P1470 Fault

[senjers]

I have been living with limp home mode for a while >3000rpm on 2001 E320 CDI

Have found reliable source of getting fault codes and discover fairly common P1470 fault.

I am confident it is not the EGR (welded shut) and I have pressure tested the whole inlet with 20psi from compresor, removed swirls flaps cleaned manifold etc.

Reading all the posts I think it must be either the vacuum system or catalytic converter.

I have checked vacuum hoses and all seem to hold vacuum with my tongue blocking the end. Could I replace the solenoid with the now redundant egr one?

If this doesn't work I will concentrate on exhaust. How will I know if the cat is blocked? Is it an easy job to remove and inspect?

Thanks in advance

 

[Alex Crow]

Hi,

Be aware that there are several definitions of P1470, an open circuit vacuum transducer will also log this code, so think on.

You could swap over the transducers, but they are different, and theoretically no interchangeable.
Yes, check the vacuum system for good vacuum draw, and check the exhaust for blockages, but a crystal clear code definition might help you pin it down better.

 

[senjers]

Alex,,
many thanks for the response, the code given from a Sealey machine was:

P1470-016 - Charge Pressure control positive control variation (Charge pressure is too low).

 

[Alex Crow]

Alex,,
many thanks for the response, the code given from a Sealey machine was:

P1470-016 - Charge Pressure control positive control variation (Charge pressure is too low).

Assuming that definition is correct.....go with the blocked exhaust and vacuum checks etc.

 

[senjers]

Many thanks for the previous reply. I knocked the second stage cat out, didn't have time for the first stage. Fault still present and now have a leaking knocking exhaust grrr.

I did notice when I revved the engine to the red line the actuator moved to the full position then slowly back, when i released the throttle the actuator blipped to full boost giving a chirping sound. Is this normal?

I also noticed once or twice that the actuator did not move at all from the start and I needed to turn the engine off and on again. I presume it started with the fault already, which made me think of a vacuum problem again, could the pump be struggling to maintain vacuum?

I can't find any leaks around the 2 solenoids or actuator is there another part of the vacuum system which might be leaking. I did read that the pumps hardly ever fail.

How could I test the output is within spec?

 

[senjers]

Going round the bend here

I realise now that the car idles with full boost, after starting the lever slowly moves towards the actuator.

It has now almost constantly loosing all turbo presssure, after starting at seemingly random times the lever just falls away and it cannot be brought back into operation without turning off the ignition.

This also happens at random times whilst driving.

This would point towrds electrical problem. If I disconnect the vacuum line the actuator falls away but will move back after reconnection.

If I disconnect the vacuum actuator electrically the lever falls away, reconnecting does not bring the lever back to life.

I have cleaned the connector, if there is a possibility of loose connection
To carry out further checks, Id like to know what is the expected duty cycle of the vacuum actuator.

The actuator humms, is this normal? Could a breakdown of the solenoid be causing overcurrent condition of ecu which is shutting it down?

Really getting frustrated here, any help would be appreciated,

 

[erzen]

Ive been having the same problemo has you,and i removed the catalyic converter and still havnt sorted the problem out.I would think its only a vacum leaking somewhere.But im not sure where.I still havnt managed to resolve the problem myself.

 

[Alex Crow]

You need to actually measure the vacuum at the same time as running the engine and doing tests.

As an example fault giving this code, I have seen split EGR valve diaphram allow soot into the vacuum system, which would block the vacuum transducer and give turbo actuation issues - intermittently.

 

[senjers]

Saga continues.

Thanks for your responses.

I found some time today to look at this again, and found the an airleak on the inlet manifold, where the mixing chamber joins the charge pipe.

The bolt wasn't tight and there was evidence of oily soot residue in the area.

After tightening all the mixing chamber bolts I took it out for a spin, I was pleased that it revved higher than before but still all the still power died- albeit at higher revs.

I revved the engine hard with the bonnet up and was shocked when there was a big puff of exhaust gas from the turbo area and the air cleaner box crumpled in front of my eyes.

The revs fell away and slowly the air box reinflated with a loud sucking noise.

I checked the air filter and it looked ok. Could it be that now i have fixed the boost leak, there is another underlying fault with a blocked primary cat? ( I have knocked out the secondary one and there was no evidence of bits of the primary one in it).

Or is possibly the exhaust and airbox is a symptom of the problem??

Thanks

 

[Alex Crow]

If you see the air filter housing being squashed when revving, then there is a blockage upstream of it (as you have said the filter is OK).
Might even just be a dead bird in the intake scoop, bad news for tweety-pie, but an easy fix.

 

[senjers]

Good times

Thanks Alex, problem sorted.

It wasn't a blockage, it was the whole inlet pipe collapsing, which was causing the turbo to suck the airbox out of air before eventually causing the turbo to stall and registering a low charge pressure fault code on the outlet side.

I removed the pipe and can now drive it like I stole it again.

Does this pipe perform a useful function ie is it worth reinforcing it or shall I just leave it off??

So glad I have eventually solved this annoying problem.

 

[Alex Crow]

If I understand you correctly, this is the intake pipe to the airbox?
If so, all it does is ensure cooler air flow to the intake, it will be fine without it, but better with it!

 

[senjers]

Yes the intake pipe to the airbox.

I guess with the engine chipped, running with higher boost, it is sucking more air than it was designed to. This could be compounded by wear and tear on the pipe corrugations.

I will leave it off for the moment and maybe build an internal frame to prevent it collapsing in the future.

Thanks for your help.

 

[Alex Crow]

There is no way that pipe would collapse in use, unless there were some kind of major blockage upstream.

 

[dieseljock]

I had this problem once- caused by the pipe from the air box to the intake scoop at the front of the car not being fitted properly at the intake scoop end (sloppy, rushed assembly by me i must admit).. Any lack of alignment or putting a locking tab inside when it should be outside the pipe etc could cause this.. My first thought was blockage, and it took a wee while to figure out the real cause as the mistake i'd made wasn't immediately apparent..