No Codes but will surge a little on steady hwy speeds or up hills Please Help!!!

[Dieselfuture]

Hi, I just joined this site but had visited it for a while now. Lots of good info,Thank you!!! I have found similar threads related to my issue, but seems like thread ends before the problem is resolved or 99% of the time everybody narrow it down to junk vp. I got a 2002, 2500, 6spd, 4x4, qwd cab, with 130k, air dog, 100hp injectors, 3.55 gears, qwad with pulse, 5" pipe, Problem I'm having is driving on highway over 65mph pulling a trailer(rated 14k gross but about 8-10k total) at steady speed , when going up hill truck starts to surge but not much it's noticeable enough to know there is a problem. And if i turn up the fuel box up it gets worse. so it tells me it's fuel related. i got this truck a few years ago, and previous owner has changed vp under warranty, and at that time he put air dog, it may have 30k on pump. i change fuel filter once a year, but only put about 3-5k ml on it a year. other than that it runs relay good starts right up has plenty of power. i thought maybe it could be that transistor in vp but nut sure if i should have codes or can it be bad and not have codes. Any help would be highly appreciated!

[02cumminsdude]

I am sure the first question popping up in everyones head here is, what is your fuel pressure (if you have a gauge) if not, that's probably the first step. I just recently fixed my surging issue with a new APPS, but mine happened more frequently than yours.

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Also, did you use a scanner or do the key trick for the codes? Sometimes the key trick will not pull up all the codes.

[Dieselfuture]

I am sure the first question popping up in everyones head here is, what is your fuel pressure (if you have a gauge) if not, that's probably the first step. I just recently fixed my surging issue with a new APPS, but mine happened more frequently than yours.

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Also, did you use a scanner or do the key trick for the codes? Sometimes the key trick will not pull up all the codes.

the only gauge i have is from pulse2 monitor that came with qwad box i had to buy fuel pressure sensor and it is after filters before vp on idle it's usuly betwen 14-16 and it realy doesn't change much , only at wot drops to 12 or so. and the codes i did chech with the key trick. i had a code 500 but i think it's from spinning tires last winter. i did change my apps last year trying to figure this out, got it from timbo with instactions.

[02cumminsdude]

Well that's a good start. Another possibility I can think of might be some kind of turbo surge? You came to the right place though, more guys will chime in and help you out more than I can.

[Dieselfuture]

anybody else has any ideas on my surge problem? and just had it scaned with a better scaner snap on and had a 0500 code but not worying about that one. how do i know if transistor in vp ecm is bad? will i have some codes for it or should i pop cover of off vp and visualy see if anithing is mellted off. drove it today after playing with air dog and got pressure to 21 idle 15 wot has all kinds of power and hit 3k rpm with no problems or serges, just defuels after gets to 1250f temp, but it never realy cut out or surged before just driving seem to only notice it when pulling somthing on steady speed anything over 65mph. just out of blue starts to miss, and after all the time and money we all have put in our trucks id like to just enjoiy it for once with no stupid problems. my wife thinks im wasting time but she don't know anybetter.

[Homestead]

Since your truck is a 6spd, your cruise control is electronic. Take the truck out and see if it does the same surging with the cruise control set at the offending speed.If the surge goes away, the APPS is on the way out. Every 01-02 6spd truck I have run across doing this has been the same thing, surge goes away when on cruise, APPS is on the way out.At this point, it probably won't throw a code either so it makes it a challenge to diagnose.Had it happen a couple of times to myself, been there.Hope it helps, Jeff

[98whitelightnin]

Have you tried a different quad tune? I know my old quad would surge and its been a problem with them for years.

[Dieselfuture]

Since your truck is a 6spd, your cruise control is electronic. Take the truck out and see if it does the same surging with the cruise control set at the offending speed.

If the surge goes away, the APPS is on the way out. Every 01-02 6spd truck I have run across doing this has been the same thing, surge goes away when on cruise, APPS is on the way out.

At this point, it probably won't throw a code either so it makes it a challenge to diagnose.

Had it happen a couple of times to myself, been there.

Hope it helps,

Jeff

i put new apps from timbo and it didn't change anything, and i did try cruse on at that speed and also no luck, but thank you for the input!

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Have you tried a different quad tune? I know my old quad would surge and its been a problem with them for years.

yea i tried just about everithing with it even unpluged it und pluged map sensor back the way it's supposed to be, as far as truck could tell there was no qwad box on it and it still diit it, just not as notisble i think qwad makse problem worse but don't think it's problem. i talket to jermy at qwad and he said that my box is resent enought has the latest softwere and bla bla bla and thats why i tryed unplugin it becose i don't always belive salesmen. but hi did give some good info. so anyway i'm thinking about poping that cover on vp to see if transistor or somthing else is fried. but would like to try other thing first. thanks!

[diesel4life]

Does it make any kind of a difference whether your truck is warm or cold? Make sure youve got good batteries weak batteries will play hell on these trucks although it doesnt sound like your problem is frequent enough to be battery related. Unfortunately it does sound like a fuel problem and if youve got good lift pump pressure that only leaves the vp to be suspect.

[Dieselfuture]

Does it make any kind of a difference whether your truck is warm or cold? Make sure youve got good batteries weak batteries will play hell on these trucks although it doesnt sound like your problem is frequent enough to be battery related. Unfortunately it does sound like a fuel problem and if youve got good lift pump pressure that only leaves the vp to be suspect.

i realy don't know about warm or cold by the time i worm it up and hook trailer and get to hwy its fully wormed up, but just driving it in colder weather does seem to run better, but i think its from air being dense, i did put new batteries lust year with all new conectors soldered in. that's why im kind of thinking vp is going but i get 20mpg on hwy and 15-16 city with bigger injectors oversized tires, that's why i think its not internals but rather electrical. if it's electrical then the only thing i heard is transistor going bad, but then again would i have codes for it or not. and what does that transistor control? a fuel silinoid maybe, if so i can see it beeing a problem, then all i got to do is take cover of vp and see if anything is cooked.:banghead:

[gassernomore]

Make sure youve got good batteries weak batteries will play hell on these trucks although it doesnt sound like your problem is frequent enough to be battery related.

I know that the OP truck is a stick, but with my auto if I don't have good connections on the battery my truck surges like the Op is saying.

[Dieselfuture]

I know that the OP truck is a stick, but with my auto if I don't have good connections on the battery my truck surges like the Op is saying.

OK, I know it's been a while but I haven't used the truck since last time I was on this site. Just went out of town round trip was almoust 300 ml, towing my goosneck and my toy on it. avareged 10 mpg. the worst i've ever got yet, but the fuel was from late fall. This time it statrted to serge around 65 mph, I set cruse on and it seemed to help a lot if not took care of it all together. I know some of you say that it's more likely APPS but i have no codes and it's only got maybe 2-3k on it. got it from Timbo. triyed reseting it but didn't help. maybe not doing it right. also got my hends on FLUKE 97 Scopemeter and tested my betteries for AC voltage highest it's got was 0.056 reved up to about 2k, idle it's between 0.000-0.005 Vrms. so I don't think it's diodes. Any other thoughts? Could it be somthing else with cruse control? it did seem to make a big diference this time with it on didn't surge as bad. It was actualy driveble.

[CUMMINSDIESELPWR]

what does it do holding steady throttle with your foot? does it do this with fuel box unhooked?

[Dieselfuture]

what does it do holding steady throttle with your foot? does it do this with fuel box unhooked?

If I keep throttle in one place when it acts up it getsworse and almost not drivable, but it won’t throw a code, seems to do it around17-1800 rpm or close to 60mph. Used 3 different scanners, only code I ever seenwas 500. I tried unhooking Qwad box and pluggingthe map sensor back the way it’s supposed to be factory not trough qwad wiring.And it didn’t seem to make any difference. Maybe I should unhook everythingthat has anything to do with qwadzilla and try it again. At this point I’m a littlelost and really don’t want to buy vp44 unless I get a code for it.

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Well I just went through all of my battery cables and re solderedall of the connectors. Then added two grounds, one to the body and one to theframe. Checked voltage to APPS and reset it again. Then I drove it again, and it seems good but there is a small hesitationaround 1800 rpm, and my tachometer is bouncing a little. If I was pulling mytrailer then I’m guessing it would be a lot worse just like always when pulling.Funny thing is I bought this truck to pull a trailer. My friend at the sametime bought a Chevy with a big block 4 times cheaper and never had a problem,thinking now I should of done same thing. But I think maybe I’m just mad wrightnow. Scanned it again when I came back with Blue Point Scanner and no codes. Canit be Cam Sensor? Or is there something I'm overlooking? Why don't I have any codes, maybe if I kick it tomorrow:kick: it will throw a code so I know what to fix.

[Ilikeoldfords]

I know you just replaced the APPS but it sounds exactly like what my truck was doing when my APPS went out. about the same rpms, same conditions, and you have about the same truck and set up that I do. I didnt have any codes either. You might also shoot Chip an email over at blue chip diesel. He also breaks down the VP to the basics so you know how it works and everything. Pretty good guy. Hope this helps and good luck figuring out the problem!!

[cajflynn]

You can try hooking up the voltmeter to the APPS and watch it to see if the values change when you are surging or not. You might also call Tim (of Timbo apps) and ask him what he thinks.

[Dieselfuture]

You can try hooking up the voltmeter to the APPS and watch it to see if the values change when you are surging or not. You might also call Tim (of Timbo apps) and ask him what he thinks.

I have a fluke 97, really accurate meter. Are you sayinghook it up and drive the truck and see what it's doing when it acts up or justhook the meter up when sitting still and start the truck, throttle it upand see if voltage jumps? either way sounds like something i should try.

[cajflynn]

As you are driving. You may have to tape the vm to windshield or something. If it fluctuates then maybe the APPS is bad. If not, maybe the vp44.

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People that have a scan gauge can see the values for the tps on their gauge. The values will go up as you press the pedal. So if the truck surges and there is no corresponding increase on the tps values then the apps is not causing the surge.

[Dieselfuture]

what does control my tachometer? I don't think I havecrank sensor I think all I have on 2002 is cam sensor. Is cam sensor what controlstach or is there something else? I would like to start eliminating some issues. Because my tach bounces same time It surges and on idle and pretty much all the time, about 100-200 rpm or so. So anyway if I can fix my tachometer it would be a start. Maybe they all do it, but I don't think it's normal got to be some wiring or something.

[cajflynn]

Cam sensor. My tach has always jittered. No idea how to fix it.