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Help with an overfuelling 1HDT

Posted: Fri Dec 19, 2008 2:11 pm
by Brendan-s
I'm relying on secondhand info here, so might not have all of this right.

About 3 weeks ago, coming home from a holiday the old man's 1HDT starting using water. Turned out the head was warped, so he dropped it at the mechanics while he was in Brisbane to have it done.

They AFAIK machined the head, new gasket, serviced injectors, reco'd pump. I believe they used a slightly thicker gasket than was on there (next one up).

On the way home after it was all done it was blowing a fair bit of black smoke and using about 20L/100km.

Now he's in Port Macquarie so took it to the local mechanic to put it on the dyno. Problem is they can't get it set right so it wont a) overfuel or b) be a slug. Can get it so it doesn't blow smoke, but it's way down on power. Can get it so it

Dunno what they did to the pump but I don't think it was a full reco. It's been back to the dyno bloke 2 times with no success, goes back a 3rd next Monday. He reckoned they had the pump set for an atmo engine instead of a turbo one.

My question is, is there any obvious tricks or problems to watch out for that might be causing this. Don't know much about Toyotas myself.

Posted: Fri Dec 19, 2008 7:03 pm
by Pauwolf
pump timing,
get it set to exactly 1.1mm throw, they can be anywhere from 0.7 to 1.3. if it is at the lower end of the scale it wont make power, if at higher end will use heaps of juice

Paul

Posted: Fri Dec 19, 2008 8:28 pm
by Dzltec
Black smoke and low power is indicating an air restriction. Pump timing needs to be checked with a dial gauge and the acsd disengauged. I think timing is 1.29-1.35mm @tdc.

What do the pump people have to say? Anyone that tests pumps do know the diff from atmospheric to boosted. Each spec is done via the pump number, not hard to mess up the specs, but can be done if tested incorrectly. Injectors are also time consuming to set correctly.

Is the boost line to the injector pump reading boost pressure correctly?



Andy

Posted: Fri Dec 19, 2008 10:02 pm
by Brendan-s
Cheers for replies. It's hard getting info as dad and I both work odd hours so only rarely get to talk.

That said. I spoke to the original mech this morning who mentioned the injectors weren't replaced, rather reco'd.

My thoughts are one injector may be leaking fuel causing the black smoke.

Thanks for that measurement. It's going back to the dyno on Monday so I'll let Dad know to get them to set it to that.

Posted: Fri Dec 19, 2008 11:42 pm
by Sic Lux
When you say they went a thicker head gasket as in next one up that may have droped the compresion enough so it doesn't get a good burn instead only just igniting giving slow or incomplete combustion just a idea to throw out there

Posted: Tue Feb 10, 2009 11:42 am
by -Richo-
Did you end up getting this sorted out? Im interested in the verdict if so.