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PSU
Dodge Dakota
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8/05/2002
01:14:58
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 Subject: Accelleration Hesistation...
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I have a 99 Dakota Sport 4x4 auto with the 318.
I have always noticed that if I am at a dead stop and give it 3/4 to full throttle, the motor will hesistate for a few seconds, then start to climb the revs. It almost seems that it would accelerate faster if I "squeezed" the gas pedal slowly then dropping the pedal after the revs got up a little. I checked the TPS and it reads .7V, maybe a little more. Anybody have any ideas???
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mj
Dodge Dakota
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8/05/2002
17:20:24
|  RE: Accelleration Hesistation...
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Pull the TPS off and do sweep test with analog meter. Might have a bad spot.
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CW
GenIII
8/05/2002
17:23:52
|  RE: Accelleration Hesistation...
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Some performance throttle bodys may eliminate this. There is no torque step in them.
2001 4.7HO RC 5sp 3.92 LSD
Click on thumbnail for mods
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Aaro
Dodge Dakota
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8/05/2002
21:15:07
| RE: Accelleration Hesistation...
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It is a auto with a 1500-1900 rpm stall, the engine has alot of cam for a stall this low. What mods (if any) do you have?
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PSU
Dodge Dakota
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8/05/2002
21:25:33
| RE: Accelleration Hesistation...
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I have no idea what you just said, but I have no major mods, all these mods have been on for a while, the truck now has almost 40k on it.
IAT Adjuster
Dynomax 3" Cat Back w/40 series Flowmaster (I thought this may have taken some low end torque away, but I tried the stock system and this was actually better)
Taylor 8mm Spiro Pro Wires
180 T-Stat
Autolite 3923
Custom Cold Air Intake with K&N Cone
Airaid TBS (did feel a little better low end but it could just be mental casue I can't see this doing much with the intake having a 90 degree turn)
It just bothers me that the truck doesnt really begin to "pull" till the RPM's slowly creep up to a little of 2k when lotsa throttle is used. In the cold, this symptom is reduced greatly.
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Erik
Dodge Dakota
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8/06/2002
15:06:54
| RE: Accelleration Hesistation...
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Hey PSU,
I know exactly waht U mean! We have almost identical trucks(99 SLT 4X4 318 Auto), and I've noticed the same thing since new.
Right now I've got just over 40K, and the same basic mods: MSD ignition & wires, Autolight 3923's, Airaid intake, "cleaned up" stock TB, TPS@.74v, Gibson CatBack etc.
The only causes I could come up with are the design of the intake manifold(even though it's suposedly tuned for maximum tourqe just off idle-2500rpm, it doesn't seem to realy "PULL" untill around 2K), or the fact that it's a 4X4 Auto w/31 inch tires (takes alot to get moving). Anyone else have any ideas, sugestions, fixes?
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PSU
Dodge Dakota
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8/06/2002
15:28:17
| RE: Accelleration Hesistation...
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Yeah Erik, I thought about the tire situation. A buddy of mine at the shop mounted some 235 75's onto my rims for me. These tires are still a decent weight, but are considerably smaller than the 31 x10.5's we have. Well, I tried them out and yes you can feel a slight, i repeat, slight difference in the truck being able to pull better in low speeds and high speeds.
I think you may be right on the intake idea. It feels like the truck maybe isnt being fed enough air or something, who knows...or it could simply be that our trucks weight too much. I'm still waiting for some suggestions if anybody has any...
Anyone???
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Erik
Dodge Dakota
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8/06/2002
15:43:40
| RE: Accelleration Hesistation...
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I agree PSU, these trucks are pretty heavy for being "Midsize", but it promising to hear that effectively lowering your gear ratio seemed to help. Maybe the only way to compensate for what feels like lack of tourqe, is to change the gearing (or get a supercharger;). Ayone out there with a similar rig change to 4.10 gears? How noticable was the change in acceleration from a standstill?
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PSU
Dodge Dakota
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8/06/2002
15:52:22
| RE: Accelleration Hesistation...
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What gear to you have Erik? 3.92 or 3.55? I have the 3.55.
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Erik
Dodge Dakota
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8/06/2002
16:15:57
| RE: Accelleration Hesistation...
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I've got the 3.92's from the factory, but the hesitation you are describing is still noticable. However, it's only from a complete stop that the sudden heavy throttle seems to cause a lag in the RPM's. The RPM's will climb quickly after about 2K though.
I couldn't imagine changing to 4.10 gears unless I swapped to bigger tires (would be hell on the freeway).
Who knows, maybe i'm just too picky or have unrealistic expectations of this HUGE 5.2 liter tourqe monster ;) LOL!
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Aaro
Dodge Dakota
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8/06/2002
19:09:43
| RE: Accelleration Hesistation...
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PSU ,
1: The intake manifold with it's 16" long runners does move the power band down and the TQ peak is at about 3000 rpm. The specs on the factory camshaft are more for a engine that should tourque peak at 3700 rpm .Dodge did this to make a wide power band (a flat TQ curve that is more useable in a truck).The down side of this is that on a warm day the intake manifold temp can run about 235 deg and the long runners will transfer the heat to the air and make sure your engine gets a breath of hot thin air when you mash the gas.An oil cooler may help but you are stuck with this one because a M1 intake(runs much cooler) will cost you some low end power.
2: On a warm day the IAT or intake air temp sensor sees 235 deg.and backs fuel and timimg off. When you go 3/4 to full throtle the computer does not use the 02 sensor but does more of a guessing game to make good power without high emisions, sometimes it gusses wrong. Buy a IAT adjuster from SpeedTweaks.
3: The stall speed is basicly the rpm the engine is allowed to turn with the drive shaft not spining. To find you stall speed put one foot hard on the brake and mash the gas then look at the tach, factory stall should be 1500-1900 rpm. The factory tourque converter is more for mpg and comfort than speed. With a low stall to much air at low rpm's can cause a bog.If you replace it with a 2300 rpm stall with lockup it will fly out of the hole and not hurt mpg much.
4: When you sit at a idle the engines fan fills the cold air box with hot air.Mash the gas and it sucks in hot thin air.I am working on a small 200 cfm fan mounted in the fender to blow cool air into the air box (towards the filter)when at a stop.
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PSU
Dodge Dakota
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8/07/2002
03:17:34
| RE: Accelleration Hesistation...
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Thanks for the info Aaro...that makes sense to me. I do have an IAT adjuster but have found that it does not make that much a difference. Maybe an M1 will.
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bassboy170
Dodge Dakota
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8/08/2002
14:50:17
|  RE: Accelleration Hesistation...
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hi guys i have the same problem on my truck i have a 97 318 cc 4x4 with 330 hp to the wheels supercharged bigger throttle body m1 intake all the goodies and my truck does the same thing your trucks are doing im still trying to figure out what is going on with it but im pretty sure it has something to do with the iat sensor because when it is cold it doesnt hesitate as bad as if the engine is hot and it is a hot day out hope this helps i will keep u guys posted with anything i find out
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PSU
Dodge Dakota
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8/08/2002
16:45:45
| RE: Accelleration Hesistation...
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330hp to the wheels!?
Well if you have all those mods and it still does the same thing....makes me believe more that it is due to the weight of the truck.
I have a IAT Adjuster and it only helps a little bit.
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