I just put the DDP4's back in and I have a fuel leak. Of course its on the #6 so you cant see anything back there and the engine has to be running to find the leak. I can see fuel pooling around the injector nut. I tried to tighten the nut but its pretty tight. Same with the return line banjo. I also put a mirror back there and I'm still not sure where its comming from. I dont "think" its comming from the supply line. Can fuel be comming out of the injector hole up through the nut? or would that just be air if that was leaky? Its not pouring out but its comming out steady enough to leak down the motor and create a puddle of size on the driveway in 5 or 10 minutes. Any other ideas or diagnosis tips?
Thanks

 

so far I've tried replacing the gasket on the banjo bolt for the return line. I cleaned the return line end and made sure there was no crud on it or the injector. I took out the injector clened it and the bore real well. stuck a rag down in there after brushing it to get everything out too. That was pretty much spotless as well. Then I torqued the injector to over 50 foot pounds insted of the called for 44. Still leaks. I'm not sure where or why though. It takes a minute or so before the leak starts like its filling up the injector bore then spilling out through the hold down nut. I would think if that was coming up from the cylinder that it would be alot of air and not nearly as much fuel. Is it possable the injector its self is cracked or in someother way leaking? they didnt leak before but the truck didnt run right. I had sent them back to DDP for testing and they replaced one injector but i dont know what one.

 

I moved the injector tot he #3 spot and the leak followed the injector. I think the leak has to be the injector its self is lekaing from in the middle somewhere and comming up from under the nut. I guess I have to call DDP... again... someday they might work right.

 

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Captain:

If the leak followed the injector like that, I would say you have a problem with the injector itself which you have already figured out. As I was reading your posts, I was going to tell you to re-check the very end of the injector line (where it fits into the top of the injector) as I have had dirt or an uneven surface cause mine to leak on occasion on my 96'.

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John_P

 

Ok heres a follow up for anyone else who may have this problem. I sent the injector back to DDP they tested it and sent it back saying it didnt leak. They said they lapped the threads too just to make sure. Sure enough it still leaked. After changing out the copper gaskets a few more times and tourqing the hold down nut to 60 foot pounds, well over the 44pounds it suposed to be at. It still leaked. DDP sent me out a new injector this time and it works great. So it was the injector however I dont know what cause it to leak. Perhaps the bottom was exactly square to the body, or it still leaked up through the body threads. I'm sure they didnt find the leak just because having a test method thats identical to a truck would be impractical. I'm sure they dont use a cylinder head and run the thing for 3 min or so spray fuel all over. At any rate its very dry now and DDP's customer service has to be up there almost at the SBC level. They have tested and returned my old injector inside of 1 week and the new injector arrived even faster.

 

I'm also having a leak that is pooling and dripping from my transmission. It looks like the #6 injector is leaking but I can't tell. Did the mirror help in seeing where the leak is from?

What's the best way to fix this???