Japmuscle

Hey guys,

So I took my AP1 on a road trip yesterday, the first part of the trip was from sea level up to 2000ft in elevation in about 1.5 hrs - its a steep ass long hill.... i drove it at about 140kms/hr (engine is going pretty hard to keep that speed uphill). Right at the top of the hill I gas it pretty good, get up to 160/hms or so.... the car starts to shudder. I ease off and when Im higher in the rpms it shudders (feels like the engine just turns off, or even that Im tapping the break - very noticeable)... I slow down and the issue seems to be lessened when at 3000rpm. the temp is at normal operating mark (not hitting 4 bars). Car drives ok when the engine isnt under a lot of load or RPM.

I drive for another hr or so under light throttle and low rpms (downhill), when I get to the next town I give it some gas and same thing, it breaks up at higher rpms under load. Stop at the gas station, fill up, check the oil - oil level is at 3/5 to full line, so that should be ok... then I get in it and gas it and it drives perfect at WOT again....

My speculation: the issue is something to do with heat of the heads??? or is something in one of the coil packs messed up because of heat?


** note I just had the engine rebuilt, full bottom end rebuild - sleeved with aftermarket 11:1 aluminum heads, new TCT, plugs, injectors cleaned and flow tested, top end is in spec and valves adjusted - 2500ms ago. Did the proper break-in as per the engine builders guidelines.


mods:
berk HFC, injen CAI, megan headers

windhund116

And the temp never went too high, during the moments when the engine started to "stall" or slow down? If the engine is newly built, why is it 3/5th full of oil? Is the car burning oil with the new build?

Pull your plugs. See how they look. Maybe oil fouled?

postman

Is it tuned?

Japmuscle

its on stock ECU

yes, the temp never went above the reg operating temp - 3 bars.

and yes, its been burning oil like crazy.... about 2L in 2500kms.... gonna talk to engine builder monday about it...

car seems to drive perfectly fine today, so weird...

The Prophet.

Given your plugs and all other stuff is good, My hunch would be the altitude.

Awhile back i was watching a long tuning video of a tuner using a Haltech system on a boosted s2000. Idk if this is a haltech ems feature or if most cars do this, but he mentioned that when your key is turned, right before the car starts, the map sensor sends a barometric pressure reading to the ecu so it knows the climate/condition youre about to run in. Maybe that explains why after you filled up on gas, cut it on, and drive again all is fine.

Please dont quote me as the truth lol, but when i read your thread i remember the tuner discussing that. Maybe its just a haltech thing, but regardless, ive personally experienced cars when running the Blue Ridge act odd when approaching peaks.

Sorry i couldnt help any more, good luck

windhund116

Did they change the pistons, too? It almost sounds like the engine starting to seize, at high R's and temp. Hope not...

Japmuscle

interesting, and yes that definitely makes sense.... actually when I did this hill a couple of weeks ago the same thing happened to a lesser extent, and I was driving up the hill pretty slowly (I assume the head temps were much lower)... so that could be the reason.... I guess a way to test this would be to turn the car off at the top of the hill and see.... thx for the info!


Yes they changed the pistons. I wouldnt think that the piston temps would'nt get high enough to start seizing with the block being at regular operating temp.... can anyone jump in on this point?? Of course, this was my primary concern, although the engine is under warranty for a year...

windhund116

"So I took my AP1 on a road trip yesterday, the first part of the trip was from sea level up to 2000ft in elevation in about 1.5 hrs - its a steep ass long hill.... i drove it at about 140kms/hr (engine is going pretty hard to keep that speed uphill). Right at the top of the hill I gas it pretty good, get up to 160/hms or so.... the car starts to shudder."

This is what I meant by possible symptoms of seizing.

starchland

How old are the o2 sensors?

Japmuscle

the primary is 2 yrs old, not sure about the secondary.

Im gonna get the ECU checked and see if its throwing any codes. The check engine light is on because my air pump is dead, so I donno if its throwing any new codes....