Please Help! engine dies at lower RPMS or at Idle

[wakesurfid]

I have Marine Power 5.7 EFI on a 2003 Tige 24V.

Engine starts fine cold, will run fine at higher RMPs (over 1400), but will suddenly die when reducing RPMs under 1200, will also die after a few minutes of running normal at idle. After it dies, it can sometimes take a few tries to get it started again.


I already replaced both the LP and HP fuel pumps, fuel/water separator, ignition coil, cap & rotor, wires, plugs, and crank position sensor. Any ideas? Could Fuel injector fouling be a possibility?

[KXCORKY]

Interested in this as well, We are having the same issue, but we get a beep from the dash.

[lee]

What about the IAC valve?

[ChrisBarnes05-12-84]

Map sensor?

[wakesurfid]

So I changed out the IAC valve, no change. It cold starts fine and idles for about 3-4 minutes then just dies, then starts and dies quickly again, then has trouble even starting after that. I think I'm going to try and change out the anti-siphon valve next.

[lee]

Have you checked the fuel pressure when running good and then running bad?

[ChrisBarnes05-12-84]

You should really look into the MAP sensor. My 07 had the same issues you are describing and that fixed it instantly. Runs like crap at idle , runs just fine underway. I especially think this because it's the exact same engine I had. Marine power 5.7

[KXCORKY]

we got lucky and it was just a bad connection at the battery. It almost sounded just like what you explained though,

[wakesurfid]

Yes I checked the fuel pressure,

Key on = 58psi while pump is priming
start and idle = 52psi
Higher RPMS= 50psi

When it I bring it back to idle and it suddenly dies, pressure jumps up to 58psi and I can hear the fuel pumps still going.

[wakesurfid]

What is the normal range of fuel pressure?

How long should the pressure hold after shutting down?

[ChrisBarnes05-12-84]

Fuel pressure seems within range to me. Replace that Damn MAP sensor and let's be done with it lol.

[ChrisBarnes05-12-84]

http://fixcars.net/map-sensor-symptoms

Read that

[wakesurfid]

Had a marine mechanic diagnose things, tested the MAP sensor, its working fine. He's checked everything on the ignition side, rechecked everything on the fuel side, everything seems to check out, but symptoms remain. He tried to connect the marine diagnostic tool to the ECM, but it will not communicate. He suspects something is wrong w/ the ECM, but says there' no accurate way to diagnose a faulty ECM, may need to replace and see if it fixes things. Any other ideas to consider before shelling out the big bucks for a new ECM?

[ericinmich]

I would not suspect an ECM at this point, I would try to get a scanner working on it. Do you know someone with the same boat, swap a known ECM in it and see if problems go away?

ECMs usually don't go a little bad, they work or they don't. Have you tapped on the ECM while engine is running?

How did he test the MAP sensor if he couldn't communicate to the ECM? Did he put it on another engine and had no issue?

[ChrisBarnes05-12-84]

You can't test a map sensor that I know of. The scanner will see the fault when u plug it in. The symptoms fit it to a T. I would personally be shocked if it wasn't the problem. If he says it's good I guess I don't have much room to stand on though.