adamzan Posted December 21, 2011 Share Posted December 21, 2011 I would look into the MAF sensor wiring at the connector, it is common for it to get weak and have this kind of problem, see if wiggling the wires helps. Link to comment Share on other sites More sharing options...
Tungsten Posted December 21, 2011 Share Posted December 21, 2011 (edited) I have had that same issue ever since I put in my 2.5" exhaust. The only fix is to wait until it warms up a little so the oxygen sensor can kick in and do its job. I'm thinking it's related to how the ECU was programmed and that's it. I also have a brand new MAF sensor and fixed that wiring for good. Let me know if you discover anything though. Edited December 21, 2011 by Tungsten Link to comment Share on other sites More sharing options...
Nefarious Posted December 21, 2011 Author Share Posted December 21, 2011 And after you ran it a while warm the ecu learned the new air flow and went back to normal? yeah there is a HUGE difference for the computer.... it was a 3.0 with stock everything and crappy exhaust and clogged air filter, now its a vg33 with full intake/headers/2.5 exhaust... i figured it would have some learning to do!! lol Link to comment Share on other sites More sharing options...
Nefarious Posted December 21, 2011 Author Share Posted December 21, 2011 i will check the maf as well tomrorow. i did have to pull some extra slack out of the harness and re tape it so i had a bit more play cause I aimed my air intake forward to clear room for my power steering reservoir. could have jostled something. although it runs GREAT once its above 800-1000rpm. Link to comment Share on other sites More sharing options...
Nefarious Posted December 22, 2011 Author Share Posted December 22, 2011 So everything with the truck is perfect aside from the hesitation/bog just when taking off initially... if u give it a lot of gas it will actually shut the engine off. if u just give it a tiny bit of a gas until it climbs from 750-900 or so rpm then u can rev it fine and give it lots of gas, and has lots of power. its just when it's going from idle to revs under load. under no load the problem doesnt seem to happen at all (free revving). Any more ideas? I know for a fact both of these engines ran well before the swap. Mine old one had low compression on a cylinder but it ran fine and revved fine and aside from being a little underpowered had no issues. The engine I swapped in came from a running truck which I pulled it out of and I ran the motor and put it through the paces before I bought the donor truck. I wiggled the maf connector and it didn't seem to effect anything although it's pretty hard to do it when I am driving the truck under load. Lol.... I need a small person to sit on my engine while i run the truck!! hahaha. I'll take some close up pictures tomorrow of the wiring.. Also could someone please post up a picture of the stock VG30E grounds and where they are routed for the ones around the coolant temp sensor? I don't like how those are grounded... I may run a ground jumper from those grounds back to the chassis to make sure they are solid. The metal they are bolted to(the only bolt hole around) looks suspect. Also there shouldn't be an issue joining the 3 grounds together in that aforementioned area should there? I do have them run together as I couldn't forget exactly how they went. ya ya I should have taken pictures first, I know.... I was eager! lol Link to comment Share on other sites More sharing options...
Tungsten Posted December 22, 2011 Share Posted December 22, 2011 No, you can combine grounds to one source just fine. The factory grounds go from the manifolds to the fenders wells. The one on the driver's side is right above the steering box on top of the fender well. Link to comment Share on other sites More sharing options...
Nefarious Posted December 22, 2011 Author Share Posted December 22, 2011 Yeah i got those grounds. But im talking the ones that come off of the main harness that runs across the front of the motor. right where the coolant temp sensor is. there are a few grounds there.... i wanted to see where they are grounded to... Link to comment Share on other sites More sharing options...
Tungsten Posted December 22, 2011 Share Posted December 22, 2011 I think I know what you mean now, I'm going to go check tomorrow. Link to comment Share on other sites More sharing options...
Nefarious Posted December 22, 2011 Author Share Posted December 22, 2011 awesome thanks man, appreciate it! Link to comment Share on other sites More sharing options...
JamesRich Posted December 22, 2011 Share Posted December 22, 2011 You can't have too many grounds on a computer controlled vehicle. You can buy grounding kits for newer vehicles but its easier to just do it yourself. If you are suspect of a ground take your multi meter on ohms and touch between the suspect ground and the negative post on the battery. You SHOULD have no resistance in a perfect world. In our world if you have more than 1 ohm run a ground from where the negative battery cable bolts to the fender to the suspect ground then check it again. If you made you cable right it should have no resistance. You can even run grounds between you body and auto trans to help it shift better. Just go poking around with your meter, if you find too much resistance between two grounds put a jumper. The main parts that need a good ground are from the battery to the intake for the injectors, from battery to the body for the ECU, battery to alternator, and body to trans on a auto. James Link to comment Share on other sites More sharing options...
Nefarious Posted December 22, 2011 Author Share Posted December 22, 2011 good tip. I will go poke my girl today with the multimeter and figure this out. Link to comment Share on other sites More sharing options...
Nefarious Posted December 22, 2011 Author Share Posted December 22, 2011 Okay so I tested around everywhere. I added a jumper to the grounds i suspected. I tested all the grounds I could find and one ground seemed pretty bad but it was the one coming off the alternator harness as well as one I am not sure what it was for but right behind the battery.. they read about 3 ohm or maybe 4. anyways I rerouted those right to the negative battery cable where it first grounds to the chassis. so that is now a 0 ohm. also the TPS connector seemed loose so I took it out, tightened and cleaned the contacts. did the same for the MAF. They are on much more snuggly now. The TPS seemed to be almost loose originally. Didn't notice when I was plugging things in in a hurry. I also put in a jerry can of premium and a heavy dose of fuel injector cleaner. I can honestly say it is running MUCH better now. The bog is nearly 100% gone now and it doesn't die out anymore!! I still have yet to throw the tail pipe on the end of the muffler but I don't see how that could effect it. I also noticed my O2 sensor bung seems a little long.... I used a nut from the auto store and it is a little wide... I think I will take that middle piece back out and grind the nut down some so the sensor sits further into the stream of exhaust. It might be held back a bit I wonder if that would matter too much. Anyways it's almost there! Definitely driveable now I'm going to insure it today!!! Woooo!!!! Hopefully this last tweak makes it perfect. Link to comment Share on other sites More sharing options...
Tungsten Posted December 22, 2011 Share Posted December 22, 2011 (edited) They have all been pretty long in my experience so don't bother with the O2 bung nut. As long as it still sticks out somewhat it should be just fine. Edited December 22, 2011 by Tungsten Link to comment Share on other sites More sharing options...
Nefarious Posted December 23, 2011 Author Share Posted December 23, 2011 Yeah I did end up grinding down the o2 bung so it was lower profile like the stock one was. Maybe I wasted my time but just trying to eliminate everything!! Finished up the tail pipe today in 3" pipe (I already had the 90 bend and tail pipe bit so I just reused it) although I would like to make one in 2.5"... The 3" just sounds so aggressive and it's just a hair too loud. Fan controller wiring is finished and I got everything ready to rock now... I'll swap insurance over tomorrow and keep updated on how it goes.. Link to comment Share on other sites More sharing options...
Tungsten Posted December 23, 2011 Share Posted December 23, 2011 yeah a 3 inch tip will sound good Link to comment Share on other sites More sharing options...
JamesRich Posted December 23, 2011 Share Posted December 23, 2011 Okay so I tested around everywhere. I added a jumper to the grounds i suspected. I tested all the grounds I could find and one ground seemed pretty bad but it was the one coming off the alternator harness as well as one I am not sure what it was for but right behind the battery.. they read about 3 ohm or maybe 4. anyways I rerouted those right to the negative battery cable where it first grounds to the chassis. so that is now a 0 ohm. also the TPS connector seemed loose so I took it out, tightened and cleaned the contacts. did the same for the MAF. They are on much more snuggly now. The TPS seemed to be almost loose originally. Didn't notice when I was plugging things in in a hurry. I also put in a jerry can of premium and a heavy dose of fuel injector cleaner. I can honestly say it is running MUCH better now. The bog is nearly 100% gone now and it doesn't die out anymore!! I still have yet to throw the tail pipe on the end of the muffler but I don't see how that could effect it. I also noticed my O2 sensor bung seems a little long.... I used a nut from the auto store and it is a little wide... I think I will take that middle piece back out and grind the nut down some so the sensor sits further into the stream of exhaust. It might be held back a bit I wonder if that would matter too much. Anyways it's almost there! Definitely driveable now I'm going to insure it today!!! Woooo!!!! Hopefully this last tweak makes it perfect. Grounds can make a big difference. Electronic components can't work like they are designed to do without the power and ground they were designed to have. James Link to comment Share on other sites More sharing options...
Nefarious Posted December 24, 2011 Author Share Posted December 24, 2011 (edited) Yeah since I went through and just made every connection immaculate and re did all the grounds to make them very strong and cleaned everything. added some jumpers. set the o2 deeper in the bung, put in some premium gas and injector cleaner. and started driving it around today. BAM. RUNS LIKE A DREAM. Everything is just perfect now! The ECU needed a bit of real driving time under load to figure itself out and now it just purrs like a kitten. Thanks for all the helps guys getting this beast running! What a difference in power and driveability, as well as gas mileage! This pathy will be on the road a LONG time. Man it was fun to go wheelin again today... Haven't played in the mud or trails for 6 months!!!!!! Edited December 24, 2011 by Nefarious Link to comment Share on other sites More sharing options...
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