77 280z idles great but bogs out when trying to rev

[77 zoom zoom]

I have a 77 280z w/fuel injection. I have replaced the fuel pump, filter, plugs, TPS, blew out all fuel lines, new injectors, new fuel hoses, cleaned out fuel tank. It idles great but bogs out when give it gas. I cannot figure this thing out! It is not drivable but idles killer. Does anyone have a clue what it could be??? I am at my wits end with this car!!! HELP

[Zed Head]

I haven't experienced it myself, but I get the impression that these engines will idle without the AFM connected, although your car should have a fuel pump relay switch in the AFM that won't allow that. Have you checked the AFM and its connection? Seems AFM or TPS related.

A little more detail on "bogs out" will help your quest also. Could mean many things.

[77 zoom zoom]

It idles great but when I give it gas it cuts outs and falls flat on it's face, won't rev at all past 1500-2000 rpm. I am thinking checking contacts in the AFM is my next step?? The car sat for 8 years before I bought it and was in fine running condition...so I was told!

[cbuczesk]

Check everywhere for a vacuum leak and make sure that all of your ground connections are good. You can connect a timing light and make sure that it's still firing at the higher RPMs just to rule that out.

Chuck

[Zed Head]

The ECU provides idle enrichment fuel when the TPS is on the idle circuit, independent of the AFM vane position (as I understand things). Could be the AFM, that's where I would start looking. You can remove the black cover on the side without removing the whole AFM and look for corrosion on the carbon trace or contact and/or spray it with some contact cleaner.

If it looks okay, you can also check the connection to the wiring harness, underneath. The AFM will have to come out. You'll need some kind of pick to get the wire spring retainer off, it's a little bit difficult.

You might also check fuel pressure beforehand though if you have a gauge available. Should be done anyway after eight years and probably easier to do than removing the AFM.

Edit - cbuczek brings up a good point about timing and the distributor, that could save some future aggravation. If you start taking things apart, take the distributor breaker plate off and make sure that the ball bearings under the plate haven't rusted to the bearing surface. They get stuck, then the plastic frame holding them breaks when the vacuum advance tries to move the plate.

Edited May 11, 2012 by Zed Head

[cbuczesk]

Did you check in the air cleaner area for a mouse nest or something like that?

Chuck

[77 zoom zoom]

No I haven't checked that yet and is a good idea! Will check tomorrow (saturday) and will get back to you...thx

[77 zoom zoom]

I am hesitant to bust that AFM open! They are spendy, but I think that is where I need to check next. I have checked timing with timing light, could the distributor or vacuum advance be bad? I am new at this. My 63 caddy is way easier to work on!!! This fuel injection system seems so complicated but I know it has to be something easy to fix....frustrated!!! Could my fuel system be plugged? I appreciate everyone's input and will try everything you guys suggest!

Edited May 11, 2012 by 77 zoom zoom

[sblake01]

Have you checked the fuel pressure? That might help to answer the last question you posed.

Edited May 11, 2012 by sblake01