97 throttle issue....
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Joined: Apr 2007
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97 throttle issue....
Ive got a 97 350 w/ 180k on it. I'm a diesel newbie, just for the record. I have a totally random issue, while driving, that occurs most frequently when i stop at a sign or light. I stop, step on the throttle, and it continues to idle, check eng light comes on. if i hold down throttle, within one or two seconds the truck engages, she BANGS into gear, and i'm rolling. if i let off the throttle when the check eng light comes on, it goes away after a second, and i can normally drive away. sometimes this happens a couple times in a row, but always picks up after a while. this seems to happen with no pattern of any kind, cold weather or warm. sometimes she wont do it for weeks. sometimes it will happen 10 times in a day. after this happens, the tranny will run through my gears all under 25mph until i stop and turn off the truck. when i start it again, she runs and shifts fine until the throttle thing happens again. is this a throttle issue, fuel pump, i'd like a little input before i start spending money! thanks.
Hotshot
Joined: Oct 2003
Posts: 17,799
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From: Ashland City, TN
no autozone or anything nearby? I think they have OBD2 codereaders.
Codes will help you out a lot.
I'd tell you TPS, but I dont know if a desil has a TPS, but then the shifting issue negates that.
Codes will help you out a lot.
I'd tell you TPS, but I dont know if a desil has a TPS, but then the shifting issue negates that.
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Is there a way to test the TPS? Sorry for the lack of info on my end, this is my first visit to the forum and i'm blown away at the info packed in the archives! any info or shots in the dark are greatly appreciated!
Post Fiend
Joined: Apr 2004
Posts: 12,835
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From: Silver Lake Dunes, MI
well the neat thing about our trucks is they are fly by wire so on the throttle pedal there is a idle validatoin switch and a TPS. neither of which are availible without buying an entire pedal assembly. I would check all of the connections on the pedal and i would use some wd 40 with the straw attached to lube both the switch and the tps. my guess is that your tps is good but the validation switch is sticking.
Hotshot
Joined: Oct 2003
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From: Ashland City, TN
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Post Fiend
Joined: Apr 2004
Posts: 12,835
Likes: 3
From: Silver Lake Dunes, MI
I don't know about the shifting issue why it would do that but I will bet money taht if you get the idle/throttle issue fixed the shift issue will also be fixed.
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Posting Guru
Joined: Mar 2007
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From: hillsborough nj
it sounds like the tranny's just not engaging, like since it "BANGS" into gear, idk don't auto trannys just kinda disengage the clutch while idling so that it doesn't keep rolling... since you know.. the RPM's don't drop to 0 lol
Posting Guru
Joined: Mar 2007
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From: hillsborough nj
idk to me if just sounds like a tranny issue... and all the sensors are going off so the truck kinda stops doing everything... but honestly i have no idea what i'm talking about and i'm just pulling this out of my @$$
Post Fiend
Joined: Oct 2003
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From: MICHIGAN
It's the Ole "Garbage in, Garbage out" theory. The PCM controls the tranny, the PCM relys on the TPS/IVS signals to tell the tranny what to do and when to do it, ect.
Check the TPS with a volt meter. It's nothing more than a reostat. It varies the signal voltage (5V) from .37V (idle) to 4.5 volts (WOT).
The IVS it just a switch, it's either on or off. At idle it's open (Off), no continuity. You need to be sure it's opening at the right time. See link below:
https://www.ford-trucks.com/forums/5...ge-on-tps.html
BTW: Check all the connectors on the tranny too. Loose or corroded connections wil cause all sorts of intermitant issues.
Check the TPS with a volt meter. It's nothing more than a reostat. It varies the signal voltage (5V) from .37V (idle) to 4.5 volts (WOT).
The IVS it just a switch, it's either on or off. At idle it's open (Off), no continuity. You need to be sure it's opening at the right time. See link below:
https://www.ford-trucks.com/forums/5...ge-on-tps.html
BTW: Check all the connectors on the tranny too. Loose or corroded connections wil cause all sorts of intermitant issues.
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New User
Joined: Apr 2007
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hey guys, thanks for the input. dissassembled pedal assembly last night, cleaned and WD'd everything, seems to be throttling AND shifting correctly now. I owe you guys a beer if you're ever in the truckee area! The IVS was really gummed up inside its sleeve. it's always the little stuff that gets me. you guys are the best!
Hotshot
Joined: Oct 2003
Posts: 17,799
Likes: 104
From: Ashland City, TN
its easier to fix little stuff most of the time. so its cheep to check there.
the only problem is, you get a build up when the little stuff don't work, and you get to the expensive stuff.
the only problem is, you get a build up when the little stuff don't work, and you get to the expensive stuff.