HumberSS Posted January 10 Posted January 10 My sis has a coaster motorhome which me and dog took wandering over Xmas. It goes really well, plenty of juice on the open road, I even overtook a fellow camper In a Mitsi Rosa just to ensure his wife knew who the Alpha was.. What it lacks however is anything resembling go off the mark. It has a big dead spot under 2k rpm and then it's away, which sucks for shooting gaps out of intersections etc over busy summer months. It's super economical and appears well maintained. I spoke to a diesel mechanic mate of mine and he said they do struggle pulling fuel all the way from the back and some people put lift pumps in. I've only ever fucked with common rail shit, surprisingly have never twiddled a pump on an older oil burner. Hit me with the how to and what potential things I need to be wary of. I really just want to cure the dead spot at this stage. I don't want all of the soot, despite my need for all of the moot.. I guess some smoke is unavoidable however when giving it the tweak. 2 Quote
Willdat? Posted January 10 Posted January 10 What does super economical mean for something this size? /sorry I've got nothing useful to add. Quote
HumberSS Posted January 10 Author Posted January 10 13 minutes ago, Willdat? said: What does super economical mean for something this size? /sorry I've got nothing useful to add. Haha no worries. I spent about $200 on diesel from Taranaki to Porirua return. I don't know what that works out to but it's roughly 650km round trip, I can't recall diesel price off hand but it seemed pretty good to me. 1 1 Quote
HumberSS Posted January 11 Author Posted January 11 2 hours ago, RXFORD said: Compounds.... My sister is already highly suspicious of me wanting to fuck with it. If it were mine it would already be in 1000 pieces and up on jack stands alongside the rest of my life. 2 3 Quote
RXFORD Posted January 11 Posted January 11 Haha I bet. @square would be the man to ask about those toyota boat anchors seeing as he has one in his van. 1 Quote
Bearded Baldy Posted January 11 Posted January 11 Apparently lcool is another forum that has bitten the dust over the years. 1hdt engines are pretty sensitive to advance so i wouldn't go there unless you have a dti and adaptors to fit up the bum of the pump. From stock i would give it a 1/4turn in on the fuel screw. And half a dozen clicks on the star wheel inside the boost compensator. You can rotate the boost rod to set it in the best performing area, but i suggest you watch a video or 2 on that before you dive in. 1hdt 12valves are one of the best engines ever made. Can handle 14psi before the stock ct26 starts to turn into a hot air pump and you lose power. As usual, only change one setting on the pumo at a time, and write down everything! 3 Quote
Bearded Baldy Posted January 11 Posted January 11 That is running as good as you can hope for too from an economy standpoint. My t3500 mazda camper gets 400km to an 80 litre diesel tank in comparison. And the 1hdt in my cruiser gets an average of 13l per hundy in eco mode. Taupo to wellington just under half a tank. In power tune hauling 2 quadbikes it hits 19l plus and the egts go past the 900c mark real fast. 1 Quote
HumberSS Posted January 11 Author Posted January 11 2 hours ago, Bearded Baldy said: Apparently lcool is another forum that has bitten the dust over the years. 1hdt engines are pretty sensitive to advance so i wouldn't go there unless you have a dti and adaptors to fit up the bum of the pump. From stock i would give it a 1/4turn in on the fuel screw. And half a dozen clicks on the star wheel inside the boost compensator. You can rotate the boost rod to set it in the best performing area, but i suggest you watch a video or 2 on that before you dive in. 1hdt 12valves are one of the best engines ever made. Can handle 14psi before the stock ct26 starts to turn into a hot air pump and you lose power. As usual, only change one setting on the pumo at a time, and write down everything! Thank man that's really helpful. Am I correct that you need to loosen the star wheel to bring the fuel on earlier? I just watched a bit of a pump video that explained it somewhat. 1 Quote
Bearded Baldy Posted January 11 Posted January 11 That is one way to look at it. By winding the star wheel down you reduce the amount of boost pressure needed to start the pin moving down adding more fuel. Half a dozen clicks clockwise is a good start. On the top of the boost compensator there is a locknut and screw, mark this and move 1/8 turn clockwise. Obviously loosening and tighten the locknut lol. There is a cam plate on the other end of that screw which preloads some extra fuel for when you want to get moving. Is the basic explaination. 2 Quote
Bearded Baldy Posted January 11 Posted January 11 Start with top screw and check to see if there is any extra black smoke when you blip the throttle, engine warmed up of course. If no smoke then give another 1/8 turn and recheck. No more than a quarter turn total between testdrives. Then wind starwheel 6 clicks clockwise. These 2 changes will have minimal effect on economy but should help move off the line better by allowing boost to starting building faster. If still wanting more powaa then 1/8-1/4 turn at a time on the main fuel screw. But economy goes downhill from there, and egts rise fast which as we all know is bad bad. 3 1 Quote
HumberSS Posted January 11 Author Posted January 11 9 hours ago, Bearded Baldy said: Start with top screw and check to see if there is any extra black smoke when you blip the throttle, engine warmed up of course. If no smoke then give another 1/8 turn and recheck. No more than a quarter turn total between testdrives. Then wind starwheel 6 clicks clockwise. These 2 changes will have minimal effect on economy but should help move off the line better by allowing boost to starting building faster. If still wanting more powaa then 1/8-1/4 turn at a time on the main fuel screw. But economy goes downhill from there, and egts rise fast which as we all know is bad bad. Excellent. That makes sense. Cheers man. 1 Quote
square Posted January 11 Posted January 11 I got my pump and injectors done by trundles, it made a big difference with a bit of boost but still gave me 50hp when I wanted 100. They have their own metering pin profile and I fell for the sales pitch. Its smokier than id like Is it definitely a 1hdt ? Most of those were 15b's which is a weapon of an engine. Under piston oiling and direct injection. I had a 60 series with a turboed one in it and it made great power, still does. 3 Quote
HumberSS Posted January 11 Author Posted January 11 24 minutes ago, square said: I got my pump and injectors done by trundles, it made a big difference with a bit of boost but still gave me 50hp when I wanted 100. They have their own metering pin profile and I fell for the sales pitch. Its smokier than id like Is it definitely a 1hdt ? Most of those were 15b's which is a weapon of an engine. Under piston oiling and direct injection. I had a 60 series with a turboed one in it and it made great power, still does. I wasn't actually a hundy on what engine it was. The reg actually says it's a 7 liter engine, but my searching revealed no such engine exists and Wikipedia said the 1hdt was a common donk in it. All I know is it's fucking huge. Actually one moment caller I think I have a pic... See attached - access looks wonderful.... I did think about taking it to Trundle. I've been recently doing bits of work for him designing cast inlets/exhausts for td42s. He's a good boy and they know their shit but I assumed he would talk me into more than just screwing the pump a bit.. Quote
square Posted January 11 Posted January 11 Yeah that does look like a 1hdt I think, 15b is a 4 holer with injectors in centre Quote
HumberSS Posted January 11 Author Posted January 11 17 minutes ago, square said: Yeah that does look like a 1hdt I think, 15b is a 4 holer with injectors in centre yeah its a 6 cylinder Quote
Bearded Baldy Posted January 11 Posted January 11 Yeah i put a trundles pin in mine. Not worth the 80 bucks unless you are going to bigger turbo and exhaust is my feelings. 1 Quote
jessemk2 Posted January 14 Posted January 14 On 12/01/2026 at 08:40, HumberSS said: I wasn't actually a hundy on what engine it was. The reg actually says it's a 7 liter engine, but my searching revealed no such engine exists and Wikipedia said the 1hdt was a common donk in it. All I know is it's fucking huge. Actually one moment caller I think I have a pic... See attached - access looks wonderful.... I did think about taking it to Trundle. I've been recently doing bits of work for him designing cast inlets/exhausts for td42s. He's a good boy and they know their shit but I assumed he would talk me into more than just screwing the pump a bit.. Rocker cover looks like could be 24 valve 1hdft the best of the of the in line 6 check the build plate. Trans lock up kit helps alot with these auto aswell 2 Quote
HumberSS Posted January 14 Author Posted January 14 59 minutes ago, jessemk2 said: Rocker cover looks like could be 24 valve 1hdft the best of the of the in line 6 check the build plate. Trans lock up kit helps alot with these auto aswell Thanks man. I will do that...when I find it.. I use the OD button on the hills etc, trans lock up kit sounds interesting Quote
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