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Post by rockacello on Sept 9, 2018 11:29:08 GMT -5
Hey guys,
So I recently made some major revisions to the engine in the form of:
-a rebuilt turbo from Charlie
-a gnari manifold
-3" downpipe
-partial removal of the A/C system (compressor and lines to and from evaporator have been removed)
Other items replaced:
-O2 sensor (w/ new NGK O2 sensor from rockauto)
-EGR tube
Everything went back together mostly OK (apart from having to fab up new coolant lines, oil lines, and the downpipe).
Now the not so fun part: the car starts up no problem and idles fine, but it bogs just off idle but then steadies at around 1500 rpm and revs fine to red line. Driving it around is the same story but as soon it starts building boost at around 8-9psi, it pulls timing. I checked timing with the spout connector removed and it was right at 10*. I pulled codes and got: 18 for KOEO and 47 for KOER. I also tried disconnecting the knock sensor to see if it would change anything, the result was that the off idle bogging went away. (My suspicion is that the coolant tube that goes behind the block is hitting the EGR tube and potentially triggering a false knock signal, I would actually like to remove this hard line and replace it with a soft line or remove it all together if possible.) However, when I drove it around the block with the sensor unplugged, the ECU was still pulling timing at 8-9 psi.
I would really like to run a Pimp ecu on this car but I want to try and get the car running with the original ecu before I dive down that rabbit hole.
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Post by Stinger on Sept 9, 2018 16:40:30 GMT -5
It's supposed to pull timing with boost, that's how it keeps from blowing the engine.
How are you seeing it pulling timing?
EGR can be removed without issue if you want.
I hope that turbo is purely a rebuild and not modified in any way.
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Post by rockacello on Sept 10, 2018 10:38:54 GMT -5
Correct me if I'm wrong, but when the power falls flat on its face at around 5000 rpm, that's the ECU pulling timing to save the engine, right?
I would pull the EGR but I'm in smog-nazi land.
The turbo had a billet impeller put on, in addition to a slightly bigger hot side because the stock one was cracked. I also had V-band adapter put on. Would that be enough to cause issues?
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Post by Stinger on Sept 10, 2018 11:11:25 GMT -5
No, that's not the ECU pulling timing, especially if it does it with the knock sensor unplugged.
Could be valve springs or fuel supply or plug gap.
Turbo isn't the problem but may or may not work well depending on what he did to the exhaust side. He likes to use the stick wheel and clip it which kills efficiency and makes it a turd.
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Post by rockacello on Sept 15, 2018 14:18:30 GMT -5
Issue seems to have come down to the factory hose between in the turbo inlet and the VAM, it was missing the spring and causing the hose to collapse. I only run this hose when I need the car smog'd so I put the silicone hoses and couplers in and everything seems to be running swell. Stupid issue but at least it was an easy fix.
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Post by Stinger on Sept 16, 2018 9:00:45 GMT -5
Yes, that's a common issue if the spring is gone.
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Post by rockacello on Sept 17, 2018 11:56:56 GMT -5
So now it appears I have a boost creep problem...
The car has a Hallman manual boost controller and currently I have it set to the lowest setting. Driving around town it doesn't go above 10 psi, but on the highway in 4th or 5th, the boost starts to climb up to 15-16 psi. I realize this is a common symptom but have I exceeded the limits of the internal waste gate? or is something else going on?
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Post by Stinger on Sept 17, 2018 14:58:43 GMT -5
Remove the boost controller and run the boost signal hose direct to the wastegate actuator. If it will hold the low boost level and not creep at any RPM or gear then it's not a wastegate flow issue.
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Post by rockacello on Sept 22, 2018 15:51:19 GMT -5
Here's a video of me diagnosing the issue with a hand-pump:
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Post by Stinger on Sept 22, 2018 23:45:12 GMT -5
That shows the actuator is functional (which we already knew) but doesn't test exhaust flow through the wastegate hole. You'll need to test it using the method I outlined above.
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Post by rockacello on Sept 23, 2018 13:30:33 GMT -5
Sorry, I had limited time yesterday to do that test. Found some time to this morning to test it using the method you described:
Still have the boost creep, so I would guess that maybe the wastegate is not opening enough due to the short throw of the actuator? If I only plan to run 15-16 psi, will this be an issue?
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Post by Stinger on Sept 23, 2018 21:26:37 GMT -5
The reason I asked you to check to minimum boost is because that's when it's typically the hardest to control boost. As boost pressure goes up the creep should be less noticeable.
You can port the internal wastegate hole to smooth flow into the hole and also enlarge it a bit if it's smaller than the puck that covers it when closed (use some grease on the puck to mark where it hits the housing). That will likely resolve the issue. You can also verify if the actuator is stopping the movement or if it's hitting the aftermarket v-band housing when trying to open fully.
Other option of course is an external wastegate.
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Post by rockacello on Sept 24, 2018 11:51:25 GMT -5
How much of an issue will this be if I want to run 15-16 psi as a base? Will I risk seeing more creep as I increase the base pressure on the manual boost controller? Also, do you think I'm OK at this point to start considering running a Pimp?
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Post by Stinger on Sept 24, 2018 13:07:15 GMT -5
As I said above, the problem should lessen as base pressure increases. So if it's climbing 5psi at low boost, it may only climb 3psi or something at higher boost, and at really high boost (25psi for example) it may not creep at all.
You can run a PiMP whenever.
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Post by rockacello on Sept 29, 2018 10:10:30 GMT -5
As I said above, the problem should lessen as base pressure increases. So if it's climbing 5psi at low boost, it may only climb 3psi or something at higher boost, and at really high boost (25psi for example) it may not creep at all. You can run a PiMP whenever. Ok sounds good, I’ll try I’m creasing the base pressure to something like 13-14 psi and see what the creep looks like. Thanks for all of the help in diagnosis!
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