Sluggish Acceleration....Causes?

[1970Matt]

Hello People

 

Im chasing some help with a problem im having with my Ba Xr6.

Its tuned on 98 with 500rwkw running factory exhaust manifold and internal gate with a PT67 Turbo. 6 speed manual, twin 044 pumps with surge tank. The motor is built and has the necessary parts to handle the power.

 

The car ran fine with the tune before I had the car parked up for the last couple of years. It hasn’t been driven more than 2000km since the tune. The last couple of months I have been driving it more frequently and It had been running pretty good. Anyway, the other day I had taken it for a drive on the highway and decided to turn back home. So I pulled over and turned back around and started driving back. As I slowed down approaching a round about and drove through it I put my foot down and the car struggled to gain revs. The revving was even and didn’t stumble but it was struggling to get much past 3000rpm in 4^th. I could still hear it building boost as it was fluttering through the anti surge compressor housing but I'm not sure how much boost it was making as I didn’t have a gauge.

When I arrived home I immediately checked the intercooler hoses for leaks and didn’t find any. The turbo spins freely with absolutely minimal play. The coils were replaced with genuine 5000km ago. The plugs were also replaced within 3000kms. Valve springs were changed 5000kms ago. I checked the internal wastegate by applying air pressure to the air line going to the IWG. It was functioning correctly and moving correctly when air pressure applied. I Believe the IWG has a 18 psi spring. I thought maybe the TPS was malfunctioning so I swapped it with a known working unit, No change. I used HP tuners scanner software to graph the Voltages of the Pedal position sensor and Throttle position sensor. They were both functioning correctly in contrast with each other. I also checked exhaust manifold bolts and they were fine. Spark plugs look sooty and black.

Im really lost on this as the car was running mostly fine and only started playing up when I drove back home. Prior to this it boosted and accelerated correctly. This was not a progressive issue. It went from good to bad in no more than 10 minutes.

These are the issues im having.

1.       Car struggles/ sluggish to rev past 3-4000rpm in gear. Revs evenly and doesn’t pop or sputter when accelerating.

2.       I noticed when I clutch in the revs drop to the point of almost stalling or stalling.

3.       There have been times when the car is at a stop and I can watch the revs fluctuate between 200rpm to 1200rpm.

4.       I did notice that the Xcal3 picked up code P2105 and P2110. I then drove the car a couple more times after this and then scanned again but the codes/ any codes weren’t detected since.

I have HP tuners Scanner software and Torque app to use to diagnose the issue but Im not exactly sure what I should be analyzing. Timing? If someone could please give some input that would be great.

 

Any help or ideas would be appreciated. Cheers.

[k31th]

 

sounds like you've got some sort of mechanical blockage... e.g a collapsed cat.

[1970Matt]

It feels that way but I have a Full 4" system with no cat. Cheers.

[k31th]

you might have a leak somewhere, too... check the piping from the turbo outlet to the intercooler and from the intercooler to the throttle body.

[Puffwagon]

If you have a wideband, can get hold of a boost gauge and can do a run without hurting the car, post up the tune and log and someone might be able to pick something.

 

If you can't record a run without it leaning out or overboosting, take it to a tuner and get them to sort it on the dyno for you. They can check it safely without hurting the motor.

 

Anyhow that's my advice.

 

If you're wondering about the timing it'll be running about 5 degrees at that power level.

[1970Matt]

7 minutes ago, k31th said:

you might have a leak somewhere, too... check the piping from the turbo outlet to the intercooler and from the intercooler to the throttle body.

Cheers Keith.

 

When I got home after it happened I thought the intercooler hose had come off, It felt similar. I pressure tested the whole Intercooler piping assembly. Basically I blocked off the 4" Turbo inlet and pumped pressure thought the whole system. From Turbo to Intercooler piping to intercooler Core to intercooler piping to Inlet manifold. No leaks.

 

I almost think its electrical because it happened so quickly.

[k31th]

well, if you pressurized the entire system, then you need to put something smoky in there to see where the might be a leak as slow leaks are hard to spot/hear sometimes.

[1970Matt]

3 minutes ago, Puffwagon said:

If you have a wideband, can get hold of a boost gauge and can do a run without hurting the car, post up the tune and log and someone might be able to pick something.

 

If you can't record a run without it leaning out or overboosting, take it to a tuner and get them to sort it on the dyno for you. They can check it safely without hurting the motor.

 

Anyhow that's my advice.

 

If you're wondering about the timing it'll be running about 5 degrees at that power level.

 

Appreciate the reply, No I dont have a wideband or a boost gauge. I have hp tuners scanner but im still new to it and it seems limited with what it can scan on the Ba fords. I dont think it would hurt the car driving it around like it is as it almost feels like it has not boost. I cant hear the turbo building boost, as it flutters when taking foot off accelerator. If I had to guess I would say its running very rich because I pulled the plugs and they were sooty black. As the car is right now it feels like it has no more than 200rwkw. Im surprised that the Xcal hasnt detected anything. I thought it could be the boost solenoid but then I realized that even it the boost solenoid wasn't functioning it should still have gate pressure as a minimum which is about 18psi. It definitely doesn't feel like 18 psi. 

 

Again If I had to guess, I feel like it could be electrical because It happened so fast. There are no odd mechanical noises etc. But I dont know where to start...

[k31th]

You can try eliminating the boost solenoid by piping the reference source for the wastegate (usually a nipple on the compressor housing) directly to the wastegate temporarily and it'll ramp in as slow as possible to your gate pressure (whatever the wastegate is rated at is where it'll peak out). See if that makes a difference to any operational parameters.

[1970Matt]

I might have to try that cheers. If my solenoid wasnt working would I still be boosting to my gate pressure minimum? I ask because it feels like the motor isnt getting much boost or no where near the base 18 psi of my wastegate.

 

28 minutes ago, k31th said:

well, if you pressurized the entire system, then you need to put something smoky in there to see where the might be a leak as slow leaks are hard to spot/hear sometimes.

After I pressurized the system I tried to listen for any leaks but I could barely hear any. Do you think a slow leak could cause my symptoms? I figured that the car made so much boost that even a slow leak wouldn't stop most of the boosted air going into the motor and I would feel the power, just not as much. But its like its not even getting much if any boost.

 

Right now its as if the car has been power restricted Heavily. Then when I looked at the plugs and they looked sooty and black I thought maybe this 'Restriction" has retarded the timing so much that its underpowered and over fueling. But im not sure what timing advance parameters I should be looking at to confirm this?