New GN owner questions/issues

[Super Gnat]

Recently picked up an 87 GN. You can see some mods and info here. http://www.ihadav8.com/forum/index.php?topic=3778.0


The previous owner gave me a new fuel pressure regulator that i need to have installed. Hopefully that will help with some of the issues im having.


I cant get the car to build boost at the line or spin the tires for that matter. I hold the brake and hit the gas and it wont rev past like 2200 rpm. Sometimes while cruising at 30mph and then going WOT, the thing will stall and sputter, other times, the turbo will spool and away i go. Also, my oil pressure has been all over the place, as low as 20 psi and as high as 80 when WOT. Dunno if thats normal.


It seems like the turbo isn't spooling very fast either. I have it set to 15 psi. When i'm WOT and i get to 15 psi, after a moment it drops to 10 and wont go any higher.


The previous owner also told me that his wife had driven it when he had the boost turned way up (22psi) and well.... it wasn't pretty. He had it turned up for some passes at the strip but his wife took it out on the freeway before he turned it back down. She threw it down to third to pass a vehicle and when the boost maxed out, the stock motor couldn't hang. Since that happened he turned the boost down to 10 psi and kept it there til he sold it to me.


My next step is to take it in for a tune up and get the regulator installed. Being in SoCal, it looks like it will end up in the hands of turbo Lou, unless anyone knows of a capable mechanic closer to Los Angeles. The heads have never been off the motor so if i need to do a serious overhaul then so be it. I want this car to perform like i know it can and last for another 25 years. Im willing to spend some money on it.


Any advice or words of wisdom? What do i need to replace or double check from the unfortunate rattle at 22psi? What would you do?


Thanks!

[Super Gnat]

Scanmaster... right i forgot i had one, Ill plug it in and see what codes it gives me. Stand by.

[earlbrown]

Sounds like you might have some severe engine damage.

I'd park it until you can run some tests and find out exactly what your hard parts are doing.

[Steve Wood]

Yep, I would say blown head gaskets, wiped bearings, damaged turbo.....but, the best would be to take it to an experienced Buick shop on a trailer

[Super Gnat]

Yea it for sure will need to see a good mechanic. It has no problem starting and idling and grocery style driving but thats as far as the good news goes. There isn't any weird mechanical noises but its definitely acting erratic.


As i was told the story about 22psi, I kept imagining the heads blowing off the motor and then the phone call to the husband that followed.

[earlbrown]

These things can run 22#s all day long if tuned right and mechanically sound.

Normally I'd recommend draining all the antifreeze out if you're going to continue to abuse the car like that, but freezing temps are around the corner....

You really need to park the car. The scanmaster can't tell you about cam lobes, head gasket seal, leak down, or cracked pistons.

[Steve Wood]

they can run 22# all day long on race gas, or alky injection.  On Cali 91 octane gas and an obsolete ATR chip, it can safely run about 10# of boost.  From the description you provided, it appears the engine is wasted and needs a total rebuild.  Hope that is not the case, but, don't be surprised if you drive over the crank on the way to the store

[Super Gnat]

I hear ya, car is parked.


The ATR chip is getting replaced. I called Turbo Lou to let him know ill be seeing him soon. We will prolly end up pulling the heads and having a look.


Pulled the radiator today for a flush and rod. The antifreeze in the reservoir had tons of gunk in it.


@ Earl, I havent been abusing it. I rescued it from a garage where it surely would have rotted away! And it rarely freezes here in Los Angeles.


As it turns out, I have a scan tool, not a scanmaster. All of the sudden i have a lot on the to do/buy list.


I don't mind rebuilding the motor if it needs it. My wallet might but i don't.     Its worth it!

[Super Gnat]

Ok i guess trying to do a burn out with it as soon as i got it is abuse.....


Anyway i found an old receipt for green stripe injectors which if im not mistaken means that it is 30-32 pound injectors. Less than the 40 pounds that i originally thought were on it. Day 2 of owning the car, alright!

[Super Gnat]

just ordered a scanmaster 2.1 and some TT chips.....

[Steve Wood]

Not necessarily... we called the 42.5# injectors green stripes as well even tho later they were marked with different colors and different parts number.  Parts number is the only meaningful ID

[motorhead]

just ordered a scanmaster 2.1 and some TT chips.....

Send the useless ScanMaster back and get the PowerLogger. What is this a flashback to the year 2000?

[Super Gnat]

Not necessarily... we called the 42.5# injectors green stripes as well even tho later they were marked with different colors and different parts number.  Parts number is the only meaningful ID

good to know thanks i think they were purchased from kirbans part number says 1544, same that kirban lists.

[Super Gnat]

just ordered a scanmaster 2.1 and some TT chips.....

Send the useless ScanMaster back and get the PowerLogger. What is this a flashback to the year 2000?

hahahhahah.


care to share your reasoning?


I think the scanmaster will be just fine until i gain more knowledge of this car.

[Steve Wood]

I believe you need both as Scanmaster provides constant monitoring of the O2s and timing retard...of course, if it is in the trunk you should have saved your money.

Powerlogger allows you to log the data stream and see many more parameters, but, more importantly, it allows you, plus anyone you wish to get help from, to see the data all at the same time so you can see if your fuel pressure drop occurs at the same time that the voltage dropped due to a tired alternator that could not handle the load the electrical sysem was putting on it.

Or it can show that the blms and o2s are acting in proper relationship to one another, or if the timing retard that was indicated happened on a shift, at launch, or if it appears to be related to detonation, too rich a mixture, or a failing fuel pump.

Experienced guys have run nines on Scanmasters.  Beginners have blown up engines because they did not understand what they were looking at and could not show a data log to some one that could.