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Old 09-20-2012, 05:06 PM   #1
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Surging throttle

Alright so I have a 88 gt with 91 5.0 engine Few mods including b303 cams bbk intake 70mm Holley TB, the problem: when at idle she revs up and down fine but when in gear (manual trans) and revd up to start rolling the throttle surges even after taking foot off throttle, if I throw it back in nuetral and give the throttle a small kick it will hesitate then come back down slowly, looking for thoughts linkage getting stuck.. Tps..fuel pressure regulator ..timing? When I checked voltage on tps it was around 8.6
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Old 09-20-2012, 05:07 PM   #2
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8.6 is extremely high. It should be around .95 I believe.
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Old 09-20-2012, 05:08 PM   #3
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.86** sorry
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Old 09-20-2012, 05:11 PM   #4
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Yeah the tps should be between .95 at idle to 4.5 at wot with key on engine off. I would make sure its set correctly otherwise you may need a new sensor.
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Old 09-20-2012, 05:12 PM   #5
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Thank you, that would cause the rev to stay and increase like it is?
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Old 09-20-2012, 05:14 PM   #6
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Quote:
Originally Posted by BigTone
Thank you, that would cause the rev to stay and increase like it is?
Possibly. Start by loosening the screw and turning it until the voltage reads correctly and go from there.
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Old 09-20-2012, 05:16 PM   #7
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is it using the 91 maf? if its speed density and has been doing this then that maybe an issue with your mods.

the useful information stickies thread has a great article about the infamaus surging idle. i would check that out.
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Old 09-20-2012, 05:25 PM   #8
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I bought her a week ago, yes I believe to maf is the 91, also when I adjust tps to .95 the idle is around 1700
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Old 09-20-2012, 07:35 PM   #9
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You may need to reset your idle, that's in the stickies as well.
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Old 09-20-2012, 07:39 PM   #10
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Yes I'm running the 91 maf not speed density, so it shouldn't be a problem with my cams, going to try and adjust tps screw again in the morning, does any one know why the or would be so high when it's reading .95 ?

---------- Post added at 08:39 PM ---------- Previous post was at 08:38 PM ----------

Yea I just went over the stickies, a lot of information thank you
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Old 09-20-2012, 08:11 PM   #11
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I would reset base idle also. It's easy to do and is a free shot.lol Might as well!
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Old 09-21-2012, 01:16 PM   #12
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Just adjusted tps screw to .95 disconnected neg For 10 mins took her our for a spin and same thing as soon as a let of the gas and press clutch it rockets up, re checked tps when I got back and it was reading 1.1xx so I re adjusted it again and took for another spin with same results And when I checked the tps this time it was around .87
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Old 09-21-2012, 03:08 PM   #13
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From what I understand, your TPS adjusts with your base idle each time you fire it up. (someone correct me if I'm wrong)

---------- Post added at 03:08 PM ---------- Previous post was at 03:07 PM ----------

I would reset your base idle man.
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Old 09-21-2012, 03:56 PM   #14
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Quote:
Originally Posted by 91notchback
From what I understand, your TPS adjusts with your base idle each time you fire it up. (someone correct me if I'm wrong)

---------- Post added at 03:08 PM ---------- Previous post was at 03:07 PM ----------

I would reset your base idle man.
I do believe the it re-adjusts on the 94-95 models, not the foxes.

---------- Post added at 03:56 PM ---------- Previous post was at 03:55 PM ----------

Sounds like your tps is sticking or worn out.
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Old 09-21-2012, 04:03 PM   #15
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Mine does the exact same thing and I have replaced my tps.
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Old 09-21-2012, 04:13 PM   #16
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Quote:
Originally Posted by JayKranz
Mine does the exact same thing and I have replaced my tps.
Replacing the tps didn't do the trick?
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Old 09-21-2012, 04:16 PM   #17
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Nope, I set my base timing also. Then I replaced my iac sensor, that didn't work either. I unplugged the iac and my car runs fine though. I'll have my tuner fix it though.
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Old 09-21-2012, 04:25 PM   #18
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Quote:
Originally Posted by JayKranz
Nope, I set my base timing also. Then I replaced my iac sensor, that didn't work either. I unplugged the iac and my car runs fine though. I'll have my tuner fix it though.
I did that when I was trouble shooting mine, made cold starts a pain the the rear. Luckily I have the 90 to swap out parts with to test on both cars.
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Old 09-21-2012, 05:31 PM   #19
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Old 09-22-2012, 12:47 AM   #20
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Re: Surging throttle

Quote:
Originally Posted by 91notchback View Post
From what I understand, your TPS adjusts with your base idle each time you fire it up. (someone correct me if I'm wrong)
---------- Post added at 03:08 PM ---------- Previous post was at 03:07 PM ----------
I would reset your base idle man.
Not the TPS, the ECU.

Quote:
Originally Posted by 93slowstang View Post
I do believe the it re-adjusts on the 94-95 models, not the foxes.
---------- Post added at 03:56 PM ---------- Previous post was at 03:55 PM ----------
Sounds like your tps is sticking or worn out.

From what I read, both models, but as with any online info, who knows for sure. One of these days I plan to check that theory on my car.
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Old 09-22-2012, 06:27 AM   #21
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Quote:
Originally Posted by Trojan Horse

Not the TPS, the ECU.

From what I read, both models, but as with any online info, who knows for sure. One of these days I plan to check that theory on my car.
I still remember that debate, haven't tried finding hard evidence other than testing my own car. So far with a good tps I've never had it change from the set voltage.
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