Having Issues on Startup After a Single Turbo Conversion

BozoBlaster

New Member
May 15, 2024
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Converted my N54 to a 6466 Pulsar single turbo with Speedtech single kit. During which I also replaced 6 loose/collapsed hydraulic lifters due to a engine knocking sound I was getting before starting the project, changed the rod bearings ( probably wasn't entirely necessary but I saw it as a more preventative maintenance thing) since I was already replacing the oil pan gasket being I was taking the subframe off for ease of access for removal and install of turbos and water pump replacement. For proper wastegate actuation I switched the pins in the ecu in accordance with ST conversion DIY'S for the new mac solenoid to properly control boost. Upon first startup after completion it has a long crank (about 5 seconds) then immediately goes into limp mode with boost disabled and I'm getting these codes;

2a98- crankshaft- inlet camshaft reference.
2a99- crankshaft- exhaust camshaft- reference.
2a9a- crankshaft- inlet synchronization.
30cf- wastegate- activation.
30d0- wastegate2- activation.
3100- boost- pressure control- deactivated.

Used a timing tool when removing camshafts for the lifter replacement so I know the camshafts,VANOS timing camshaft sprockets, and sensor wheels stayed at top dead center during removal and reinstall.

At around 600 rpm the engine now shakes very noticeably not sure its its timing related because of cams throwing codes or if it has to do with the new rod bearings, I followed procedures correctly with proper torque values and rotation degrees after using old connecting rod bolts to plastigauge new bearings to confirm clearances are within spec. I know that 3100 just means limp mode has been initiated, but as for the rest I am at a loss. I have a data log for reference if it helps.


Before I reinstalled cams I took a video of the cam ledges condition being the car has just over 106k miles. Since this is an earlier model with the old metal cam seals that there are visible grooves made from the seals that didn't seem to me very deep at all and looked more like scratches than grooves that weren't very textured when using my fingernail to kind of scratch across it horizontally. They were replaced with the newer teflon ones, but if the grooves are too deep for the new seals can this potentially cause issues resulting in the codes I'm getting? Video just shows exhaust side ledges but intake side LOOKS slightly worse but same feeling when using my fingernail to scratch across the groove. Other than the knocking sound it didn't cause any issues with the old seals in place like some folks have experienced when those seals fail, I just though it would be a good idea to replace them since I had the cams out.

[u2b]

If I replaced cam ledges does anyone think this might solve the issue? I just want to be 100% sure that it is necessary before spending 12-1300$ on new ledges. Any and all inputs helps immensely, thank you for taking the time to read and thank you for any advice.
 
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BozoBlaster

New Member
May 15, 2024
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Thanks for everybody's help... I figured it out myself. Thinking I might've not had timing correct after reassembly I removed the valve cover to confirm timing and found that timing was spit on but two exhaust side rocker arms had been knocked off their valve springs when I reinstalled the camshafts and ledges even while being highly aware how easy it was to do so and trying to avoid that happening. Still getting a slight engine shuddering at idle and when immediately after giving throttle from a stop but after 8-900 rpms (more than 2 mph) it smooths out and nothing through all gears during any throttling or coasting while moving. As soon as I come to a stop and idle again I can feel it again, I'm assuming since I have yet to get a custom tune that it can be tuned out. My theory is that the single turbo is dumping a higher volume of air into the engine than what's its currently tuned for but once the engine moves faster it can balance out better but that is just speculation. Any and all opinions are welcome.
 
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wheela

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Jun 4, 2021
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Thanks for everybody's help... I figured it out myself. Thinking I might've not had timing correct after reassembly I removed the valve cover to confirm timing and found that timing was spit on but two exhaust side rocker arms had been knocked off their valve springs when I reinstalled the camshafts and ledges even while being highly aware how easy it was to do so and trying to avoid that happening. Still getting a slight engine shuddering at idle and when immediately after giving throttle from a stop but after 8-900 rpms (more than 2 mph) it smooths out and nothing through all gears during any throttling or coasting while moving. As soon as I come to a stop and idle again I can feel it again, I'm assuming since I have yet to get a custom tune that it can be tuned out. My theory is that the single turbo is dumping a higher volume of air into the engine than what's its currently tuned for but once the engine moves faster it can balance out better but that is just speculation. Any and all opinions are welcome.
Do you have any logs of the lumpy idle since fixing the exhaust valve issue? Your LTFT% and STFT% may shed some light on if the issue is due to extra unexpected airflow through the larger turbo.