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Let's get her healthy again 83 280ZX Turbo - Runs well with CHTS unplugged


bsmuwk

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They don't burn on thier own.

 

Something caused it.

 

If that something has been corrected already, you should have no further issues.

 

might have just been burned from when i purchased the thing. oh well, right?

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Edited by bsmuwk
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I see that burning often.

 

The smaller burnt trace goes directly to two relatively large Zener diodes while the larger burnt area is on the line that comes directly from the fuse links that also gives the positive to the injectors.

 

The most common causes of this are....

 

1. Battery connected with reverse polarity or car jumped with reverse polarity.

 

2. Body ground from negative battery terminal to engine lacking causing car to seek ground through the ecu or said lifted ground causing a great overcharge from the alternator.

 

3. Battery loose and either tipping to cause positive terminal to touch hood, A/C lines, or some other part that is grounded to engine or body.

 

4. Wiring of sensors or grounds on the engine management system with incorrect polarity.

 

It's just something to look for before having to get another ecu.

 

Other damage you might see is injector drivers fused closed meaning they are always on when the key is on and zener diodes "blown open".

Edited by HowlerMonkey
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I see that burning often.

 

The smaller burnt trace goes directly to two relatively large Zener diodes while the larger burnt area is on the line that comes directly from the fuse links that also gives the positive to the injectors.

 

The most common causes of this are....

 

1. Battery connected with reverse polarity or car jumped with reverse polarity.

 

2. Body ground from negative battery terminal to engine lacking causing car to seek ground through the ecu or said lifted ground causing a great overcharge from the alternator.

 

3. Battery loose and either tipping to cause positive terminal to touch hood, A/C lines, or some other part that is grounded to engine or body.

 

4. Wiring of sensors or grounds on the engine management system with incorrect polarity.

 

It's just something to look for before having to get another ecu.

 

Other damage you might see is injector drivers fused closed meaning they are always on when the key is on and zener diodes "blown open".

 

Everything is fine on this car, the entire wiring harness is made by me at this point and has no defect. I checked it all again this past day and everything was peachy. Car has been running just fine these past few days.

 

ALTHOUGH, seem to have come across another problem. lol

 

Once I hit close to 5 or so lbs of boost, or depress throttle more than half way UNDER boost, the car seems to dump gobs of fuel. Everything else is perfect - idles on its own. Revs wonderfully. Drives flawlessly when not under boost or under what seems to be around 4 lbs of boost.

 

Maybe a new ECU might cure that as the one of the car I'm very skeptical about, we shall see. Other than that, ideas as to what would cause the car to dump fuel under boost? You can safely assume that EVERYTHING ignition related has been replaced other than the coilpack.

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  • 1 month later...

Okay, well took the car to an event and it did fairly well. Car has some severe hesitation issues right now. Had to extend my drift with my hydro ebrake before the car even figured it had enough balls to break the wheels loose.

 

Here's where I'm at with everything.

Z31T ecu swap - maf is set up as a blow through after the turbo

New chts

New plugs/wires/cap/rotor

GM hei ignition module

Boost controller - boost is at 14-16 lbs

Fuel pressure is 32psi at idle

Supra 440 injectors - low impedance (matches ecu) - new Bosch ev1 connectors for them

New tps

Shaved intake manifold - no egr, no idle control, nothing.

3" exhaust straight thru

New O2 that matches ecu

Timing is at 20* btdc

Evo intercooler with 2.25 intercooler piping

List goes on, anything new you can think of for the engine has been replaced.

 

My issue, cruising on the highway around 65 I get damn near perfect afr's on my wideBand. on load it drops down to about 9-11 (rich), when I let of the gas, you'd imagine on deceleration afr's would jump to around 19-22, however, it doesn't. My afr's are around 15-16 when I let of the gas. I'm burning a lot more fuel than I need to be right now and I can't figure out why.

 

Additionally, when I'm on the gas, it hesitates and then gets going. I feel as if I'm flooding the engine with fuel and I'm not burning it well enough. There's something a miss. Don't get me wrong, the power feels good, but there's a hesitation while on the gas and what feels like a flat spot in power while in boost.

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Had to extend my drift

 

Z31T ecu swap - maf is set up as a blow through after the turbo

 

Supra 440 injectors

 

Shaved intake manifold - no egr, no idle control, nothing.

 

My issue, cruising on the highway around 65 I get damn near perfect afr's on my wideBand. on load it drops down to about 9-11 (rich), when I let of the gas, you'd imagine on deceleration afr's would jump to around 19-22, however, it doesn't.

 

I'm burning a lot more fuel than I need to be right now and I can't figure out why.

 

Additionally, when I'm on the gas, it hesitates and then gets going. I feel as if I'm flooding the engine with fuel and I'm not burning it well enough. There's something a miss. Don't get me wrong, the power feels good, but there's a hesitation while on the gas and what feels like a flat spot in power while in boost.

 

Drift car? You never mentioned that.

 

MAF? Hot wire or stock 83 vane type AFM?

 

The BCDD that you shaved off would normally add air to clean up the closed throttle mixture. Some of the other stuff might also be designed to lean things out.

 

Hesitates, then goes, is more like a lean mixture. But 440 cc injectors with a stock Z31 ECU almost guarantees rich. Looks like just a mis-match of parts and ECU. Reading back through the thread, it's kind of odd that you ended up with this setup. Even the Z31 ECU is designed to work with a certain set of parts, I don't think that you can stray far from stock. It's not self-tuning, as I understand it.

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Drift car? You never mentioned that.

 

MAF? Hot wire or stock 83 vane type AFM?

 

The BCDD that you shaved off would normally add air to clean up the closed throttle mixture. Some of the other stuff might also be designed to lean things out.

 

Hesitates, then goes, is more like a lean mixture. But 440 cc injectors with a stock Z31 ECU almost guarantees rich. Looks like just a mis-match of parts and ECU. Reading back through the thread, it's kind of odd that you ended up with this setup. Even the Z31 ECU is designed to work with a certain set of parts, I don't think that you can stray far from stock. It's not self-tuning, as I understand it.

 

yup, drift car. fully caged, etc etc etc. when pictures from the event pop up i'll post them up. why not.

 

its a z31 hot wire maf set up.

 

 

If i dont come up with any sort of solution i'll cut my losses with this whole thing and just spring for megasquirt. should have done it from the get-go, but you live and you learn, right

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the problem with this is, i dont mind the extra fuel when i'm driving. the car has balls when i'm in boost. i get fairly decent fuel mileage when on the highway (again, afr's are near perfect).

 

the problem is my initial hesitation. from idle, i can jab the throttle and it'll hesitate and then rev up very quickly. if i dont have that initial hesitation, then i'll be golden and ultimately happy with the car. season's just about done here in the midwest, so i have until feb/march to get on a solution or new management system

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  • 3 weeks later...

OKAY, made some progress with the car and payed attention to my afrs in regards to that hesitation.

 

leaned out the MAF screw and she's a pretty wild beast in all sorts. my idle afrs are just about perfect. (14.5-14.9) my cruising afrs are in the same place. deceleration afrs jump around from (15.5-17.9 or so which is good). HARD acceleration afrs on 10-12psi of boost are in the 12s-11s with the occasional dip in the 10s (really dont mind that, thats just about perfect). car pulls harder than ever and has no problem breaking traction. HOWEVER,

 

i have a lean spike. either in first or second gears, from a stop i'll slam the throttle down, car will pull nicely until it gets to about 5psi boost or so, roughly that RPM range 2500-3500 i'll get a massive lean spike that builds with boost. i'm pegging out my innovate WB at 22.4 lean and the car is bucking. i can baby the throttle through and build boost slowly and get over the lean spike, but running lean while doing so.

 

if i drive calmly, there's no lean spots. the cars a cruiser.

 

any ideas? as before, everything is damn SPOT on with this thing. once it gets into full boost it pulls like a bat out of the hell. its awesome.

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adjusted the TPS. it revs up a lot nicer in neutral and drive. it was a good mm or two off of adjustment from the idle contact. now it just opens with a touch of the throttle. still has the lean spot. any ideas?

 

to appease, when i do manage to get around the lean spot. this was just me burning off the rest of some bald federals i had on and using my hydro.

 

 

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adjusted the TPS. it revs up a lot nicer in neutral and drive. it was a good mm or two off of adjustment from the idle contact. now it just opens with a touch of the throttle. still has the lean spot. any ideas?

 

to appease, when i do manage to get around the lean spot. this was just me burning off the rest of some bald federals i had on and using my hydro.

 

 

 

Have you checked your fuel press. ?

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Have you checked your fuel press. ?

 

 

I have my fuel pressure adjusted to factory spec. It jumps to high 30s/40 when vacuum is disconnected from it, just like factory.

 

 

I am not, however, able to check my fuel pressure while I'm driving. So I'm not entirely sure where it sits while I hit boost on initial throttle. I have a brand new fuel filter on there so I wouldn't imagine that to be the problem. Is there a slim chance that my fuel pump is on its way out?

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I have my fuel pressure adjusted to factory spec. It jumps to high 30s/40 when vacuum is disconnected from it, just like factory.

 

 

I am not, however, able to check my fuel pressure while I'm driving. So I'm not entirely sure where it sits while I hit boost on initial throttle. I have a brand new fuel filter on there so I wouldn't imagine that to be the problem. Is there a slim chance that my fuel pump is on its way out?

 

 

That's poss. . With the way it acts i'd hook a gauge to check fuel press. while driving . My ZX pump has a screen on the inlet side . Check to see if it's clogged .

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