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Discussion Starter · #1 ·
the car has at for most of the 3 yrs 99%went to paint shop 3 mnths ago 5 min drive, it starts to ping at 11psi auto meter gauge shows needle stop at 15psi stock turbo motor using n/a F.I.with turbo injectorsand a conguest intercooler no pov on intake and a adjustment on the wastegate rod like a tie rod egr and little valve before it plugged off at the vacuum ,but the car is fast before ping,any ideas help full im going backsaturday ill fill up with 93 oct
 

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So how do you like the NA FI on a turbo motor setup? I'm just curious cause I'm going to be doing it real soon. and what intake manifold are you using? NA or turbo?


Justin T
'77 280Z low budget turbo project
'80 280ZX 10th AE
 

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Maybe your timing has slipped, the N/A computers do not retard ignition at WOT.

Or it may be a combination of higher compression N/A motor and 11psi, along with timing. You could have a stuck injector, or bad fuel pressure, or your fuel pump could be running out of poop at 11 psi over stock fuel pressure.
 

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You didn't put regular in, did you?

Turbos won't run on anything but premium. If this problem started soon after you filled up, I'd drain the gas almost all out, refill with a name-brand premium and see if that cures it.
 

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...i've been looking for someone who has done that wastegate mod (if i understand you correctly) has this car been like that long?..does it (ordinarily work well)...you definately need premium gas..was it running fine ..and then just started doing this?
....i always heard @ wot the stock ecu no longer senses the air/fuel and stops compensating for it....do you have an a/f or egt ?.....it would be real good to know if you are going lean or something else is causing it.....some guys use 1-2 heat range(s) cooler spark plugs.....
...you arent using the stock (turbo) injectors are you?..........i dont think the 260cc will give you enough fuel over 12lbs ..........s
 

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Discussion Starter · #7 ·
this car sat for 3 yrs99%of the time, it was driven 3 mnths ago1%of 3 yrs for a 5 min ride to the paint shop,im interested in buying ,dont know how old gas is ,itll peg 15 psi on the auto meter boost gauge stars to ping after 11 stock turbo motor,stck turbo inj,pov on intake has been removed and plugged,wastgate rod has threaded adjustment to lenghthen rod,mitsubishi conguest intercooler,stock 1980a/f and harness and brain ,oxy sensor unplugged. a colder plug is a 5 or a 7?
 

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I would tend to change the gas, and a colder spark plug, but I would think your problem would lie in the injectors, like schmaydee said. If your injectors reach 100% duty cycle, there is nothing more the computer can do to put more fuel into the mixture, which would be leaning you out. The other problem here is that you never really want to be running your injectors at 100% duty cycle, rather like 70 at WOT, it gives you much more reliable fuel metering, and longer injector life.... Kindof like how shifting at 3000 rpm is better than 6000 rpm :)

Now this is all assuming that it has the stock turbo injectors, which, like said are good to about 12 psi, but if they are slightly clogged, that could lower your number right there to 10 or so, giving you detonation at 11 PSI. Also, check the timing and try retarding it a few degrees.

So If I remember correctly, you are looking to buy the car.... I would find out more information on it. If the owner doesn't really know, and it seems good otherwise, I'm sure you could always get the problem worked out, if you were to get a slight price break ;o)

Hope I helped,
Kris

P.S. Thinking about what you said and the gas topic... If it has been sitting for three years, and that is the same gas... definitely change it, as the octane level of gas goes down over time, and 3 year old gas isn't great, 8 year old gas could make a high compression engine not start... we've had that problem before :) If you just put it in, then I would just try the highest octane you can from now on... if you didn't use it already.
 

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The problem is your stock N/A ECU .. it fuel curve was not made for the turbo.. ie.. not providing enough fuel for 12PSI of boost.. I know alot of people using this set up and they only run 6PSI of boost max.. YOur solution is to buy the turbo harness and ECU and related item to complete the swap.. then you can run up to 14PSI of boost if you like..
Vinh
http://vvu.tripod.com
 

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Re: none of my bus..

..its none of my business...but if you dont have the stock ecu...its been setting for a long time...its got stock injectors....AND NO POP-OFF....i wouldnt run it up till it pings......good news is ..if you have been going to 15 (when it started pinging @ 11)..you got a damned good ic....you gotta have that stock turbo ecu (or something) to get those injectors metering right (as best they can ...i think they're too small)..but anyway....they might be ok w/your ic..(if you had the turbo ecu)..but you really need to make sure youre getting the very best you can get out of 'em......
.......id siphon that old gas out and change both fuel filters...(if i didnt remove it and wash it out).. fill it w/about 5 gal of 93 and put 2 (truck size) bottles of good injector cleaner.....and drive most of that gas out of it (and be real easy on it)....then fill it full w/93....might even want to put 3-4 gals of leaded cam3 in there w/it....what the ****...then retard your timing and put in some cooler plugs....
....or put in the stock ecu, 6-370cc merkur injectors....(that sucker will COOK)......and you'll be ready to spend all the money you have on rear tires (every couple of weeks),differentials, court costs & speeding tickets.....and life will be the way it ought to be!.....s
 

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Re: none of my bus..

yes...i've talked to some guys that have them..they go in real easy and work well w/ the stock ecu and no pings @ 18psi of boost....(mildly intercooled)...you can get them almost anywhere i checked (only) auto zone they wanted $60ea new.. (should be able to get them for a lot less).....s
 
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