bad idle

[Syntist]

hey im new to the site and i have a few questions that i hope you can answer. im in the prosses of trying to buy a 91 syclone with 91,000 miles on the clock. the body and paint are good, only one little rust bubble about the size of a quarter on the box above the cladding. all the cladding is there and looks good. now the interior of it, the owner put an aftermaket steering wheel on, and a quarter stick shifter and, the drivers window wont roll down, other than that the rest of the interior is nice. the only thing holding me back is how it runs, when you rev it up and let off the rpm's drop way down and it wants to die, and on occasion it will. i was thinking it was a vacuum leak or somthing like that. the truck has no exhaust on it from the tranny crossmember back, could that have anything to do with it?
they want 8500 for the truck, what do you all think?

 

[100in6]

Re: bad idle

i think 8500 bucks for a sy that doesn't run too well and is starting to show rust with almost 100K miles is kinda high. the miss could be anythin from wires, plugs, and distributor to plugged injectors or computer. can all probably be fixed, but you may be able to find a nicer one that doesn't have the problems for about the same or not that much more money. sy's have been coming down in price lately, although a really nice one is still holding value. sy's can be troublesome, and i don't think i would buy one with problems because it can cost you more than you want to get it right. post on this board that you're looking and keep checkin the for sale section for a nice one. try to get one without too many modifications internally and do them yourself. that way you'll know how well things were done

 

[conlyn]

Re: bad idle

a bit of rust isn't a big deal, i mean afterall, it's all s10 sheetmetal.
and, as far as the idle goes...
i would have to hear it to be able to tell if it's missing, doesn't have enough FP, or it's just the typical rough-as-all-hell idle that most of these trucks have.
my typhoon shakes more at idle then my 72 nova with a built 396 and soild motor mounts
and it stalls sometimes going into stops too. :rant:

 

[Syntist]

Re: bad idle

whats color is the stock injector? the truck has a new turbo, new taylor plug wires, and the engine had a stock rebuild. the truck is at a local dealership so i might tell them to fix the idle or give me the diagnosis and i'll fix it depending on how much it is.

 

[SYO237]

Re: bad idle

The stockers are redtops.

Something to consider as well that most forget is that the low production number Sys (up to around 1200) had a slightly different stock chip that made the idle very rough (3086 if memory serves). This was later changed in the mid run numbers with a campain chip. Typhoons obviously never saw this problem.

As for the dealer, I would take what they say with a grain of salt. I havent heard of a dealer experience yet with these trucks that netted in positive results or correct diagnosis.

 

[100in6]

Re: bad idle

a bit of rust isn't a big deal, i mean afterall, it's all s10 sheetmetal

thats true. but it's amazing how much it can cost to get sheetmetal fixed. i'm startin to think the prima donnas of the mechanical world are body and paint guys. you're probably right about the rough idle. sy's never really idle good on stock chips. that's no biggie to fix. call phillip long and he can cure that problem for about 400 bucks and it'll run a lot better too. he might even just have a different chip for a bunch less too. might just see if the guy will come down because of the rust though

nova sounds cool. send me pics

les

 

[Syntist]

Re: bad idle

its not the dealer telling me that it was rebuild, the old owner is a tech at the gm dealership its at now. and people i know on a local car site know the kid. the production # is like 600 somthing.

 

[HotRudyRod]

Re: bad idle

My Sy (#1275) used to idle funny ( the tach's needle had a lil jump every engine turn ) when i first got it and it would also stall at sudden stops. I now have an Ultimate and Alki injection and it's hardly even noticeable anymore and it wont stall no matter how hard i get on the brakes. The former owner had told me some guy with very fast GNs told him it was cause these trucks have a very lean mix at idle.

 

[Syntist]

Re: bad idle

thats the same thing this ones doing, i have a laptop and ALDL cable that i can tune with, what is the program you guys tune with? i have a 90 454ss with a 489 stroker with a vortech supercharger. i also have a 68 nova that runs mid 10's, so i have no problem with working on car/tucks.

 

[HotRudyRod]

Re: bad idle

Most use Datamaster to tune, i have it but my tranny burned 1st gear clutches and didnt get time to tune anything. Its goin to be the chip whats making it jump around.

Good Luck.

 

[jwaller]

Re: bad idle

8500 isnt so bad if the running/bad idle isnt serious. it's going to be up to you to be able to diagnose the problem before you get to the bottom line.

 

[Syntist]

Re: bad idle

well i gave them an offer of 7500 and he accepted it so im thinking im getting it