Now I see why people sell these cheap. Help!

[ChrisF]

I have owned a GN for 10 years now, and this board and it's members have been very helpful throughout the years. I have read these posts for a long time and learned a lot, and of course read the posts detailing someone else's abject frustration with these cars, and threatening to sell the car off cheap or even destroy it. I never have posted one until now.

I regrettably have finally joined the ranks. I never before have carried on about hating this car on here in 10 years, but here I am. I am tired of fixing this car. It seems you get it right for a while, and there it is, something else is broken.

This latest episode started late last fall when the cam gear and cam sensor gear decided they no longer wanted to play nice, this being brought on by some unknowing prior owner buying nearly everything in the Kenne Bell catalog, including a high volume pump that is completely unnecessary. This additional load ate the gears.

After a cam and lifter change and basically a total top end rebuild, I get this car back together and it runs and drives great at less than 1/3 throttle. It idles smoothly (except for occasionally going up 500 rpm and back for no reason at a light) and drives great until you put your foot into it. Then it stumbles or even backfires.

Changed the MAF as the values for it seemed low and I last changed it in 2002, and wow the problem was fixed for about 3 miles. Then right back at it again. WTF?

It acts lean, but T link shows the o2 values at 746, 804, 796, and 792 when it hit 3rd. The last 3 numbers are closed loop on the T Tweak chip. The 1st frame # is from a 15 mph rolling blast. Tps was 4.75 the whole time, and LV8 and MAF were both 255, and no trouble codes showing. NO knock at all.

Boost was at 15 psi solid the whole time, hitting 15.5 right before 3rd gear, then dropping to 14.

Fuel psi is @ 44 line off, FP does rise with boost. Idle vac ~16 or so in gear, steady.

After using my scantool as well as a friend's professional engine analyzer everything seems fine, except it didn't like the secondary ignition values. I am going to put fresh wires on it and regap the plugs @ .035 tomorrow, but my gut tells me there's more to this than that.

Any help would be awesome, if someone can help me get this thing running right again, I might decide to keep it. But this BS is making a coat of paint on the GN and ebay this spring real tempting. The 2010 Dodge Challenger isn't helping, either. At least I wouldn't be constantly fixing it.

Thanks for letting me vent, and thanks in advance for any help.

[Little6pack]

I hate to say it, But you either walk away and never look back or you mothball your car for a couple of years & maybe the excitment will come back. Plus it might be worth more in a few years. Selling right now is tough unless you give it away.. (I know)

Any good tuners in your area??

Or maybe a trip to OTTO or JACK seems to be a 5 hr ride for you???

[Buix893]

I hear ya brotha....

These cars are a love/hate relationship, when they run its all fun but when they break it is a pita...I guess I have dealt with so much BS with my car that I expect it to mess up and it does not even bother me anymore.

I love these cars, they are truly amazing but I can see after a while how you can get sick and tired of blowing money on them, I could have painted my car 2 times already with the amount of $hit I put into this car. Last spring I parked the car for a whole year cause I didn't even want to look at it, it really got me that mad. I fixed it up in April with a newer turbo and IC and it ran AMAZING...a few days later the car gets a short (my fault) and here I am still trying to figure it out. I might have to put the cover back on her cause I can't afford it anymore...

[Chuck Leeper]

"
After using my scantool as well as a friend's professional engine analyzer everything seems fine, except it didn't like the secondary ignition values."

Unless the analyzer loads the coilpak, I suggest another test:
Caspers coilpak tester.
Do it w/ the engine hot.

[kingots2004]

say the word and ill make the drive and haul it off for free.that way you never have to look at it again .

[Joe 1320]

My bet would be coil pack and ignition module.

[TurboBuRick]

I would be taking a close look at the crank sensor.
Make sure it's not getting hit by the wheel. Also make sure the balancer is tight. 2ft pipe on a breaker tight.
Make sure the sensor is not cocked. Make sure the wheel is not too deep in the sensor. It all makes a difference.
Look at this very carefully and take your time. In some cases the sensor bracket may need modification to be perfect.
The sensor should be gaped .020-.025 or so. Main thing is it's not making contact with the wheel.
Need to rotate the crank and check gap all three blades that pass through

[vacuum 6]

Assuming its the coil, module or whatever, do yourself a favor and purchase new genuine gm parts or OEM replacement parts from someone that sells it.

IMO - buy thru Highway Stars Buick Grand National Parts Home Page only

Hope you get it fixed soon.

[murphster]

Originally Posted by ChrisF

Changed the MAF as the values for it seemed low and I last changed it in 2002, and wow the problem was fixed for about 3 miles. Then right back at it again. WTF?

What MAF did you put in? I would switch to a translator or borrow one just to rule out. I had lots of MAF problems until I switched to translators and sometimes they were hard to diagnose, with the main symptoms being stumbling/hesistation issues.

[ChrisF]

Thanks guys!

Rick - I will look at the crank sensor again, but when I reinstalled the balancer during the timing cover overhaul, I was able to get a real good look at it and make sure it was clearing the sensor. There was a "sweet spot" that it went into where it wouldn't make any contact at any of the three positions, and that's where it went. It also is brand new. The balancer not only had an oil slinger behind it on the crank (of course) but also a small steel washer that went around the crank - I guess a couple out of 10 of these engines had one - I am assuming this was to add a little extra distance to the balancer depth relative to the engine. It's on there real tight too.

Murph, the MAF is a reman AC Delco piece from NAPA. About $90 bucks, and on the latest t-link run is showing a full 255 value at WOT, so I am assuming it's not that, but it's sure acting like one.

Do you guys think the O2 values I posted are a touch lean?

TIA again

[XLR8]

Originally Posted by ChrisF

I get this car back together and it runs and drives great at less than 1/3 throttle. It idles smoothly (except for occasionally going up 500 rpm and back for no reason at a light) and drives great until you put your foot into it. Then it stumbles or even backfires.

Flat tappet or roller cam? If a flat tappet you can try pulling the valve covers and runing the engin making sure all of the rockers move the same amount.

[ChrisF]

XLR8 - The cam is a brand new flat tappet cam. Broken in with ZDDP and Mobil 1 by running it at about 2500 rpm for about 15-20 mins. Cam was initially coated in assembly lube. Lifters were soaked and pumped up. Oil pump was primed and run for about 3-5 minutes with a 1/2" drill motor to be sure everything was oiled prior to startup. Valvetrain is quiet. Oil is clear like honey with no metal in it.


**Update - brand new set of ignition wires, absolutely no change. Balancer is tight, crank sensor appears fine. Still no codes.

** Oddly it ran fine for a mile or two with the new MAF, then bad again...defective MAF? My test showed 255 at WOT, wouldn't that tell the ECM max airflow?

*** The car acts exactly like an old car with a bad 4 barrel carb. It runs great on the primaries, but when the secondaries open it stumbles, backfires, you name it. It feels like a classic lean stumble, but fuel psi and O2 readings while it's happening seem normal?? What the ???

[TURBOPOWERED68]

i had a similar problem and it was the coil and/or module (i changed both at the same time)
Good luck

[TurboGA]

Originally Posted by ChrisF

XLR8 - The cam is a brand new flat tappet cam. Broken in with ZDDP and Mobil 1 by running it at about 2500 rpm for about 15-20 mins. Cam was initially coated in assembly lube. Lifters were soaked and pumped up. Oil pump was primed and run for about 3-5 minutes with a 1/2" drill motor to be sure everything was oiled prior to startup. Valvetrain is quiet. Oil is clear like honey with no metal in it.


**Update - brand new set of ignition wires, absolutely no change. Balancer is tight, crank sensor appears fine. Still no codes.

** Oddly it ran fine for a mile or two with the new MAF, then bad again...defective MAF? My test showed 255 at WOT, wouldn't that tell the ECM max airflow?

*** The car acts exactly like an old car with a bad 4 barrel carb. It runs great on the primaries, but when the secondaries open it stumbles, backfires, you name it. It feels like a classic lean stumble, but fuel psi and O2 readings while it's happening seem normal?? What the ???

I feel your pain. I race a GN for about 5 years and it was fun but there was also alot of stressful days with it(breakage, expensive parts). I ended up selling it in 2005 and promise myself not to race them again if I bought another one. I just recently bought a mint 87 GN last fall from a good friend of mine that was the original owner. Car mostly car (plan to keep it this way) but it so much fun to drive now. This will be a true collector car.
Good Luck with your ride.

[KevinB]

Almost sounds like the cam sensor is 180 degrees out.

[rag231]

I have never hurt the car racing it and I have owned it and raced it for about 14 years. I used to work about 6 miles from where I live and it broke down on me more times than I have fingers and toes. I had the trans line rub up against the x-over pipe ( before twins) and started to leak fluid so bad that the fire marshal pulled me over to ask me if my car was ok, This was a few blocks from my job and all my co-workers would pass by laughing @ my "super mobile". I had the Essex external fuel pump go bad on the way home ,the car was bucking and sputtering,(because it kept running lean) I would pull over and let it cool down for a few minutes, hop back on the road ,go a few miles pull over, there was a funeral procession behind me a the sherriff's car came up behind to pull over in front of the cemetary to let the traffic turn in and my car shut off right in front of the entrance.Talk about frustation , embarassment, and disrespect all at the same time. I took my dad for a joy ride and the intercooler hose blew off at the throttle body and dented my hood, this was in total darkness with no tools or flashlight. To make a very, very long story short full of frustration and anger short, "every" single time I drive the car now whether it to a show, race, gas station, cruise, street race whatever, heads turn, that car has major respect on the street. It now has a full stage 2 with twins, it will run high 5's in the 1/8 easily( and I do mean easily) and I will drive it literally every day that Uncle Sam isn't riding my back to make a $. I hate my car.......But I love everything it does for me. Maybe you need to have a one on one talk with your car... Man that's deep, real deep. I promise you your story is no different from any one else on this board and the real kicker is a lot of people on this board have more than one turbo buick. I am sure that many have had not 1 but 2 broke buicks and the same time, explain that to your wife or better yet your friends. Maybe I should start a poll on the frustration or most common problems that people have had. Good Luck with your decision.

[protracracing]

I would try and borrow a good stock mass air sensor (not a reman)and see if the problem goes away.Those Reman's are very hit of miss.

hope this helps

Dennis

[Steve V]

You broke the cam in with Mobil1 use dyno and zddp for breakin.

Toss the remans they are usually off see other thread,Richard Clark has been in that one. Translator and 3 in 0r 3.5 and never look back.

[ChrisF]

Keven, I am told these will not idle right if the sensor is 180 deg out - is that true? I suppose it's possible...It drives just great until you put your foot into it.

[ChrisF]

ttt

anyone else?

[scot w.]

Originally Posted by ChrisF

ttt

anyone else?

Chris,

There can be several things causing this issue! Donnie brooks just had a WOT stumble/fall on face issue recently and he discovered that one of the spark plugs was cracked. This was found after several other parts were bought and nothing worked. New plugs fixed his....

The best and easyiest way to solve issues like this is to have someone let you swap (Known good) parts back and forth untill you find the gremlin. It saves you Money and you know their parts are good & Work!!

Hope you solve it, Please stop back and let us know what it was...

SW.

[boostified]

I really hope you figure out whats going on with your car, cause mine was doing the same thing. I wish I had a scan master or something to diagnose my car. I have a gen 2 translator in mine and everything looked fine except the o2 volts were reading 0.0 I assumed it was the display only, as i checked continuity between the ecm and translator, and it was o.k. Mine detonated so bad with only 7 lbs. boost that it beat the main and rod bearings out of it. I feel your frustration. My car has been done for about 6 months , and has seen all of 5 miles on the road. Good luck

[pmoore4321]

I had a little scare this week also. My car has been running perfect and I decided to take my kid on a little drive around the neighborhood. Everything is going great until we get a few block from the house. I leave a stop sign and the most gawdawful rattle/knock sound radiates from underneath the car. I figure "oh well" there goes a bunch of money in a rebuild. I leave for work, unable to immediately diagnose the problem. I sweat it out all day reading various posts on this forum about everything from rod knock to cracked pistons to valve train problems. I pray for loose converter or flywheel bolts. I get home that evening, pop the trans guard plate, and sure enough a converter bolt was out 1/2".

What did I do after that scare? I grabbed that actuator rod and LENGTHENED it about three turns. As much as I like playing with this car, I know it is going to catch me slipping one of these days.

At any rate, I hope you guys get your cars running.

[Turbo6Smackdown]

Originally Posted by ChrisF

I have owned a GN for 10 years now, and this board and it's members have been very helpful throughout the years. I have read these posts for a long time and learned a lot, and of course read the posts detailing someone else's abject frustration with these cars, and threatening to sell the car off cheap or even destroy it. I never have posted one until now.

I regrettably have finally joined the ranks. I never before have carried on about hating this car on here in 10 years, but here I am. I am tired of fixing this car. It seems you get it right for a while, and there it is, something else is broken.

This latest episode started late last fall when the cam gear and cam sensor gear decided they no longer wanted to play nice, this being brought on by some unknowing prior owner buying nearly everything in the Kenne Bell catalog, including a high volume pump that is completely unnecessary. This additional load ate the gears.

After a cam and lifter change and basically a total top end rebuild, I get this car back together and it runs and drives great at less than 1/3 throttle. It idles smoothly (except for occasionally going up 500 rpm and back for no reason at a light) and drives great until you put your foot into it. Then it stumbles or even backfires.

Changed the MAF as the values for it seemed low and I last changed it in 2002, and wow the problem was fixed for about 3 miles. Then right back at it again. WTF?

It acts lean, but T link shows the o2 values at 746, 804, 796, and 792 when it hit 3rd. The last 3 numbers are closed loop on the T Tweak chip. The 1st frame # is from a 15 mph rolling blast. Tps was 4.75 the whole time, and LV8 and MAF were both 255, and no trouble codes showing. NO knock at all.

Boost was at 15 psi solid the whole time, hitting 15.5 right before 3rd gear, then dropping to 14.

Fuel psi is @ 44 line off, FP does rise with boost. Idle vac ~16 or so in gear, steady.

After using my scantool as well as a friend's professional engine analyzer everything seems fine, except it didn't like the secondary ignition values. I am going to put fresh wires on it and regap the plugs @ .035 tomorrow, but my gut tells me there's more to this than that.

Any help would be awesome, if someone can help me get this thing running right again, I might decide to keep it. But this BS is making a coat of paint on the GN and ebay this spring real tempting. The 2010 Dodge Challenger isn't helping, either. At least I wouldn't be constantly fixing it.

Thanks for letting me vent, and thanks in advance for any help.

I've been thru many cars in my life. Some performance and some not. Either way, they break down man. They're machines, made by man, with many moving parts. Most of them purposely built to break down. I know I know, "newer cars don't break down as much as old cars." Bull****. They all break down man. Do you want to pay twice as much for a challenger part, just cuz it's the new rave? Screw that. The ride may be better in the challenger, but how much are they? The buick's still going to be cheaper overall. You just got to do the research before you pick a part and install it, or fix it, that's all.

Keep this in mind, they ALL break down...

[pdzz]

Chris I'm 20 miles from Rochester, about 80 miles from Buffalo. If you make it down this way, I would be glad to take a look for you. PM me if you drive out some weekend. Things to check.... If the car never exhibited the problems before the top end was re-built, maybe something was overlooked. Grounds on the back of the pass. side head.. clean, tight? Any of the ign. module terminals hogged out during dis-assembly, or re-assembly? Cam sensor set correctly? It almost seems when you replace a componet and it runs good for a little bit, maybe a connector or something is being disturbed to correct the problem temporarly. I hope this helps, but, offer still stands. Phil.

[ChrisF]

Thanks guys for all of the encouragement.

Phil, I am with ya. I am going to check all of the grounds and such again, but I am pretty confident they are all good.

Someone else mentioned the cam sensor being 180 out; but no one has answered the question: Will it idle and run good 180 deg out? I heard it wont idle well at all this way, but this car idles pretty good, and drives well too, until you ask it for any kick.

I think its in the fueling somewhere. It's lean. I am going to get with a buddy and really check fuel pressures on his engine analyzer instead of driving around with the fuel psi gauge taped to the windshield.

It runs too nice at 35% throttle or less to have something major wrong, I would think.

Thanks for the offer Phil! I don't want to drive it 80 miles busticated though. I would rather catch up when it's running good.

[ChrisF]

ttt

[84BuickGNYorkPA]

You need to have a friend with the same car come over and start swapping parts untill you find your problem. I had the same thing and it was the ECM (computer), I would offer Pdzz (Phil) some $$ to come over and start swapping parts out untill you find the problem.
The cam sensor is easy to set if you have a volt meter.
Vortex Turbo Buick Performance look at the "Tech pictures/Instructions" area. By the way this a top notch web site, it's in my "Favorites" on my computer, refer to this website all the time.

Chuck

[Sal 87WE2]

Originally Posted by Turbo6Smackdown

I've been thru many cars in my life. Some performance and some not. Either way, they break down man. They're machines, made by man, with many moving parts. Most of them purposely built to break down. I know I know, "newer cars don't break down as much as old cars." Bull****. They all break down man. Do you want to pay twice as much for a challenger part, just cuz it's the new rave? Screw that. The ride may be better in the challenger, but how much are they? The buick's still going to be cheaper overall. You just got to do the research before you pick a part and install it, or fix it, that's all.

Keep this in mind, they ALL break down...

Yea, i keep tossing the idea of installing a supercharger on top of my 6.1L Charger SRT-8 BUT why would i blow $6-$8 for a blower when i can spend the same amount and be waaaaay faster in the Buick?! And turn more heads too

If it makes you feel any better everytime i fix or touch something on my GN something else breaks, i am soooo tired of it but i keep working on it

Whenever someone comes over and they see the GN in the garage they always ask, "Is that a Grand National?" Makes me feel good about the respect and legacy it has.

I really hope you find your problem, i know i definately have problems of my own with my Buick.

-Sal

[ChrisF]

Anyone want to weigh in on the cam sensor question, being possibly 180 out?

[vacuum 6]

Originally Posted by ChrisF

Thanks guys for all of the encouragement.

Phil, I am with ya. I am going to check all of the grounds and such again, but I am pretty confident they are all good.

Someone else mentioned the cam sensor being 180 out; but no one has answered the question: Will it idle and run good 180 deg out? I heard it wont idle well at all this way, but this car idles pretty good, and drives well too, until you ask it for any kick.

I think its in the fueling somewhere. It's lean. I am going to get with a buddy and really check fuel pressures on his engine analyzer instead of driving around with the fuel psi gauge taped to the windshield.

It runs too nice at 35% throttle or less to have something major wrong, I would think.

Thanks for the offer Phil! I don't want to drive it 80 miles busticated though. I would rather catch up when it's running good.

Fueling issue, have you checked the pump's output?

Here's what I did...Walbro 255L/Hr HP fuel pump

[JDEstill]

Originally Posted by ChrisF

Anyone want to weigh in on the cam sensor question, being possibly 180 out?

My car idled and ran just fine with the cam sensor 180 out, but if memory serves (this was at least a decade ago) mine would get a little detonation at 12 or 13 psi boost. Getting the cam sensor set right gave me another pound or two boost before it started tickling the knock sensor. If you are really worried about it, it doesn't take very long to check...

John

[boostified]

My car idled fine, and ran out fine, until you opened the throttle blade past 1/2 way. Then it felt like a gorilla grabbed onto the flywheel or something. Did this twice and then it started knocking. When I tore it down, all the main bearings were trashed, along with the rod bearings. Long block is back together now, but I'm almost scared to put it back in the car. I hope some other guys have some ideas.

[KevinB]

Originally Posted by ChrisF

Anyone want to weigh in on the cam sensor question, being possibly 180 out?

Car will idle fine. Above 1/2 throttle is when the running issue appears.

Follow the gnttype process. It's very easy to install one 180 out by mistake. I've done it before. To make sure you have the engine on the right stroke, just remove the #1 spark plug, rotate engine by hand until you feel compression coming out of the spark plug hole. You now are on the compression stroke. When the crank and timing tdc mark line up, you have tdc. Go 25 degrees and set your sensor. Very easy to check. Just go out and do this process. My money is on it being 180 out. If it's not..you have at least eliminated it as the problem.

[boostified]

Do you think that alone could trash the bearings like that?