 
     |
| 1986 GT stumbles badly off idle (Page 1/4) |
|
balaseca
|
APR 17, 05:46 AM
|
|
Hello everyone!
I recently purchased an 86 GT (2.8L, Muncie 4 spd) that hasn't been on the road since 2010. I've gotten it running and driving. New brakes (calipers, rotors, hoses), fuel tank repaired, new sending unit/pump assembly from Rodney, oil change (10W30, MG filter), new temp sensor and connector from TFS, new Oil Sender switch, cleaned plugs, and timing checked in diagnostic mode (~ 10 deg BTDC). I did run a can of Berrymans through the fuel system before the full repair of the gas tank as well.
Now, the car starts and idles wonderfully. However, once its warmed up, it really wants to bog and stall from idle/stopped. The other issue I have is that it has very little power on acceleration.
What could be my issue(s)?
|
|
|
Filben
|
APR 17, 08:56 AM
|
|
| quote | Originally posted by balaseca:
Hello everyone!
I recently purchased an 86 GT (2.8L, Muncie 4 spd) that hasn't been on the road since 2010. I've gotten it running and driving. New brakes (calipers, rotors, hoses), fuel tank repaired, new sending unit/pump assembly from Rodney, oil change (10W30, MG filter), new temp sensor and connector from TFS, new Oil Sender switch, cleaned plugs, and timing checked in diagnostic mode (~ 10 deg BTDC). I did run a can of Berrymans through the fuel system before the full repair of the gas tank as well.
Now, the car starts and idles wonderfully. However, once its warmed up, it really wants to bog and stall from idle/stopped. The other issue I have is that it has very little power on acceleration.
What could be my issue(s)? |
|
I would start with a new coil, cap, rotor, wires, and plugs to rule them out.
|
|
|
Vintage-Nut
|
APR 17, 09:01 AM
|
|
|
Did you install a new air filter? ------------------
Original Owner of a Silver '88 GT
Under 'Production Refurbishment' @ 136k Miles
|
|
|
|
balaseca
|
APR 17, 10:11 AM
|
|
The airbox is another issue. The genius that owned it before me stuck a cone filter on the end of the stock tube that goes to the throttle body (finding a new stock filter housing isn't fun).
I've looked at the cap and rotor and they don't look worn at all.
|
|
|
|
fierosound
|
APR 17, 10:18 AM
|
|
|
|
|
balaseca
|
APR 17, 11:42 AM
|
|
|
@fierosound - Brand new pump and sending unit from Rodney.
|
|
|
|
cartercarbaficionado
|
APR 17, 12:58 PM
|
|
| quote | Originally posted by balaseca:
Hello everyone!
I recently purchased an 86 GT (2.8L, Muncie 4 spd) that hasn't been on the road since 2010. I've gotten it running and driving. New brakes (calipers, rotors, hoses), fuel tank repaired, new sending unit/pump assembly from Rodney, oil change (10W30, MG filter), new temp sensor and connector from TFS, new Oil Sender switch, cleaned plugs, and timing checked in diagnostic mode (~ 10 deg BTDC). I did run a can of Berrymans through the fuel system before the full repair of the gas tank as well.
Now, the car starts and idles wonderfully. However, once its warmed up, it really wants to bog and stall from idle/stopped. The other issue I have is that it has very little power on acceleration.
What could be my issue(s)? |
|
you still got a cat? if so loosen the downpipe just infront of it, as for low power our 88 has had that for awhile and i reccomend checking your valve lash and egr pipe and then checking vacuum signal from there should be ~16 inches of vacuum if its stock with a dead steady needle
|
|
|
|
Patrick
|
APR 17, 01:04 PM
|
|
| quote | Originally posted by balaseca:
The airbox is another issue. The genius that owned it before me stuck a cone filter on the end of the stock tube that goes to the throttle body (finding a new stock filter housing isn't fun).
|
|
Is the IAT sensor connected? If so, where is it located (since it appears you no longer have the OEM air box in place)?
| quote | Originally posted by balaseca:
Brand new pump and sending unit from Rodney.
|
|
"Brand new" means next to nothing. Check the fuel pressure.
| quote | Originally posted by balaseca:
...timing checked in diagnostic mode (~ 10 deg BTDC).
|
|
Did you check to make sure that 0° on the timing scale actually lines up with the wide timing mark when #1 cylinder is at TDC? It's rather common for the outer ring of old harmonic dampers to slip... thus throwing off all the timing marks.
If all that checks out okay, I'd check the TPS next.[This message has been edited by Patrick (edited 04-17-2025).]
|
|
|
|
balaseca
|
APR 17, 01:18 PM
|
|
The car currently does not have an IAT installed (on the list to be rectified). Plan is to temporarily zip tie it at the filter.
I will check the fuel pressure.
The timing mark and the scale line up well. I dont think there's been any slippage.
As to EGR, there are blockoff plates on both the intake and exhaust, no tube or valve there. The solenoid is plugged in, but one vacuum line is pluged with a small screw and the other still travels under the intake.
The car does have a Cat, and I've been thinking that may be of some issue.
|
|
|
Patrick
|
APR 17, 01:28 PM
|
|
| quote | Originally posted by balaseca:
The car currently does not have an IAT installed (on the list to be rectified).
|
|
Well, that's no good. The ECU relies on it for temperature readings of intake air.
| quote | Originally posted by balaseca:
The timing mark and the scale line up well.
|
|
Line up well with what? Did you actually check to make sure the piston was at TDC. (Use something like a plastic straw inserted through the spark plug hole.)
| quote | Originally posted by balaseca:
I dont think there's been any slippage.
|
|
I don't think you're trying hard enough.  [This message has been edited by Patrick (edited 04-17-2025).]
|
|
|
|
