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Accord 2.2 i-ctdi - Boost Pressure not stable

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ian.cox

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Location
Birmingham
Car
Honda Accord
Hi Guys,

I bought Honda Accord 2.2 ctdi 2004 Executive Tourer 2 months ago.
A week later the turbo failed...replaced it with a second hand one in visually good condition.
Meanwhile I bought Honda HDS to check whether everything is OK.
I did a few road tests with the diagnostics and it turned out that the pressure is not following the target:



Then I thought OK probably the VNT actuator rod is not adjusted properly, so I started playing with it:





But so far...over a month tweaking the actuator rod length and recording the data, I don't have a stable pressure after the initial peak.
Also I think that before the turbo failed, the car was acting the same way - after it passes 2000RPM it pulls hard, then around 3000RPM the acceleration drops and around 3700RPM I can hear the turbo gaining speed again.
So I believe it is not the turbo that is faulty.

What I've tried so far:
1) The replacement turbo was stripped down and vanes cleaned
2) New Fuel filter(Genuine)
3) New air filter(Mann)
4) EGR, Intake manifold, MAP, MAF - Cleaned
5) Temporary blank on the EGR and road test with HDS - no improvement
6) Turbo boost solenoid valve was replaced - no improvement
6) Checked the Injector coding with HDS - OK
7) Done all tests with HDS and it is failing the Fuel rail pressure test, due to "The injector quantity was out of range".
I've checked the recorded values for the fuel rail pressure during the road tests, it follows the target perfectly.
The correction quantity on the injectors is very minor (0 to 0.5 mg)
In relation with that I am planning to do back-leak test on the injectors in the next few days.

Does anyone know what should be the Max MAP Sensor Target on a stock MAP, as I have suspicion that the car has been mapped.

I will appreciate any suggestions!!!
 
The targets will change according to load and engine speed, can you get the car to me I'll check if it's stock or not
 
Yes, this is true - the targets will change, but the stock map maximum should be lower than the custom map maximum.
My maximum MAP target (3rd and 4th gear full load) is 225kPA (2.25Bar).
The atmospheric pressure is 1Bar, so the boost is 1.25Bar.
It looks to me a bit high for a stock map.
 
A boost leak will also alter the numbers as it causes overboost
 
That was the other test I was thinking about, after the injectors leak test, but I haven't made the end caps to blank the hoses and pressure test.
Thanks for the suggestion!

Forgot to mention in the first post - I also ran full tank with BG244, but didn't notice any difference...probably the fuel system was clean enough.
 
Here is some update,

I've checked for boost leaks, but didn't find any.
Also opened the tank from where the level sensor is and checked whether the filter inside is clogged, but it wasn't.

Just to be 100% sure that the fuel filter is fine I've bypassed the filter and the fuel heater, and connected the hose from the filter outlet directly to the fuel inlet pipe from the tank. Did a short run and but no difference.
Another thing is - in the first post When I mentioned that around 3700RPM I can hear the turbo gaining speed actually the acceleration doesn't improve when this happens.
Also it struggles to go passed 4000RPM on 3-rd and 4-th.
 
Still thinking boost leak and most likely a punctured intercooler. I've seen this before
 
Here is how I've checked for boost leaks:
Bought a nailon rod - 100mm long, 50mm diameter(sameas the hoses)
Cut it into 2 pieces.
Bought tyre air v alve.
Drilled one of the nailon rods and installed the valve in it.
Took of the hose from the turbo outlet and blanked it with one of the rods.
Took off the hose from the intake manifold and blanked it with the other rod with the air valve on it.
Then with air compressor - pressurised the hoses and the intercooler to 1.2 bar and left it for a few minutes.
After that checked the pressure on the compressor gauge and it was still 1.2 bar.
 
1.2 bar is what it is probably making at low requests.. Remove the intercooler and inspect it. Also a sticking actuator could be causing the car to overboost as it doesn't release the vanes
 
Update from the injectors leak test:
Cylinders from left to right:
1) 80ml
2) 80ml
3) 70ml
4) 65ml

I found the following sequence in another forum:
2min idle
30sec 3000rpm
30sec idle
30sec 3000rpm
30sec idle
30sec 3000rpm
engine off

Does anyone knows whether these figures are normal.

F6HAD: I'll inspect the intercooler in a few days. Regarding the actuator - I keep the one from the old turbo and before the new turbo was installed I connected them together with the hand vacuum pump and they were moving exactly the same way, so it should be fine.
 
Then if there are no leaks you have sticking vanes..
 
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