difficult starting

[Reel Poor]

Re: difficult starting

When I checked the voltage at the Ignition control module it showed 10 -12 volts at the Purple/white timming lead not 8-10 like the manual says

That should not affect the system operation.

Are you still chasing this problem?

took engine to 3000 rpm advance appears to only pick up 5-10 deg Im guessing.

Question.....Why are you guessing? Do you have a timming light with a manual advance degree knob on it? If not, you can't properly check timming advance.

As for the knock sensor.....It would only stop spark advance if it was shorted to ground, sensing a knock, or the blue wire is routed to close to spark plug wires.

You can check the sensor with an ohm meter for short to ground.....check the blue wire routing......if your still running the 87 octane fuel this would also cause your problem.....Your engine is running to much compression for 87 octane fuel you NEED 92 or 93 octane.

With the proper timming light, and the right fuel in the engine, you can disconnect the blue wire from the sensor and see if the timming is advancing properly (boat should be in the water and run under a load). If it's not, I would suspect a faulty ignition module. With voltage present on the purple /white wire (and it's definately getting to the Ignition Control Module, check both module terminal plugs for corrosion) and the knock sensor disconnected, the timming should work properly. WARNING: DO NOT CONTINUE TO OPERATE ENGING WITH KNOCK SENSOR DISCONNECTED

Also, be sure both modules are properly grounded, they have both wire and case grounds.

 

[jwkoehn]

Re: difficult starting

Problem believed to be solved . I took it to a new marine dealer who is supposed to be very sharp. He had it pegged in 15 minutes . Don S, I am really supprised that did not nail this one. It turned out to be 2 wires crossed, the sensor wire from the gear lube resevoir and the wire in the harness for base timming They both have the same fitting on them. I think the boat was this way when I bought it since I had trouble with it shortly thereafter. It now starts without a problem and runs well w/ one exception It dogs under hard acceleration until it hits about 3000rpm Then it goes like a bat out of hell It maxes out @ 5100. The dealer set Timming at 8/10 deg btdc I am thinking of moving it to 12 deg btdc Will this be hard on the starter and will it likely eliminate the dogging in the mid range Fyi this is a 96 Gm 5.7 now a 383 stroker carbed also This is a TBI 5 system One last ? Does this system have a rev limiter in the ign module? Thanks for any assistance JWK

 

[BAYLINER185]

Re: difficult starting

I do beleive there is a rev limiter on these motors. I wouldnt want to find out though by trying to over rev it

 

[Don S]

Re: difficult starting

Don S, I am really supprised that did not nail this one. It turned out to be 2 wires crossed, the sensor wire from the gear lube resevoir and the wire in the harness for base timming

You don't suppose being able to look at the engine had anything to do with it do you? We can only go by the info you give us, and nothing to look at.
You actually should have found it almost 2 years ago by following your OEM service manual wiring diagram and tracing out all the wiring.

 

[jwkoehn]

Re: difficult starting

Don, you are right I guess thats what I get for assuming it came to me wired correctly any thoughts about bumping the base timming to 12 btc to eliminate the dogging issue?

 

[jwkoehn]

Re: difficult starting

I tried 12 deg btdc engine performs well but there is a little bit of kickback during starting . Is their a different ign module I should use for a stroker that will give me more advance during midrange 3000-3600 rpm in a tb5 ignition bravo3 system thanks for any help

 

[Coors]

Re: difficult starting

You might try looking at the carb under aceleration, see if the secondaries don't open until 3000 rpm.

 

[jwkoehn]

Re: difficult starting

at what point should the secondaries open they are mechanical not vac

 

[Coors]

Re: difficult starting

Is it a Qjet? if so, the air shutters allow it to pull vacuum, and fuel. When do they open?

 

[Coors]

Re: difficult starting

If they open at, or before 3000, I think that is too soon.

 

[jwkoehn]

Re: difficult starting

had weber 4 bbl secondaries rejetted to next size larger made a huge improvement still get a small hesitation under hard acceleration is it worth it to go to next size larger jets ? (383 stroker)

 

[wca_tim]

Re: difficult starting

I'm 10-15 hours into a new 383 and did a lot of checking before the engine build. In loking at ignition systems, it was recomended that I use a Thunderbolt i4 because the advance is all in the module and is preset and predictable. I have been walking total timing up 2 degrees at a time and when performance doesn't increase with the move, then drop back 2 degrees.

I wouldn't move your timing much of the stock specs unless you're quite sure would suck to lunch a new engine...

What do your plugs look like?

Good luck with it...

 

[jwkoehn]

Re: difficult starting

we pulled the distributer cap & found excessive play in the rotor .then we pulled the dist & found excessive wear on the dist gear we could rotate the rotor 1/8 of a turn . can this mess up the base timming during starting enough to cause kick back when starting ?