TD27T power issues - help appreciated

[edmistral]

Hi team, Problem finaly found and solved !

I'm new here - first post - directly from New Zealand. Hello to all the tinkerers and enthusiasts who read this.
Currently working on a friends Mistral/Terrano2 1996 TD27T without intercooler and with standard mechanical VE Pump.
For some reason the engine has not the power it should have. We have annother similar one here for comparison. Checked all the obvious things like boost/boost compensator/compression/valve clearances/fuel filter/exhaust blockages etc.
The EGR pipework was removed at some earlier stage.
I have replaced the o-rings (complete genuine gasket set) between the high pressure block and main body and the injection advance piston of the injection pump. They were both leaking heavily but it made no difference to the power issue.
I want to check and get the basics right first - so:

#1 What is the correct injection pump timing for that engine?
Somewhere I have read that the non EGR TD27T has a different timing than the EGR equipped one. I'm inclined to use the non EGR timing, thoughts?

#2 What is the function of the solenoid which sits on the VE Pumps return line ? Has that something to do with the fueling / EGR ?

#3 How to set/test the TPS sensor on the pump - I assume it is important for the auto box to function properly ?

#4 I can't really find the appropriate Nissan workshop manual for a download - that would answer most of my questions.

I got the one which covers the later electronically controlled engine - but not the earlier versions. And one for the MD21 TD27T .... A link would be helpful here - happy to pay for the right one.

I'm a certified mechanic - but the TD27T engine is new to me, so it would be very much appreciated if someone here could point me in the right direction.
Cheers Tilmann

 

[edmistral]

To #2 :
I searched again and finally found the purpose of this solenoid in the return line.
It is called "Solenoid Timer" and is used to advance the injection pump timing by increasing inner pump pressure during cold starts. I'll check the function but I believe that this one is not responsible for my problem.

 

[solarman216]

Hi and welcome, first thing to check is the pressure regulating valve, this is located at the front top of the pump and is recognised by the fact it has a round head with two flats on it, a 10mm spanner fits but you will be lucky if you can get an open end spanner on it, once you have this out you will find a small spring loaded piston, gently test it for free movement, it should be completely smooth in operation, any stickiness and it will need to be stripped, removing the spring ring can be a tease, next to check is the return banjo it has a small metering orifice, protected by the famed mini filter, if you screw the bolt into the pump without the pipe and pump the primer on the filter you should see a fine jet of fuel that will travel more than a foot, come back with the results, Rick

 

[edmistral]

Hi Solarman,
thank you for your thoughts.
Over the years I worked on heaps of VE pump equipped vehicles but never had issues with the internal pressure. In my apprenticeship years which ended in '91 I was schooled on these pumps. I'll give it a shot on the weekend.
I found a minifilter in the fuel feed supply banjo right next to the pressure regulating valve but have not seen one in the return banjo - must check again.
What are your thoughts about the timing ?

 

[solarman216]

In my experience pump timing does not dramatically alter power, what it does effect is exhaust gas temp, similarly the TPS will only effect gear shit patterns rather than power as being a mechanical pump it cannot alter anything in the pump, my VE pump is on my RD28t inline six and has been completely stripped many times while experimenting with different size plunger heads, which reminds me you should have a compensator on the top of the pump, is the diaphragm good? does it have oil in the bottom and is the pin sticky? Rick

 

[edmistral]

Thank you for your thoughts Rick,
I had the pump in some, not all pieces to be able to replace the leaking head o-ring. The pin was not sticky and I replaced the still good diaphragm with a new one. As I don't know the history of that engine I want to get the basics right and go from there. I got the timing informaton for engines up to '93 and just wonder which timing to choose. Somewhere, and here is my lack of information, I've read that the non EGR TD27T had a different timing as the EGR equipped ones. Can you proof that ? As all the EGR stuff is gone now I want to set the timing to the best -factory used- setting for the engine.
As I still haven't got the right manual for the last mechanical pump Terrano 2/Maverick/Mistral etc. (Do know a link to it ?) I'll use the setting from the '93 MD21 TD27T below. Have you got other factory data ?

 

[edmistral]

I have searched but can't find a proper workshop manual for the last mechanical pump equipped TD27T Terrano 2. Or at least the relevant pages or data for the pump timing adjustment.
If anybody here could point me towards it, that would be very much appreciated.

 

[solarman216]

My manual only shows the TDi version, Rick

 

[edmistral]

Short update,

still missing lots of ponys in this TD27T.

Facts so far...

It begun like this:
Ponys are missing in new to owner '94 Terrano2 / Mistral
IP is heavily leaking between high pressure casting and main body and advance piston covers.

New fuel filter
New air filter
Adjusted valve clearance
Checked compression good
New Injectors
Deleted complete EGR system
Checked free flow of exhaust system
Boost 0.6 - 0.7 bar / 10 psi
Took IP apart to renew most of o-rings and input shaft oil seal, cleaned both inlet and return gaze filters.
This made not a difference in terms of power output

Checked and adjusted Injection pump timing from .45 to .60 BTDC
Upped main fuel screw 1/4 turn
Adjusted diaphragm to 75% was at 25%

This aswell made no difference to the power output.
No smoke visible at all
It feels like the pump is just not delivering enough diesel.

Next is:

Will run pump with an external fuel tank to eliminate any blockages in supply.

Please feel free to pose any suggestions.....

Cheers T.

 

[solarman216]

Yes pump will run fine on external tank, just remember to feed return to same tank, sounds to me like it has been run on alternative fuel in the past, this pump has a 10mm plunger so as a test I would up the fuel screw till I got smoke, once past a turn or so the idle will become difficult to control but do not worry about that just see if it improves performance on the road, Rick

 

[edmistral]

I dearly hope that the pump is not getting enough fuel from the supply side. That would be easy fixable. The culprit must be somewhere there - pump issues are quite rare - I haven't seen one failing since my apprenticeship as a mechanic started in '86.

 

[edmistral]

So we ran it direct out of a 5 litre can - no difference at all. It is like having a 2x4 under the acellerator pedal.
Then yesterday night I thought - bingo - something I haven't checked before, the injection pump lever alignment with the actual shaft it's sitting on.
Moved it one notch towards acceleration - but now I can't get the idle down anymore. backed off the main fuel screw. but that makes the engine completely sluggish. IT'S REALLY frustrating. Never had that in my entire life as a mechanic.
Maybe the advance piston is stuck....but than we would see smoke I guess.
It puzzles me that the pump is not responding to fuel adjustments - that makes me think that it is not getting enough fuel internally - or the internal pump pressure is way to low. I could modify annother return banjo to attach a pressure gauge.
Please post any thoughts what it could be - I'm grateful for any hint.
I have the feeling that in the end it could be something which is unbelievable easy to fix.
Please post any thoughts what it could be - I'm grateful for any hint.

 

[solarman216]

Make up an adaptor on the outlet from the pump and fit a pressure gauge, keeping the banjo restrictor bolt and solenoid in circuit, but you will need to obtain the test figures some how, most UK pump rebuilders will not divulge this info or even sell spare parts, how many turns have you screwed the max fuel screw? Rick

 

[edmistral]

Problem solved !

Finally found the issue, It was just that little pin between the boost compensator cone and adjacent lever which was stuck.
Since I finished my apprenticeship as a mechanic in 1990 I have never had that happen or heard about it. Worked heaps on Bosch VE pump equipped vehicles.... It was not even badly stuck but enough to stop the metering lever from moving far enough forward.
The TD27T runs happily now, freed up heaps of ponys.

By the way - measured internal pressure at around 1 bar on idle to 7 bar at around 3500 rpm. Fine according to the manual.

There is an unused casted (return)port at the injections pump cover - cut a 1/8 npt into it - perfect to attach your pressure gauge.

Cheers everybody !

 

[solarman216]

Glad you got it sorted, if you look at my post "5" you will see I hit on that one way back then, Rick

 

[edmistral]

By that time I was still thinking that you would refer to the cone pin as 'the'
pin. You never stop learning in live

 

[edmistral]

By that time I only thought about the cone pin when you were referring to the 'pin'
You never stop learning in live - still puzzles me that I never had that issue before since 1990 ... all the 200/300 tdi Landrover engines I worked on for years..

 

[solarman216]

I am 76 and still learning, Rick