5.7LX just quits

[SlapShotE77]

I am in need of some help to pinpoint my problem. I have a 1996 5.7LX with 2 bbl carb and Thunderbolt V. A few weeks ago the engine just quit after running perfect all day, as if I shut off the key. Started right back up. I got about another 2 minutes and the same thing happened. By the time I made it to the ramp, this had happened several times. I sat idling at the ramp for about 30 mins without any problems.

After some troubleshooting, I replaced the ignition sensor (in the dist.), but no improvement. I finally got her running after cleaning the cannon plug. Went out for about an hour with no issues. I thought I had it fixed until the next day when the problem returned.

Next I found that the ignition control module had water in it. It was not seals all the way around. I dried it out and resealed it and had no problems for the entire day. The very next day the problem returned. Now it will start right up, but will only run for about 15 seconds. I am now considering replacing the entire ignition system or getting the $500 ICM 'replacement'. But I want to know what the problem is first.

I have run the engine with the cannon plug disconnected and with a jumper to the coil, with the same result. So I think this is not a hull wiring issue. The enginer has a new alternator, new coil, new ignition sensor, new plugs. Checked resistance in wires and all are OK. I also checked fuel system (even though this does not seem to be fuel related) and all is OK.

I really need some help here. My wife is now saying I wasted my money on a lemon.

(Sorry for the long post but I wanted to give the whole story)

 

[John_S]

Re: 5.7LX just quits

Do you have the service manual and have you gone through the T5 diagnostic flowchart while it is failing?

Are you sure you have a LX model. All 2brls during those years were L models, that I know of. The LX should have a 4brl carb and a knock module right next to the ICM.

 

[SlapShotE77]

Re: 5.7LX just quits

Do you have the service manual and have you gone through the T5 diagnostic flowchart while it is failing?

Are you sure you have a LX model. All 2brls during those years were L models, that I know of. The LX should have a 4brl carb and a knock module right next to the ICM.

I have a SELOC manual and have gone through that diagnostic. Plus what I mentioned above.

The serial number I have is off the engine cover, and that also says LX. Of course it is possible that the cover is not correct for the engine. I'll have to verify that.

 

[John_S]

Re: 5.7LX just quits

I can't say how the Selec compares on the diagnoisis of T5, but on other things, it is not as clear as the merc one.

Have you also checked that the shift interupter is not causing it?

I suspect you have a cover swap. The ICM will have the engine model and drive type under the barcode for the part number. But, matching serial numbers on the block would be best.

 

[SlapShotE77]

Re: 5.7LX just quits

I have checked the shift interrupt switch and that is not causing it. I need to get the Merc manual, for sure.

Let's treay this as a 5.7L, not an LX, because it appears it is an L. I'll try to get more info on this though.

 

[John_S]

Re: 5.7LX just quits

PM me if you are interested in a ICM to help you diagnois. It is for a 5.7L bravo, and the shift interupter will not work. If you run it on the water, it will not come out of gear, until you shut the engine off. It should be sufficient to see if your engine dies every X minutes though. After testing, you will need to return it.

 

[SlapShotE77]

Re: 5.7LX just quits

OK. I installed a Hardin Marine billet distributor, MSD 6M-2, MSD coil, and 8.5 mm wires. Everything runs perfect. I believe the ICM was faulty.