Running issues

[Eager]

So the other day I took my 34 gtt to work, it’s running a 3076 6 boost power F.C. and z32 etc etc, got to work fine which was a 8 mile basic commute with the last mile a poor road surface 

anyway came out of work to drive home and noticed a miss or a bit lumpy, looked down at the wideband and it’s running 18 or so to 1. So very lean. From idle to cruise right through its lean

I went into the power commander fuel adjustment and dumped the fuel in up to 1.3 to get it running smoothly and back to about 15:1 and limped the car home

so first investigation was car seemed low on fuel so chucked a can in, in case it was to low, 

also inspected some hoses and noticed the pipe on my z32 afm to turbo was not sealed perfect, it wasn’t off much but I squared it up and tightened it anyway, started the car and it seemed spot on so assumed it was fixed, 15 minute test drive and all was fine so put the car back in the garage

Went to take it a run tonight and reversed it out of the garage and it’s lean again, at idle and through revs do just put it back in the garage, 

any pointers ?

its a fairly recent top mount turbo install and map, 300zx fuel filter and a new Walbro was fitted at map time 500-700 mile ago just. Injectors are r35 gtr and also low miles. Voltage still regulates for pump so would like that hard wired, 

I want to swap a different z32 in too just to rule it out but any other ideas ?

Edited August 3, 2018 by Eager

[Ben C34]

A misfire will read lean so just dumping in more fuel to make the wife and read correct isn’t the right thing to do. Check the plugs

[Eager]

Oh I know, it was just to get me home, but even I richened it up there was no missfire present 

but certainly no missfire is evident, and on the 15 minute test drive the other night it ran perfect. With power F.C. on its map just, no adjustment, I thought the pipe adjustment sorted it as it ran perfect  

At idle there tonight it’s stable just lean, not missing 

Edited August 3, 2018 by Eager

[Eager]

Ok

so ive had another look around the engine bay and noticed there is a loom that runs along the suspension strut area, off it comes a few things like the o2 sensor, stock boost solenoid plug, it runs over to the afm and then into the wing, maybe headlight?

it seems a bit charred, it’s not completely burnt but certainly has had some heat from the top mount install running fairly close

can anyone tell me is that part of the main loom or is that a piece I could replace easily ? 

It might not be at fault but it doesn’t look great

Edited August 4, 2018 by Eager

[Eager]

So plugs changed to no difference. Z32 swapped for a known food item and still same, fuel pump swapped for known good item

still lean and struggles to idle or rev

Edited August 12, 2018 by Eager

[GTSBoy]

5 hours ago, Eager said:

known food item

Donut?

[Eager]

Lol. Ye. Then I tried a known good z32 afm too. 

[Eager]

Car still is using the factory voltage regulator or modulator at the pump. I intend to run 12v from battery, but is that something that plays up ? 

Other than that Is the stock fuel pressure regulator known to mess about ?

[GTSBoy]

FPR shouldn't be crook.  Pump controller might, but not too common, unless overworked with a big pump.  Easy to check though.  Just put a voltmeter on the wires to the pump and see what happens when it's driven.

[Eager]

That’s the next plan as even at idle it’s like 16 to 1 and that’s cold start so fuel enrichment be running on power F.C.  few revs to 2 or 3 thousand rpm sees 17 or 18:1 and lumpy. 

 

Add lots of fuel in the fuel adjustment area and it comes back to normal 

[Eager]

Sooo done a quick compression check. She isn’t good boys lol. 

What’s the official number order by the way?

1 being at radiator, in this case below, 6 at bulk head

Results on cold engine  

140-150 odd on 1,2,4,5
3 gets to 140/145 but takes a few extra cranks. 6 is 60 or so and jumped to 70 odd with a little oil in the cylinder. 

 

Going to do a leak down test and bore scope next to decide what is leaking. But the car runs fine, revs fine and has no misfire or nasty noises once the fuel is adjusted on the hand commander. 

Edited August 18, 2018 by Eager