2003 DT 150 starting problems

[Saltyfish3]

The motor cranks but will not start unless I spray starting fluid in the intake. Once it start, its runs like a scalded dog. I can run it for an hour, shut it off and try to restart- no dice. I have replaced the fuel bulb and the filter with no luck.

Any suggestions?

Thanks!

[Saltyfish3]

No clues on this post?

[Motorman0889]

Starting problems

You should check the temp sensors because there is one sensor that enrichens the fuel mixture on cold start ups just like you need to choke a carb motor when cold.

[Saltyfish3]

Thanks for the response! The next questions would be where are the temp sensor(s) located and how does one run a function check on these?

[seaox230c]

There are two of them one at the top of each cylinder bank under a teardrop shaped cover with a slot in the middle for the wires. Need to know the colors of the wires off each one to get the proper resistance values...even if bad, they shouldn't stop you from starting a hot engine..don't have access to my manuals until tuesday. All you do is spray some starting fluid and it starts right up? and runs great until shutdown...then no start again..thats odd

[Saltyfish3]

That would be correct- and it has me baffled as well. The only thing that might be the culprit is the two fuel pumps behind the oil reservoir. The diaphragms might be bad and not send fuel? Using starting fluid might fire the engine and draw fuel past the pumps? Thanks for the reply.

[seaox230c]

This is a fuel injected motor..if your HP fuel pump isn't working...your engine wouldn't run after you got is started

[seaox230c]

With that said...if your hp pump does not run during the crank..then it will not start but will run if it works with the key in run (on)

[Saltyfish3]

So are you saying the HP ( high pressure?) fuel pump is bad? Is there a way to test it before I spend about 5 bills on a new one?

[seaox230c]

No the pump is probably ok..it either runs or it doesn't..but a relay or keyswitch might be bad..I will see if I can find a test for the keyswitch

[Saltyfish3]

Thanks for your help on this seaox. I hope its something simple.

[seaox230c]

Havent had too much free time...the pump should turn on for 2 or 3 seconds in the on position then run continuous with the engine running..can't tell whats its supposed to do in start. You need 2 people...one at the engine...turn the key to on...you might hear a click but you should hear the pump hum for 2 seconds..I will continue to research

[Saltyfish3]

Thanks seaox- I will give this a try.

[seaox230c]

Any luck with this...there are other tests but you need to purchase a pressure gauge 0-50 psi, some 1/4 inch fuel tubing, and a couple of brass fittings and you need to be slightly mechanical. This takes about 1/2 hour to set up but it gives an excellent indication of your fuel delivery system

[dspar00a]

Can anyone tell me what the outcome with this was? My motor is doing similar things and so far I've had no luck. I'm getting the click but no hum from the hp pump after I turn the key to the on switch. I'm getting nervous as a new efi computer is in the area of 1500-2k and I'm really hoping that's not my issue. My motor is older but has less than 100hrs. Can't see how the ecu would go out that quick?