Volvo 5.0 gxi Stalls at idle. Hard start.

[mallardmasher]

Is there any sign of air in the fuel system ? By sound of the pump when key on or at the schrader valve ? Any sign of fuel in the oil ?

No sing of air except when I swapped fuel pumps I noticed no gas came out of the supply line. I was ready with towel to catch any drips and point supply down into bucket but when I popped it off it appears empty like it ran back into tank. I put a cheep aftermarket pump on but it does exact same thing. Starts easy runs for a second then stalls. Also pressure tested new pump. High side 52psi. Low side starts at 10 but drops alittle. When I turn pump or engine off low pump drops to 0psi on both the oem pump and cheep one. I Can keep it running with throttle open feathering it. Can start and idle perfect when I unplug both the old and new tps sensor. Shouldn’t the supply line from tank stay full of fuel after I turn it off ? I’m going to check out the check valve when I get boat home. I tried a remote tank last month but that tank also didn’t have a check valve. Thanks.

 

[mallardmasher]

Mechanic tried selling me a $1700 fuel pump even though pressure is ok.
Got it home and played alittle. I’ve narrowed it down to the tps. I’ve replaced it twice one cheep o and one real one. It will not stay running at start up with tps plugged in. I unplug it and it idles perfect. I plug it back in and it wants to stall or does stall. I removed tps and moved little wheel all the way to the stopper side. Plugged it in and layed it on a rag next to throttle body. Fired up and idle perfect. The second I barely move the tps wheel it will stall. I tried to adjust throttle body plenum to closed more to mimic me turning tps to right but then I lose my perfect start up and air flowing in. Do I need a mechanic to use a scanner tool to adjust tps settings ?

 

[alldodge]

Scanner is not used to adjust the TPS, it either is or is not at the correct voltage. Idle about 0.5V and WOT about 4.5V

When TPS is unplugged the voltage goes higher, and being higher this tells the ECM increase the fuel. Something is off but don't know what it is. With a scanner connected we need to know what each sensor is telling the ECM

IAC counts
MAP volts
TPS volts
Temp volts
Fuel pulse width

When TPS is unplugged there should be a code thrown. Would also be nice to know what the volts were when unplugged

 

[mallardmasher]

Scanner is not used to adjust the TPS, it either is or is not at the correct voltage. Idle about 0.5V and WOT about 4.5V

When TPS is unplugged the voltage goes higher, and being higher this tells the ECM increase the fuel. Something is off but don't know what it is. With a scanner connected we need to know what each sensor is telling the ECM

IAC counts
MAP volts
TPS volts
Temp volts
Fuel pulse width

When TPS is unplugged there should be a code thrown. Would also be nice to know what the volts were when unplugged

I tested tps with multimeter. Key on - voltage wire at tps is 5v. Back probed the ground and signal wire. Idle sits at .76v , wot sits at 4.47v I don’t have a scanner. Thanks.

 

[alldodge]

TPS looks good
The GXI-D may be a MEFI-3 or 4, not sure
Being a MEFI find the DLC connector (will have cover on it). Will need a 12V resistor LED or a multimeter with tone. Use a jumper and LED/Meter as shown. Turn key ON and don't start, then start counting flashes.

No codes will be 12 - flash long pause, 2 short flashes and long pause again..Will do this 3 times and then start again. Same goes for other codes, it will flash all the codes 3 times then start back over

 

[mallardmasher]

TPS looks good
The GXI-D may be a MEFI-3 or 4, not sure
Being a MEFI find the DLC connector (will have cover on it). Will need a 12V resistor LED or a multimeter with tone. Use a jumper and LED/Meter as shown. Turn key ON and don't start, then start counting flashes.

No codes will be 12 - flash long pause, 2 short flashes and long pause again..Will do this 3 times and then start again. Same goes for other codes, it will flash all the codes 3 times then start back over

Wow that was awesome advice. I didn’t know you could do something like that. Thanks.
First code was the 12.
Then I got code 21 tps voltage high
Then I got code 22 tps voltage is low.
I unplugged batteries and going to try again later incase those two codes came from me playing with tps sensor off throttle body in my hand when I figured out it idles perfect when I manually move tps wheel clockwise ?

 

[alldodge]

Clear codes, turn key ON move throttle to WOT and return. Key OFF wait 20 seconds and then see if codes clear

 

[mallardmasher]

Clear codes, turn key ON move throttle to WOT and return. Key OFF wait 20 seconds and then see if codes clear

Awesome I did that and cleared codes. Now I only get code 12 Normal.yay.
Is there a way to reset iac and tps? When searching online I found how to reset tps in gm cars. With the adjusting throttle at pedal and turning ignition on then back off. Would this kind of thing work on these motors since they are a gm base ? Or maybe a trick with the throttle while jumped a to b terminals in service mode ? Thanks

 

[alldodge]

Have not seen anything abouta TPS reset

 

[mallardmasher]

Have not seen anything abouta TPS reset

Or reset iac ? What if it’s the iac not set correctly and when I unplug tps, that more fuel demand is idling good because iac is not sitting just right. I can see the iac move in tiny increments. And that hissing sound I was hearing is air entering at iac as it trying to to it’s thing to keep idle. I saw when I paper clipped into service mode iac fully retracted inward causing the idle to sit high when started. I noticed idle sat at about 1000 in service mode and about 650 out of service mode.

 

[alldodge]

The change in idle with the jumper indicates the IAC is functioning properly. In service mode the ECM increases idle to set timing correctly

 

[mallardmasher]

Update. Still have the same no idle to stall problem.
I even did a full rebuild on fuel pump. Removed all paint replaced both fuel cells. Replaces check valve on fuel tank.
Still starts up runs for a second then stalls.
Unplug the tps sensor then Starts up idle perfect until I turn key off.
Plug tps back in while idling and it revs high for a second then revs down to normal. Then stalls.
If I give it a tiny spray of gas at throttle intake just as it’s about to stall , it will catch itself and find idle. Fuel pressure is perfect on both sides.
I have noticed if engine is warmed up it seems sometimes I can start it and idle ok with tps plugged in.
I’m tempted to move distributor a tiny bit in each direction to see what effect it might have. Would timing being off a degree cause an engine to stall at idle but allow it to run perfect at all other rpm’s? Perfect idle with tps unplugged ?

 

[alldodge]

Don't see a slight change with Dizzy causing your issue. The slight bit of gas makes me wonder if your injectors are spraying correctly.

It might be that the TPS needs to be adjusted. When its unplugged the voltage goes higher so motor gets more gas. It doesn't do it so much when warmed up. Might look at the TB and see if it can be adjusted open more just a hair

 

[mallardmasher]

Don't see a slight change with Dizzy causing your issue. The slight bit of gas makes me wonder if your injectors are spraying correctly.

It might be that the TPS needs to be adjusted. When its unplugged the voltage goes higher so motor gets more gas. It doesn't do it so much when warmed up. Might look at the TB and see if it can be adjusted open more just a hair

I tried to open up throttle plate alittle but it didn’t help and brought my idle up higher. When I can idle.
When I pull tps off and lay it next to tb, still plugged in, I turn tps wheel all the way “closed” it will fire up and idle perfect. So I even tried closing the throttle plate more to mimic what I did by hand but then I lose that extra air that was sucking in around throttle plate and it won’t start at all. I’m almost tempted to get a second throttle plate and drill I tiny hole in it , so I can set it fully closed, so tps sits fully closed, to make up for that air loss when I close plate past the factory setting. Iac is working ok, can see it doing it’s job when I play around, or when it’s about to stall iac opens up like it trying to help at stall.
Engine runs excellent through all rpms except start up/idle.

 

[alldodge]

I'm out of ideas, @muc

 

[ripjmk]

I don't know if this will help but here is the print out of my 5.0GXI-E after a cold start. (Data from Fox Engine gateway). I would examine closely the end of the throttle shaft where the TPS connects for damage.

 

[Wave34]

Your throttle opening shows 0.00%.
But, when the ignition is ON without starting, is it 0% or another value?

On mine, IGN ON = 0.39% and then when the engine fires, there is an offset added to show 0%.
I have a video of when I was troubleshooting a hard start:

 

[mallardmasher]

Back at it again this summer. Still hard to start stall at idle. It Will idle perfect with tps sensor unplugged. It Will fire up and idle perfect when engine is warm.
If engine is cold it will fire up, run for a second, then stall.
Fuel pressure is perfect before and during start up. Fuel pressure is perfect while running.
Replaced all of the following
TPS sensor.
Iac.
Distributer cap and rotor.
Fuel pump.
Pressure regulator.
Check valve
Cleaned the fuel rail
Sent injectors out to be serviced/cleaned
I sprayed motor down and found no vacuum leak. Pcv valve work as it should , ball rattles and air only flow one way. iac valve moves as it should when needed.
This is a new long block engine. Mechanic gave it back to me with no idle, told me to open throttle to start it. Runs excellent at all rpm except idle. No change while using a remote tank. Today I’m gonna pull plugs and replace them as I’m out of ideas. Anyone here have any ideas for me ? I’ve got spark. I’ve got gas. I have no cold idle…

 

[QBhoy]

Hi. How long after starting her, was the data taken ? I’d be keen to see what the cooling temperature shows when literally just started from cold. When cold, these things should over fuel and run rich as can be, until they warm up. Perhaps yours isn’t doing this ? Is the IAC filter sponge in place and not missing ?
Any sign of water ingress from the manifolds or risers ? Evidence might be on the plugs if so. Does she have the proper iridium plugs in there, whilst I’m on the subject ?
I think I’d also maybe get her running at an rpm that she will sit at, then spray wd40 or something similar around the throttle body gasket and intake manifold. Just to see if it causes the engine rpm to change. I’d also make sure that there is no air getting drawn into the suction side of the fuel system. From the filter sealing interface, fittings in and out of it and anything else similar. Listen to the fuel pump when you turn the ignition key on. Make sure it has a constant, steady mono tone to it. Showing that it’s not drawing air

 

[mallardmasher]

Hi. How long after starting her, was the data taken ? I’d be keen to see what the cooling temperature shows when literally just started from cold. When cold, these things should over fuel and run rich as can be, until they warm up. Perhaps yours isn’t doing this ? Is the IAC filter sponge in place and not missing ?
Any sign of water ingress from the manifolds or risers ? Evidence might be on the plugs if so. Does she have the proper iridium plugs in there, whilst I’m on the subject ?
I think I’d also maybe get her running at an rpm that she will sit at, then spray wd40 or something similar around the throttle body gasket and intake manifold. Just to see if it causes the engine rpm to change. I’d also make sure that there is no air getting drawn into the suction side of the fuel system. From the filter sealing interface, fittings in and out of it and anything else similar. Listen to the fuel pump when you turn the ignition key on. Make sure it has a constant, steady mono tone to it. Showing that it’s not drawing air

I have no scanner to get any data.
It had no iac songe before. I purchased one and put it in. The only change I noticed with the sponge is the iac flow is nice and quite no more loud suction at iac. I haven’t changed plugs yet was going to today. Plugs have about 8hrs on them since the new long block.
No sing of air suction at fuel anywhere. Old fuel pump was loud. Brand new fuel pump is about 1 hour run time and sounds great.
I tried spraying everything with carb cleaner last season and found no vacuum problem.
If engine is cold I fire it up. Runs for a second then stalls.
If engine is cold I can unplug tps sensor. Fire it up and idle perfect.
If engine is warm I can fire it up and idle perfect.
I’m tempted to buy a rinda scan tool but I fear I won’t know what to read on it. Like what to cross reference info to. I have a solec service manual.
I really don’t want to have to open throttle ,warm up engine, then back down to idle every Time I touch the boat with a cold engine. This efi makes me miss my old carb boat. Thanks.