Engine Foxbody idle/throttle issues
- Thread starter red5.0fox
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TwoRockTwo
Member
That TPS sensor is faulty. Replace it.
You shouldn’t test it with the car running, just turn the ignition ON without actually starting the car and then test it.
You don’t need help, you can manipulate the throttle yourself from under the hood while testing.
Just swapped it, however I can’t even keep it at an idle before it dies. That didn’t start happening until I did the timing so maybe I need to go ahead and do it the proper way. For the short period of time I did have it running with the maf plugged in I still couldn’t rev it throughout its rpm range. Same issue.
TwoRockTwo
Member
Now you should test the new one. (TPS)
About .98v with the throttle closed
About 4.8-5v with the throttle wide open.
A smooth transition between the two points.
Then get your timing set correctly.
About .98v with the throttle closed
About 4.8-5v with the throttle wide open.
A smooth transition between the two points.
Then get your timing set correctly.
Car does not have to be running to check the sweep on the TPS. Go to post #2:
stangnet.com
Tps Voltage Question
Hi all, just picked up a 86 LX, and think I've run into a idling issue. The motor is a 306 EFI, GT40 Crate motor 42lb injectors Bama 4 Bank Chip 70MM TB 76MM Turbo/w 10lbs boost B303 Cam GT40X Heads The car has a hard time idling for the first 30 seconds or so. I've got play with the gas pedal...
stangnet.com
I'll be doing that next time I get a chance. Hopefully tonight.Car does not have to be running to check the sweep on the TPS. Go to post #2:
Tps Voltage Question
Hi all, just picked up a 86 LX, and think I've run into a idling issue. The motor is a 306 EFI, GT40 Crate motor 42lb injectors Bama 4 Bank Chip 70MM TB 76MM Turbo/w 10lbs boost B303 Cam GT40X Heads The car has a hard time idling for the first 30 seconds or so. I've got play with the gas pedal...
Anything between 0.5 and 1.25V is acceptable at idle. You don't need to target a specific number (0.99 for example). Just turn the key to on. Do you have around 1V? then you are good. Depress the pedal. Does it go to more than 3.5-4V? Then it's range of sweep checks out.
A running car might have a slightly higher voltage. Might be 0.85v with engine off, and 0.86 with it running. Both are acceptable
A running car might have a slightly higher voltage. Might be 0.85v with engine off, and 0.86 with it running. Both are acceptable
Just tested it. .95v throttle closed, gradual sweep all the way to 4.6v. Guess that’s checked off..
I’m pulling my heads here soon as my shop teacher is going to resurface, aswell as port them. So it won’t be running for a while but I’m gonna take the time to do the timing and such on it before I’m thinking. That way I can properly eliminate that.
TwoRockTwo
Member
I would get it timed correctly and see if your issue is fixed now. (The TPS might have solved most of your issue)
That way when you do upgrade parts in the future, you won’t have an underlying issue that could be further complicated with additional issues arising from swapping out more parts. Which makes troubleshooting harder.
Porting a set of GT40’s … well are you talking about gasket matching or the more in depth porting of runners and bowls?
It’s almost not worth the effort/ money to begin with, but the more in depth porting requires alot of experience & knowledge. Without it you could end up with a worse off flowing head than it was stock.
I say get it running and drive it some, you might not see the need for porting afterwards to get that handful of extra power.
That way when you do upgrade parts in the future, you won’t have an underlying issue that could be further complicated with additional issues arising from swapping out more parts. Which makes troubleshooting harder.
Porting a set of GT40’s … well are you talking about gasket matching or the more in depth porting of runners and bowls?
It’s almost not worth the effort/ money to begin with, but the more in depth porting requires alot of experience & knowledge. Without it you could end up with a worse off flowing head than it was stock.
I say get it running and drive it some, you might not see the need for porting afterwards to get that handful of extra power.
The porting is free through the school. It would be full in-depth with the CNC machine aswell as flow tested. We’re in that class right now so since I applies to the school I can get it done for free. I’ll definitely get the timing done and such because I’d like to drive it here to get it done.
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