Re: 91 ZR-1 Cutting Out Under Load
 

The steps you listed will check the primary injector coils only. Take a look at the schematic and you will see why these steps only check the primaries and you will have to make additional measurements to check the secondary injector coils. There is a good chance secondary coils are going bad if the primary coils are failing and you might as well check and take care of everything at the same time.

Re: 91 ZR-1 Cutting Out Under Load
 

Thanks Tom, are the secondary injectors the same units as the primaries? IE......... do I just buy two sets of the Accels?

Re: 91 ZR-1 Cutting Out Under Load
 

I don't know for sure for your '91, but there are other threads about injectors if you do a search, several of the people who have replied to this thread have replaced their injectors. My '90 with a little over 36,000 miles still has the original injectors, but as far as I can tell I have never used gasoline that had alcohol in it. That will probably change now since California is removing the MTBE and I believe is going to alcohol in the gasoline.

Re: 91 ZR-1 Cutting Out Under Load
 

Well, I do know for a fact that I've never used gasoline with alcohol in it. I'll try to do the injector resistance test this weekend.

Re: 91 ZR-1 Cutting Out Under Load
 

http://cgi.ebay.com/ebaymotors/Accel...QQcmdZViewItem
You need two sets plus the thicker rubber Orings from Marc Haibeck. I think there twenty bucks. I don't know about the later style injectors. How about ethanol? All the gas here has 10%.

Re: 91 ZR-1 Cutting Out Under Load
 

OK cool, now all I need to know is if these Accels can be used on both the primary and secondary side. I do know according to GM parts, the primary and secondary injector part numbers are different.

Re: 91 ZR-1 Cutting Out Under Load
 

I believe you order 16 same part no of the accels just get the o-ring setup from mark

Re: 91 ZR-1 Cutting Out Under Load
 

Yes.

Lots of info.

http://forums.corvetteforum.com/sear...archid=3367392

http://forums.corvetteforum.com/show...ight=injectors

Re: 91 ZR-1 Cutting Out Under Load
 

My 2 cents: My '90 had a similar problem, cutting out (missing) under load when the engine was hot (all was fine with cold engine). Did all the usual and simple stuff first. The guy's at the corvette shop suspected a coil breaking down when hot. My fuel pressure was 42psi on either pump or both pumps together. Should be 52-55 psi. Is yours still 32psi? not good. Under load the engine would be starving for fuel. Anyway, since the plenum was coming off, I replaced the fuel pressure regulator (pressure is now 52psi) and all four coils. Problem gone, I can now do 180mph again. Regulator was $125 at GMPartsdirect.com.

Good luck

Re: 91 ZR-1 Cutting Out Under Load
 

Well, finally after 2 years I have now ordered the Accel fuel injectors and a new fuel pressure regulator. This morning I have a new problem. I am now informed that the 90-92 Corvette ZR1 fuel pressure regulator is a discontinued item. I'm still reading 32 psi with a new fuel filter. Any suggestions on where to get a FPR ? An adjustable one would be ideal.