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1996 454 Crusader XL TBI Stalling Issue

You must be close to finding it.....or not. I mean it is a boat.

Still thinking about the 10-15 second delay before shutdown and what could cause it. Mako knows these distributors and could comment but I am wondering about the possibility of an installation/wiring issue where somehow there is a "floating" ground that causes the engine to get a signal from the distributor for a while, but then a charge difference builds up and the MEFI is no longer told to send a spark. I mention this because the new distributor could be fine, but when you take it out and move it you could solve the problem by accident but not really need a new part.

Weird idea and maybe not really possible. But boat electricals are always a little weird. You might go back and examine your installation with an eye on weak or missing grounds.
 
I would think if would be beneficial to go over the distributors with a fine tooth comb if the swap exercise is done....just because the source of the unit was never called out....I don't have any idea how many EST kits were made by Delco before they stopped marketing them.....

My understanding on the MEFI-1 & -2's is the engine's state is determined by the pulses provided by the ICM that originate with the pickup coil....loose them when in the RUN state and you loose the spark....as far as the inputs to the ECUs, Delphi got them right a long time ago.....they are very robust and the design hasn't changed much over the years....that said, a bad wire in a harness, is a different issue.

I'd say the plan is viable and the only other suggestion is to revisit the MEFI manual again, just to make sure nothing has been overlooked....hopefully the two remaining exercises will be sufficient.
 
[FONT=&quot]Pretty sure I fixed the damn issue. I think the culprit was 3-4 little dots of rust in the injector cavity (but I don't see how it would effect anything... the screens over the injector pickup looked fine, and the regulator looked fine; untorn and the spring looked brand new) [/FONT]

[FONT=&quot]Swapped upper TBI units with the port motor, and it fired right up, and kept running. Not sure if the injectors are bad, but everything else inside looked good, other than the couple dots of rust. Injectors on that motor are brand new, and had a nice spray pattern... I'm going to have to investigate further as to the actual cause, but at least I seem to have found the solution. Any ideas? Injectors had a nice spray pattern, but motor would stall after 30 seconds. Seems weird to be caused by a couple specs of rust in each injector cavity.
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[FONT=&quot]In any event, hopefully splashing tomorrow. Thanks for all of the direction and advice![/FONT]
 
So did you swap the TBI and the problem went away, or did it move to the other engine? Or did you swap, fix/clean something during the swap and then it went away? I have fixed a lot of things by taking them out, taking them apart and finding nothing wrong but when they were reassembled and put back in they worked. It means something was sticking, a connection was bad , or "who knows?" Often they stay fixed. Sometimes not.

Good luck!
 
Congrats on the progress!!!

Like Cabo, not exactly sure what was swapped....i'm thinking a partial swap of the TBI units....from the injectors up?

I don't think those injectors are different from the newer designs - they don't tolerate any form of dirt....maybe some of that rust was in the 'wrong spot' and the 'swap' moved it to where it wasn't an issue....anyhow, more details to add to your logbook....
 
I took the TBI upper off of the Starboard motor, put it on the Port motor, and it fired right up, and kept running. While I had the port motor TBI uppper off, I'm rebuilding it before putting it back on the other side. I rebuilt it more to take it apart and see what's wrong with it. I honestly expected to see a gummed up fuel pressure regulator, or gas passages, but there was nothing significant. There were 3-5 tiny pebbles or dots of rust in each injector cavity, but I'm shocked that it could have been the whole issue. The regulator and regulator spring were in perfect condition. The injectors in that motor were new.

After some run time I may put the injectors that I took out of the (now working) starboard motor back in. The port motor is getting new injectors for the time being. If I put the damn thing back together and the other side doesn't work, I'd be furious. The injectors currently in the starboard motor are original to the boat. The ones I took out are much nicer, brand new borg warner (orig equipment) injectors (@ $97 each). After the frustration calms down and I'm willing to tinker a bit, it's only a 15-20 min. project. Until then, I want to get some wake time in, and enjoy it before I go tearing it apart, but honestly, I enjoy tearing it apart and making it better (I think we all do in a masochistic way...), so I'm sure I'll tinker with it further later in the year.
 
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