GQ , TD42 injector pump

Submitted: Wednesday, Feb 26, 2014 at 18:38
ThreadID: 106436 Views:9197 Replies:8 FollowUps:1
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hi all .
can someone please clarify for me ,
have just fitted DTS turbo an 3in system ,in the fitting instructions ,a bit vague .
it says to adjust the max fuel scew in 1/4 turn , I have an aftermarket W/Shp
manual which says virtually nothing about the pump , could someone please
explain or email a photo of the screw I need to adjust ,
cheers mechpete
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Reply By: Member - Niss42 - Wednesday, Feb 26, 2014 at 18:44

Wednesday, Feb 26, 2014 at 18:44
G'day Pete.
Suggest you try the "Patrol" forum here:-
There is some great info to be found there !

AnswerID: 527283

Reply By: pop2jocem - Wednesday, Feb 26, 2014 at 18:46

Wednesday, Feb 26, 2014 at 18:46
Pete, not familiar with the Nissan pump but maybe ask the question of a local fuel injection shop or post on the Nissan Patrol forum.

AnswerID: 527284

Reply By: wjh41 - Wednesday, Feb 26, 2014 at 18:58

Wednesday, Feb 26, 2014 at 18:58
Hello mechpete,I don't know what state you are in but I had a similar situation with mine.Forget the guess work I took mine to MTQ in Dandenong where the vehicle was tuned on the dyno,very happy with the results. Wally sorry just read your in Shep
AnswerID: 527286

Reply By: Member - Duncs - Wednesday, Feb 26, 2014 at 20:59

Wednesday, Feb 26, 2014 at 20:59

Having owned a GQ with an aftermarket turbo I can recommend using a good diesel fuel injection workshop to get the turbo sorted.

I note that you are a mechanic but think this is still worthwhile.

The turbo was fitted to mine by a previous owner and I did have problems. The biggest was overheating but all were caused by over fuelling. Adjusting the fuel screw by 1/4 turn sounds a bit vague to me. Diesel fuel injection is not vague.

My problem required a two stage fix.

The first place I took it to fitted a unit which automatically adjusted fuel supply based on turbo boost, I think they called it a boost compensator. If you look at the top of a diesel pump in a vehicle with a factory turbo you will notice it looks different to one without a turbo, that is the boost compensator. This did improve things but didn't provide a complete fix. I took the car to another fuel system specialist who properly tuned the fuel system, balancing the opening pressures on all 6 injectors and getting the fuel rate right.

Good luck with the upgrade. The GQ is a great old bus and should serve you well for many many miles.

AnswerID: 527300

Reply By: Ross M - Wednesday, Feb 26, 2014 at 21:03

Wednesday, Feb 26, 2014 at 21:03
I believe screwing it inwards increases the amount of injected fuel, but, some caution should be exercised, BECAUSE, you don't know if it is already in or out or where it is.

Theoretically, more air will cater for more fuel but you just don't know.

Now you are in the realm of SOP testing ie seat of pants, and to do that you will need to know what is required and have an EGT gauge fitted and have some experience in the concepts involved so excessive EGT's can be avoided.

If you make a mistake, what is the cost of a TD42 now?
AnswerID: 527301

Reply By: Brett and Julie - Thursday, Feb 27, 2014 at 08:14

Thursday, Feb 27, 2014 at 08:14

I had a Denco turbo fitted to my TD42 GQ which was put on a dyno and had the pump adjusted to suit. 5 years later never been touched and has been bulletproof. Best accessory I ever bought. Good luck with yours. cheers
AnswerID: 527326

Reply By: mike39 - Thursday, Feb 27, 2014 at 08:36

Thursday, Feb 27, 2014 at 08:36
The max. fuel adjusting screw you are looking for is directly above where the injection pipes mount to the pump.
A small screw about 25mm. long with a 6mm. hex on the end, a small sleeve and an 11mm locknut.
To adjust (in for more fuel) you have to remove this screw and grind off the spot weld on the sleeve to remove it.

Once you have done this you are in "no mans land" this sleeve was to prevent overfuelling of the pump but now you can do whatever you want, possibly at your peril.
Its also nigh impossible to go back to the original calibration
Although extremely robust, all these old NA engines do not suffer overfuelling, particularly with now a turbo boost. Even a 1/8 turn of the screw results in more fuel than imagined, the pump is initially calibrated y.xx cc's/1000revs. which is why the sleeve is spot welded on.

As an aside, when I turbo'd my 1hz (125000km. ago) I actually had to decrease the fuel to obtain best power/economy ratio.
AnswerID: 527329

Reply By: Member - mechpete - Thursday, Feb 27, 2014 at 11:44

Thursday, Feb 27, 2014 at 11:44
thanks everyone !!
gunna get it dynode
AnswerID: 527341

Follow Up By: Member - Craig F (WA) - Thursday, Feb 27, 2014 at 22:29

Thursday, Feb 27, 2014 at 22:29
Wise move. The money spent will be returned in Performance and economy. After fitting an aftermarket Exhaust Turbo and Intercooler to mine I had it tuned resulting in a massive increase on economy. Went from 20ltr per 100km to 15.
FollowupID: 809770

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