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Joined: Nov 2002
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OP
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Posts: 12 |
Greetings,
First, I'm an avid user of this site, great information.
OK, while searching around for help with the notorious bucking/hesitation problem I found the thread on secondaries being stuck open. While checking the secondaries I noticed mine do open at around 3700RPM but it seems they just open momentarily, The linkage moves as if they are opening then moves back to the original (less than 3700rpm)position. Could this be a bad IMRC (I think thats what it is)? or is that how they work? If this is faulty could that cause low rpm hesitation? Thanks for any help.
99 SE MTX
KKM intake
res removed
Diablo Chip
Ford 9mm sport wires
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Joined: Nov 2002
Posts: 392
CEG\'er
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CEG\'er
Joined: Nov 2002
Posts: 392 |
Sounds like a bad IMRC. If the secondaries were working properly, they would stay open until the car dipped below 4000 rpms.
1998 SVT
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Joined: Nov 2002
Posts: 12
New CEG\'er
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OP
New CEG\'er
Joined: Nov 2002
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Thanks, the odd thing is they seem to work ok while driving the car, I don't have any hesitation while at that rpm or higher.
On a side note I'm one of the many on here chasing the low end hesitation. Would it be of any benefit for me to remove/clean the fuel pump screen? I have already changed coil pack, wires, plugs twice, fuel filter, UIM/LIM cleaning, would that or the throttle position sensor, IMRC, MAF, etc. be the next thing to try? By the way I have no CELs and the hesitation is the same no matter the amount of fuel in the tank. This hesitation is EXTREMELY frustrating and I've been battling it for a while. The kicker is the engine never even hiccuped until I changed the plugs initially at about 80,000 or so. Now I have 120,000 and still haven't permanetley fixed it. Anything I've done has only helped for a couple of days and yes I've reset the PCM after doing any troubleshooting. Any help out there would be greatly appreciated. Thanks!!
99 SE MTX
KKM intake
res removed
Diablo Chip
Ford 9mm sport wires
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Joined: Jun 2002
Posts: 644
Veteran CEG\'er
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Veteran CEG\'er
Joined: Jun 2002
Posts: 644 |
Originally posted by pctour:
Thanks, the odd thing is they seem to work ok while driving the car, I don't have any hesitation while at that rpm or higher.
On a side note I'm one of the many on here chasing the low end hesitation. Would it be of any benefit for me to remove/clean the fuel pump screen? I have already changed coil pack, wires, plugs twice, fuel filter, UIM/LIM cleaning, would that or the throttle position sensor, IMRC, MAF, etc. be the next thing to try? By the way I have no CELs and the hesitation is the same no matter the amount of fuel in the tank. This hesitation is EXTREMELY frustrating and I've been battling it for a while. The kicker is the engine never even hiccuped until I changed the plugs initially at about 80,000 or so. Now I have 120,000 and still haven't permanetley fixed it. Anything I've done has only helped for a couple of days and yes I've reset the PCM after doing any troubleshooting. Any help out there would be greatly appreciated. Thanks!!
Here's something you can try that I actually just did on my SVT by accident. Look at the orientation of your IAT sensor in your accordian tube. Make sure that sensor is lined up properly (wiring harness directly on top side). I rotated mine back and forth and it actually (!!!) made quite a noticeable difference in the low speed bucking. I guess that when the throttle plate is closed and air is swirling around between the TB and the filter, the sensor can get confused depending on its orientation. (But that's just a guess!  )
Also, make sure your intake and filter are as straight and level as possible - this improves the efficiency of the intake and allows the air to enter the engine more smoothly - I'm guessing again that turbulence in the airstream can contribute to the bucking behaviour as well.
1999 Red / Tan SVT
#1969 of 2760
Built 4/21/99
K&N, DMD, FMS Wires, ES Insert / Bushings, PF End Links
17" FSVT 5-Spokes
Factory Spoiler
35% Tint All Around
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Joined: May 2000
Posts: 635
Veteran CEG\'er
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Veteran CEG\'er
Joined: May 2000
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you say you are watching the linkage, I'm assuming your reving it with the hood up. Not actually being drive, course I'd like to see that mehtod!  Any how that's normal the PCM knows it's not under load or something like that. Paul
Paul
98 Mystique LS 2ea (07/97)(08/98)
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Joined: Nov 2002
Posts: 12
New CEG\'er
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OP
New CEG\'er
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Thanks (F111DF)that makes sense about the engine not being under load.
(delmar) I'll try the IAT and intake tube method, I'm up for anything. I had a problem with my cone filter from KKM rubbing on the underside of the hood when I first installed it. I fixed it but I know the intake is not as level as it could be. Also my IAT wiring harness is stretched to its limit would there be any problem with splicing in some wire extensions? Also did anyone have an opinion on the fuel pump screen or other possible low rpm hesitation solutions mentioned earlier? Thanks
99 SE MTX
KKM intake
res removed
Diablo Chip
Ford 9mm sport wires
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Joined: Jan 2003
Posts: 566
Veteran CEG\'er
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Veteran CEG\'er
Joined: Jan 2003
Posts: 566 |
What kind of plugs did you change to? Get autolite double plat plugs. 
99 Blk SE Sport
2.5 CD4E
Euro Focus SVT Wheels
5 % tint
Mesh Grilles w/indiglo ford
KKM intake filter
FMS 9mm wires
Superchip
Signal mirrors
Fog lamp mod
Dingless
A6 sidemarkers
Duals
SVT springs/struts
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Joined: Mar 2003
Posts: 7,117
Hard-core CEG'er
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Hard-core CEG'er
Joined: Mar 2003
Posts: 7,117 |
(taking notes - as usual)
Must be that jumbly-wumbly thing happening again.
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Joined: Nov 2002
Posts: 12
New CEG\'er
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OP
New CEG\'er
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I did use the autolite double plats both times that I changed them, gapped to .054 fixed for a couple days then right back to low end hesitation. I beleive it to be in a sensor more than likely because of the inconsistency but who knows I'm just looking for tips from anyone who has solved this problem or might have any good ides, I still need to try the intake solution offered earlier in this post, Thanks
99 SE MTX
KKM intake
res removed
Diablo Chip
Ford 9mm sport wires
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Joined: Jul 2001
Posts: 4,168
I am Canuckian
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I am Canuckian
Joined: Jul 2001
Posts: 4,168 |
Just food for thought. My low end buck/hesitation appears to be the secondaries being stuck open. Not that it is the case for you but it is something to look at. 
Green 96 mystique gs 4cyl mtx
16.9 in the 1/4 mile @102500 miles
95SE in Midnight Red MTX
MSDS headers and y-pipe
SVT exhaust
SVT UIM
Optimized se TB.
Full pre 98 SVT body kit
15.741 @ 87.73mph :)
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