For strictly cosmetic reasons, I replaced the intake manifold on my well running 1991 Mustang 5.0L engine to a 1993 Cobra unit. I also installed a 70mm BBK throttle body, new 19# injectors, new fuel pressure regulator, new ACT, new PCV kit and hose and new valve covers. I retained the stock MAF. The engine started hard when work completed. I had to vary the throttle and nurse it from just a few cylinders firing as the starter kept it going until it finally started. Once started, it wouldnÂ’t run on its own without throttle help for a minute or so but then ran smoothly at a 700 rpm idle and responded well to throttle up to ~3,000 rpm. Vacuum at idle was a steady 18hg. Car is on jack stands in garage so not yet driven. After checking for leaks and running to operating temperature to check coolant system I turned off with the key. I started it again twice while it was still warm and had the same hard starting issue both times. After the third time I turned it off from idle with the key and it hasnÂ’t started since.
i have gone through the jrichker Stangnet “no start” check list. I have spark from the distributor, I have fuel squirt at the schrader valve, with ignition on I have 12v at injector#5, computer pins 37 and 57, fuel pump primes. I got KOEO codes 19, 69 and 6 but have good vpwr at computer pins. I disconnected computer and connected a known good spare which did not help. After reconnecting computer in car I got KOEO codes 12 and 2 when checking before and after cranking. 19, 69, and 6 were gone. Engine does not respond to 3 seconds of ether sprayed past throttle plate. Plugs all look clean and have strong fuel odor. I didn’t measure compression but when putting finger in spark plug holes I get good puffing around finger when cranking.
Any ideas about what to try next would be greatly appreciated.