Crazy Scanmaster Readings After Hydroboost Install

[Jonasterg]

I finished swapping out the old Powermaster for a hydroboost unit this weekend. I took the car out on Saturday (first time this year) to enjoy the weather.

The car felt great and all the Scanmaster readings looked solid so I decided to get into the boost. I had to let off when I saw 30* KR and 000 02s. I didn't hear any knock and the alcohol seemed fine (green light around 10 psi). I drove around a bit more and everything seemed fine.

I took it out again today but decided to just cruise around. O2s were bouncing up and down like normal. I hit the alcohol test button and they jumped to 800-850. All the sudden I saw the readings get weird. O2s dropped to 000 and KR showed 11*. Then the readings refreshed to normal, then weird, then normal again. At the time I was doing maybe 45 MPH and less than 1/4th throttle.

I turned around to go home and on the way back the readings got weird again. It happened a few times during the 10 minute drive. I tried to get video but I couldn't start recording before the readings became normal again.

I'm guessing (hoping) that I bumped something loose under the dash while I was wrestling with the brake booster, or that I forgot to reconnect something under the hood after the install.

Any ideas?

 

[Jonasterg]

Forgot to mention - I was cycling through the SM while I was driving and saw the INT drop from 128 to ~60... flipped back to the main screen and it showed 30* KR and O2s at 000. I had cruise control on at the time. No boost, not much throttle applied.

 

[Chuck Leeper]

What's voltage doing when this happens?
Did you secure the PM wiring?

 

[Jonasterg]

I covered the old PM connector ends with electrical tape and zip tied them securely out of the way.

I'm not sure about the voltage... I'll need to flip to that display on the SM and see if it gets squirrelly.

 

[TurboBuRick]

Something is interfering with the data stream or it's loosing the signal. A few things come to mind. . Check the data wire connection. Check ecm plug for corrosion. Remove the chip. Retention the leads in the chip socket.

On a side note, how old is the alky pump and how long did it sit without use?

Rick

 

[Chuck Leeper]

What Rick said..,

 

[Jonasterg]

Thanks Rick and Chuck. I'll trace the wires and see if anything got bumped loose while we were under the dash. I'll also reconnect the chip and make sure the connections are secure.

The car (and alky pump) sat from November until April. I filled the reservior with methanol and did cycle the pump every 4-6 weeks (put the hose in the reservior, hit the test button, hold for 15 seconds, wait 5 min, repeat). The alky system was installed 2 years ago... could it be time for a pump rebuild? I guess I'll know if it starts knocking once I sort out the current gremlin.

 

[Jonasterg]

Only had a few minutes outside last night to look around (and won't have more time until next week). I found one thing that may have contributed... I bolted the plastic hotwire kit fuse to the back of the alternator and probably decreased the contact surface available to the wiring. I'll keep digging around next week and see if anything improves once I drive it again.

 

[Bescurred]

My had a similar issue where it would give me all kinds of crazy #s. I got in contact with turbo Bob. At first he said it could be the low fan relay. That wasn't it so I sent it in and he had to put some kind of "noise filter" due to some sort of interference...

I'll dig up the link

Posted from the TurboBuick.Com mobile app

 

[Bescurred]

http://www.turbobuick.com/forums/index.php?threads/392368/


Posted from the TurboBuick.Com mobile app

 

[Jonasterg]

I found a few loose connections under the dash, and one that was disconnected completely (4 amp fuse in-line with it, not sure what it does). I tightened all the connections, especially the Scanmaster to ALDL wire (it was barely seated).

Everything seems fine now. Went out today and all the readings look steady and clean. Didn't get on it much (traffic on the back roads). When I did roll into the throttle, everything looked good. Zero degrees knock, alcohol spraying correctly, 02s around 810.

Thanks for the help everyone. (Now it's time for a new thread... why does the Temp idiot light on my dash keep flickering? I'm guessing it's yet another loose connection.)