bad idle and poping at 2500 rpm but no knock

[daver]

this is my last resort guys . ijust don't have any other ideas. Ihave 87gn heavily mod. Ihave recorded multiple runs on direct scan in my garage w/ e-brake. i bring car up to 2400-2700 rpm 2-6lbs boost if that . starts to break up and pop but no backfire. the warmer car gets the easier and quicker it comes in even at 0 boost. idle is rough most of time. i have twk alc chip in now but also i try to put full thr. ext/pro chip in and soon as i put car in gear that chip wants to die so im using the turbotweak chip for now since the car will run. direct scan shows all vitals look great except the o2 values go crazy when sputerring starts but i think this would only be normal. here's what ive checked so far

bypassed dis4
plug+wire swap
coilpac swap
ign. mod swap
put stk maf back on instead of 3.5 ls1
swapped main computer
tryed all 3 chips i have
fuel pres. at wot holds good
plugs look good
readjusted cam sensortwice with caspers tool
checked cam sensors ring and cap ok
i fixed exhaust leak at croossover on my hye tech per. headers
i actually thought this was the fix but it wasn't
could it be head gasket?
i also thought about crank sensor but i think it wouldn't run and its not loose.
tps has no dead spots
maf goes up steady
voltage holds at 13.7 -14.3v
one other thing i noticed is when car is really warmed up on the road 10-15 mins driving that overdrive will really make car vibrate and shake until i put it in 3rd then its not as bad. this could be related but i thought this was strange.
but never no knock on direct scan or scanmaster ANY IDEAS

 

[84BuickGNYorkPA]

Take the time to give us a signature to see your mods. First thing that I would do is a compression test, that will tell you what your working with. While your plugs are out replace them, only a few bucks. After you get your engine warm replace the O2 sensor(got to wrench on this while the exhaust manifold is hot to get it out) The O2 are not that exspensive and another prime suspect, replace with a AC Delco if you can find one. Get your modifications in your signature, and keep this thread updated with your progress.... Good luck and welcome to the board!

Chuck

 

[daver]

hey chuck ,here is the list of my mods
87 gn
109 block .030 over
trw forged pistons
center 2 billit mains
stock crank
hi vol. oil pump 15-20psi idle hot 10-30w
stock irons ported 1.77, 1.6exh.
stock pushrods
stock rocker shafts with roller lifters for comp c. 206-206 roller cam
stock intake ported by myself
k.b. upper
k.b. 65mm thr body
eastern perf. 2.5 " front mount - old one
te61 turbo w/ precision .82 exh. housing
3" terry h. down
2.5" atr s.s. duals
hye tech per. headers and crossover
no cat w/dump
heated o2 i replaced recently
esp coilpac
dis4 ign.
stk. computer w/ chips from turbo tweak and full throttle
smc alc kit
Ls1 3.5 maf w/ generation 2 translator from full throttle
reds double pumps
55lb siemans
stock lines
2004r built by dynotec in n.j.
9.5" vigilanti 3000 stall multi disc
rear end girdle
stock axles and 3.42s
hotchkis sway bars and lowers
comp. enginer. adj. shocks
volt booster
scanmaster -old one
direct scan and laptop
11.0 @ 124 , 1.80 60', 25 lbs boost

hope this helps

the more i think about it i think its not a head gasket but probably still an exhaust leak at the head or leak at the lower intake gasket

 

[mikestertwo]

1) Do a compression check. If it's popping in the exhaust, could be a head gasket.
2) Get rid of the volt booster. Can cause electronic failures. Been there, done that got the t-shirt.

 

[daver]

hey mikestertwo,
thanks for the info

i will do a compression test

any other ideas?

 

[84BuickGNYorkPA]

1) Do a compression check. If it's popping in the exhaust, could be a head gasket.
2) Get rid of the volt booster. Can cause electronic failures. Been there, done that got the t-shirt.

In the Buick Club I'm in, a fellow member was having problems and it was the volt booster.

Chuck

 

[daver]

chuck,

what symptoms did u or they have with the volt booster. ive had mine for 10 years from red armstrong. on direct scan my volts during my problem are steady and linear13.5-14.2v. i think u are saying that the v.b. could cause other elec sensors to go up or get fluctuations, if so would i see it on direct scan because i have no codes and d scan is telling me everything is fine. if anyone else has had problems traced back to volt booster please ring in.

thanks , dave

 

[Blazer406]

You got a ds log of this popping? if so... send it to me....

bdykes@beabulldog.com

 

[daver]

hey blazer406

yes, i do have 5 or 6 recorded runs on direct scan
all with emergency brake on
i will send them to you as soon as i can

thanks in advance, dave

 

[84BuickGNYorkPA]

chuck,

what symptoms did u or they have with the volt booster. ive had mine for 10 years from red armstrong. on direct scan my volts during my problem are steady and linear13.5-14.2v. i think u are saying that the v.b. could cause other elec sensors to go up or get fluctuations, if so would i see it on direct scan because i have no codes and d scan is telling me everything is fine. if anyone else has had problems traced back to volt booster please ring in.

thanks , dave

Dave,

Sorry I don't recall, but at the track they unhooked it and it ran much better, he is on turbobuick.com and if you post in the MAGNA (Mid Atlantic Grand National Assoc.) You will get some answers.

Chuck

 

[Clark6]

whats the fuel psi at idle? (poppin means lean or too much air)
bad idling could be the coil pack but maybe you need to try a different maf, I had to try 3 before mine quite runnin rich & surging. I also changed the o2 sensors. but it was my maf. with the battery unhooked of coarse.
bad idling could be maf or too rich, and stumbling. but i doubt somethings wrong with the ls1 sensor i was thinking about gettin me one of those asap
im wonderin if i should get the Lt-1 or the Ls-1 and trans+.

 

[84BuickGNYorkPA]

Dave,

Do a compression check first, what state are you in? There may be a good Buick mechanic close by, I'm lucky over here, lots of good knowledgeable people around this area.

Chuck