Thread: TD5 Surging around 2,500 rpm

Hi, just to clarify, you have a VNT turbo, an LPG injection system and a boost box, correct? some questions:
1. what other mods have you done? did you eliminate the wastegate modulator or it's still there?

2. the EGR modulator is still there or it's plug is free?

3. this symptom came all of a sudden or progressively started to behave bad?

4. is yours 10P or 15P engine?(year, manual or auto)

5. remapped or not?

6. larger or standard intercooler?

by having a boost box you can't rely on the readings you get on the MAP cos the voltage is limited, you better fit a pressure gauge and measure the real boost... read live data and see the AAP sensor's reading, does it fall when you floor the throttle?

describe as well as you can everything and we'll figure it out

Hello,
To answer some of what you asked.
It is a 2004 Auto
the boost box I made works as a volt switch so at 4.5 volt switches on a regulator set at 4.7 volts so the readings are true till about 20 psi have a boost gauge
a 18p engine
The wire just hanging there no modulator always been like that fitted it on last month no change
I am trying a different pump later today, hopefully......
It has a re-map over a year so not that, the fault is new slowly getting worse no diesel in the oil

The things I am looking at now are the engine loom and connectors, the turbo hose to the actuator, not sure how to check injectors I have no faults can they still not work properly ?? The turbo is a Turbo Technics S208 possible sticky veins ?? I am just ruling out things
I am concerned the TPS has a fault.
It really behaves like the injection harness is still faulty, but brand new I did seal up the connector before installation.
Ian

The TD5 will keep getting enough fuel for light throttle even though the fuel pump is dead. Breaking the supply line, eg, R&R the fuel temp sensor, will result in the engine not re-starting, so I suggest that you don't investigate until you can get by without the vehicle until a new pump can be sourced.

Hello,
A bit of a update......
Well been working on the car all morning changed the fuel pump as have spare still the same. So put a new actuator hose on the turbo as had trouble before. I checked the oil at the plug on the head it was dry. So the plug on the engine harness has a nice big rubber seal on it so I prized this out and found it damp with oil enough to cause problems. Cleaned it all and went for a spin. It went much better, but now it missing at 3500 rpm and sort of fades a bit sort of fades a bit, so maybe on the right track. I do not have any gauge to test the fuel pressure. I did look at the red plug and very dry the pins as sealed separately there but might have a look later. I am still a little conceded about the timing as since I had the head off there is little more black smoke and slower to spool the turbo and higher egt's which makes me think it still is a little retarded maybe. The timing pins do go in.
Ian

yes, the timing is very important, you told me about the wastegate modulator but nothing about the EGR modulator...so if the EGR modulator is still there unplug it cos as the valves being removed the ECM keeps it constantly under power trying to force it work and it puts load on that circuit and your's being an auto might suffer from that cos the status of emission controll is part of the CAN

to rule out the TP sensor if you have a tester read the outputs on live data and as long as track 1 + track 2 = supply with track 1 growing as you push the pedal the potentiometer is good

the CAT is still in situ or do you have a de-CAT downpipe fitted, cos if it's still in situ you better rule this out too...undo the pipe from the turbo and try this way (just disregard the noise during the test)