Power Down - Pyro up - Diesel

On the last 2 trips out in my boat, my cruise speed has decreased from<br />3200 rpm to 2600 rpm because the has been lost and the pyro stays hot. I<br />have had to back off the throttle because the pyro goes up. I don't know<br />what the limit is but I backed off to keep it under 1050 degrees. Before<br />I got 3800 rpm full throttle, now I can only get 3200 rpm.<br />I thought when you have a loss of fuel delivery, The power would<br />decrease but the pyro would also decrease. I checked one spot in the<br />exhaust (that was restricted with exhaust crud) and it was clear. Down<br />in the outdrive is the other point that might be restricted. The<br />outdrive normally is OK for a 5.7 gas engine. Mine is a 2.8 liter Isuzu<br />turbodiesel with 10 pounds boost<br />The water temperature is normal.<br />I have not checked the advance, but I have no reason to believe it has<br />changed.<br />Any clews as to what might be wrong?<br />Don

Re: Power Down - Pyro up - Diesel

umm so its overheating?

Re: Power Down - Pyro up - Diesel

if im not mistaken the pyro mesures exaust gas temp at the turbo. keep looking for a restriction also this can be caused by a lean fuel mix might want to have the injectors checked

Re: Power Down - Pyro up - Diesel

Isuzu makes a fine diesel engine. I would check the oil line to the turbo for any restriction and I have known of mechanics that have increased the oil line size (larger diameter) to facilitate turbo cooling.<br /><br />As for the other suggestions....you may have a clogged (or clogging) injectors and worse case scenarios is a failing injector pump or a failing turbo.<br /><br />An in-exspensive (cheap) way is to add some Diesel Service to your fuel or even a cup of ATF (automatic transmission fluid) to the fuel tank. This will help clean the injectors. I have owner a few Isuzu diesels (both turbo and non turbo) and they are good motors. If you suspect the injectors need to be repaired carefully shop at truck mechanics who are equipped and know Isuzu injectors. It does take special tooling but the injectors can be re-built for far less $$$$ than replacement.<br /><br />Bob

Re: Power Down - Pyro up - Diesel

Check your boost, as the injector may add same fuel and if boost is low it will be too much. It should smoke if this is true but might not in the water. I would look for a restriction in exhaust first.

Re: Power Down - Pyro up - Diesel

The pyro is measured 2 inches after the turbo.<br />The boost pressure is normal (10 PSI). The turbo bearings are water and oil cooled. I will check for fuel flow after the AUX fuel pump and filter today.<br />Thanks<br /><br />The fuel flow directly to the engine after the filter is fine.<br />Help<br />Don