New chip, new fuel, new problems

[Jon Early]

Hey everyone,

I installed new 80# injectors, Racetronix 450 pump with hotwire, -6 return line, TA49, custom Husek D5 converter, and a new chip last year while I had the engine out for all new gaskets. The car runs much better than it ever did before all this resealing and welding the headers, but it's still not running the way I expected. I have some questions that aren't covered in the chip instructions.

What should my O2 mV look like at WOT on E85? I'm used to seeing 700-800, but they're as low as 400 since switching to E85. I raised overall fueling a little bit so that it's in the 500s, but I'm not sure if that was a solid move.

I noticed yesterday that my KR was pretty much gone which made me happy, but that was when I noticed that the car is only making 16-17psi. This leads me to two more questions. 1.) What would be causing a mostly stock GN on E85 to knock? I have new poly engine and trans mounts in it. Could it be the shift shock? The KR is definitely at its worst worst on the 1-2 shift, but it doesn't go all the way back to 0 until it's almost ready for third. It never knocks in first. 2.) Does the chip control the wastegate solenoid or do I need a boost controller? I spent days fiddling with the wastegate arm on my Bowling Green Customs downpipe elbow so that it wasn't sticking anymore. I still have to diagnose, but I don't want to chase my tail if the number on my chip (23-25psi) is only what it's good for and not what it actually commands.

Thank you!

New chip on top

 

[EricM]

The O2's for E85 will be the same as gas, so 750-800 or so at WOT. So either your O2 sensor is bad (or wiring), or something is wrong in your fuel system.
The computer controls the wastegate solenoid, and in your chip its set to 100%, which would normally give you 22-23psi with a stock type wastegate actuator, or more if you adjust it tighter. It's possible your solenoid is not bleeding boost properly.

For the knock, if its really that lean, then it could be real knock. I would get the low O2 situation straightened out first. I would change the O2 sensor, and if that doesn't help, then connect a fuel pressure gauge you can read under boost. It should rise 1:1 with boost.

 

[Jon Early]

The O2's for E85 will be the same as gas, so 750-800 or so at WOT. So either your O2 sensor is bad (or wiring), or something is wrong in your fuel system.
The computer controls the wastegate solenoid, and in your chip its set to 100%, which would normally give you 22-23psi with a stock type wastegate actuator, or more if you adjust it tighter. It's possible your solenoid is not bleeding boost properly.

For the knock, if its really that lean, then it could be real knock. I would get the low O2 situation straightened out first. I would change the O2 sensor, and if that doesn't help, then connect a fuel pressure gauge you can read under boost. It should rise 1:1 with boost.

Thank you! Lean knock was my suspicion. I'm pretty confident that the sensor is good. I changed it out with a new NTK when I noticed the issue, but it didn't help. I'll double check the regulator adjustment and all that. Hopefully both issues are simple.

My Accufab regulator was on the car when I bought it. I think it's about 15 years old at this point, so it might need a rebuild. I'll throw a gauge on and go for a ride.

 

[Jon Early]

Adjusting my regulator might have fixed my fueling issue. I must have had some back pressure on the regulator when I was still using the stock return line. However, I won't know if it's fixed until I figure out why that car is not making any boost at all. I swear this thing breaks faster than I can work.

Low fuel pressure

I installed an upgraded pump and filter, but also upsized the return line. Time to turn up the regulator!

youtube.com

 

[Jon Early]

I'm back! The no boost issue was a stuck wastegate puck. I got it unstuck and the car is back to making just 16 psi. I confirmed that with a vacuum line from the compressor straight to the actuator I was getting 12 psi. Then I turned to the solenoid. I am still a little confused on how exactly this works but I mimicked a test I saw somebody on turbobuick posted.

With the key on I measured a steady 12V across the solenoid. I don't have a scope handy, but I assume that the duty cycle is set to 100% per the chip. When I applied 30psi to the solenoid as shown above, it didn't bleed anything.

However, when I switch to the top port it bleeds. I didn't think these solenoids were directional, but I suppose it's good information. I'll be sure to use the top port!

As I regulated air lower and lower, the solenoid continued to bleed off until about 16 psi. I couldn't hear or feel any air coming out at lower pressures. However, it tried the same test again with the key of and the results were exactly the same. I assume that this solenoid is stuck, but I admit that I'm not entirely sure how it's supposed to work.

I'm thinking it's time for a manual controller, but I might just unhook this system completely and see if I can control the boost with the throttle. I would think that if I surpass 16 psi (very carefully) with the solenoid hose unhooked, the boost should be unlimited. Can anyone confirm? Thanks!

 

[EricM]

You cannot test the solenoid like that. It does not sense boost. It bleeds off boost, so the actuator will start opening later (at higher boost).

Your chip is set to 100% wastegate dc, since you want high boost, and it won't activate unless the car is running and you start to get into boost. At that point it would open and start bleeding. It's possible that it's not opening, so your boost is lower than intended.

 

[Jon Early]

You cannot test the solenoid like that. It does not sense boost. It bleeds off boost, so the actuator will start opening later (at higher boost).

Your chip is set to 100% wastegate dc, since you want high boost, and it won't activate unless the car is running and you start to get into boost. At that point it would open and start bleeding. It's possible that it's not opening, so your boost is lower than intended.

Gotcha That makes more sense. I figured it had to be more complicated that that otherwise, they could have just made it an orifice.

I pulled the line off the solenoid and retested as carefully as I could. I saw boost go over 20 before letting out, so I'd say its time to ditch the solenoid and install a manual controller. From there, I'll get back into why my o2s are still in the 500s.