Fully Built Blacktop having multiple issues....

[JesterX18]

After 4 years of building my SR20DET I finally have it starting. The bad is that it wont run with the Z32 MAF Plugged in.... In addition I have the quest alternator conversion on this car and it wont charge the vehicle...It has a brand new wiring specialties harness and a Jim Wolfe ECU tuned for the supporting mods. So for starters I just tested the MAF voltage at idle. Its got good chasis and ECU grounds. It has its 12V switched power and is putting out just over 1 volt at idle. I have tried unplugging other sensors as well with no change with the maf plugged in... When the MAF is plugged in its running lean over 17 AFR and then stumbles a bit then dies.... the car idles around 1800 with the maf unplugged and the AFR is about 10. Any ideas or suggestions from the SR savy on this site would be greatly appreciated...just sick of set backs with this car and wanna get it on the road. And as stated previously it runs smooth when in limp mode, a lil rich and cant rev. Thanks everyone in advance. :bow:

[steve shadows]

After 4 years of building my SR20DET I finally have it starting. The bad is that it wont run with the Z32 MAF Plugged in.... In addition I have the quest alternator conversion on this car and it wont charge the vehicle...It has a brand new wiring specialties harness and a Jim Wolfe ECU tuned for the supporting mods. So for starters I just tested the MAF voltage at idle. Its got good chasis and ECU grounds. It has its 12V switched power and is putting out just over 1 volt at idle. I have tried unplugging other sensors as well with no change with the maf plugged in... When the MAF is plugged in its running lean over 17 AFR and then stumbles a bit then dies.... the car idles around 1800 with the maf unplugged and the AFR is about 10. Any ideas or suggestions from the SR savy on this site would be greatly appreciated...just sick of set backs with this car and wanna get it on the road. And as stated previously it runs smooth when in limp mode, a lil rich and cant rev. Thanks everyone in advance. :bow:

Have you tried process of elimination? I.e. stock alternator?

Also have you also made sure that the maf wiring is correct to the Z32?

Common sense but it sounds like you're running with no maf reading.

[JesterX18]

I have an 8 pin connector that when double checking my wiring specialties instruction is supposed to plug into fuse box, unfortunately there is no connector for it to plug into. So I think that will fix my alternator charging issue when I figure that out.... As far as the maf goes ive triple checked the wiring, but It was all done by wiring specialties and it all reads out good.... I would love to know what the 8 female pin connector is supposed to be used for though. Being that it goes into the fuse box it may fix all my problems.... Its one of the three that are on the lower transmission harness that connects to fuse box.... theres a brown connector on the side of the fuse box that seems like its 8 pins but this connector wont snap into it... My car has been 5 speed swapped so im thinking the connectors may be different... Currently messaging both Jim Wolfe and Wiring Specialties to sort it out. Thinking my ECU may have been turned for the wrong MAF. Only ideas ive had so far....

[JesterX18]

So I've sorted out a few of my issues. The charging issue was caused by the wrong specialties harness which doesn't provide the proper connection to the fuse box.(for auto to manual swaps) simply contact yury and hell send you the correct connector to repin. Since this last post I have set timing, fuel pressure,compression tested,vacu tested and tested my MAf and wiring to the ecu. Problem I'm having is that the car runs rough with MAf plugged in and idles smooth unplugged. Car is all there if you drive it with maf plugged in but stalls out when're you come to an idle. I'd like to try to pressurize my intake system as some people has stated it works, but I don't see that method working with valves being open in the head. Suspect a vacuum leak at this point...

[jr_ss]

Soapy water in a spray bottle and go over all couplers and connections. You can also use some carb cleaner around your injectors, throttle body and IACV. You'll know with either one if you have leaks some where. You can also build a boost leak tester that goes on to the turbo inlet and pressurized the entire system. You'll just have to find a cap to work on the end of the line so pressure cannot escape. Pressurize up to 25lbs.

[Mikester]

Do you have a spare OEM MAFS laying around? I wonder if JWT didn't correct for the Z32 MAFS...

Another question: Is it an OEM Nissan Z32 MAFS, or the ISIS knockoff? ISIS Z32 MAFS's have been known to be very hit/miss and most of us with Z32 MAFS stick to Nissan units.

Sucks about your alt charging problem... I had the same issue with the auto/manual swap connector at the fuse box, but only affected the speed sensor... There are two 8-pin connectors that are fairly identical... Hopefully you have the right ones going to the right plugs... because my alternator charges fine and I have not yet installed the connector Yury sent me for speed indication.

[JesterX18]

I have a Isis sr20det maf(new) and two oem n62 mafs because I assumed the MAf was bad immediately... Been back and forth with Ben from jwt, I had to send him a label to confirm programming for the tune. He said its for the z32... The voltages seem to be spot on for the MAf too. It was 1.3 volts at 1100 Rpms and all signals, power an ground were good.(back probed ecu) thinking it may have something to do with the higher idle...( gonna sweep the whole motor for vacuum/boosts leaks this weekend. And yeah that wiring issue could of just been the last batch he made, I'm sure hell have it straightened on the next batch of sr harnesses. You have to convert the 8 pin to a 4 pin and match up wire colors... To the fuse box. Hoping to have it straightened out this weekend so I can finally drive this thing... I'll update with what I find to help other people that may have similar issues. Thanks for all the input everyone.: )

[Def]

Voltage sounds about right for a cold idle. This is one of the reasons I'm not a huge fan of ROM tunes over the mail, as when you've got a problem it's really hard to eliminate them as an issue (they are usually not the issue, but like I said, hard to troubleshoot).

Only vac leaks that will really make an engine run really lean at idle are between the TB and head, so that narrows it down. It running lean when you plug in the N62 is strange.

[Mikester]

^^Not if he got one of the junk ISIS Z32 MAFS's... I hope it's something else silly... but I would NOT rule that MAFS out.

If it still ran shitty with the N62 MAFS' plugged in, it is probably indeed set for Z32 MAFS and the ISIS MAFS is the problem... Unless I read that wrong(?)

[JesterX18]

^^Not if he got one of the junk ISIS Z32 MAFS's... I hope it's something else silly... but I would NOT rule that MAFS out.

If it still ran shitty with the N62 MAFS' plugged in, it is probably indeed set for Z32 MAFS and the ISIS MAFS is the problem... Unless I read that wrong(?)

No what I meant was I have an Isis sr20 MAf just kickin around in my garage from the first time I attempted swap. Both z32 mafs I have are 100 percent oem Nissan. I upped the quality of parts second time around for this swap. It's really fast when your driving it and doesn't really hesitate, but at idle it just wants to die...

[JesterX18]

basically everything is new and never been ran. I don't think my intercooler is leaking cause the couplers fit real snug and I double checked all clamps. The only spots that i feel it could leak would be at the brake booster internally....( never driven this swapped car) or at the injector seals... There new injectors and were flow tested for the tune but I did reuse the big rubber seals for the manifold, that and the circuit sports rail only has two points for support when you pair it with a greddy manifold. I still am not sure how it is gonna hold up. Guess I'll start there


Sent from my iPhone using Tapatalk (http://tapatalk.com/m?id=1)

[jr_ss]

Here's a thought; have you messed with your IACV at all? Have you adjusted it in or out to see if it changes anything idle related? Pull it off and clean it, unless you know it's clean. Spray some carb cleaner in the screw adjustment hole(obviously remove screw) if you don't want to pull it off and mess with it until it idles.

Also, do you have a BOV? If so, is it venting to atmosphere or plumbed back to the intake tract?

[ultimateirving]

If it's a new build 100% assure you a boost leak test will help find those hoses you missed. Pressurize the whole system don't wait.

[JesterX18]

So first let me say that I spent all weekend to get this car road prepped. Bumper,hood, fender,lights installed,fixed leaking heater hose,tape measure alignment(new rack), and finally installed my flexalite fan controller for the fans.(it's the next best thing to a discontinued dif...IMO ) only issue is mounting the screw in sensor.) best mounted with a self modified greddy radiator temp coupler. Anyway after installing I bled the coolant system with a spill free funnel, set fan temp and once warm the idle dropped to a steady 800rpms with a bit of a skip. But no stalling once warm. Previously I think the coolant wasn't bled enough and coolant may not have been warming iacv. Anyway aside from the engine running a bit rough it seems ok. Them I preceded to drive it again... Drives solid up until you come to a stop then immediately stalls...everytime...but wait there's more... I bypassed my tru boost solenoid cause my boost was creeping up into the twenties a few times on a 10lb spring... I have a codyace set up with tial 38mm v band. It crept up to 17 on the last test drive.wtf...! Got the external gate to avoid this boost creep problem... And lastly I compression tested engine once warm with a reputable compression tester and got 125 to 130 psi across the board...seem low for a fresh rebuild with 5 miles I on it? I'm running wiseco 9 to 1 pistons...for all that wondered about bov it's a greddy fv recirced to a greddy intake airnix kit...so my thoughts are possible faulty iacv, or low compression affecting idle? Btw I also pinched of brake booster hose, double checked all couplers, sprayed brake clean on intake manifold at all vacuum ports,injector seals,everything that has vacuum..no change in 800 rpm idle. Sorry for the lengthy post but this car is gonna be registered in a few days and I'm looking for any more ideas cause I'm stumped... Af ratio is odd too. Over 18 idle, 15 cruising, 14 boost. Fuel pressure is set to 43.5 and injectors are flow tested my jwt for tune...

[Mikester]

43-44psi FP is WITHOUT vacuum, yes? With vacuum, it should be 33-35.

[JKTUNING]

Why not get a system that you can actually use to get the car dialed in or take it to a tuner to break the engine in and help you sort out the issues?

If you are using just a mail order tune and aren't logging the car while doing these pulls on a fresh motor, you are simply asking for trouble.

As far as the WG creeping issue is concerned, what turbo and turbo manifold are you using? If there is a restriction on the WG elbow or you have a large frame turbo on the vehicle it might have issues keeping a lower pressure.

Did you do the compression test with the engine WARM and WOT? If not, try it again but this time with the throttle wide open.

Maybe snap a few pictures of the engine bay and we might be able to help you out a bit more.

[JesterX18]

Ill b driving this car by sunday and will have a much better idea of what its doing once a get some time with it, but yeah 43.5 with vacuum off. Know pressures is good also cause its air fuel ratio is good in boost and powerband is smooth. And yeah throttle open, warm, all spark plugs pulled, 4 revoliutions. Pretty certain after doing some more searching the compression will be ok after a proper break in. So as far as my boost creep goes...its a 2871r... I have the aem tru boost and with that you have to install boost source on the turbo or close to the inlet. Its tapped on my greddy intake elbow about 2 inches from turbo outlet. the fitting is about half the size of the wastegate fitting, so the vacuum line seems kinda small for the wastegate. (maybe the problem)I bypassed the controller for now, I may try to use another vacuum port for my wastegate to see if anything changes... Another possibility is that somehow the springs I installed are not correct, although im 100 percent going by the chart they were. So for this weekend I plan on adjusting the iacv to see if my decel stalling goes away... when I can get it to my work im gonna smoke the intake with an evap smoker as a doublecheck....just 2 many variables in the mix since I never drove it stock(motor was fried) I just wanted a simple rom tune....and now its becoming an issue...here are the only pics I have at the moment, not the greatest detail...but the best I can do for now. I will not leave this post unresolved and am going to update until its running like a champ:x:

[Def]

Open up your IACV screw a bit, like around 1/2-1 full turn. With cams you need quite a bit more idle air bleed area to maintain an idle due to the overlap and low vacuum. The stock IACV duty cycle ramps up too slowly to catch a car coming down to idle quickly with a low amount of constant bleed area (i.e. high IACV duty cycles).

If it gets better with that much IACV bleed added but still doesn't completely solve the stalling, add a bit more.

[JesterX18]

That is a very good explanation. I hadn't even thought of the overlap as a reason my vacuum was 15 in hg... Very good point and the fact that my crank has lightweight pulleys and crank which would Cause it to come down from decel a little faster and more abruptly than stock. Thank you sir!