I recently purchased an 86GN. The gentleman i bought it from said it sat in his garage for quite sometime.. I changed all the fluids plugs and wires. Since i bought it it seems to run very rough, upon startup it idles high for the first 5 seconds or so, the it dips down to almost stalling and runs very rough, and stalls when shifted into gear. Once she warms up its better i can shift into gear but shes still rough running and likes to stumble when i accel then smooths out after it gets up in the rpms.. The car is stock except for k&n and inlet pipe... Im very new to these cars and im not sure if a chip would helpp, nor do i know what kind and where to get it.. I also see alot about a scanmaster is this a must and also who carrys it? Sorry to ramble on i just wanted to describe in detail whats was going on... I appreciat any help.
86 GN stalls when cold/runs rough
- Thread starter djj624
- Start date
murderedout87
New Member
- Joined
- Jan 26, 2008
subscribing, mine doesnt really run rough, but it does stall sometimes when i first put it into reverse. id like to know as well. Im guessing its something a maf translater and new pipe would fix
BetMinesFaster
Turbo LSX Trader
- Joined
- Aug 7, 2007
The first thing I can suggest to the both of you i to do is to do a search on spring cleaning on this board, its basically a list of must do's to keep these cars happy. you can throw parts at them all day long when they run poorly but many problems can cause the same symptoms. Its best to start with the easy stuff, AKA the spring cleaning, making sure those bases are covered, then proceed from there, vaccum leaks, things of that nature, there is a wealth of knowledge on this board and you will likely find the help you need, but start with the spring cleaning...HTH, Ryan
As far as the scanmaster goes, heres a link
FULL THROTTLE SPEED - Items Page
Most anything you need for these cars can be purchased from the following places:
FULL THROTTLE SPEED - Store Front Page pretty much everything
GBodyParts.com Online pretty much everything
TurboTweak Home chips, injectors and such
As far as the scanmaster goes, heres a link
FULL THROTTLE SPEED - Items Page
Most anything you need for these cars can be purchased from the following places:
FULL THROTTLE SPEED - Store Front Page pretty much everything
GBodyParts.com Online pretty much everything
TurboTweak Home chips, injectors and such
I would clean the injectors, clean throttlebody and your IAC, check with a scantool and reset your IAC/TPS, check the PCV valve to make sure it's working, and eliminate any vacum leaks you may have. I would also update the computer chip to a TT chip or some of the others that are available.
Well i went over to my garage today to look at things more closely. I pulled the inlet tube off, looked at the mass air, checked the TB ect ect. I put everything back started her up and she ran normal no problems at all except for an overly rich condition. I looked around and noticed i forgot to plug the mass air back in, as soon as i did she started to stumble and act up again, disconnected it and shes good.. Im guessing the mass air is bad. Is there any way to clean it?
Is your SES engine light on? With the mass plugged in and the car running, lightly tap on the mass air flow sensor, it will stumble or stall the car when they go bad. Aftermarket replacement rebuilt mafs i found to be horrible, I went through quite a few of em, they're junk in my opinion. I would buy a maf translator and a 3" LT1 or a 3.5" LS1 mass air flow sensor and never have to worry about the MAF.
stack1
Senior Stacker
- Joined
- Oct 7, 2006
Hopefully you can find someone local that has a good known MAF to try on your car. Even if it turns out to be the MAF. You'll need to upgrade the stock fuel delivery. A Walbro 340 fuel pump with hot wire kit is a must. I'd replace the stock injectors and get an adjustable fuel pressure regulator also. Then order up a Turbo Tweak chip and you'll be good to go.
Edit: You mentioned getting a Scanmaster, you needed that when you bought the car. Get it now!!!
Edit: You mentioned getting a Scanmaster, you needed that when you bought the car. Get it now!!!
I recently went thru the same scenario you are,just purchased,sat for a while yadda,yadda.Spring cleaning is a must do.I went one step further and replaced all the vac lines I could get my hands on and yet still had a small stumble and was pulling 10in at idle(see title Vacuum woes at bottom of screen).Anyhow thru the process of elimination concluded that the EGR was shot.Crimp the line smooth as silk,plug back in same old song and dance.Don't make my mistake and overlook the obvious,It'll drive you nuts! Good luck....
johnnyttype
Active Member
- Joined
- Apr 18, 2007
the translator allows u to run a modern MAf sensor on our not so modern cars. they are way more reliable than the stockers. i recently changed over to a Lt1 MAF and translator setup because i had just finished off my 5th stock MAF in the cars life
two of them died the way u have described! hth!I'm not sure about cleaning it...maybe do a search. However, when my MAF was going bad, the car was hard to start. Well, not really hard, but it took 2 or three tries instead of the usual one. When it finally died, it ran real bad. Did a lot of coughing like it wanted to die out. So I don't think the problem is your MAF. My 86 runs like yours. I think an updated chip would do wonders, either from Full Throttle or Eric Marshall. Good luck and let us know how it turns out.
johnnyttype
Active Member
- Joined
- Apr 18, 2007
if he unplugged the MAF sensor and all was well, then plugged back in and car ran bad again... i'd say the mass air flow sensor needs to be replaced. i have had two of my five die this exact way! two more of them died by throwing massive amounts of fuel into the engine, and the last one just stumbled under load! stockers suck! just my experiences:biggrin:
oh and yes u can try to clean the MAF with some MAF safe cleaner for advance auto or napa.
oh and yes u can try to clean the MAF with some MAF safe cleaner for advance auto or napa.
I think it depends on how bad it ran with the MAF plugged in. Mine was so bad I couldn't drive it. It sounds like his isn't that bad, so it could be something else. He might have to try a known good one to be sure.
Heres the deal.. The car does take about 2 tries to start sometimes on the first. It stumbles and lopes, clears up then stumbles again eventually evening out to a rough idle, shift into gear and she will stall until she warms up... As far as driving wether i put her into reverse or drive when i give it gas she stumbles then goes somewhat smooth... When i unpluges the mass air it stumbles then comes up to idle and revs very smooth(drives like **** and very rich) When i go to plug the mass air back in it immediatly wants to die then comes up to the normal stumbling and loping then rough idle...
johnnyttype
Active Member
- Joined
- Apr 18, 2007
i hear ya
he should def. try a known good unit if one is available. ive just had MAF's that were bad all the time, sometimes, and ones that magically would fix themselves, thats why i said that the stockers suck...just bad experiences the one that sounds like his would run completely horrible on cold startups and then once the car was warmed up it would not be noticable anymore. when cold it was a very up and down idle, almost dying one time and then the next RPM dip or putting into gear it would stall!
the translator allows u to run a modern MAf sensor on our not so modern cars. they are way more reliable than the stockers. i recently changed over to a Lt1 MAF and translator setup because i had just finished off my 5th stock MAF in the cars life
When my stocker died I also went with the LT-1 MAF/translator. A buick mechanic (who bought an 87 GN new and still owns it) told me the stock MAF's were no good from day one....and he should know.
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