Slow Start and Low RPMs

[maxumized]

I've been troubleshooting a low RPM at wide open throttle on my 3.0LX for quite a while and coming up empty handed. One thing I've realized at this point is how slow the engine turns over on crank, even with fully charged batteries and good wiring connections.

I put a meter on it and saw 370 amps in rush... is that normal? It was enough to pull 2 fully charged 650cca batteries from 14v to 11v in a matter of seconds.

I'm wondering if the resistance against starting is the same resistance that's keeping the engine from reaching optimal rpm at wide open throttle...

Any takers on this theory?

 

[searay3]

Re: Slow Start and Low RPMs

You don't say what year package your working on....Is the ignition in good shape? Timing can cause difficult starting. Good? Pull the starter and have it checked. There is a WOT trouble shooting chart that DONs has. Do a search on it. Compression is good and a fresh tune up right?

 

[maxumized]

Re: Slow Start and Low RPMs

1997 Maxum 1750SR 3.0LX/Alpha One.

Delco EST ignition.

Full tune up has been done. Have checked the fuel system. Brand new starter. New battery. Extra battery.

Anyone know what the typical max amp pull of a properly functioning starter/engine? I know 370 sounds high. Way high for the OEM 4ga wire between the battery and starter.

I've also been working my way through don's rpm problem list. Haven't found the issue yet and was wondering if anyone agreed this might be related. Wondering why the engine has so much trouble turning over at a decent speed and got me wondering if this "extra resistance" might be causing the rpm issue...

When you mention timing, its not like its sputtering and back firing trying to start... the darn thing just turns over suuppperrr sllloowww.... which led me to check the amp draw and it ended up being 370 and some change.

 

[Uraijit]

Re: Slow Start and Low RPMs

Did you actually check the timing? It's not necessarily going to be backfiring, in order for your timing to be way off...

 

[maxumized]

Re: Slow Start and Low RPMs

I have not checked the timing of the EST system, but I don't see where that would cause a slow turn over...

 

[Uraijit]

Re: Slow Start and Low RPMs

Well, you didn't ask either. You came and asked for help, and then ignored the advice your were given.

If your timing is too advanced, it will push the piston back down before it gets past TDC, and will try to spin the engine backward. This causes the starter to have to work extra hard in order to turn the engine over, which can cause a slow turn-over, and excessive current draw.

You're having trouble starting, and trouble AFTER the engine is started. Which points to an issue with timing.

You asked for help. You got it. Take it or leave it.

 

[maxumized]

Re: Slow Start and Low RPMs

Uraijit, I apologize if I seem like I'm ignoring advice. I certainly appreciate you taking the time to reply.

I really hope you're correct and it's just that simple. That's the very next thing I'll do as soon as I get hold of a timing light.

I'll keep everyone updated. If anyone else has any ideas, please chime in as well.

 

[Uraijit]

Re: Slow Start and Low RPMs

No worries. I'm not trying to brow beat either. I too hope it's just something simple.