Wont go past 2500 rpm

[alldodge]

tee from my fuel pressure kit between the in tank pump

This should be zero psi, it's before the pump. You need to place gauge between fuel pump and throttle body

Go to post 15 and click one the word "FUEL" it takes you to the TB and shows were it can be connected at

Don't run motor above 1500 on a hose. The hose can not supply enough water to keep from burning the impeller. Also not being under load will not provide the needed info

 

[richw03]

Ok this is what I got from fuel pressure test

 

[alldodge]

Tad low (might be the gauge) but looks good for idling

 

[richw03]

Ok Mr alldodge I jumped code port its flashing 3 times and then a pause and then 3 times repeatedly

 

[alldodge]

33 is MAP voltage high - yours is a MEFI 1
Means either the MAP is bad or signal lead is shorted to power 5V or grounded

 

[richw03]

33 is MAP voltage high - yours is a MEFI 1
Means either the MAP is bad or signal lead is shorted to power 5V or grounded

View attachment 396698

I'm going to do it again with my multimeter ill get back to you thanks so much

 

[richw03]

I'm going to do it again with my multimeter ill get back to you thanks so much

Yes just did it again it came up 33 map sensor will a new one fix it or is there something else I need to do?

 

[alldodge]

Yes just did it again it came up 33 map sensor will a new one fix it or is there something else I need to do?

The MAP circuit is causing a problem, and can be the MAP or the circuit. In most cases it is the MAP but look close at it to see if it has already been replaced by prior owner

Merc does really like there parts, really high
Original was 861249A1
Updated one is 8M0186195 $280

Item 12
https://www.mercruiserparts.com/bam/subassembly/31844/2704/100

 

[alldodge]

Searching around using old number I found one at walmart for $97, do look around
https://www.walmart.com/ip/Sensor-M...21-556102-8M0054726-861249-861249A1/905199679

 

[richw03]

Searching around using old number I found one at walmart for $97, do look around
https://www.walmart.com/ip/Sensor-M...21-556102-8M0054726-861249-861249A1/905199679

No it looks old part numbers are worn and there's black gunk around the orange seal on the nipple so I guess I'll do some shopping..
Thank you so much for your help I'll let you know what I find out once the new one is here.

 

[alldodge]

Do make sure the electrical wires and connections are good. A bad connection will give same issue

 

[richw03]

Do make sure the electrical wires and connections are good. A bad connection will give same issue

I will for sure I just checked the part number on the one thats on it and it says it's for a chevy 5.3 could that be the issue that it's not even the right part?

 

[alldodge]

I will for sure I just checked the part number on the one thats on it and it says it's for a chevy 5.3 could that be the issue that it's not even the right part?

That may or may not be an issue. It's a GM part and may be able to get it from a GM dealer. It's a 1 Bar (1 atmosphere) pressure sensor

 

[richw03]

Well I guess I'll find out I went ahead and ordered the one from Walmart I'll keep you posted.
Once again thank you so very much for your time and information.

 

[Scott Danforth]

Also it will rev over 2500 rpm but it's not under load being its in my driveway

it will do that running on 2 cylinders. that doesnt mean squat

 

[richw03]

it will do that running on 2 cylinders. that doesnt mean squat

Mmm thanks for being so helpful and contributing to the issue.

 

[Scott Danforth]

Mmm thanks for being so helpful and contributing to the issue.

you have slightly low pressure if your gauge is correct.

you are flashing a MAP sensor code

you havent verified the neutral safety switch.

you added a second fuel filter in-line with the stock one which doubled the inlet restriction

have you checked compression?

running in neutral on the trailer in your driveway on the hose means nothing, other than you starved the raw water for flow. there is no load on the motor, so it only requires a drop of fuel between two cylinders to hit redline. under load you need gallons of fuel going to all 8 cylinders.

how is the spray pattern of the two TBI nozzles? is one dripping?

 

[richw03]

Second fuel filter is gone, nozzles are both working like they should, compression is good ,
I never even reved the engine past 1000 rpms
I have a map sensor on the way
And everything I've read says neutral safety switch wouldn't be the issue if it starts and shifts between the gears with no hiccups

 

[alldodge]

Your motor doesn't have a in neutral/gear switch according to the serial number

 

[Scott Danforth]

, compression is good ,

What does "good" mean?

Range?
All numbers within 10 psi?