Mustang doesn't like heat


I have a 1989 ford mustang. originally it had a 2.3l but i swapped it to a 5.0l. The engine is bored 30 over with a forged rotating assembly, its running 11:1 compression with trick flow twisted wedge heads that have been ported and polished, a ford racing x303 camshaft, an edelbrock performer intake manifold and plenum, factory replacement spark plugs at .050, 30lb fuel injectors along with a calibrated mass air flow sensor for the injectors, a walbro high volume fuel pump, and a crane cams intercepter II piggyback ecu. I just put it all together with the correct wiring harness. It starts up and runs great now that i have turned the idle up to 1100 rpm. But once it has run for about 30 seconds or more it will not start back up unless i alloy it to cool down for a while. then it’ll start right up. It appears to be getting spark when it won’t start (I tested it with an inline spark tester) and it is getting plenty of fuel but it won’t even sputter. I put a new ignition module and coil in it but still no differance. im out of ideas with it and was hoping someone on here could help me out. thanks in advance, Billy

I assume it’s turning over strongly.

Have you checked the spark pluugs when it fails to start? Are they wet with gas?

yes it turns over strong. i have a high torque starter and an optima red top battery because it didnt want to turn over fast enough before. the timing was also an issue but i set it to 10 btdc with the pip connector out so that is not an issue anynore either . the plugs do get wet if i try to start it right away. thats why i started looking into ignition parts. but they didnt help either

It sounds like it’s flooding to me. It sounds too rich.

Did you program the ECU yourself? Perhaps a speed shop can reprogram it to back off on the excess fuel a bit. Or perhaps they can make other adjustments such as different injectors that’ll get it running better.

I have not tried tuning it yet. Im not real comfortable with that kind of stuff but i will try turning the fuel down a little bit and see if that helps. I don’t have much more money to spend on dyno tuning yet but it will definitely need it.