One last shot... Breaking up!

[WyoSyclone]

Re: One last shot... Breaking up!

...and I'd sure follow John's advice about checking the factory wire where you were tapped in for the AF gauge.. if that wire is intermittent it could be a cause... and, you say it started as soon as that gauge was removed.

 

[AB TY 752]

Re: One last shot... Breaking up!

Anyone think this could be related to the coolant sensor? I was advised to check into this when i had a very rich condition. This is completely the opposite,but you stated that this gets worse the hotter it gets. Am i way off base?

 

[BoostedSUV]

Re: One last shot... Breaking up!

Rob that's not dumb question and you're not the first to ask me that. There is an aluminum hollow adapter that screws onto the fuel rail and raises the sender/guage about 2 inches up off the rail so it would be impossible for it to interfere with flow. That's definitely a logical question though. As far as the purple O2 signal wire that I tapped into for the A/F gauge it looks good and didn't appear to be broken. I will give it a good look tonight however. I may just cut the section out that I t-tapped into and reconnect the wires with a heat shrink terminal. it seems too coincidental that I removed the t-tap and the wire from it that went to the ECM and this all started. Like I said I visually looked at It and I didn't notice anything but I will "repair" it tonight just to eliminate that.

 

[2kwik4u]

Re: One last shot... Breaking up!

We had a goofy ass stumble in Jeff's Typhoon after he put the V8 in there. Running Code59, it would go into "Quasi Ansychronys Fuel Delivery" under cruise. It would basically shut off 1/2 of the injectors under certain cruise conditions around the same RPM you are referring to. We were able to change the parameters on that inside the bin file, and got it to go away by keeping it out of that goofy fueling mode.

Dig:

Any thoughts on if this might be the same scenario? It has the same symptoms as Jeff's problem with the exception of Jeff's problem was at cruise not at a stand still like this guys. Any thoughts?!?!?!

 

[BoostedSUV]

Re: One last shot... Breaking up!

In response to the above ^ it does it when I'm driving the truck as well... Pulling out from am idle the truck really stumbles at very specific RPM's. Under a boost load the truck is fine. I can make it do it at a stand still in park but its worse when the motor is under a load

 

[turbodig]

Re: One last shot... Breaking up!

We had a goofy ass stumble in Jeff's Typhoon after he put the V8 in there. Running Code59, it would go into "Quasi Ansychronys Fuel Delivery" under cruise. It would basically shut off 1/2 of the injectors under certain cruise conditions around the same RPM you are referring to. We were able to change the parameters on that inside the bin file, and got it to go away by keeping it out of that goofy fueling mode.

Dig:

Any thoughts on if this might be the same scenario? It has the same symptoms as Jeff's problem with the exception of Jeff's problem was at cruise not at a stand still like this guys. Any thoughts?!?!?!

I'd doubt it. Jeff had different issues since it's a different type of motor entirely. On a stockish truck, shouldn't be the case.

He also mentioned trying the stock memcal, which rules out a bad calibration, provided a stock MAP sensor was used with it.

Something getting in the fuel rail and plugging injectors could do this too. As could a couple bad injectors, but it would be odd that they'd go bad like that at once. You'd see it in the plugs, too, which ones it was.

Gotta go back to what 'caused' the problem, which was the removal of the AFR and install of the FPR.
My bet is that there's a wiring snafu somewhere...

 

[turbodig]

Re: One last shot... Breaking up!

In response to the above ^ it does it when I'm driving the truck as well... Pulling out from am idle the truck really stumbles at very specific RPM's. Under a boost load the truck is fine. I can make it do it at a stand still in park but its worse when the motor is under a load

All of this points to the o2 sensor circuit - Under boost, the sensor doesn't get used (open loop). When the vehicle first starts, the o2 doesn't get used, but does as the vehicle gets warmer.

Only other option I can think of is a really massive vacuum leak, like the lower intake gasket on one side or another.

 

[NecroWolf]

Re: One last shot... Breaking up!

Anyone think this could be related to the coolant sensor? I was advised to check into this when i had a very rich condition. This is completely the opposite,but you stated that this gets worse the hotter it gets. Am i way off base?

i've seen this happen before. the guage sensor was fine but the ecm sensor was in tolernce but reading way off to the actual condition. if its closed loop only then i'd check what the ecm gets input from for that.

 

[BoostedSUV]

Re: One last shot... Breaking up!

i've seen this happen before. the guage sensor was fine but the ecm sensor was in tolernce but reading way off to the actual condition. if its closed loop only then i'd check what the ecm gets input from for that.

Gauge sensor and ECM sensor read the same acording to Datamaster. I would asume the reading I see on DM is via the ECM sensor and not the gauge sensor

 

[BoostedSUV]

Re: One last shot... Breaking up!

Well guys... I worked on the truck for 3 hours tonight and still didn't get anywhere. I cut out the section of o2 signal wire where I had A/F gauge t-tapped and I put in a heat shrink butt connector. I'm positive that wire is a solid connection now. I dropped ECU out of glove box and pulled harness down to the floor and inspected every wire... nothing. I even ohm tested the ground to the ECM case and it was .20 OHMS so I ran a ground wire to the case and got it down to .09 ohms with truck running (just trying things)

I unplugged the 02 sensor from the truck and that did nothing as well... No check engine light or anything but didn't make the breaking up go away. (wideband goes to 17-19+)

I messed with fuel pressure and if I set it 30psi at idle it barely breaks up, if I turn it up to 42 at idle it breaks up real bad. The truck was tuned for 50psi base FP which is about 42 at idle so turning it down would not be a safe "cure." I did verify correct Fuel Pressure with a mechanical gauge.

One thing I noticed, with base fp set to 50 the truck will idle at 42psi with 15hg in vacuum (on the gauge). Shouldn't it idle at 35 with 15hg in vac? isn't it 1 for 1 for boost and vac?

If anybody would like to look at the DM files, or the .bin file I'm using I will send them over! I know the truck had this issue before Nolan and I started tuning it and we were able to make it stop. Maybe it's fixed now and whatever fueling he changed is compensating in the wrong direction now??

I bought NGK TR55 plugs to try.. I will throw them in next day I'm around. Any more input?? Thanks everyone! Stick with me and help me get this fixed!

 

[BoostedSUV]

Re: One last shot... Breaking up!

All of this points to the o2 sensor circuit - Under boost, the sensor doesn't get used (open loop). When the vehicle first starts, the o2 doesn't get used, but does as the vehicle gets warmer.

Only other option I can think of is a really massive vacuum leak, like the lower intake gasket on one side or another.

Dig the truck Idles fine, 875/900 IAC is at 35 counts, TPS .55 volts. A massive vacuum leak would raise the idle for sure and I would not see 15-18hg in vac. Just for sh*ts and giggles I did spray carb cleaner around the TB, Lower, and Uppers gaskets just to see.

If I sent you the .bin I'm running could you see if anything looks shakey? I know Nolan made a move that affected the Short Term counts and that made this stumble get better a over a years ago. The S-Terms are always on the negative side, now when it breaks up they jump to +42. I'm not a tuner, I just know what I see so I'm not sure what this all means? +42 is obviously trying to compensate for the lean condition...

 

[BoostedSUV]

Re: One last shot... Breaking up!

Dave any good tips for tracking down each wire? once the three ECM connectors join, about 8 inches down, everything just goes into one big harness wrapped in tape. Would a wire diagram of where each ECU wire ends up and a multimeter be my best bet? This way I can verify everything starts and ends where/as it should? I'm convinced it's something silly and I just need to find it.

I'm thinking way back and I always recall a few "rough spots" in my RPM range even back when I had the Ultimate chip before the custom tune days. It's always been the same 1100, 1900, 2500. It just seemed to "go away" one day and now it's back!

 

[BoostedSUV]

Re: One last shot... Breaking up!

Hmmm. I would start by inspecting the terminals at each connector as suggested above.

Then inspect the harness covering carefully for any signs of burns or abrasion. If you find any suspicious spots, cut them open and check the wires physically. If it looks OK, then do the continuity check.

I think the pins and terminals are the most likely thing to break, or have a bad/intermittent connection. Rarely do I find bad wires. And those are always visible upon close inspection.

when I wired the WBO2 to the ECU last week I looked over every wire at the 3 plugs and I didn't see anything broken off? I guess what you're saying could happen is the terminal pin breaks inside the main connector but it will remain clipped in therfore the wire will not fall out or appear to be broken but it will not be making a good connection to the ECU? Just want to verify I'm following you correctly. So I should look into the ecu side of the connector and pull each wire in and out and verify the terminal is moving on the ECU side... makes sense, I didn't try that yet. Thanks Dave, if I'm way off here point me the right way.

 

[WyoSyclone]

Re: One last shot... Breaking up!

I guess what you're saying could happen is the terminal pin breaks inside the main connector but it will remain clipped in therfore the wire will not fall out or appear to be broken but it will not be making a good connection to the ECU?
Exactly!

Just want to verify I'm following you correctly. So I should look into the ecu side of the connector and pull each wire in and out and verify the terminal is moving on the ECU side...
Yep, that's it.

makes sense, I didn't try that yet.
It's a long-shot, but I did find exactly this on the Jeep. Many, many hours were spent chasing shit until I found it.

Thanks Dave, if I'm way off here point me the right way.
You're Welcome. You'll get it.

Those are great tips Dave.... one thing I've also done in the past is to get a male teminal (say out of a bad ECM) and slide it into each female connector in each terminal housing. If you get one that feels loose and sloppy (clean it up guys ) you can make an assumption that that connector may be causing problems.... then you can take it out of the housing, slightly collapse it with a pair of pliers, then retest with the male terminal.... just a thought....

 

[NecroWolf]

Re: One last shot... Breaking up!

you get the datamaster files up?

 

[BoostedSUV]

Re: One last shot... Breaking up!

Those are great tips Dave.... one thing I've also done in the past is to get a male teminal (say out of a bad ECM) and slide it into each female connector in each terminal housing. If you get one that feels loose and sloppy (clean it up guys ) you can make an assumption that that connector may be causing problems.... then you can take it out of the housing, slightly collapse it with a pair of pliers, then retest with the male terminal.... just a thought....

another great thought Rob... I was actually trying to think of way to do exactly that. When I did the WBO2 install I noticed how easy it is to bend a terminal and wondered if it was possible one could have 'opened up' making a bad connection. I dont have a bad ecu to mess with but I'm going to try and come up with a way to check exactly that. Paper clip maybe? It obviously has to be the correct diameter to accurately test if I have a loose terminal. .

I will be away racing from thurs- sun but I will be back at this on Monday! I'm close to giving up but I'm not ready to throw in the towel yet. Keep the ideas coming!

 

[BoostedSUV]

Re: One last shot... Breaking up!

you get the datamaster files up?

I can email them but I don't know where to host them so I can post a link...

 

[BoostedSUV]

Re: One last shot... Breaking up!

Alright I finally got around to working on the truck again.. here's what I tried: I did as Dave P suggested and I pulled on each individual wire and verified that the terminal was still connected and intact all the way through the connector. All was well...

I then did as Rob(WyoSyclone) suggested and found a small drill bit the same diameter as the ECU connector pins and I slid it in and out each and every terminal on the ECU connector harness. I found a few moderately loose but nothing off the wall loose. I did pull the looser ones out and crimp them tighter and placed them back into the connector.

I checked ground wire on back on driver head to be sure that was tight and wires weren't broken off, and I verified ground to the O2 sensor.

I fired the truck up and I still have the same thing going on! Truck goes lean and starts popping at 2500-2600 (WB reads 19+) and if I continue to hold the throttle and that spot it will clear up and jump to 3000 and be pig rich (WB reads 11.5) If I continue to hold the throttle the position the ECU will compensate for it being rich and the WB will steadily work its way back to a 14.5 reading.... It apears that all functions of the ECU are working and the truck does really go lean but I'm not sure why in that RPM range every time? I'm out of ideas guys! What else can I look for??

 

[WyoSyclone]

Re: One last shot... Breaking up!

Wow, looks like you've covered just about everything... at this point I'd probably have to try swapping a few sensors (MAP and O2 being first). I haven't thought it through so don't know if a TPS could do it, or not.... if you sit with the truck off, key on, TPRT or DM running... can you slowly press throttle to 100% and check for linearity?

 

[kentuc]

Re: One last shot... Breaking up!

Magnetic pickup coil.