Brief "cammed" idle at start up please help!!

[stroker001]

Hey guys new to this forum so bare with me. Ok I have a 97'obs 7.3 Zf5speed. It has 230k,new hpop,fuel pump,and not sure what else yet I just got it. Ok it runs and pulls like a train,but...Almost everytime you shut it off and start it up it will have this eratic "cammed" idle until I give it some fuel then it idles way down to about 400rpm then idles right back up to normal smooth as a sowing machine...? Anyone have any suggestions to what I should do or have any idea whats wrong with this thing??? Thanks a lot guys!

[madpogue]

How old is the oil? How's the level? Could be if the oil is low/old, it's not building sufficient HP oil pressure at startup idle.

You also mentioned "...shut it off"; are you hearing an unusual noise at shutdown?

[stroker001]

I havent checked that yet,good idea I will go check it now. And no not any weird noises at shutdown. I unplugged the MAP sensor and it seemed to hep some at first but I havent fooled with it enough to actually know. Thanks a lot

[Fordman247365]

Check the ICP sensor for oil in the plug

[stroker001]

Oh I've looked at icp it looks dry and ok,I've also looked at about all those sensors.the oil was about a quart low but I don't think a quart would cause that but maybe,the oil looked pretty good tho. After it starts loping just hit the throttle up to about 2300 and then it idles back down to about 400rpms then back up to 6ish fine. So idk.. It doesn't do it all the time but 90 percent of the time it does..? Thanks

[madpogue]

This isn't a swap/conversion from an automatic, by any chance, is it?

[jesilvas]

Mine does that, but only on really cold starts cause the HPOP can't keep up with the #6 injector and #8 firing right after with the cold, thick oil.

[atvrider93]

Try changing the oil. mine was doing the same thing until I changed mine.

[stroker001]

It's the original engine as far as I know. Doesn't look to have been changed. Has a new HPOP and fuel pump if that helps tell anything. It's like when it's firing up it has some timing knock for just a second until you rev it up til about 2200 then it idles back down. Like I say the truck runs perfect smooth loads of power just at start up it does some strange idleing. I will changed the oil tho and see if that helps. Any help would be appreciated thanks!

[jesilvas]

When the HPOP was changed, were the little poppet springs are in the ends of the HPOP lines put back in?