My cavalier is being odd.
Just fired up the new engine. Changes to the car from last year are, turbo cams and a new AEM wideband. Car idles around 11.6:1, and when boost comes on its pegs full rich 10:1 and starts to break up. Even with my EBC @ 100% I can only make 12# of boost it breaks up /bogs that bad...
WTF? I have hahn stage2 with 60# injectors. Everything ran good last year, til I blewed it up. Did my FMU @!#$ the bed? How could I test if it did?
what is the injector duty cycle?
what plugs, what is plug gap?
FU Tuning
I have no way to check duty cycle, plugs are ltr7ix-11 gapped at .032
I run the same plugs but I think my gap is .028.... cant recall 100% and my plugs are gone right now haha.
isn't 10:1 the riches the AEM shows?
I'm thinking it is tune related, and the car is too rich it is fallen on it's face.
FU Tuning
Addicted to meth wrote:isn't 10:1 the riches the AEM shows?
I'm thinking it is tune related, and the car is too rich it is fallen on it's face.
I cant fathum that the turbo cams would make it that rich...
But none the less, I will start looking into stuff.
Also starting to wonder if an animal made a nest in my intercooler. Like a dumbass I left the inlet pipe open all winter and stored the car outside under a cover. That would cause a restriction to the manifold, but because the fmu signal is off the compressor its seeing boost, when the manifold is not. Well I'm gonna rule that out tonight.
Can't think of anything else to check out.
What kind of fuel pressure are you running???? Is the factory O2 sensor still hooked up???
Currently #4 in Ecotec Forced Induction horsepower ratings. 505.8 WHP 414WTQ!!!
Currently 3rd quickest Ecotec on the .org - 10.949 @ 131.50 MPH!!!
The turbo cams will make a difference. How much? Its hard to say. When I rebuilt, I needed a new tune, but other factors instead of just camshafts came into play.
I would check two things first before anything.
1 - Timing Chain. Lined up correctly?
2 - o2 Sensor. Is it faulty? Going bad?
Either can cause a rich condition. I wouldn't suspect it to be any vacuum issue because that would cause a lean condition.
If those aren't the culprit, Check fuel rail pressure @ idle. I really don't think it is a fuel pressure issue, because of your symptoms tassuming you are in closed loop?).....but it isn't a bad idea to check it anyway for good measure.
I think it idles way to nice to be a tooth off on the timing. I did a comp test today. 170, 175, 18,0 175
Little low but not bad for 8.9:1 pistons.
I need to get hold of the Hahn instruction for his fmu. Waiting to hear back from him. Fml.
Something Fetter and I were talking about is getting the cams dialed in 100%. Not sure if you have the adjustable cams or not. But he was saying a kid gained 30psi of compression just by dialing the cams in perfect with the adjustable gears....
something I need to heavily look in to before getting mine going....
is the fmu adjustable? if so, readjust it. if its not, then @!#$can the fmu and get a tune. the wideband can only read down to 10:1 afr so the true afr is unknown. since its bogging down under boost your true afr maybe in the 8:1 afr or less. i dont know why people keep using fmu's. its 20 y/o technology and its not considered a tune.
blackbirdracing wrote:I think it idles way to nice to be a tooth off on the timing. I did a comp test today. 170, 175, 18,0 175
Little low but not bad for 8.9:1 pistons.
I need to get hold of the Hahn instruction for his fmu. Waiting to hear back from him. Fml.
Compression test will not confirm correct cam timing...Nor will a smooth idle... Alot of engines will run beautifully at idle with one or even two teeth off.
You need to sync a pressure transducer up with the crank and cam or find a good reference signal with crank and cam on a stock motor to be able to tell. Either way your going to need to get it on a scope. then you can decide to tear it down or not.
Your clogged intercooler idea sounds legitimate...
Buildin' n' Boostin for 08' - Alex Richards
I think checking the timing to make sure all marks line up is easy enough and worth it to do (after checking the intercooler).
FU Tuning
JOE L wrote:is the fmu adjustable? if so, readjust it. if its not, then @!#$can the fmu and get a tune. the wideband can only read down to 10:1 afr so the true afr is unknown. since its bogging down under boost your true afr maybe in the 8:1 afr or less. i dont know why people keep using fmu's. its 20 y/o technology and its not considered a tune.
ill disagree. I made 300+ on an fmu and going for 400+. He is running FMU + HPT, just like I am. Its not a perfect way to do it but considering our ECU's dont read boost, gotta make do with what we can.
Blew through the intercooler without issue. Tomorrow I'm trying a new coil pack. Then when that doesn't work, ill try to put The stock cams back in.
Hahn is going to get the instructions to me for setting the FMU. He is probably going to take forever though.
Any one else got the Hahn kit? Wanna read me the directions?
blackbirdracing wrote:Blew through the intercooler without issue. Tomorrow I'm trying a new coil pack. Then when that doesn't work, ill try to put The stock cams back in.
Hahn is going to get the instructions to me for setting the FMU. He is probably going to take forever though.
Any one else got the Hahn kit? Wanna read me the directions?
When I was still running that BEGI II FMU, I changed it from the Hahn directions, because I didn't like how my fuel pressure was working under boost and it made it difficult to tune with HP Tuners above 10psi. I guess I don't trust a needle valve and diaphram, lol.
The FMU that Hahn supplies in his kit is the 2025 model.
This is coming straight from Corky Bell :
Bell Engineering FMU Instructions
Hahn claims to not use corky's instructions because he had the units tweaked for his kits. He had them put in different springs or some @!#$.
Ok, so... Your saying use the corky instructions. Cause they say to hook the signal to vac/boost. And I have it to boost only.
blackbirdracing wrote:Ok, so... Your saying use the corky instructions. Cause they say to hook the signal to vac/boost. And I have it to boost only.
I still think when I said that the first time it was right
give it a shot and report back!
Vince, totally off topic but I cannot help but giggle and watch your signature 4-7 times in a row...
Buildin' n' Boostin for 08' - Alex Richards
Found the problem... Head is @!#$. After I injected the cylinder with air. Intake valve on cylinder 4 leaking back into intake.
blackbirdracing wrote:Found the problem... Head is @!#$. After I injected the cylinder with air. Intake valve on cylinder 4 leaking back into intake.
Did you rotate the motor/cam to make sure the valves are closed completely?
FU Tuning
Yeah, 100% sure. Cams were in the "rest" position. As if I was timing the engine. Crank at tdc.
Cause I actually re did the timing to see if that was it. It was timed right.
