Rough running tpi
08-11-2015, 08:45 PM
#1
Member
Thread Starter
Join Date: Nov 2013
Posts: 112
Likes: 0
Received 0 Likes
on
0 Posts
Car: 85 Trans Am
Engine: 5.7TPI
Transmission: 700R4
Rough running tpi
Hi. Haven't driven my 85 Trans am in about a couple weeks took it for a burn today and is running pretty rocky at about 3000rpm. And idling a bit rough and seems to have a bit of power loss. It's a 91 350TPI. Any suggestions on where to start? Looked under the hood and everything appears fine. Battery wasn't dead or anything so I don't believe I wiped out the computer and gave it fresh gas to rule out bad gas. Any help would be greatly appreciated because no performance shops locally know how to tune this motor.
Thanks so much.
Thanks so much.
08-11-2015, 09:10 PM
#4
Member
Thread Starter
Join Date: Nov 2013
Posts: 112
Likes: 0
Received 0 Likes
on
0 Posts
Car: 85 Trans Am
Engine: 5.7TPI
Transmission: 700R4
Re: Rough running tpi
No check engine. When the motor swap was done last year there was no communication between interior and engine harness. So the engine light bulb was pulled. Car ran great when I parked it then today not so much lol
08-11-2015, 09:24 PM
#6
Member
Thread Starter
Join Date: Nov 2013
Posts: 112
Likes: 0
Received 0 Likes
on
0 Posts
Car: 85 Trans Am
Engine: 5.7TPI
Transmission: 700R4
Re: Rough running tpi
Hmm I will definitely change the fuel filter and see how that goes. Cat is a brand new magniflo so hopefully not cooked. Once I pass about 4000rpm it clears up and runs smoothly but still a bit of power loss but no hesitation would be the best way to explain it lol
08-11-2015, 11:29 PM
#7
Junior Member
Join Date: Apr 2015
Location: New Mexico
Posts: 62
Likes: 0
Received 0 Likes
on
0 Posts
Car: 1991 Z28 Convertible
Engine: LB9
Transmission: 700R4
Axle/Gears: 2.73
Re: Rough running tpi
I had similar issues recently, it was a bad TPS. My car felt like it was slightly out of timing. Poor throttle response and shook like it had a cam. Its easy to check the tps, get a volt meter, turn on ignition (dont start it), stick the (+) on the volt meter in the center wire on tps and (- ) ground on the engine. It should read .54v closed and over 4v at wot, voltage rising evenly as you open the throttle.
Thats where I would start
Thats where I would start
Last edited by 91REDZ28VERT; 08-11-2015 at 11:34 PM.
Trending Topics
08-12-2015, 12:34 AM
#8
Re: Rough running tpi
Check egr for proper function clean and maintenece
Check fuel pressure
Adjust tps.
Maintenance IAC and adjust odle
Clean maf
Check for vacuume leaks
All these things are free to do if you have the tools. If not you can rent them for free at autozone
I take these steps before shelling out cash
Check fuel pressure
Adjust tps.
Maintenance IAC and adjust odle
Clean maf
Check for vacuume leaks
All these things are free to do if you have the tools. If not you can rent them for free at autozone
I take these steps before shelling out cash
Thread
Thread Starter
Forum
Replies
Last Post
Sanjay
Engine/Drivetrain/Suspension Parts for Sale
1
08-12-2015 03:41 PM
