Need a recommendation


New Member
Apr 19, 2022
Hello all,
I live in the Kansas City area and would appreciate a recommendation for a local Buick GN tuner/shop. I acquired an 87 GN a few months ago from an old friend who is in poor health. I know very little about the car but have been trying to learn more online. It gets poor mileage, has a very slight miss and seems to be running very rich. On a recent trip, the cc reading on the Scanmaster was a steady 254 at 65mph. I replaced the O2 sensor, and it now resets and climbs like it should, but in very large steps. It didn't seem to help much with the overall engine operation. I have no idea what tweaks my friend made to the ECU, etc. I know the engine is built with performance heads and a bigger turbo but other than that, I have no specs. My buddy has dementia and other health issues, so I can't really get any help from him. So, if anyone can refer meto a shop in the area that has some experience with Buick Grand Nationals, I'd certainly take it to them for diagnosis and repair. Thanks!
Not sure if Boost Crew Motorsports is still in business, but they are in Louisville. They were Hella Good, but it's been 6 years since I've had dealings them.

Try 270.300.8046
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Phoneguy is in St Louis , anybody heard from him lately ??
All suggestions are welcome. I'm not opposed to driving or trailering it to a good shop if it's within reason. I'd like it to be as close as possible so I could interact with the staff but it's not a deal breaker if it's out of town. Thanks!
The turbo dojo(Jason Bertram) might be an option but he is up in Minnesota.
Are you running a stock ecu? If so, what chip? you say built, and larger turbo, but from the interwebz that is pretty vague. Maybe some pix of what you have there might help.
Let us know. Always willing to try and help.
I can check the ECU tomorrow - probably should have done it long before now but as mentioned, I'm not very familiar with this tech. My buddy had a poster he carted around with him that has a bit of info on it, but some critical specs missing. Not sure you can tell much from photos, but I'll post one anyway.
Steve's site has a plethora of information. Unless you just don't want to work on it yourself and learn about the vehicle, this is a good place to read up on what should be happening.
Thanks, Rich, I bookmarked the page and will read thru it ASAP. Good info! I don't mind learning about the car; however, I tend to do better when I see something rather than reading about it. An experienced mechanic could probably diagnose the problem(s) in a few minutes while I might spend weeks reading, swapping parts and still wind up no further ahead than when I started. But if I can't find that person locally, I can wade in with both feet.

I did get the ECU out and it appears to have an aftermarket PROM. Unfortunately, there are no markings on it, so I have no idea about the manufacturer. It has a wire bundle coming out of it that goes to a selector switch that sits in the glove box. It's currently set to 5 but can be dialed up or down. Again, no idea what it should be set at or why it's even in there. The car had alcohol injection on it, but the pump was corroded, and the container was seriously degraded, so I removed it and the controller. I figured since I only use the car for cruise-ins, I could get by without the alcohol shot. Maybe add it later if I ever decide to take it to the dragstrip.

Thats a Poston's thumb wheel chip circa 1998, i wouldnt trust or run that, make a call to Turbotweak for a new chip and injectors
Dont get into boost with that old junk...
Verify the Mass air flow sensor is good, i dont even see one in the pic
Thanks for the heads up! I'll contact Turbotweak and test the MAF. I don't know if a bad one will set a code or not, but I don't currently have any showing. I had to clear a 13 code after replacing the O2 sensor. The MAF sits about 24" from the air inlet on the turbo due to the addition of a CAI.

That is a stock maf. Need to look at the gr/sec on the scanmater to see if it is working.
A bad MAF will not always throw a malfunction code. The stock MAFs are notoriously problematic. Part store replacement versions are almost always not calibrated correctly. Replace it with a LS1/LT1 MAF and a translator box. These work incredibly well and is a simple install. Eric can hook you up along with a modern chip.
On our way home from a cruise a week ago, we recorded the following Scanmaster readings at ~70 mph.
O2 375
KR 0.0
AF 5.7
L8 117
BAT 12.7
INT 150
BL 150
MPH 69
CLT 164
ATS 93
R 250? in OD, tach reads more like 1600 at that speed IIRC
TPS 1.24
IAC 131
CC 254 steady
NAL blank
BL and INT are pegged. A good indicator that something is seriously out of whack.
As suggested, get rid of the stock MAF and chip, before you drive over the crank.
Once the new parts are in and adjusted, start with more SM readings.
Recommend reading Steve Wood's page above, and getting more familiar with the scanmaster readings. Some need to be taken at idle (TPS, IAC), others while cruising (INT, BL), while yet others should be cycling steadily.

Chuck and others are giving great advice. An ounce of prevention, and all that...
Thanks everyone! I'll contact Eric and get the parts on the way. Will report back once they're in.
Phoneguy is in St Louis , anybody heard from him lately ??
He's a busy guy. There are quite a few guys here in the Saint Louis area that could be of assistance. I can't speak for everyone's scheduling though. That's the only bad part.