1994 Diesel Turboed gets pauses in reving

[ludacris]

Ok guys I recently turboed my 1994 4.2 diesel which replaced my 4.5 petrol. I have turned up the fuel screw and pyro is lucky to hit 500 if worked hard. Now as I go through the gears foot flat I get occasional pauses in accelaration then it continues on like it should. I have a 4 - 7 psi lift pump. The turbo is boosting at 9 pounds max. It is a Garret. I will intercool it soon with a water to air.

I am thinking more fuel but I cannot turn the idle down any more unless there is a way to shift the accelarator spring by loosining of the bolt on top of it. What have you done.

I am trying to get everything sorted as best I can before I get its timing changed and dyno tuned.

Cris

[5inchgq]

Does it happen all the time or just occaisonally ? I get the same thing (pauses in acceleration) with my TD42 (hitachi GU turbo) when it went in for a tune recently the specialist who tuned it said that there was a dry seal in the pump (no leaks?) but that would be the cause. This is with a standard GQ pump with fuel screw adjustment.

[smash250]

I would check your, fuel filter, also there is a small fine mess filter on the fuel pump. for your pump you will not even be using you lift pump. if you really want to be able to reduce your idel, you will have to take you fuel pump off and have a aneroide installed onto it. beacause your fuel pump is on the TD42 it will not be set for turbo. where as all the TD42T engines have fuel pumps with aneroides or"Boost compensators" this means you have almost like a two stage pump, ON boost fuel and off boost fuel. because yours does not have this, you have wound up your off boost fuel to compensate for on boost which means you idel will be alot higher than usual. before i had my pump modified my idel use to run at 1100rpm.

few things to think about any way hope it helps.
cheers
Ash

[ludacris]

Does it happen all the time or just occaisonally ? I get the same thing (pauses in acceleration) with my TD42 (hitachi GU turbo) when it went in for a tune recently the specialist who tuned it said that there was a dry seal in the pump (no leaks?) but that would be the cause. This is with a standard GQ pump with fuel screw adjustment.

Yeah it does not happen all the time and it is at different rev range aswell. I have almost done evrything I can do so I will book it in with a specialist shortly. just have to fit my bleeder valve. I have heard that you can use an aftermarket boost compensator on some toyota diesels if you turbo them. Can this be done with patrols aswell.

Cris

[5inchgq]

Does it happen all the time or just occaisonally ? I get the same thing (pauses in acceleration) with my TD42 (hitachi GU turbo) when it went in for a tune recently the specialist who tuned it said that there was a dry seal in the pump (no leaks?) but that would be the cause. This is with a standard GQ pump with fuel screw adjustment.

Yeah it does not happen all the time and it is at different rev range aswell. I have almost done evrything I can do so I will book it in with a specialist shortly. just have to fit my bleeder valve. I have heard that you can use an aftermarket boost compensator on some toyota diesels if you turbo them. Can this be done with patrols aswell.

Cris

I have a GFB bleeder valve on mine (silicon lines to and from the turbo) and was told by the guy that tuned mine that the seal I mentioned was dry and able to suck air for a short time (and a whole heap less fuel) hense the pause. This is who tuned mine (I tried to link it but his name here is 'sswaffie' I know he is miles away from you but might be worth a call. He races a TD42 and really knows his stuff.

[ludacris]

Does it happen all the time or just occaisonally ? I get the same thing (pauses in acceleration) with my TD42 (hitachi GU turbo) when it went in for a tune recently the specialist who tuned it said that there was a dry seal in the pump (no leaks?) but that would be the cause. This is with a standard GQ pump with fuel screw adjustment.

Yeah it does not happen all the time and it is at different rev range aswell. I have almost done evrything I can do so I will book it in with a specialist shortly. just have to fit my bleeder valve. I have heard that you can use an aftermarket boost compensator on some toyota diesels if you turbo them. Can this be done with patrols aswell.

Cris

I have a GFB bleeder valve on mine (silicon lines to and from the turbo) and was told by the guy that tuned mine that the seal I mentioned was dry and able to suck air for a short time (and a whole heap less fuel) hense the pause. This is who tuned mine (I tried to link it but his name here is 'sswaffie' I know he is miles away from you but might be worth a call. He races a TD42 and really knows his stuff.

Cheers for the info bud and I might give Swaffie a call but will try local first today. Have you done anything to rectify the problem or got and estimate of cost. Is it a pump rebuild or just put new seals through it. i might go through and check that all the fuel lines are tight although I am sure it will leak if they were loose. I will enquire about a boost compensator today aswell.

Cris

Cris

[ludacris]

Does anyone know if a GU injector pump will bolt up to a GQ 4.2 diesel?

[giantracing]

put the right turbo on it, sounds to small , sounds like you have a gt2560 on it....................

[ludacris]

Has a GT2860 on it which alot of people have used with no problems.

Cris

[Clanky]

My 1995 GQ does the same thing. Its a std GQ (10mm plunger) pump and running 15psi.
The pump guy told me that wear in the pump body can make the advance mech sticky and give similar symptoms.
I had the pump rebuilt and the boost compensator fitted but still does it. More so if you are up it for a while (long hill on full throttle) - so I am thinking fuel delivery.
My mesh filter in the inlet line on the pump is new too.
I have new HD296 filter on it too.

I also have a Walbro FRD-11 lift pump on my desk ready for install so was hoping this might fix it after reading about this issue on patrol forum.

Are you sure your lift pump is working properly?
When was your last filter change?

Other than that, I am wondering if a fuel line is kinked or there is something different in these later models which restricts fuel.

[Clanky]

Does anyone know if a GU injector pump will bolt up to a GQ 4.2 diesel?

Apparently yes if you get the earlier mechanical timing type, the later ones have electric timing adjustment and need a box of electrons to work.
The GU factory turbo pump has the 11mm plunger and boost compensator.
These can be added to the std GQ pump to make it the same spec.

From memory my rebuild cost around $1200 with boost compensator fitted but kept the 10mm plunger (mainly coz I didnt know about the bigger one at the time )

[ludacris]

My 1995 GQ does the same thing. Its a std GQ (10mm plunger) pump and running 15psi.
The pump guy told me that wear in the pump body can make the advance mech sticky and give similar symptoms.
I had the pump rebuilt and the boost compensator fitted but still does it. More so if you are up it for a while (long hill on full throttle) - so I am thinking fuel delivery.
My mesh filter in the inlet line on the pump is new too.
I have new HD296 filter on it too.

I also have a Walbro FRD-11 lift pump on my desk ready for install so was hoping this might fix it after reading about this issue on patrol forum.

Are you sure your lift pump is working properly?
When was your last filter change?

Other than that, I am wondering if a fuel line is kinked or there is something different in these later models which restricts fuel.

I have all new fuel filters. I will check that the lift pump is working properly (getting the right voltage) as it was wired up to the original 4.5 petrol fuel pump wiring. I am also ordering new injectors as this may need to be done anyway.

Turbo is only running 9 pounds of boost.

Does anybody know if the timing is advanced when they get tuned to suit the Turbo.

Cris

[ludacris]

This is the lift pump I am using. http://cgi.ebay.com.au/Electric-Fuel-Pu ... 1c131505d1

It is getting over 12v and usually you would only need 1 - 2 psi of pressure so it should be upto the job.

Cris

[300WinMag]

That pump should be fine I used one of those for about 2 yrs and then replaced it with a walbro facet pump thats looks the same. My Patrol is getting 121RWKW on 33" tyres with this set up GU pump and turbo spec injectors from Desiel Tech in Melbourne. No surging or flat spots.

[Clanky]

From this thread it would seem that the pump you have may not be ok
(note the last post on the page). But did you size the hose fittings to the same as the fuel line as mentioned?

http://www.patrol4x4.com/forum/showthread.php?t=20487

Is the pump volume enough to supply the engine at just over 2L / min?
Dont know what an angry 4.2TD would use on full noise but 2L seems feasable.
Only reason I ask is that the elec pump might become a restriction rather than a help if its not enough volume

Too bad you dont live closer I would lend you my Walbro for a test.

P.S In the Ebag ad pic it shows two barbs and another fitting. I can only guess this is a non return (which you dont need) and may be causing a restriction. Just a thought

[Clanky]

Another thread which might help (also something different in the last post)

http://www.exploroz.com/Forum/Topic/119 ... ation.aspx


Have you tried going for a run without the fuel cap on? Maybe the tank breather is blocked and causing a vauum in the tank.

[5inchgq]

Cheers for the info bud and I might give Swaffie a call but will try local first today. Have you done anything to rectify the problem or got and estimate of cost. Is it a pump rebuild or just put new seals through it. i might go through and check that all the fuel lines are tight although I am sure it will leak if they were loose. I will enquire about a boost compensator today aswell.

Cris

I havn't done anything about it yet as the issue is only very occasional at the moment. I have another GQ pump that swaffie is going to modify ( bigger plunger etc) so that should sort it out , From what he said he can do the mods for a very reasonable price (cheaper than a rebuild ) So I'm saving some pennies to get it all done.

[Clanky]

Does anybody know if the timing is advanced when they get tuned to suit the Turbo.

Cris

X2

This thread , although a little hard to follow seems to be pointing at the pump timing adjustment at the rear of the pump (only thing I know of you use a dial gauge there for)
http://www.4wdmonthly.com.au/forum/sitemap/t-35827.html

I have the tools for pump adjustment and have set it up to std specs at the moment. Does anyone know if changing the pump timing will remove this flat spot - if so how much and what direction...Adv or Ret?

[ludacris]

When I did the conversion from 4.5 to 4.2 and added a turbo I used the two diesel filters and left the original petrol filter in. Last night i removed the petrol filter and it seems to have fixed the problem. Today I will hit the highway for a final test to make sure but I hit 3500 in 3rd and 4th and no signs of surging. I will let you know.

Cris

[Clanky]

Wow! You had 3 filters in?

[ludacris]

Wow! You had 3 filters in?

Yes 3 but the thought was more the better except it wasnt. lol.

Cris

[tufftruckin]

bahahahahahahahaha

[Clanky]

Wow! You had 3 filters in?

Yes 3 but the thought was more the better except it wasnt. lol.

Cris

Its like women. The more you got the messier its gonna be...gees one is more than enough

[tufftruckin]

Wow! You had 3 filters in?

Yes 3 but the thought was more the better except it wasnt. lol.

Cris

Its like women. The more you got the messier its gonna be...gees one is more than enough

Nice one Clanky:)

[ludacris]

Wow! You had 3 filters in?

Yes 3 but the thought was more the better except it wasnt. lol.

Cris

Its like women. The more you got the messier its gonna be...gees one is more than enough

True that.

Keep us updated about the lift pump sorting your problems aswell.

Cris

[bazzle]

Pity you didnt mention the filters in the 1st post

Bazzle

[ludacris]

Pity you didnt mention the filters in the 1st post

Bazzle

I know but it did not to me seem like it would have been a problem especially after adding the lift pump but as I found out it did.

Cris

[fnqcairns]

full marks for coming 'clean' many wouldn't!

My Na does it (one filter), thanks for the valuable insight into the problem, it is what I suspected was the problem and a lift pump will fix it.