So whenever my girlfriend and I hit full boost in vtak at 3500rpm we always have a big fight and break up. . . On a serious note, I've recently gotten insurance and all the DMV stuff taken care of so Im driving the Z again for the first time since I've gotten the motor back together but, now when Im in gear and try to go past 3500rpm, the engine sputters and breaks up refusing to go past 4000rpm. I've tried messing around with the timing a few times to no avail (currently set at 11 degrees) and Dave pointed out that it could be a fuel supply issue but, if anything the car seems to be running rich, I won't rule that out though. Anyone else have experience with this problem? Any ideas or advice is greatly appreciated. . . . and yes, I always have to ask you guys for help when it comes to anything more than an oil change haha.

 

that sounds really weird, do you have a camcoarder, if so can you host a video on photobucket and post the link for this one, it may be easier to diagnois such a problem. im wondering about ignition, maybe the advance mechanism, what is your total advance when the engine is reved up at 2500rpm? and is the problem only inder load, or is it when in neutral as well?

 

Well, unfortunately I don't have a camcorder, the problem only happens while under load and I don't know about the total advance, am I supposed to have someone rev the car while I check the timing at that specific rpm? Another drawback is eventhough I've been around these cars for a couple years know these past few months are the first time I've ever had to actually work on the beastie, my previous Z never had problems. . . except for rust and lots of it.

 

any way you can check fuel pressure. and for total timing you are right, have someone (or a contraption) hold the rpm around 2500, then check for total timing, you need a good timing gun for this, its one with the little dial on the back if you didnt know, for a really stout na motor, it should be about 36 degrees, for stock, it will be lower, about 28-30. our advance systems vary on our cars as the springs and vacuum vary causing everyones to be different if set at the 10 deg base line.

 

when I boght my car it did the same thing. turned out to be the afm. I replaced it, now I have some good performance. every once in a wile, I will hit that problem slightly when I am geting low on fuel, but the problem is gone.

 

check air and fuel filters, check the distributor shaft for play, and check all the plug wires, cap rotor as well. also check ALL electrical connectors under the hood for corrosion/burnt or cracked wiring. you should be able to get Bosch style injector pigtails from auto zone or the junkyard and they will replace all the two pin connectors under the hood. As far as I know there aren't any sources for new connectors for anything else, unless you can cross them over to another make of car, which is probably possible. If none of this fixes the problem, then you're doing something wrong, cuz from what Ive seen thats every problem on a Z. Well maybe pressure test the fuel pump too, but if low pressure was a problem and you've been driving it, it would have burnt up by now

 

Bosch injector plug repair kits:

http://www.freewebs.com/pallnet/products.htm

This sounds exactly like an AFM issue. If you have an FSM, follow the testing process included. You'll need a volt meter to do it.

 

Problem fixed and this is how, last year when I was driving my 1980 Z I rebuilt the afm on the (then non-running) 1979 Z and when I installed it on the Z it the car wouldn't idle, so I figured I did something wrong and slapped the original one back on, whelp when I did get the 1979 Z running I took the afm from the 1980 Z and was using that, I swapped afms so that the 1979 had it's original afm, and I also advanced the timing and voila she runs great.

I also ran seafoam through the intake manifold according to the instructions and I think I need to pick up a new set of plugs because now the car hesitates a bit and then the power comes on all at once.