car running lean under boost

[usetaboost]

Like I said, there' could be a 1-2lb variance to these numbers, but it varifies that fuel psi is going up and holding consistently.

 

[usetaboost]

Just checked voltage at the back of the car backprobed into the connector on the sending unit harness on the tan wire, it's got a solid 16 volts at idle

 

[kidglok]

maybe its too rich, never did trust a narrowband

 

[usetaboost]

This is the PM I recieved from Eric

The chip is made for the Siemens, I just didn't change it on the order sheet. It wouldn't make much difference on the high end anyway.
The injector duty cycle is averaging 75% at around 5400rpm in that chip. You had stated your 1/4 mile goal was 11.0, so I fueled up the chip for that, assuming the alky is spraying the typical amount.
Let me know if you want to add more fuel, but if taking the chip adjustment way up doesn't help, then there might be something else going on. If you take it to +20%, you'll be about 95% duty cycle.

 

[bison]

maybe its too rich, never did trust a narrowband

^^^this

 

[INEEDAGN]

Alright, I thought on it. I drank on it. I slept on it. I'd start looking at your injector harness. Injectors can't do what the ecm tells them to do, you will go lean even with perfect fuel pressure. I'd bet you got a corroded pin somewhere at a connector or you got a power feed problem to it. I could easily be wrong but I think the ecm toggles the ground and the injectors have a costant positive connection. Could also be a rogue injector doing weird sh!t leaning out one cylinder. If you had a marginal injector harness connection somewhere, the first time it's gonna show itself is when you are really leaning on it. AND it would probably be different every time you got on it...

A powerlogger would REALLY help eliminate some variables here.

 

[usetaboost]

Damn near two years later the car still runs the same on the same setting. 11.0 at top of third with wot fuel maxed out, saw 1.2 kr at the very top of third. Car shifts around 52-5300 rpm. I find it hard to believe the car makes enough power to run injectors near max but the car pulls like a freight train through the entire pull. Did this three times back to back. Bob and I have ruled out the fuel pump. No leaks of any kind.

 

[tonka]

Ever have the injectors flow tested?

 

[we4Mateo]

Damn near two years later the car still runs the same on the same setting. 11.0 at top of third with wot fuel maxed out, saw 1.2 kr at the very top of third. Car shifts around 52-5300 rpm. I find it hard to believe the car makes enough power to run injectors near max but the car pulls like a freight train through the entire pull. Did this three times back to back. Bob and I have ruled out the fuel pump. No leaks of any kind.

That's messed up. The alky is probably what's keeping you alive. I'd hate to see how lean it'd be just on gas even with race gas. That may be worth a shot though so you can not worry about how the alky is affecting the other fuel system?

 

[usetaboost]

When I add fuel to it the o2s come up and wb goes down. If I left the settings default on the chip it would probably kill itself

 

[we4Mateo]

When I add fuel to it the o2s come up and wb goes down. If I left the settings default on the chip it would probably kill itself

Weird. I guess your car just flows a lot of air! I'd think he'd fix that for you though. Have you had a reburn yet?

 

[usetaboost]

Nope. Probably gonna wait til I do injectors and get my moneys worth.

 

[INEEDAGN]

Do you have any idea what duty cycle they are running at? Injectors aren't known for being linear above 90%.

You need a powerlogger. borrow one, steal one, whatever. I guess if not I can hook up my old directscan.

 

[usetaboost]

According to Eric the injectors should be around 95% duty cycle with the fueling maxed out.

 

[Raeban]

I had the same problem for almost a year. Turned out to be a bad Map sensor that would seperate at the case when under boost. The way it was plumbed in with my boost gauge kept me from picking up on it and in actuality my boost was significantly higher than what the alchy or I thought. I found it by doing a pressurized leak check.

 

[usetaboost]

Hnmm provacative. I'll have to check that out sometime. Now I gotta make my windows work. THe manual conversion is starting to look more worth it every day.

 

[TTA308]

Alright, I thought on it. I drank on it. I slept on it. I'd start looking at your injector harness. Injectors can't do what the ecm tells them to do, you will go lean even with perfect fuel pressure. I'd bet you got a corroded pin somewhere at a connector or you got a power feed problem to it. I could easily be wrong but I think the ecm toggles the ground and the injectors have a costant positive connection. Could also be a rogue injector doing weird sh!t leaning out one cylinder. If you had a marginal injector harness connection somewhere, the first time it's gonna show itself is when you are really leaning on it. AND it would probably be different every time you got on it...

A powerlogger would REALLY help eliminate some variables here.

Yep, yep ,yep and yep