Issue When Idling
Hello all,
Took a video of an issue I've been having pre and post engine rebuild/tune. Engine was rebuilt by Lucky 7 and tuned by Nelson. While idling, a quick and slight jab of the throttle will cause the vacuum gauge to rise toward zero and the car will stumble and almost die. The idle is set a bit high in the video but is now set to 900rpm, car is basically stock with all emissions in place. Checked the VTA1/2 ranges which were within factory spec, also replaced the throttlebody Oring but I'm no expert so any help on what else to look is much appreciated! |
Have you checked the TPS?
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It's like the accel enrichment isn't working. With the engine off, key on, if you look at the sensor check screen and watch the TPS values do they both go up nice and smooth?
Do you have a way to save the map for the PowerFC (datalogit)? If so I'd do a reset on the PowerFC and see what happens. Also it may be worth looking at the enrichment settings compared to the stock PFC map and see if something's up. I'm assuming it's only a hard jab on the throttle that makes it do that. If you slowly raise the RPM I'm assuming it will rise up and not stall out? Could also be a dirty ISC or something. Dale |
The builder and tuner should be fixing this problem free of charge.
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Originally Posted by DaveW
(Post 12235803)
Have you checked the TPS?
Originally Posted by DaleClark
(Post 12235828)
It's like the accel enrichment isn't working. With the engine off, key on, if you look at the sensor check screen and watch the TPS values do they both go up nice and smooth?
Do you have a way to save the map for the PowerFC (datalogit)? If so I'd do a reset on the PowerFC and see what happens. Also it may be worth looking at the enrichment settings compared to the stock PFC map and see if something's up. I'm assuming it's only a hard jab on the throttle that makes it do that. If you slowly raise the RPM I'm assuming it will rise up and not stall out? Could also be a dirty ISC or something. Dale |
Thanks for the help all, mentioned to lucky7 at sevenstock but it's difficult being about 5 hours away from them otherwise it'd be back there asap.
Rechecked the TPS voltages after warming up the car and it looks like they're still good. Did notice that VTA2 topped out about 2/3rds of the way opening the throttle, not sure if that's normal but otherwise they're nice and smooth. closed open VTA1: .56v 4.40 VTA2: 1.07 4.97 I'll check the ISC next, all the throttlebody stuff is original and hasn't been touched or adjusted. |
Originally Posted by DaleClark
(Post 12235828)
Do you have a way to save the map for the PowerFC (datalogit)? If so I'd do a reset on the PowerFC and see what happens. Also it may be worth looking at the enrichment settings compared to the stock PFC map and see if something's up.
I'm assuming it's only a hard jab on the throttle that makes it do that. If you slowly raise the RPM I'm assuming it will rise up and not stall out? It did this before and after the rebuild when running on the PFC base map so I'm not sure. I'm really just blipping the throttle, if you do it lightly/quickly enough it stumbles and almost doesn't catch itself. |
Originally Posted by jsemerica
(Post 12235941)
It did this before and after the rebuild when running on the PFC base map so I'm not sure. I'm really just blipping the throttle, if you do it lightly/quickly enough it stumbles and almost doesn't catch itself.
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Originally Posted by RCCAZ 1
(Post 12235987)
Well, stop doing it then ;)
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RCCAZ might be into something here. :P
Its normal to have the TPS voltage top out at 2/3rds full throttle. My brand new TPS and my old one did it. The one thing I noticed from the first video was when you blipped the throttle it looked like it just didn’t catch itself. This can be from the throttle dashpot not working right. The dashpot is a little dampener for the throttle plates that slows the closing of the plates. This helps prevent the plates from slamming closed and starving the motor of air. If you open the throttle body and the little white plunger of the dashpot is sticking out about an 1/8 inch, then the pot is bad and needs to be replaced. Matt |
You need to load the map and also put this post in the correct forum.
I say that the injectors map or the 2 acceleration maps might be bad. |
Originally Posted by cewrx7r1
(Post 12236310)
You need to load the map and also put this post in the correct forum.
I say that the injectors map or the 2 acceleration maps might be bad. Will post up in the PFC forum if I need anymore help. Thanks! |
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