BaxterCat
New member
Hi all,
Posting in this section as the engine has had power enhancements but may have had underlying issues prior to tuning.
This is the 5 cylinder AJT Engine that has had Bosch .216 injectors (DSLA150P502) 2.5 Inch front pipe and exhaust as well as a custom remap from a respected tuner.
This should be making in the region of 150-165 bhp.
The problem began to be noticable following the upgrades as more boost was being requested and the underlying issue is preventing actual boost to reach requested.
Requested boost is 2.3 bar absolute and after numerous logs it is only making 1.8 bar absolute. After checking MAF pump timing and other obvious issue such as coolant temp, N75 etc I began to add some more preload to the actuator and boost sure enough increased on line with the preload being added to the point where it made requested.
After a long trip towing a load it started going in to limp mode again and after logging again it was back to only making 1.8 bar Abs. so I changed the MAF for a chinese one and the MAF values dropped so I got a genuine one and the MAF values are back to making more than requested, pump timing is spot on, fuel temp is 50C, N75 seems to work as expected, It was replaced just in case.
I then removed the hose from the N75 to the actuator and logged it again - 3rd gear pull from 1100 rpm to redline and there was no change, it was still underboosting change to actual boost. To me that rules out the N75 as the underboost cause. I then began to suspect the turbo so I reached down and tried to move the actuator rod by hand and it would not move. I applied pressure from a compressor to the actuator and the hose began to balloon and no movement from the rod was seen. The connection to the hose from the compressor as only push fit so I am not 100% that is was a valid test. With a wrench clamped on to the rod I could get it to move 1/2 an inch or so and it returned to closed position but without pulling the unit I dont 100% know that the WG is fully closed.
Then I found a tear in one of the boost hoses to the intercooler so this was replaced and the engine started making better boost 2.1 Bar Abs. but still not making requested and does not feel like it has the power it should have, it only goes to 70 mph. I have 2 of these vehicles and my other is running 150 bhp and I can tell the difference, this one doesnt seem to want to make full boost and only seems to make boost after 2500 rpm.
So where to go from here ? Seems like its not the N75 as it doesnt boost any better with it disconnected and no boost control, actuator moves but im not 100% convinced by it. Fuel is there as injectors are known good, fuel pump is assumed to be good too.
I have added a screen shot of a log from before the boost leak was repaired.
Posting in this section as the engine has had power enhancements but may have had underlying issues prior to tuning.
This is the 5 cylinder AJT Engine that has had Bosch .216 injectors (DSLA150P502) 2.5 Inch front pipe and exhaust as well as a custom remap from a respected tuner.
This should be making in the region of 150-165 bhp.
The problem began to be noticable following the upgrades as more boost was being requested and the underlying issue is preventing actual boost to reach requested.
Requested boost is 2.3 bar absolute and after numerous logs it is only making 1.8 bar absolute. After checking MAF pump timing and other obvious issue such as coolant temp, N75 etc I began to add some more preload to the actuator and boost sure enough increased on line with the preload being added to the point where it made requested.
After a long trip towing a load it started going in to limp mode again and after logging again it was back to only making 1.8 bar Abs. so I changed the MAF for a chinese one and the MAF values dropped so I got a genuine one and the MAF values are back to making more than requested, pump timing is spot on, fuel temp is 50C, N75 seems to work as expected, It was replaced just in case.
I then removed the hose from the N75 to the actuator and logged it again - 3rd gear pull from 1100 rpm to redline and there was no change, it was still underboosting change to actual boost. To me that rules out the N75 as the underboost cause. I then began to suspect the turbo so I reached down and tried to move the actuator rod by hand and it would not move. I applied pressure from a compressor to the actuator and the hose began to balloon and no movement from the rod was seen. The connection to the hose from the compressor as only push fit so I am not 100% that is was a valid test. With a wrench clamped on to the rod I could get it to move 1/2 an inch or so and it returned to closed position but without pulling the unit I dont 100% know that the WG is fully closed.
Then I found a tear in one of the boost hoses to the intercooler so this was replaced and the engine started making better boost 2.1 Bar Abs. but still not making requested and does not feel like it has the power it should have, it only goes to 70 mph. I have 2 of these vehicles and my other is running 150 bhp and I can tell the difference, this one doesnt seem to want to make full boost and only seems to make boost after 2500 rpm.
So where to go from here ? Seems like its not the N75 as it doesnt boost any better with it disconnected and no boost control, actuator moves but im not 100% convinced by it. Fuel is there as injectors are known good, fuel pump is assumed to be good too.
I have added a screen shot of a log from before the boost leak was repaired.
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