EFI GT40 HElP and opinions

ok so here is the story. I have a 98 air with a GT40 EFI set up and the boat has decided after running fine for a long time to start acting up. I have tested for fuel and spark and i have neither. The boat cranks (turns) but never actually fires. Currently I have tried testing the fuel pumps with a test light and even jumped them off of the main power wire to see if they would run when getting a constant 12 V. Both pumps work flawlessly. I have a new cap and rotor installed as well as a new ICM, coil, wires and plugs... but no spark. When i test my connection at the coil i dont see 12v. So long story short..... I have an electrical problem that is keeping the boat from sending 12V to the ignition and fuel systems.

Could this be a bad computer?! Bad Wiring harness? what the heck is going on here.

I honestly am so over fuel injection that I want to rip it out and convert the boat to a carb set up. My last boat was a carb set up and the boat fired everytime after it was primed.


Have you guys ever hear of this happening? And am i crazy for wanting to convert back to a carb set up?!


My pros and cons are as follows.

I could be crazy and buy a new ECM and wiring harness for the boat at a cost of around 1300 bucks (estimate) and it work fine or i still have the problem after all of that.


Or i could convert to carb for around the same price and eliminate all the crappy wiring on the engine and hopefully it solves the problem.

The way i see it is that with EFI i have 4 things that have to happen for the motor to fire correctly (fuel, air, spark and the dreaded electricity) and with a carb i only have 3 and it eliminates (to some degree) the electrical computer component.


HELP GUYS!

sorry. i said ICM... i meant TFI-IV. The problem is those parts arent even getting power. im so frustrated. ive never had this much trouble with a correct craft boat.

would the ignition problem be keeping my fuel pumps from priming?

Check the PCM manual Section 3 chart 4 in the troubleshooting guide for "cranks but does not start, . Gary's idea is one prognosis but connections are culprits too. Read through the manual
And act logically and you'll get there quickly and less expensively.

This is the diagram to work from if you have no power to coil check terminal 87 on EEC relay for 12 volts. (Page 6-10 of manual).

The ECM power cct on your 98 also may not have been retrofitted. The inline 50 amp fuse item 14 in diagram was a known problem PCM released a modification to delete this fuse. It is located in the battery box. This EEC Retrofit thread will help if you still have this fuse.

im printing the ENTIRE manual right now. hahhaa. this thing is 301 pages long. haha. i guess it will be more than a toilet read this evening.

This is the EEC fuse I was talking about when I updated earlier post.

No--but that dang fuse could be what ails you.

i just read that thread lewy posted and it looks like that fuse would keep power from making it to the eec which im guessing would keep the pumps from priming and prevent the coil from sending spark to the dist.

anyone know how many ohms of resistance that eec fuse is supposed to have?

I think that's an in-line fuse holder. Just pop it open and see if it's blown or not.

jellison wrote: i just read that thread lewy posted and it looks like that fuse would keep power from making it to the eec which im guessing would keep the pumps from priming and prevent the coil from sending spark to the dist.

You are correct. Mine is an all black wire,when I first got the boat,I repaired all the battery terminal ends. I hooked that black wire to the - side of the battery and no start. Quinner comes over and says why does a wire on the - side have a fuse? Well duh!
Looking at a good fuse on the ohm scale it should read the same as when you touch both leads together. If the fuse is blown it would read the same as if the leads do not touch.

just tested the fuse.... looks to be dead. multimeter is not moving at all. tested three fuses that i know are brand new and good and the meter moves to zero.

i think you guys might be right.... this fuse could be bad.....

I will repost tomorrow afternoon when i get off work at 1.

thanks for all the help guys!

Then just look for smoke!

GT-40s have a 160. Carb'd usually 143.

Great to see your problem solved so quickly! Go Lewy