I have a 1987 buick regal grand national.. It wont start just cranks i have no injector pulse and the fuel pump isnt coming on. I jumperd the fuel pump relay and the pump comes on. all fuese are good, fuel pump relay good, has a new pcm and that didnt fix the problem either.. Any ideas?

does it have spark ?
No Start No injector pulse shorted injector part 1

No Start Testing Basics Spark Injector Pulse and Fuel Pressure Hyundai...

GM Bypass Ignition System Operation part 1

If you watch any of these ,watch the last one .Ignition control module can cause no injector pulse but still have spark

If it cranks good but won't start, have a helper crank it while you visually check for spark at the spark plugs. If spark everywhere, use a gage and check proper fuel pressure, also, check fuel injector pulse, engine cranking.

As far as overheating, it could almost anything, thermostat--water pump--radiator--radiator fan-- combustion gases in the coolant--cts. Can you check for applicable trouble codes? Some of the national brand autostores will check codes for free, if there are any.

Are you getting voltage and pulse to the injectors ?
Sounds like something is disconnected in the wiring harness.

you don`t say where they keep breaking.if its around the bolts then you can use a thicker washer this might help.if the tracking system that the seat slides on then if there is room you might be able to weld a re-enforcing plate to the system where it cracks to stop it.

you need to see if you have spark and check all fuses and see if you have fuel pressure and injector pulse if no spark and no injector pulse suspect crank sensor or ignition control module if no fuel pressure check fuses then relays and then suspect pump

its toward the back on the driver side by the rear end on the under carriage

Symptoms Like this usually point to the Fuel pump.

Also these cars suffer from inferior wiring to the fuel pumps and a substantial Voltage drop is noted between the Fuel pump relay and the Pump harness.

The fix for this is a "Hotwire" Kit

Fuel pump kits with a Hotwire kit are available at numerous Buick performance Vendors but the best stuff in my opinion come from Racetronix,com

You should also change the Prom Chip in the ECM to a modern
Chip from Turbotweak.
This will improve driveability greatly.

HTH

i have a 1987 buick grandnational and put a new fuel pump in and the car will run about 5 min then just shut off

if it runs on starting fluid its a fuel problem.. check fuel pressure even if its a couple of pounds off, the vehicle will not run. but using starting fluid may give you the extra poundage you need to make it run . also check vacuum hose at pressure regulator on fuel rail

sounds like an ignition module