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Discussion Starter · #1 ·
I'm working on my 1976 280z, and it seems to be getting around 9 or 10 MPG. This is even worse than my '79 that used to get 12 MPG! Whenever I punch the throttle, I almost instantly smell gas. I've checked the distributor, ignition coil, throttle switch and ignition wires, and have done preliminary (continuity)checks on the AFM, air temp sensor, water temp sensor, air regulator, and fuel pump.
The only thing visibly wrong with the engine are the fuel injector connectors- they are all broken and cracked at the base, as in no little spring-clips holding them on. If you wiggle the harness even slightly, the motor will run rough and drop the idle from 800 to 500, or more.
The car idles and revs great, tons of power, but is a little rough around 2000 RPM. What should I check next?
Thanks Z dudes!
NathanZ
 

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You answered some of your own questions. The busted FI connectors... are part of the problem. Some of the items that you said your performed a continunity check on does not need a contuninity check, but needs to be checked on the ohm setting of the meter. Do you have a factory service manual? If not, get one from www.ideal-z.com. The ideal-z site will have a link to Courtsey Nissan where the cd-rom version of the manual is available. While at the Courtsey site look in their video section and order the Ztherapy FI tune up video too. It has a ton of good info.
Start by cleaning and replacing all broken FI connectors. AutoZone has replacement ends (self sealing, no boot needed). The are GP Sorenson brand, part number 800-9213 ($3.99 each). You will need to solder them to the harness, be sure not to get the wires crossed.
Other things you can do is perform the tests in the factory service manual engine fuel section... All the info you need is in there.
 

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Discussion Starter · #3 ·
Excellent

I didn't know you could just buy the injector connectors. I thought I could only buy the entire harness! Man, I'll bet they want some cash for it too!
This site rocks.
Thank you!
Nathan
 

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Re: Excellent

and those GP Sorenson connectors have a quick release clip built in! No more fumbling with those little wire clips. Just be sure to solder the pig tails into the harness (no crimps!), seal the joints with heat shrink, and be sure to disconnect the battery ground before doing ANY cutting or soldering. It may be eaiser to remove the harness from the car, That is what I did. Unhook the ecu end and the 4 pin connector by the ecu. Then unhook all the other sensors, dropping resistors (located by the clutch master cylinder), grounds, ect. Push out the sealing ring from the firewall, and slide the ecu connector thru the hole.
Here's a tip... each wire in the FI harness has numbers on each connector wire (under the outer insulation, each individual wire has white numbers). The numbers correspond to the schematic in the engine fuel section in the factory service manual. (another good reason to get the manual!)
Before cutting anything, get a piece of paper and a pin and draw the connector as looking at it from the front and then strip the outer insulation to reveal the wiring numbers. Inside the connector you drawed, write the number of the wires going to it. Thats what I did to keep thing straight. Take you time and only do one connector at a time. The replacement connectors will have pig tails about 7" long... USE THEM! Odds are your harness is corroded back at least that far! Be sure to keep the lengths of the connectors the same as stock too... it will suck if you find out that you are too short when reinstalling it.
I also use a meter to "beep" out each new connector from the ecu plug to the connectors. Again the service manual schematic is used.
 

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Discussion Starter · #5 ·
Sounds good

Yeah, I'll bet you're right about the wires being nasty beneath that nice, shiny black insulation! If I as much as pinch the harness where it goes into the black insulation tube, the engine will stumble! Thanks for the advice; I'm going to even replace the cold start connector while I'm at it. And thanks a TON for the part no. and where to get those replacement connectors! Doin' it tomorrow! BTW, this $900 '76 280z seems to have even more power than my old '79 280zx I had in high school. Z's rule!
Nathan
p.s. Man, just not having to deal with those **** F.I. connector clips is worth the cost and trouble of replacing them! I am in your debt.
 
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