Pontiac GTA Enhancement information and discussions with Technical DIY and performance tuning information for the hardcore Pontiac GTA Owners and Enthusiasts.
Forum | Register Now | Members | Search | How Do I... | Calendar

Go Back   The GTA Source Page Message Forums > GTA SPECIFIC > GTA TECH

GTA TECH Want to discuss technical topics about your GTA.... engine tuning, mechanical upgrades, problem areas, etc.? Then post it HERE!

Reply
 
Thread Tools Display Modes
Old 03-09-2015   #1
Roadrunner
87 GTA 305 Auto
 
Join Date: Feb 2010
Location: Cincinnati Ohio
Posts: 147


Weird Problem

Today I took my GTA out on a 140mi trip (70 each way).
When I started out, it ran fine & strong for ~30 miles then it started running rough - losing power and bucking.
When I tried to give it gas I got a lot of detonation.

I found if I downshifted and kept it above 2000 rpm, it would run smoother but not quite normal power.
It would idle ok but maybe a little rough.
Between idle and 2000 rpm, it would fall on its face power-wise (guessing severe knock retard).
Going up slight hills requiring more throttle, it would do OK as long as I was above 2000 rpm.
On highway in 4th it would go 70~80 mph OK but for 55~65mph I had to downshift to keep it above 2000 rpm.
Below 2000 rpm, it could not hold 55 mph on flat highway.

When I started on the return trip, it was doing the same but not quite as severe.
By the time I got home, the car was back to normal and now I can't find anything obviously wrong (of course).

The last time I had it on the road was a fair weather weekend in January.
When I started out today, it had 2~3 gal of gas left that was put in there January and I put in another 8 before starting my trip.

Car has no mods.
Injectors have #523530 on side (not sure if this is multitech).

I also noticed that whenever I shut the engine off there is a gurgling noise that sounds like its coming from gas tank and lasts 5~10 sec (it may have been there before but I never noticed).

Has anyone seen this before?
Roadrunner is offline   Reply With Quote
Old 03-10-2015   #2
rhomanski
The Born Loser
 
rhomanski's Avatar
 
Join Date: Nov 2010
Location: Southside Batesville Arkansas
Posts: 396



GTA Year: 1988
GTA Engine: 350 TPI Automatic
Re: Weird Problem

A bad MAF? Bad burn off relay. Most of the time when mine does something like that I pull over and shut it off and start it again. That gives the MAF a chance to clean itself. EGR to reseat itself or anything else that might be having trouble. In mine it was the burn off relay. Replaced the relay and it was fine for a while.

I don't know about the gurgling unless it's the engine coolant. When it's low they will sometimes gurgle as it drains down. That's a big problem with another vehicle of mine, the heater core is higher than the radiator so it's hard to get all the air burped out of it. Of course it could be the fuel tank. It does have a vent.
__________________
A Country Is Built On Cooperation
An Empire Is Built On Slaves
rhomanski is offline   Reply With Quote
Old 03-11-2015   #3
MunsonGTA
Bad luck or no luck
 
Join Date: Jun 2004
Location: Ravenna, OH
Posts: 1,948



GTA Year: 1987
GTA Engine: Custom
Re: Weird Problem

Sounds like the MAF sensor to me also. Did the ses light ever come on?
__________________
87 GTA: Forged 408 LSX short block, TEA stage 2 cnc ported 243 heads, BTR Stage 3 stroker cam, Fast 102 intake, NW 102 TB, Longtube headers, custom 411 ECM, custom harness, custom tuned, Performabuilt stage 2 4l60E with PTC 2800 stall, 9 bolt rear with 3.70 gears and TAP girdle.

11.16 at 123 mph.
MunsonGTA is offline   Reply With Quote
Old 03-11-2015   #4
Roadrunner
87 GTA 305 Auto
 
Join Date: Feb 2010
Location: Cincinnati Ohio
Posts: 147


Re: Weird Problem

Thanks - didn't think about MAF or EGR.
(I was thinking on the lines of some kind of vacuum leak or bad injectors)

Check engine light did not come on.
It was not running hot and cat didn't seem to be getting too hot.

From what I can tell, the injectors look like they may be original and are still painted black like they have never been cleaned. Car is pushing 125k miles so changing them has been on my to-do list.

In the meantime, I have been rooting around trying to find my old Actron scanner to keep in the car with me in case it does it again.

Would either MAF or EGR problem throw a code?
If it is the MAF, do these ones hang on for a long time with intermittent problems before dying?
Roadrunner is offline   Reply With Quote
Old 03-12-2015   #5
rhomanski
The Born Loser
 
rhomanski's Avatar
 
Join Date: Nov 2010
Location: Southside Batesville Arkansas
Posts: 396



GTA Year: 1988
GTA Engine: 350 TPI Automatic
Re: Weird Problem

EGR will almost always give a code. The computer will cycle the EGR system everytime you start the car to test it. If all is good it says nothing. Otherwise it will light the SES light. Mine didn't affect driveability hardly at all. When the MAF burn-off relay starts to go it becomes intermittent. One time the engine will run fine and then the next it will run horribly. Stopping and restarting the engine will fix it for another time. Replacing the relay will fix it permanently. I think The relay is 10$ or so. Get it from GM and replace the other one as well. The MAF sensor is several hundred dollars so try the relays first.

Injectors will usually make it run poorly with a miss and poor gas mileage but won't usually cause it to bog and buck like the MAF does. Yesterday I walked to the back of mine after shutting it off and heard a gurgling sound from the gas tank area as well. It lasted about 5 seconds and stopped. It's just the fuel coming back and releasing the pressure from the lines.
__________________
A Country Is Built On Cooperation
An Empire Is Built On Slaves
rhomanski is offline   Reply With Quote
Old 03-17-2015   #6
Roadrunner
87 GTA 305 Auto
 
Join Date: Feb 2010
Location: Cincinnati Ohio
Posts: 147


Re: Weird Problem

Thanks for the advice.

Scanner showed no codes and nothing appears out of the ordinary.
Car has been running strong so far.
Still planning to change relays as suggested though.
Roadrunner is offline   Reply With Quote
Old 04-03-2015   #7
Roadrunner
87 GTA 305 Auto
 
Join Date: Feb 2010
Location: Cincinnati Ohio
Posts: 147


Re: Weird Problem

Since last post, I replaced both relays.
Tried to order from GMpartsdirect but when I went to check-out, shopping cart said one of them is discontinued and no longer available.
I was able to order both from GMpartsgiant though (10094701 & 10067925).
Top casing was shaped a little different from original, said "Made in China" and the power relay had an additional extension bracket riveted to it that I didnt need.
I ended up re-using the original top casing and just replacing the lower/interal part to keep original appearance.

A week later, I re-started car after driving a bit and it would stall whenever I took my foot off the gas.
This time it came up with a code 34.
Has been running fine since that time though.

So it looks like I am in MAF hell at the moment - not sure if a replacement will be better than the intermittent one that is on the car (it is Bosch and "Made in Germany").

Also I noticed it still has a K&N air filter that has to be oiled.
I am not a fan of having oil upstream from a MAF sensor and I thought I had changed this years ago but must have forgot.
Roadrunner is offline   Reply With Quote
Old 04-03-2015   #8
86TA355SR
Registered User
 
Join Date: Oct 2012
Location: IN
Posts: 552


Re: Weird Problem

A MAF sensor virus must be going around this board. I had issues this week also. Luckily when I got the code I had an extra MAF in my tool box from year ago. Swapped it out and no issues yet.

Hard to compare mine to your problem because I had another issue. It fell on its ass during the test drive after the MAF change which caused me to look for other issues. I found a set of original plug wires, cap and rotor also (car has 26K miles). The wires were literally falling apart. I can't believe it even ran. Ripped all of it out, took the module out and cleaned it, replaced grease, put new rotor, cap wires and plugs in it.

Runs great now.

Hope you figure out the issue. Keep us posted.
__________________
1991 GTA, SLP Perfomance Package
1989 GTA, 26K Original Miles
1988 GTA, Stock
86TA355SR is offline   Reply With Quote
Old 03-21-2016   #9
Roadrunner
87 GTA 305 Auto
 
Join Date: Feb 2010
Location: Cincinnati Ohio
Posts: 147


Re: Weird Problem

Never expected this - distributor pick-up coil rotted out.
Anyone have this happen before?



I could see it if the car had been abandoned in a bog for years or if hood weatherstrip & distributor cover were gone but everything is in place, relatively clean & no rust.

Not sure if its related to the previous problem I had.
Symptom was bogging down and losing power a couple times. It would clear itself up after a few minutes.
Then one day it became a constant problem. Parked car for a while, changed injectors, cleaned TB & EGR, and when I tried to start again there was no spark at all.

After I took it out of car, it puked out some of these little triangle notches.



Shaft felt fine and did not have excessive side play.
All I can figure is maybe previous owner got water in distributor when cleaning engine.
Roadrunner is offline   Reply With Quote
Old 03-21-2016   #10
90 L98 TransAm
Registered User
 
Join Date: Mar 2006
Posts: 465


Re: Weird Problem

I wonder if those triangle notches you are holding are the tips of your reluctor?

here's what mine looked like:





I was shocked when I saw the rust inside there on a garage kept rust-free car.
90 L98 TransAm is offline   Reply With Quote
Old 03-21-2016   #11
DynoDave
Registered User
 
DynoDave's Avatar
 
Join Date: Mar 2015
Posts: 259


Re: Weird Problem

Dang. That is a mess RoadRunner. What the heck?

And 90 L98 TransAm...I had not planned to pull the cap on my all original '88 with approx. 55k miles. But I guess I had better!
__________________
DynoDave
1988 Pontiac Trans Am
POCI #72200
DynoDave is offline   Reply With Quote
Old 03-21-2016   #12
90 L98 TransAm
Registered User
 
Join Date: Mar 2006
Posts: 465


Re: Weird Problem

Quote:
Originally Posted by DynoDave View Post
And 90 L98 TransAm...I had not planned to pull the cap on my all original '88 with approx. 55k miles. But I guess I had better!
Yeah - my car had ~60K miles when those photos were taken.
90 L98 TransAm is offline   Reply With Quote
Old 03-21-2016   #13
rhomanski
The Born Loser
 
rhomanski's Avatar
 
Join Date: Nov 2010
Location: Southside Batesville Arkansas
Posts: 396



GTA Year: 1988
GTA Engine: 350 TPI Automatic
Re: Weird Problem

Another thing to look at is the throttle position sensor. You can put a meter on it and do the adjustment or just pull it and check the resistance. In either case your looking for a smooth transition. If the meter drops out and then comes back with a reading as you move the arm, it could be bad.
__________________
A Country Is Built On Cooperation
An Empire Is Built On Slaves
rhomanski is offline   Reply With Quote
Old 03-22-2016   #14
Roadrunner
87 GTA 305 Auto
 
Join Date: Feb 2010
Location: Cincinnati Ohio
Posts: 147


Re: Weird Problem

Quote:
Originally Posted by 90 L98 TransAm View Post
I wonder if those triangle notches you are holding are the tips of your reluctor?
Yep - that's what they are.
I'm amazed that it was still running considering how easily they broke off - err no wait...it wasn't running LOL
Roadrunner is offline   Reply With Quote
Old 04-29-2016   #15
JonBlake
Hopefully soon to be restored Third Gen owner.
 
Join Date: Apr 2016
Location: Pacifica, CA
Posts: 251


Re: Weird Problem

Quote:
Originally Posted by Roadrunner View Post
Never expected this - distributor pick-up coil rotted out.
Anyone have this happen before?



I could see it if the car had been abandoned in a bog for years or if hood weatherstrip & distributor cover were gone but everything is in place, relatively clean & no rust.

Not sure if its related to the previous problem I had.
Symptom was bogging down and losing power a couple times. It would clear itself up after a few minutes.
Then one day it became a constant problem. Parked car for a while, changed injectors, cleaned TB & EGR, and when I tried to start again there was no spark at all.

After I took it out of car, it puked out some of these little triangle notches.



Shaft felt fine and did not have excessive side play.
All I can figure is maybe previous owner got water in distributor when cleaning engine.
Wow that's bad. Looks almost like flood damage. I've seen boat motors with damage like that. What would cause such deterioration?
JonBlake is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Weird weird problem with the GTA quickbird144 GTA TECH 15 06-13-2012 06:16 PM
Weird Problem wilkink GTA TECH 16 01-19-2012 09:01 PM
Headlight problem tandy806 GTA TECH 4 03-31-2007 10:33 PM
are you ready for a problem boys? 87 transam gta GTA TECH 11 06-03-2004 08:49 PM
weird problem 88BlackGTA GTA TECH 2 04-08-2002 12:02 AM


All times are GMT -5. The time now is 08:45 AM.


Powered by vBulletin® Version 3.8.5
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.