2007 RTX Max RPM 5000 - 5500

[Sharpester]

1st i would like to say hello all. My name is Paul but better know as Sharpy. Hopefully i can be of contribution to the group as well.

Currently i have 4 2007 RXT215's projects ... 2 complete engine rebuilds from pwc's that had been sank in the ocean 1 with a rpm problem and 1 thats perfect... so a lot to do... :willy_nilly:

After reading some of the other posts related to maxing out the rpm at similar values and having taken actions on such items i am wondering what else could possibly be the problem ..

My list so far and brief description of my issue

Issues:

Max rpm 5000 in the water .. out of the water it will red line
in the water in reverse it will hit 6500 7000. (strange in my mind lol)

Tops valve error .. from memory i think it was code 1502... i have since reset the codes
but not correctly functioning.

Action taken thus far:

1, Tops valve and sensor have been changed to see if this is part of my max rpm problem.
2, I have changed the super charger from a previous perfectly working machine. or it was perfect till it had been sank lol
3. all the clamps / clips to hoses checked and tightened to the SC.

My thoughts are that it could be a pump/impeller problem or am i far of the mark and wasting my time investigating this?
i also have just received a brand new SC but really think the one i have on now has no faults ...
tomorrow or the day after i hope to drop it back into the water to check if the problem has been resolved.

What i would like is to know if there is something else i can check or change before i drop her back in the water

Thanks in advance Paul.

 

[Seadoodoc]

great detailed explanation. my guess is not pump prop situation. it wud over spin rpm in that case. Low boost SC pressure causes 7500 rpm range. likely you have downed cylinder via fouled plug ... or low compression. your running two cyls imop.

 

[Sharpester]

Ummm. Compression test it is then .. I have ran candoo whilst the engine is running and am sure it's not plugs or injectors. Could you suggest maybe another test whilst in the water if my compression is good.
Thanks again

 

[Digdog]

Fuel pump could be bad, or the filter plugged. Should be 60psi and hold it after 2 seconds on power up, did you put in new plugs?

 

[Sharpester]

Yes new plugs have been fitted.. just waiting for a competition tester .. had thought about the fuel pump and filter .. really strange how it will review out to 6500 7000 in reverse but will only rev out too 5000 in forward .. had it back in the water yesterday and still the same ..

 

[Sharpester]

How can I edit this post lol.. anyway .. compression tester

 

[Sharpester]

Compression test done ..

All are similar to my perfect machine .

Fuel pump test next

 

[Digdog]

Do you have an intercooler? check it for water inside on the hose that goes to the intake.

 

[Sharpester]

I don't think it has .. fairly sure anyway lol

 

[Sharpester]

It does have an intercooler lol.. just got a workshop manual.

 

[Sharpester]

Do you have an intercooler? check it for water inside on the hose that goes to the intake.

I am taking it that if it doesn't this could be my problem? Not too sure about the intercooler setup ..

 

[Sharpester]

Update .. so I have now changed out the fuel pump and tried a different ECM.
Next is TPS reset .. then check the timing chain adjustment. And possibly change out the entire fuel rail and injectors ...

 

[Sharpester]

Update ... Found a bad fuel injector. Now I got 7000 RPM. Yeh some success but still not perfect

 

[nateccnn]

Check your compression again. All but one were below specs before, right?

 

[mkov608]

Was the injector clogged, or was it on the electrical side of the injector? How did u determine it was a faulty injector?

 

[Sharpester]

Was the injector clogged, or was it on the electrical side of the injector? How did u determine it was a faulty injector?

It was clogged .. you remove the fuel rail and turn the engine over you should see a healthy spray

 

[benjilafouine]

How expensive is that compression tester? There is a lot of junk out there. I was almost ready to ditch my engine last year with a cheap one. Turned out it was perfect.

Benji.

 

[Sharpester]

I hear you on the compression tester .. I have 2 running rxts one 95% perfect .. one 80% perfect .. I used the 1st one as my bench mark and then tested the 2nd .. so as for it being a cheapish tester this doesn't really matter..

 

[Sharpester]

Ok so here's where we are at!

I have now changed the SC and fitted a new one .. whilst doing this I replace the crank shaft sensor then cleaned the carb and replaced the TPS sensor.

Huge difference made ..
Now what happens is from stand still.
Throttle full we jump out of the water at 8000 RPM then once we are leveled off it drops to 7000 rpm .. 50 ish miles an hour .. now I am at a loss .. basically I have changed everything .

Going to post a video of this so you all can see .. any other suggestions are welcome