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Timing/Gutlessness Resolution


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After I put my new engine in I set the timing by ear and by idle speed.. I have adjusted it back and forth since then without any real results but a persistent gutlessness until 3k RPM. It was a pain, a chore, to drive in any fast paced traffic since I simply couldn't speed up as quickly as everyone else... not just a little less quickly but painfully less quickly so that I had to floor it to get up above 3k RPM.

 

So I searched high and low for a rental timing light and for someone who might let me borrow theirs, no dice. So finally I bought a bluetooth scan tool, the BlueDriver which I'm going to make a separate thread for, and used the live data to set the timing.

 

So on the live data feed I selected "Timing Advance for Cylinder #1" and then while looking at the feed I slowly adjusted the distributor until the feed was at its absolute lowest point (which was +5deg). It worked!

 

I don't have power that wasn't there before or anything but now I can access what power is there below 3k RPM. It's really great. I mean it's still the VG33 but it does just fine now. It's still slow getting up to speed but it's not outrageous anymore and doesn't cause people to be angry with me because I'm so slow..

 

I didn't screen shot the Timing Advance before and it's too late now but here is what it looks like:

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ad97283e4a899902d8b8a7292fa9130b.jpg

 

 

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Edited by onespiritbrain
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I left out something important...

 

So before I adjusted the timing I was getting a knock sensor (p0325) code. I cut in the old knock sensor from my other engine and put it on top of the intake which reduced its ability to hear and call for timing adjustments. After the relocation I had probably twice the gutlessness. It flat out bogged down between 2k and 2.5k RPM.

 

Just FYI

 

 

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So I've noticed now that in place of the bogging I have a bit of surging. It's "quicker" than surging, more like jerking.. well something in between surging and jerking.

 

The amount of power is constant, increasing smoothly with the RPM, but there are half-second bursts with a slight lull at the end before returning to the constant power of acceleration.

 

There are about 2 or 3 of them between 1700-3000 RPM.

 

I want a smooth acceleration..

 

 

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  • 4 weeks later...

Dirty MAF causes issues. At wide open throttle it does not apply because it goes to max duty cycle on the injectors. or at least a pre programmed max. so you could simply have something going on where it takes a wide open throttle ready to get any acceleration. check the ground on the MAF plug and clean the maf. dont clean it after the truck has been running a long time. let it cool off. that hot thin wire may not like cooling down quickly with maf spray.

 

Whatever it is, you will probably know it if you find it. everything is check-able. do a check on suspected components.

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I am honing in on some misfires.

 

I can’t use this scanners mode 6 function because apparently Nissan used different hex system for identification so I can’t make out what any of it means except o2 pass/fail results. Otherwise I’d be able to see exactly which cylinder is misfiring and whether or not it’s ignition, air, or fuel related.

 

I plan to get a low-as-possible mileage distributor next time I go to pullapart. Also I want to get MAP and MAF sensors.

 

Also while my car is on the way to getting warmed up I still have some long slow surging during acceleration. Once warm I am still seeing smooth power thru upper rpm.

 

 

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The more symptoms you observe the better, more data = better diag. surging during warm up could be misreported fuel or air. Pull the plugs and see if they are wet and smell like gas. If not it is probably an air thing. The idle air control under the upper intake plenum causes problems when it sticks. so does the coolant temp sensor in the top of the lower intake. "there are two" one is for the guage and the other for the computer. "wish manufactures would just use the same one for both". would make life so much easier there lol. Anyways. Put ur hand over your tail pipe and make sure you get a good rhythmic thump thump thump from each cylinder. if not possible cats stopped up and motor cant breath. If egr is still in play, you could have a stuck open egr making a perma vacuum leak. could be a malfunction with the valve that controls the outflow from the charcoal canister making another "perma vacuum leak" sometimes you can hear an air flow sound coming from the fill cap area in that case, not always though so take that with a grain of salt. could be a lot of stuff. But narrow it down to too much fuel or air or not enough spark and you can go from there. Start with the stuff that is easy to check, idle air control, example...if you are idleing at operating temp turn the steering wheel and see if rpm goes up 50 to 100 "sometimes more" that is a quick and dirty for the idle air control. clean the MAF stuff like that. probably something relatively standard in the end. I am rooting for you. hope this helps some.

 

 

Pat

Edited by fixinto
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I just saw this reply man, thank you. I actually do have an issue with gas dripping out of my charcoal canister.. I also have a hissing noise coming from where the brake pedal linkage travels thru the firewall which disappears the instant I barely press the pedal.

 

Thanks again man

 

 

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