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I have new clamps everywhere, including the beefy larger T clamps from the Turbo outlet to the IC inlets:
Am I right in thinking that the wastegates are closed by default, and then are held closed with the boost control solenoid? If there is a vac leak from this solenoid or its not working, what is the default wastegate pressure?
If I clamp the boost line that comes from the Intercooler, I saw 18psi once, then it went into limp mode.
Got Xentry on it, was an over boost code, so the turbos are making OK pressure and there aren't any boost leaks.
Additionally, the pipework to and from both the Divert actuator and the boost solenoid seem to be intact with no breaks. This must also rule out weak diverter valves.
All 4 MAP sensors are the correct ones and in the right place too. Air filters are new.
Off for a dyno on Tuesday with boost tied in as well so will be interesting to see if its 15psi is by design or if its low (I think its low)
Was waiting on the dyno numbers. Numbers are a bit low, but since a mustang dyno reads low they are prolly ok. Sort of.
On boost- most 65 cars make anywhere between 18'- 24 psi at full tilt. So 18 is ... acceptable. But ... a bit low. I like to see the amgs at 21-22 when all is sorted out.
Mechanical and vacuum problems usually result in significant boost drop, so I don't think you have such issues.
Is your car tuned? It has to be as you are showing the typical 800 tq early in the rev range, but then sort of falls flat on its face as boost doesn't build accordingly. What I am trying to say is that boost starts properly and then doesn't build (and hp) accordingly. My guess is you have a leak. Or your tune is bad. Or your learned fuel trims are bad- have you done an ecu reset?
Also, have you pressed in the two schreader valves on the intercooler coolant circuit? Is coolant shooting out? Your iats are good (what is outside temp?), but bleeding the ic circuit is tricky and I have seen more systems with trapped air than I care to.
Thanks ALX. I have another graph with boost on the right, here:
The boost is in inHg so top of the graph is 35psi inc atmospheric.
I have never tuned it, but its possible a previous owner has. I was not told that it had been. Would be surprised If I have a leak as I have checked everything but will check it with a boost tester.
I wonder if its possible to leak from the PCV system at the front?
I think its also possible that it does not have a good tune.
I have not reset fuel trims, so will do that next.
IAT and IC circuit is good. Recently swapped out a leaking intercooler. Vac filled the system and then bled 20L of coolant through exactly as per WIS. I have a header tank with a 5% bleed off into the swirl pot and those are showing good flow through both.
IAT's today where 35degC under load with an ambient temp of 18Deg C (64F/95F)
Update, pressurised the intake system today and found a few small leaks.
The large vac pipe with the one way valve was leaking where it goes from hard plastic to rubber and back. Now fixed.
The Y pipe is leaking at the throttle body side, but not at the clamp, instead at the rubber lip above the clamping point, new one on order.
Both rubber hoses on the outlet of the IC's were leaking very slightly. Now fixed.
The big one though is the back of the inlet manifold, I have a sizeable leak from the pipe that goes to the brake booster. If I push the pipe in with my hand, I can stop it. It would seem that there is an O ring here but looks a ******* to change, anyone know if it can be changed in situ?
Last edited by alexanderfoti; 04-18-2017 at 02:00 PM.
I am literally battling this same thing right now. I can't seem to see more than 2050 hPa when datalogging using my Car-Soft i980. I just had the brake booster hose and the plastic piece and cap at the back of the manifold replaced. Car feels faster, but still only get 2050 hPa max. I replaced the line check valve and oil separator piece at the front of the engine and it made a difference on my S600. I am going to replace the piece on the 65 shortly.
Did you replace the O ring inside the plastic cap for the booster line?
Which check valve? I was thinking of replacing the oil separator as a precautionary measure, buts its big money. My check valve on the hard plastic line on the front of the engine was leaking (not the one that goes to/from the oil separator). I added a new one in line and it no longer leaks.
I was not able to confirm it leaking on the boost leak test.
Yesterday I checked my waste gates to make sure they weren't loose. They weren't, but one had lots more rod showing than the other. I adjusted the passenger side bank so its tighter, same as drivers side.
Will see what happens today. Not convinced it will make a difference.
Its very frustrating. I feel like I am leaving about 100 hp on the table. Dyno above was 445 WHP which is about 530 Crank hp
Last edited by alexanderfoti; 04-23-2017 at 02:18 AM.
Update, lots of work. Was preparing the car for the drag strip, but hit problems.
All boost leaks fixed now. New Y pipe from the intercoolers, new O ring at the back of the inlet manifold to brake booster line, New ring clamp at bottom of Y pipe. New one way valve on PCV system.
Have pressurised the inlet system up to 25psi with no leaks (started turning the engine over from air pressure!). I am sure that the inlet system is now air tight.
I also tightened the waste gate rods. I hit 22.3psi in 3rd at 4050 rpm. Car logged overboost and misfire codes. Also found a good tuner who could read the original ECU software. Software was stock and asking for 21PSI in the boost tables. The boost control solenoid duty cycle appeared to be fixed. It would seem the boost control maps equate boost pressure to solenoid duty cycle, so is unable to compensate for boost leaks or waste gate leaks.
Loosened wastegates again, back to same position as before. 15PSI then have to hammer to get 17-18psi.
I think the cause is worn or leaking wastgate diaphragms (and possibly a coil pack issue I will uncover when boost is at the right level).
Thoughts?
Last edited by alexanderfoti; 05-07-2017 at 09:48 AM.
I replaced the diaphragm on my 03 S600 with 85k in February. The had virtually no wear. Did you replace the boost control solenoid? Get a i980 from Carsoft and you can watch the values live and get a better idea. I'm chasing this same issue on my S65. T bolt clamps on everything still can only get 15-16 psi. I replaced the brake boost line and o ring. During data logging i noticed my down stream map sensor shows a higher pressure than the upstream and it starts pulling boost. I have orders all 4 new map sensors I'm hoping this will solve it. I got my car dyno tuned and she put down 500 whp at 15psi. After tuning it did 540whp but still only had 15psi. My boost control solenoid (which is new) will only show 65% when data logging. Very frustrating. Will report when back after changing my map sensors.
Further adjustments today. Tightened wast gates to a point between initial setting and nearly fully wound in. Same 15PSI boost. I am now 100% sure the ECU is limiting boost for some reason. So far, I am unable to find the reason.
I, like you, have already swapped all 4 map sensors with genuine MB sensors. No change.
I have not replaced my boost control solenoid. I am sure its working properly as boost seems to be well regulated to 15 PSI in the midrange!
I have both STAR and Icarsoft I980. I may try and monitor them with a friend whilst driving, its rather hard.
I thought that maybe the ecu was limiting boost due to pressure difference between the airbox MAP's and the intake MAP's, but I know that it logs a code when it does so, so not likely that.
I also vac tested the divert valves and pipework. No leak.
Pressure tested the boost control solenoid and pipework. No leak.
No idea what to do next.
Last edited by alexanderfoti; 05-07-2017 at 12:54 PM.
When accelerating do you feel a surge the almost cut as the boost pulls back? The duty cycle of my boost control solenoid barley breaks 65%. On my tuned s600 it pins to 95%. I'm positive my ecu is pulling the boost also.
Yes its an odd feeling. It feels like the boost is building and just as you expect a torque wave you get this odd flatness. As the revs build the car does feel fast (and goes fast) but its not right.
Its getting on my nerves, I have addressed nearly all the common issues on these cars.
03-26-2017, 03:22 PM
