New Buick Owner Bad Idle

[s3dcollier]

Hi, new to the Buick Turbos, have always wanted one, now I got one. Purchased an 87 Buick T-Type, had a little bit of a bad idle, was told that it was the exhaust leak when I bought it, but the guy supplied the repaired Header (Drivers side) to fix it. We'll I have since replaced that and ended up welding the original due to the one he gave me having some warpage on the outlet. Any way I have a small ticking sound (small leak now) however the idle still hasn't gotten any better. I have a scan tool on the dash and this is what I see, however the gntype.org is down so I am stuck on viewable documentation on this car.

Here's what I have:

RPM - jumps 775-825 at idle
TPS - .42 - .44
IAC - 64 - 65
CC - changes from 177, 194, 210....
nal - 13
AF - 06 - 05
L8 - 38 - 41
Bat - 13.6
Int - 129 - 141
BL - 125
CLT - 148 - 160
ATS - 97

I have cleaned out the throutle body, cleaned the IAC, replaced all vacuum lines, it has a new gas filter, new plugs, wires.
Car gets up and goes, sometimes chokes when first started and given gas in gear to go. I have noticed 2 bent fins on the turbo fan going into the turbo that I don't think is related to this issue. Car shifts hard from 1st to 2nd and chirps tires. I need to fix the idle issue first, would the bent fins be a bad thing to leave as is for a while? Not sure if the turbo outlet hose being blown half off caused this fin bending or not, the fan doesn't seem to have much play in it. Any help would be great. Thanks

Scott
s3dcollier@earthlink.net

 

[1ARUNEM]

Get the IAC down to around 20 and go from there. 60 range is a bit high.

Good luck.. and congrats on the purchase!!

 

[pacecarta]

gnttype is up again

http://www.rennie-macintosh.com/

 

[turbojimmy]

Originally posted by pacecarta
gnttype is up again

http://www.rennie-macintosh.com/

Yes and the search engine works, too. Just replace the "gnttype.org" in the search results URLs with "rennie-macintosh.com".

Jim

 

[Marc87GN]

I also just bought my first 87 GN on 6/10 and it had a bad idle. I found the TPS was set to .51 and the fuel pressure was set to 54 psi with vacuum line off. I set the TPS to .43 and the FP to 44 psi and it would idle lower, but was missing badly. I checked the resistance across the secondary windings on the coil pack and this is what I found: 11.85, 11.72 & 25.00-18.00 kohms. 2 cylinders are barely firing if at all. I ordered a coil pack and 10mm wires & replaced the plugs. Since you replaced the wires & plugs, check the resistance of the Primary & Secondary windings of the coil pack.

 

[turbojimmy]

Originally posted by Marc87GN
Since you replaced the wires & plugs, check the resistance of the Primary & Secondary windings of the coil pack.

My brother's car has a similar problem. How do you check the windings? I have a DVOM but I'm not sure what to check.

Thanks,
Jim

 

[Marc87GN]

Originally posted by turbojimmy
My brother's car has a similar problem. How do you check the windings? I have a DVOM but I'm not sure what to check.

Thanks,
Jim

Set your DVOM to ohms or Kohms and remove 2 plug wires on the same coil. They should be adjacent to each other. Touch the leads to both contacts at the same time and you should get a reading of 11.00 - 13.99 kohms if they haven't started breaking down. This is to check the secondary windings.

The primary windings, which creates the magnetic field around the secondary windings, is tested by removing the coil pack.

 

[scottyb]

Congrats!
Most numbers look proper except for IAC and MAL. I don't know how to handle a 13, gnttype says "oxygen sensor circuit open". Is that bad sensor or sensor unplugged????

Many good TR peoples in the Orlando area. You will get better local action on turbobuick.com, except add an 's' to have plural buicks.

 

[turbojimmy]

Originally posted by Marc87GN
Set your DVOM to ohms or Kohms and remove 2 plug wires on the same coil. They should be adjacent to each other. Touch the leads to both contacts at the same time and you should get a reading of 11.00 - 13.99 kohms if they haven't started breaking down. This is to check the secondary windings.

The primary windings, which creates the magnetic field around the secondary windings, is tested by removing the coil pack.

Thanks. I just swapped out the coil pack and module with ones that I had laying around. Didn't change the behavior at all. Might've made it worse actually (there's a reason those parts were on the shelf and not under the hood I guess). Idles rough and stumbles off idle. DS doesn't show anything obvious. The numbers look a lot like the original poster's numbers but my IACs are mid-high 20s.

Jim

 

[s3dcollier]

I checked the Coil, each set ranged from 12.4 kohms to 12.69 kohms. The left set was the lowest, while the other 2 sets were about the same around 12.69. My oxygen sensor is not unplugged, I could remove it to see how much carbon build up is there. I am not exactly sure how to adjust the IAC. I did notice that there is a tube stem coming off the bottom of the throttle body that has nothing plugged into it and nothing around it looks like it goes to it. There doesn't seem to be any suction or pressure coming out of this tube however thought I needed to point it out. Could it be a leaky injector, can they be cleaned or should I just replace them. I would like to put green strip injectors on it. Was watching ebay for a good deal on a low mile set in case this didn't fix my problem.

 

[mrwiizrd]

Steve Wood's site is a great source for IAC adjustment, click on the "IAC Adjustment" link at the top.

http://www.vortexbuicks-etc.com/tuning.htm

 

[1 RARE T]

1. You need a new o2 sensor.

2. Pull the grey plug off the throttle body (dr.side) to find the I.A.C. adjustment screw. Turn it in to lower #'s.

Be patient it takes a bit to adjust itself and give a new #.

Some say to restart the car after each time.

Watch the T.p.s. because it too will have to be reset after.

Mike

 

[murphster]

After putting in a new o2 sensor and playing with the IAC and TPS settings, you should be able to get a better idle.

Also, the IAC #'s will go up if you are in drive. I believe those are normal numbers in drive, but in park should be closer to 15-30 or so.

If all said and done the idle still isn't good, you may want to try a chip with an open loop idle. My idle was ok before, but still jumped around a little. Changing to an open loop idle chip (turbotweak) made it much better. The Thrasher chips are open loop idle too and are a good deal.

 

[Turbo6inKY]

Originally posted by s3dcollier
I have noticed 2 bent fins on the turbo fan going into the turbo that I don't think is related to this issue.

Exactly WHICH fan are these two bent fins on?

 

[s3dcollier]

The bent fins are on the driver side of the turbo (inlet area). Can I just replace that without doing a rebuild. I am sure it's effecting my boost. The hose coming off the turbo has come off 2 times now and am not sure if that may have caused it. I will be ordering a new hose probably after next paycheck.

I replaced the o2 sensor today, the idle seems to still be fairly close to what it was, maybe a little better. The idle will sometimes stay consistant for a small amount of time then go back to up and down then correct itself. Numbers have changed slightly:

af - 06 -07
l8 42 - 55
bat 13.3
int 123-135
bl 115
clt 160 - 182
ats 103
r 750 - 875 until it really jumps occasionally up to 900+ down to 650
tps .46
iac 78 - 81
cc 5 - 222
nal 00
first data on left side of scan master 210 -781 looping - no data on right side.

I have tried adjusting the screw on the bottom of the throttle body, however no changes occur. I am sure the screw is turning, it is pretty far in now.

 

[Danster]

Your IAC numbers are out of whack. Reset (reprogram/adjust)your IAC and TPS and then see what the idle is doing.

Dannyo