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Author
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Topic: Hesitation & mild surging on Fox
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Tyrant89
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Member # 1033
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posted
 
 
ok, we just replaced a head gasket, and now the car has small "stumble" at around 1800-2000 RPM. It's very slight, but when cruising within this rpm the surging is very annoying.
When slowly given throttls, I can feel thehesitation, but as the rpm's climb, the engine feels great.
Any sugestions?
89 LX w Novi 2K
42# injects,fuel ressure at about 39 psi. Heads, intake, cam.
Posts: 260 | From: Salinas, holmes! | Registered: Mar 2002
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Glenn
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Member # 520
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posted
what is your timing set at?
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S-Trim,331,H/C/I
"JohnB groupie train"
My Car
DragGuam
Posts: 2009 | From: Stationed on a Pacific Island, Guam | Registered: Oct 2001
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Primer GR40
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Member # 476
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posted
quote:
Originally posted by Tyrant89:
ok, we just replaced a head gasket, and now the car has small "stumble" at around 1800-2000 RPM. It's very slight, but when cruising within this rpm the surging is very annoying.
When slowly given throttls, I can feel thehesitation, but as the rpm's climb, the engine feels great.
Any sugestions?
89 LX w Novi 2K
42# injects,fuel ressure at about 39 psi. Heads, intake, cam.
I have the same problem with my SC 96 cobra, but at around 3krpm. I think I need a retune. I wish that apex would do it for free. I already payed them for thier employees break time. ![[Roll Eyes]](rolleyes.gif)
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Superdupercharged Cobra
No Transmatic Notch
Posts: 2108 | Registered: Sep 2001
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Tyrant89
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Member # 1033
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posted
Timing is around 9 deg, any less it drives like crap, any more, & it pings (on a hot day).
It has a chip from Byron, but still pings alot if I dont watch it, or if i try & run pump gas. I'm running about 95-96 octane usually
Posts: 260 | From: Salinas, holmes! | Registered: Mar 2002
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Stimson
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Member # 51
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Bump down initial timing another degree and check for vacuum leaks?
Posts: 2373 | Registered: Jun 2000
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Stimson
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Member # 51
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Anyone know what the bleeder type screw on the side of a paxton fuel pressure regulator does?
Posts: 2373 | Registered: Jun 2000
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Tyrant89
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Member # 1033
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Thanks for the bleeder question, ST, I will ask around this week and try & find out if that's effecting my idle. I should have my pressure test and verify my timing by Thursday.
Posts: 260 | From: Salinas, holmes! | Registered: Mar 2002
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Tyrant89
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Member # 1033
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posted
OK, well, i havent found any vac. leaks yet.. but I'm still looking. I'm also going to change the plugs this weekend.
Paxton claim that the extra crew on my FP regulator is for auxiluary(sp?) reasons, say forrunning a gauge or whatever and is not for any kind of adjusting.
Posts: 260 | From: Salinas, holmes! | Registered: Mar 2002
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Stimson
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Member # 51
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posted
Okay then, that makes sense. I'm willing to bet you're running both too much timing and too much fuel pressure. Even the slightest pinging on a blower car means you're running too much timing and risking popping a head gasket or worse.
Posts: 2373 | Registered: Jun 2000
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Jdub07
( O Y O )
Member # 2728
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posted
quote:
Originally posted by Tyrant89:
ok, we just replaced a head gasket, and now the car has small "stumble" at around 1800-2000 RPM. It's very slight, but when cruising within this rpm the surging is very annoying.
When slowly given throttls, I can feel thehesitation, but as the rpm's climb, the engine feels great.
Any sugestions?
89 LX w Novi 2K
42# injects,fuel ressure at about 39 psi. Heads, intake, cam.
Did you remove the throtle response sensor when you did the head gasket? If so you'll need to "re-adjust" it or "recalibrate" it. I guess it can cause mild serging or bad idle. I still need to finely tune mine. It idles a bit rough after I removed mine.
Posts: 7282 | Registered: Apr 2003
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