fuel issues?

[Guest miss moneypenney]

hi,

have a problem with my s130.

she's idling rough, dead spot on throttle application and a popping occasionally on DE acceleration, everything tells me its some fuel issue.

in neutral you can rev out the rough idling and dead spot,get her running nice, however you go to drive it and the problem resurfaces, you can drive this out of it by going threw the gears on dirt roads with a heap of wheelspin, she then lasts maybe a day or two before returning.

no backfiring and no sign of unburnt fuel in exhaust emissions.

i checked the spark plugs, there sooty which is normal for the size cam {power band 3500-7000)she has and not being driven hard for awhile.

i checked the fuel filter,that seems OK, checked all connections to sensors,seems ok.

im thinking maybe the pcv valve is sooty like the plugs were, does anyone know if this is a problem? the symptoms line up but im not sure about revving the engine clearing the problem momentarily adding up to pcv valve.

I checked my dizzy.leads and such but spark doesn't seem a case.

since this problem has surfaced idling has dropped by maybe 200-250 revs.

could i have an injector issue despite all 6 spark plugs being identical in there sootiness?

i aint losing water ,not a drop and it takes to long to rev out the rough idle and dead spot for me to be getting water in the cylinders as the car sits.

when i removed the fuel filter there didn't seem alot of pressure but im not sure on whats normal.

it sounds like a blockage but being able to rev it out seems strange?

 

any ideas be much apreciated.

[woldson]

Well, well.... interesting.

 

If I were me Id mozey on down to the local parts place and myself a fuel pressue gage thing.

Also, what there year is this car? Original engine?

Did you put in an after market cam?

It's tough to tell what them there problem is, aint gonna be too easy..

[Guest miss moneypenney]

Well, well.... interesting.

 

If I were me Id mozey on down to the local parts place and myself a fuel pressue gage thing.

Also, what there year is this car? Original engine?

Did you put in an after market cam?

It's tough to tell what them there problem is, aint gonna be too easy..

july 1982 l28.

The previous owner had the engine properly built around the cam (733a) a reground solid, engines only done 30 thousand kilometers, i was instructed to drive it hard as it was built too be.

the things always run rich, even after i had it dyno tuned at 192 rwhp.

today i applied a little throttle in neutral after start up and it missed like a pig but then slowly picked up revs until it where it was suppose to.

computer has had a number done to it, no emission control, being told its getting cold air, but im thinking fuel issue as it can clear itself, doesnt matter if its hot or cold behaves the same,whether its night or day.

sometime today ill go threw the check on the pcv valve the manual instructs

 

 

i guess its a process of elimination.

[woldson]

I will guess that this is being ran on stock electronics?

Popping on decel with my cammed 82na was normal.

Ran pig rich 1500-2000 rpm.

I never was able to resolve this but I did not know what I do today.

If not for another dyno tune, you may also want to get a wide band, play with stock stuff and consider a stand alone ecu.

It will take some searching and someone better then myself to elaborate on your situation.

Post some good pics of engine, mostly of intake. In case you are not sure of all the parts that are still there or not.

Read up on the efi bible as well.

 

Good luck.

[FlatBlack]

Sounds like my car did when my fuel pump was going out, it wouldnt accelerate at all unless very little throttle was applied, but sounded fine over 2500-3000 or so. I would suggest getting a pressure gauge and check that first.

[Guest miss moneypenney]

I will guess that this is being ran on stock electronics?

Popping on decel with my cammed 82na was normal.

Ran pig rich 1500-2000 rpm.

I never was able to resolve this but I did not know what I do today.

If not for another dyno tune, you may also want to get a wide band, play with stock stuff and consider a stand alone ecu.

It will take some searching and someone better then myself to elaborate on your situation.

Post some good pics of engine, mostly of intake. In case you are not sure of all the parts that are still there or not.

Read up on the efi bible as well.

 

Good luck.

cheers, Ive always felt uncomfortable about the original ecu, apparently the old owner was going to get some Weber's so never bothered.

she runs rich upon full throttle application, the dood who dyno tuned her is quite brilliant and he couldn't work it out but he was quite taken aback by the dyno graph reading of hp, but stuff all torque.

 

may i ask what sought of cam you had and what results for hp gain?

 

 

I checked the pcv valve which was ok, i checked all hoses and found a broken vacuum hose(the one hidden by the dizzy cap near no1 extractor pipe) it run abit better, checked the spark plug gap it had narrowed considerably and now she lumps over again and revs cleanly.

i changed the pod filter and she idols back to where she did.

tomorrow I'm getting new plugs.

 

ps- i did a search here on my ailment, found numerous similar stories of engine behavior all with different problems,(scared the heck out of me)

[Guest miss moneypenney]

Sounds like my car did when my fuel pump was going out, it wouldnt accelerate at all unless very little throttle was applied, but sounded fine over 2500-3000 or so. I would suggest getting a pressure gauge and check that first.

that worried me, i can buy a second hand stock l28 in good nick cheaper than a new fuel pump.

[woldson]

Glad to here you got her a running well again.

 

This is why a wide band can help you. If you need to fiddle with stuff you can get some hard results that can give you better idea what is happening.

[luvmy280zxt]

Glad to here you got her a running well again.

 

This is why a wide band can help you. If you need to fiddle with stuff you can get some hard results that can give you better idea what is happening.

What is wind band exactly? Im kinda having the same issues.

[woldson]

Wide not wind hehee.

Wideband 02 sensor with gauge. It will give your fuel air ratios.

Seach abit and you will find lots of information in order to make an informed decision on brand and functions.

In the vendor section that one company has them on sale!! DIY?

[Guest the_bond_mowbeal]

that worried me, i can buy a second hand stock l28 in good nick cheaper than a new fuel pump.

if this is true why complain? buy another l28 stock car then not only get your fuel pump but have the rest to use for parts? or throw away your modified car an stick to standard they perform better than your modified motor for sure! how do i know? i have a standard s130 280zx an i know a chappy who owns a modified motor exactly like you described and he went on an on an on an on about how much better and faster his car was compared to mine TILL we went cruisin on some dirt an bituman roads an even i was surprized how easy it was not only to keep up with his supposed hotty but able to pass no worries. i chose not to overtake cos i know it would have crushed his spirit and as a result he'd go into a sykiatric episode. he even changed his tunes, critisizing my driving, so i said i accept his critisizm an can see benefits from joining dirt circuit (DC) to be coached proffesionally an he said NO ya dont wanna do that you learn more by hooning, whereas prior to the racing THAT day he was trying to get me to join DC. so buy yourself that cheap car use the pump an strip n sell all the rest you'd gain heaps financially and stop grumblin about cost of parts when there are ways and means to get what you need without busting your bank account :fmad::icon28::ass: