture.