6.2L 350 MPI great spark, 30 PSI fuel, will not start???

gunny609 · Dec 27, 2011

I have great spark, tested fuel pressure and that also was great, I am now clueless on why she wont even sneeze, just cranks?? any suggestions would be great, thanks

Don S · Dec 27, 2011

Re: 6.2L 350 MPI great spark, 30 PSI fuel, will not start???

Need the engines Mercruiser serial number.

gunny609 · Dec 27, 2011

Re: 6.2L 350 MPI great spark, 30 PSI fuel, will not start???

gunny609 said:
I have great spark, tested fuel pressure and that also was great, I am now clueless on why she wont even sneeze, just cranks?? any suggestions would be great, thanks

OM327932, any suggestions would be greatly appreciated, I am at my whits end with this thing!!

Don S · Dec 27, 2011

Re: 6.2L 350 MPI great spark, 30 PSI fuel, will not start???

You have 30 psi of fuel pressure, are you sure it's really fuel? Have you checked your water separating fuel filter for water?
Are you getting spark to the spark plugs, a faulty cap or rotor would keep the plugs from firing, but still show spark from the coil.

tpenfield · Dec 27, 2011

Re: 6.2L 350 MPI great spark, 30 PSI fuel, will not start???

With your safety hat on, I'd be looking at ways to see if the MPI is really doing it's thing. I am also assuming you checked for spark at the plugs?

gunny609 · Dec 27, 2011

Re: 6.2L 350 MPI great spark, 30 PSI fuel, will not start???

tpenfield said:
With your safety hat on, I'd be looking at ways to see if the MPI is really doing it's thing. I am also assuming you checked for spark at the plugs?

yes, yes and yes... I did check for water and actually dumped the filter into a pickle jar to confirm and it was good. I used my spark tester and confirmed a good spark at each cylinder, i did remove the cap and replaced with the cap from the good motor and still no start. What gets me is that I dont even get a sneeze out of her. She just cranks and thats it. I have been on this thing for 3 days now and cannot think of anything else?

scoflaw · Dec 27, 2011

Re: 6.2L 350 MPI great spark, 30 PSI fuel, will not start???

Compression, timed spark and fuel. That's all it takes. I think your fuel pressure should be in the low 40's

tpenfield · Dec 27, 2011

Re: 6.2L 350 MPI great spark, 30 PSI fuel, will not start???

Are the injectors injecting? That is what I was suggesting . . . maybe they are not injecting the fuel into the ports.

Bondo · Dec 27, 2011

Re: 6.2L 350 MPI great spark, 30 PSI fuel, will not start???

I used my spark tester and confirmed a good spark at each cylinder,

Ayuh,... Did ya actually pull the sparkplugs, 'n Look at 'em,..??
Are they Dry, or fuel soaked,..??

Btw,... A 6.2l is Not a 350, so which do ya have,..??

Don S · Dec 27, 2011

Re: 6.2L 350 MPI great spark, 30 PSI fuel, will not start???

Do you have the OEM service manual for troubleshooting the 555 system. If not, download it here; http://www.4shared.com/document/FWwx1Vs7/Service_Manual_36_Rev_1_SBC.html

Don S · Dec 27, 2011

Re: 6.2L 350 MPI great spark, 30 PSI fuel, will not start???

Bond-o said:
Btw,... A 6.2l is Not a 350, so which do ya have,..??

I've been scratching my head on that one too. The serial number could be for any, but it was for a model number 4M42027PS, which turns out to be a 5.0L MPI. :facepalm:

Now you know why I like serial numbers ........

Fun Times · Dec 28, 2011

Re: 6.2L 350 MPI great spark, 30 PSI fuel, will not start???

gunny609 said:
OM327932, any suggestions would be greatly appreciated, I am at my whits end with this thing!!

Your fuel pressure is to low at 30 psi, The correct specification is 43 psi.

Once you get to 43 psi and it still won't start, then you will want to take a look at Mercruiser service bulletin number SMC-03-06 - V6 AND V8 GMEFI WITH NO START, ENGINE MISS-FIRE OR ENGINE SHUT-OFF CONDITIONS, as your serial number is within range.

Also while cranking the engine over, check to see if you're RPM gauge is moving up to around 300-400 RPM?

Good luck.

rte592 · Dec 28, 2011

Re: 6.2L 350 MPI great spark, 30 PSI fuel, will not start???

Timing chain issue??
Verify compression

Verify the distributor rotor is turning

You have spark with good looking plugs you should be able to shoot some starting fluid in the intake and get something

Don S · Dec 28, 2011

Re: 6.2L 350 MPI great spark, 30 PSI fuel, will not start???

rte592 said:
you should be able to shoot some starting fluid in the intake and get something

Do NOT use starting fluid on these engines. You are just asking to damage things. :facepalm:

mxcobra · Dec 28, 2011

Re: 6.2L 350 MPI great spark, 30 PSI fuel, will not start???

You have spark with good looking plugs you should be able to shoot some starting fluid in the intake and get something

Thats what I would do to veryify if its fuel related - she will run on starting fluied.

and if it dont run on starting fluid, you will know its spark or timing!

Have some one crank it while you spray! zoom zoom it should go.... if not well.... - dont blow youre self up!

mxcobra · Dec 28, 2011

Re: 6.2L 350 MPI great spark, 30 PSI fuel, will not start???

dont run it a bunch on the juice - just enogh to verify the problem area

dubs283 · Dec 29, 2011

Re: 6.2L 350 MPI great spark, 30 PSI fuel, will not start???

mxcobra said:
she will run on starting fluied.

and if it dont run on starting fluid, you will know its spark or timing

terrible advice

the engine WONT run for long on starting fluid IF there is spark and COMPRESSION, there will be disasterous results if the op does this

im pretty sure the op has bad fuel (water, and does not know how to i.d. it) or zero compression on multiple cyliders

mxcobra · Dec 29, 2011

Re: 6.2L 350 MPI great spark, 30 PSI fuel, will not start???

Give us a reason why this is so terible, I have done this more then once with great results.
Not sure if you are awere but a gas engine is full of fire and explosions any way, I think they are made to handle flames!
what comes from this method is flames.
You act like I am asking you to poor dirt into the motor!

Dshow · Dec 29, 2011

Re: 6.2L 350 MPI great spark, 30 PSI fuel, will not start???

I was also going to suggest starting fluid just to see if it fires... What are the negative consequences of using starting fluid just long enough to see if it will fire?

RogersJetboat454 · Dec 29, 2011

Re: 6.2L 350 MPI great spark, 30 PSI fuel, will not start???

Dshow said:
I was also going to suggest starting fluid just to see if it fires... What are the negative consequences of using starting fluid just long enough to see if it will fire?

Because Ether does not burn like gasoline. From the information I can find, Diethyl Ether (starting fluid) has an octane rating of 0. In other words, there is no delay in it burning. It burns more rapidly than parts have a chance to move. You hammer the pistons/rings with detonations and combustion pressures that can far exceed what even the crappiest gasoline can do. What's the result? Pistons and rings with holes and cracks.

6.2L 350 MPI great spark, 30 PSI fuel, will not start???

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