Volvo 5.0 gxi Stalls at idle. Hard start.

[mallardmasher]

Volvo 5.0 gxi. Fuel injection. I need some of your expert advise please.
Runs excellent through all rpm except idle. Needs a tiny bit of throttle in neutral to start engine. If I let it run for a min with throttle open and back it down to idle the engine will almost stall but catch itself and idle and a can run great all day until I turn engine off.
If no throttle is given it sarts for a second and stalls when warm or cold. I thought it was the iac so I put in new iac but didn’t resolve problem. The throttle body sounds extremely loud sucking air in at the top. When I remove spark arrester I can really hear the loud sucking of air draw in around the plenum. Is my iac out of wack ? Like the circuit is forcing iac to stay plunged closed, forcing the air to be draw in at plenum ? I’ve never remembered this loud vacuum sucking. It’s loud so I’d imagine I would have noticed this before. Any input is gratefully appreciated. Thanks

 

[Wave34]

Volvo 5.0 gxi. Fuel injection. I need some of your expert advise please.
Runs excellent through all rpm except idle. Needs a tiny bit of throttle in neutral to start engine. If I let it run for a min with throttle open and back it down to idle the engine will almost stall but catch itself and idle and a can run great all day until I turn engine off.
If no throttle is given it sarts for a second and stalls when warm or cold. I thought it was the iac so I put in new iac but didn’t resolve problem. The throttle body sounds extremely loud sucking air in at the top. When I remove spark arrester I can really hear the loud sucking of air draw in around the plenum. Is my iac out of wack ? Like the circuit is forcing iac to stay plunged closed, forcing the air to be draw in at plenum ? I’ve never remembered this loud vacuum sucking. It’s loud so I’d imagine I would have noticed this before. Any input is gratefully appreciated. Thanks

Is your PCV valve working?
Is it a new problem?
Any work done on the engine before that?

 

[mvn]

What IAC did you use as a replacement?

 

[mallardmasher]

Is your PCV valve working?
Is it a new problem?
Any work done on the engine before that?

I assume pvc is ok. There is no smoke and no sing of oil issues. This is a new problem. Engine got a new long block. When I picked it up it took 4 turns of the key to start it. I contacted mechanic after a day he said I need to give it alittle throttle to start. I said I thought fuel injection shouldn’t need throttle? It runs great and sounds great everywhere but idle. Sounds like someone is holding a vacuum under the throttle body at idle.

 

[mallardmasher]

What IAC did you use as a replacement?

I used an aftermarket off Amazon $35. I ordered a real one that should be here next week. Just incase Amazon one was crappy. Should I see the iac move at all when I remove the arrester at idle ? It looks like it’s just sitting in one position.

 

[QBhoy]

Hi. Sounds like another candidate for the famous crap cap. I’d replace the distributor cap and rotor. I’m always banging on about this on these engines. But honestly causes 99% of all issues on these particular engines.

 

[Wave34]

I assume pvc is ok. There is no smoke and no sing of oil issues. This is a new problem. Engine got a new long block. When I picked it up it took 4 turns of the key to start it. I contacted mechanic after a day he said I need to give it alittle throttle to start. I said I thought fuel injection shouldn’t need throttle? It runs great and sounds great everywhere but idle. Sounds like someone is holding a vacuum under the throttle body at idle.

Maybe worth a try to remove it and shake it to see if it moves freely (not clogged).

At idle, there is some combustion air coming from the PCV in addition to the throttle body. And may be the IAC is at its maximum opening and can't compensate.

In the past, I bought a IAC from Amazon, and it has been working fine for the last 2 years. May be I was lucky?

 

[QBhoy]

Could also be bad fuel too.

 

[mvn]

I, too, got an IAC from Amazon and it did not work. The OEM Mercruiser one did! Buyer beware.

Mark

 

[Donald0039]

Hi. Sounds like another candidate for the famous crap cap. I’d replace the distributor cap and rotor. I’m always banging on about this on these engines. But honestly causes 99% of all issues on these particular engines.

Why so?

 

[QBhoy]

Why so?

These gxi and mpi engines are now very well known for the cap failure. I have the same engine. I’m on my 6th cap in 7 years. Especially affected in some climates and especially noted after winter storage and moisture gathered in them. Even those that look perfectly fine, can be the source of issues. Have a wee look up on here and google. There are literally now almost uncountable accounts of them causing issue. Google mpi distributor cap problems. Or crap cap distributor

 

[Lou C]

It is also well documented by people who owned GM trucks that used the same system. Sometimes these "improvements" are anything but. In the old days GM HEI caps lasted a long time as do the Prestolite design caps I have used on my old points distributor. I replace 'when I see corrosion on the terminals but honestly I've never had one "Fail".
That's why I kept the old boat. I don't see electronic ignition with those troublesome caps, or throttle body fuel injection, as improvements over a maintained points distributor or a well tuned Quadrajet.

 

[Lou C]

What I wish was certified for marine use was the old GM points distributor with the window in the cap. The points and condenser were mounted on one plate, simple to replace, and you set the dwell with the engine running via an allen tool. Elegantly simple and worked great.
Even on my old Prestolite the points last at least 5 seasons....I just check the dwell and timing with the meter and then set the idle speed and mixture when its in the water. Really simple. I feel sorry for people stuck with "better" new technology. I am pretty much independent of marine mechanics.

 

[mallardmasher]

I tried running with a remote tank and still no change. New iac came today and new cap/rotor will be here tomorrow. I’ll try them and see what happens.
If I had a vacuum leak somewhere wouldnt that effect more then just idle, and cause a higher idle ? If I open throttle and idle at around 800rpm it sounds perfect but when I close throttle and idle between 600-650 it wants to die like it’s starving for fuel or air. It doesn’t matter if engine is cold or warm Idle is still barely there and either stalls or or catches itself

 

[mallardmasher]

So I replaced iac, Distributor and Rotter, fuel pressure regulator, no change to idle and still wants to stall at idle. Pulled fuel pump and completely disassembled cleaning every inch of it (wow those screens looked horrible) and replaced some o-rings in there. Reinstalled fuel pump. Still stalls at idle but sounds better, starts with 1/2 key turn now.
When I unplug the throttle position sensor and start it, the engine idles perfect, sounds perfect. No stall. No hesitation what do ever.
My tps sensor is bad right ? The second I plug it back in the engine stalls.
Thanks.

 

[ejnichol]

Would definitely try replacing tps if its not first a calibration issue with ecu.

What year motor/drive is this?

 

[mallardmasher]

Would definitely try replacing tps if its not first a calibration issue with ecu.

What year motor/drive is this?

I think it’s a calibration issue. So I changed all those things. Dissy cap. Rotor. Iac module. Fuel pressure sensor regulator. Cleaned every part of fuel pump. Just replaced the tps today from thinking it was bad since it will idle perfect when tps unplugged. But no change is still get a stall at idle during start up. Or an almost stall and it catches itself just before stall. Idles sounds like it’s starving for air at 600rpm. But Idle sound excellent if I keep throttle just between 750-800 rpm.
If I unplugged tps it idles perfect at 600rpm. I’m wondering if I can have the iac module calibration done on mechanic scanner ? Like tell the iac to open a millisecond earlier before stalling. It looks like the iac moves to “open” at the second it’s stalling.
2003 Volvo penta 5.0gxi. Sx or sxi out drive

 

[QBhoy]

Have you tried running off a remote fuel source to be sure it’s not a poor fuel quality issue ? Sorry if it’s been asked before. Sounds as if it’s struggling to fuel at low rpms.

 

[mallardmasher]

Have you tried running off a remote fuel source to be sure it’s not a poor fuel quality issue ? Sorry if it’s been asked before. Sounds as if it’s struggling to fuel at low rpms.

Yes I tried that. Even cleaned fuel pump/screens. While running motor at idle it sounds like it’s starving for air. I can hear massive sucking sound at top of throttle body as it’s trying to suck air in around plenum.
Does anyone know why the engine will start and idle perfect with tps sensor unplugged ?

 

[QBhoy]

Yes I tried that. Even cleaned fuel pump/screens. While running motor at idle it sounds like it’s starving for air. I can hear massive sucking sound at top of throttle body as it’s trying to suck air in around plenum.
Does anyone know why the engine will start and idle perfect with tps sensor unplugged ?

That noise is probably to be expected. That’s just the IAC doing it’s job of trying to control and counter what’s going on with the engine trying to stall.
So what rpm is it actually idling at when it’s all as normal and on the verge of cutting out and what rpm does it idle at when the tps is unplugged?