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Discussion Starter · #1 ·
Hi guys, I've recently had a new Denco turbo installed + tune, dyno and 2 1/2 inch exhaust. Motor at 300k and only running 9lb - all very mild. Pump wasn't rebuilt as it was stamped as being done about 6 or so years ago (previous owner).
In the last couple of weeks on 4 random occasions the motor has surged. Never done this before.
Now its done this twice while idling at traffic lights and more concerning, twice while driving. At idle it went to about 2000rpm and refused to drop. After giving it a few revs it eventually decided to drop back. While driving it just jumped up in revs and speed - not ideal...
Will be bringing it back to the turbo place Mon or Tues (they are good to deal with). Their gut feeling is this wouldn't be caused by the turbo, but probably pump related - maybe something sticky in there?
Obviously I'm hoping like hell it's not the pump and I've read some other posts about possible sticky cables, A/C idlers. Any other ideas or theories I can work through?
I was also thinking about running some 2 stroke through the fuel to lubricate the pump, and while I've visited the discussions about 2 stroke from time to time it looks like something that can't hurt to try?
Thanks.
 

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Part of the furniture
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yay! intermittent fault finding! gotta love that.


your throttle, does it feel sticky? is it smooth the full throw of the pedal?

when a mate of mine had his old mav, he had a dirty throttle cable and it would stick, and throttle would jam on.
 

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Make sure turbo oil drain is not kinked and working well, also make sure air filter is clean with no inlet restrictions. If it's only started happening since turbo install i reckon turbo is the issue. Did they tune it when they did turbo install?
 

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Discussion Starter · #4 ·
yay! intermittent fault finding! gotta love that.


your throttle, does it feel sticky? is it smooth the full throw of the pedal?

when a mate of mine had his old mav, he had a dirty throttle cable and it would stick, and throttle would jam on.
Tks OSH, yeah throttle feels sweet, and for sure it won't do it when I go into the workshop :neutral:
 

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Discussion Starter · #5 ·
Make sure turbo oil drain is not kinked and working well, also make sure air filter is clean with no inlet restrictions. If it's only started happening since turbo install i reckon turbo is the issue. Did they tune it when they did turbo install?
All braided lines, proper fittings and no kinks. I put in new air filters, fuel filter, oil filters, fresh oil etc at the time of install. Its odd that this has started about the same time as the install but I've got an open mind on the cause - happy to look at everything. I'm no mechanic but not sure how a turbo (in isolation) could cause those sort of symptoms?
 

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If it's not draining properly then oil can be forced into the compressor and turbine housings, I was thinking the engine could be running away from oil coming in through the inlet. A big restriction in the inlet to the compressor can also cause this like a blocked air filter
 

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Discussion Starter · #8 ·
Well turns out to be good news (the pump itself is ok).
On the side of the fuel pump below the accelerator cable is a vacuum device with hose that runs up to the firewall on the drivers side. This device controls revs (seems related to the A/C cutting in and out). There is a rubber boot on the shaft of this device that was perished and has over time let contaminates in. Occasionally the shaft sticks as the revs increase causing the revving (as it can't return). A bit of WD40 and all sweet again so proves theory. Seems this device isn't really needed so its been isolated pending if parts are available (and $$$). I can live with it dropping 50rpm when the A/C kicks in. Mechanics consensus is just leave it like that. Will do and see what happens. At least it won't surge in traffic now :)
 

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So is the TD42 not meant to just up in idle with the AC on? It ****s me how it idles at 1150 with the AC on.
 

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^^You can adjust the air con idle up. It has a screw in the back.
 

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In the back of what exactly? cheers for the reply by the way
 

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Glasshouse Bogan #1
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The actuator on the side of the pump has a screw. Or disconnect the vacuum hose from the actuator and the revs should drop. You dont really need the idle up on a td42 anyway.
 

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Yeh thats what i was thinking, that being such a big engine it shouldnt really need it. Even worst the AC system is the same stuff on wagons and utes, except im cooling 1/3rd of the size. My AC rapes the fuel buy 2L / 100kms hoping that lowering the rev( load) it might make a bit of a difference.
 
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