Engine/Transmission (1998.5 - 2002) can some one help me? no one can figur this 1 out

[grass hopper]

so i have read a lot about hard starting, no wait to start lights, fast idle & bad vp44. i got a new one for ya'll

my '99 for the last few weeks has been doing some thing very odd off & on. some times when i get in the truck and go to start it there will be no wait to start light nor will my LP not sound (it's been relocated to the back of the cab very loud) but all the other lights on the dash will light up. then when they go out the WTS light comes on and the LP starts a buzzing. after they go out i start the truck. now here lately after all that and the truck is running i go to give it a little bit of pedal & the darn thing revs to 4000 rpms or higher and i will have to turn the truck off & restart it some times it will work like it should some times it does the same thing over & over. so has any one ever had this happen to them or am i the only one?



PS. i have tryed unplug the batterys over night & in the morning hook them back up but it still does it after its wormed



just to make clear what it's doing after it's wormed up i can start the truck just fine. it's when i put the truck in gear and go to drive it (or give it some gas ) the engine will revv very fast and if i were to try and drive it would do a burn out i'm sure (making it if very unsafe to drive in trafic)



in the mornings when its cold it does fine but as soon as it gets worm it starts acting up and i will have to wait until its cool to run it again





1 more thing i have checked for codes & it tells me passed so no codes.

 

[JFaughn]

Not sure but is that yr run by wire [ not throttle linkage ] ?
Bad Throttle Position Sensor , use good meter to test , also a Co2 fire extinguisher , it gets warm & fails , so cool it to test .
Just some thought till you get some others .

 

[DCreed]

Welcome! please fill in your sig. so we all know exactly what we're looking at. YR. , model,auto/stick,2 or 4x4, ANY mods. Thanks.

 

[Gary - K7GLD]

Another member recently has had that same problem - was a bad APPS unit (Accelerator pedal position sensor).

 

[grass hopper]

i have an extra apps that is good so i tryed replacing it with the one on the truck and it did the same thing.



i own a 1999 3500 4x4 mostly stock other the a edge ez. in 07 i replaced the VP44 & LP also moved the pump to the back framerail & used the big line kit.

 

[grass hopper]

i was messing with the truck just now. its not at full op-temp but it still did the same thing like alway as its ideling i unpluged the water temp sending unit (next to the thermostat housing) and gave it a little bit of pedal same thing so i turned the motor off let it set for a few min & then restarted the truck and it's acting fine give it pedal and its smooth like it should be. so i pluged the temp back in and its still smooth & is acting fine. could it be the temp is bad or some thing? not sure what the temp does other then controil the gauge on the dash.

 

[DCreed]

the coolant temp as well as the IAT and speed sensors all play a role in the grid heater cycle. and dielectric grease is a wonderfull and cheap thing. also the IAT can be cleaned for 0$. it is on the back of the head under the intake.

 

[grass hopper]

the speed sensor was replaced about 3 months ago so were good there. i cleaned the ITA about 2 or 3 years ago so i should do that. if not for any other reason just to say its clean and thanks for any other info.

 

[grass hopper]

Well it’s back doing the same thing as yesterday morning. i guess the temp sender is not the problem. i cleaned the IAT today did not help. i noticed some thing new not sure if this is part of the very fast revving or not but as i went to get out of the truck i got a little shock now this has happened before but now i wonder if this & that are working together.

 

[obert]

My old Van Aaken box, similar to the EZ, does something like that occasionally. It dont wait for throttle input, though. She'll start and head for 2000-2200 rpm. Its over before you can get to the key, but when it does that, the drive just doesnt feel right, like a little less power. I chased my tail for a bit, but unplugged it for further diagnosis. Prob went away. Put my VA on a compatible truck at work and replicated the problem. The dead pump code comes up, too.



All that said, this started after a very cold start (-28*), and unintended shutdown a few miles down the road. Shutdown was like running out of feul, and with the temp I figured waxed fuel. (didnt have a fuel PSI gauge then) I did get som cummins troubleshooting info, just in case, and checked over the electronics a bit, but I think all I did for restart was prime the fuel. Of course that was also sans VA, my cummins source told me it might throw off any readings on the T/S info.

I didnt have the resources then I do now, so I cant positivly say what caused the shutdown. BUT, (after such a long story ) take the EZ out of the picture. A very EZ way to at the very least say that it isnt the problem, so on to the next.

 

[grass hopper]

thanks for the reply.

i started thinking folks were all taped out on idea's. well i tryed removing the EZ and drove it for a full day and it did the same thing. i am getting real close in selling the truck. i am starting to hate my truck. my wife asked me today if this is a commen thing with these truck to brake down all the time. i told her i think it's just mine. man i hope i get it fixed soon its getting worse every day. getting to be were i can only drive it one way then i have to wait until it cools off before i can drive it the other way.

 

[mhenon]

..... when i get in the truck and go to start it there will be no wait to start light... ... ... .

Somebody else may chime in here but I think the wait-to-start not lighting up is the sign of a bad ECM.

Mike

 

[obert]

Huh.....

that it isnt the problem, so on to the next.

You know anyone who has a good scan tool to watch sensor feedbak? I hope its some thing simple for ya. I know that sinking feeling-- Ive had a nuber of probs. Each time my wife is the same ,but she's from a GM family. I change the oil and its "workin on it again , huh?



Now the truck sits alot, that in of itself is starting to cause undesirable issues... .





Is that new-ish VP still under warranty? I know its a sick thought, but.....

 

[grass hopper]

I Don't Think It The Vp I Sent It In For A Check Up About Three Months Ago And It Checked Out Fine. I Got A Scan Toll From Auto Zone To Read Codes. And So Far There Has Been No Codes On This. I Have Done A Search To Try And Fine Old Post But The Darn Search Page Will Not Let You Put Any Words With Less Then 3 Letters. I Would Take It To The Dealers But I Don't Have That Kind Of Money.

I Will Keep Trying To Fine The Problem Or Maybe Some One Will Pipe Up And Tell Me Whats Going On.

Thanks For All You Help Obert Maybe One Day I Will Have A Dependable Truck.

 

[grass hopper]

can the ECM be checked? and if so do i have to take it to the dealer? if its bad are they costly?

 

[mhenon]

can the ECM be checked? and if so do i have to take it to the dealer? if its bad are they costly?

Yes... yes and yes You can check eBay as there are some occasionally for sale. Have yours checked first. You don't want to start throwing money at it 'til you know what's going on.

One thing you can do is go around the rig and check/clean evey ground wire. Sometimes it's better to hit the body or frame with a dremal tool or emery paper to get down to bare metel. Make sure you have a good ground path wherever it's required. Good luck.

Mike

 

[grass hopper]

i have been thinking about the truck and what it is doing and was woundering if the intake heaters were stuck open would that make the motor have the fast revv problem that i am having after it get to op temp.

 

[obert]

mhenon snuck in while I was typing that last post. Now I feel silly for thinking about the VP, guess I got blinders for the high rev thing. ECM kinda makes sense over all. That is an odd mix of problems, but when a brain goes bad, anything can happen. The equipment I work on isnt fully electronic but we still see some wierd stuff from controllers once in a while.

About the heaters, if the engine is hot it shouldnt want them on, so stuck open may not be an issue. There are P-codes on the heaters, so the ecm does monitor them. I found if you try to cold start with dead batteries-- so dead the heater relays cant engage-- it sets a grid heater code. I think it even sets off a MIL cause that would effect exhaust emissions.

And I'll second mhenon on the grounds. Some circuts work on sensing resistance to ground. Changing that resistance causes awfull problems. Along with not having "clean" voltage through any circut.

 

[JFaughn]

Its time to find some one with a real scanner [ professional - so that some who know what there looking at can see data going back & forth ] to see whats missing / wrong , theres only so much that can be done with out experience & the right tools .
Make sure that they are good enough to find out why some thing went wrong , what can happen is lets say a relay went bad , putting a ground going back to the ECM on what was once a power wire , that can fry the ECM , so throwing a part at it , even if its the right one , the problem was not the ECM but the grounded power wire .
I've seen this happen a lot .

 

[DCreed]

good call JFaughn.