87 EXI - Prospective purchase - Will not start

[omianan]

I went to look at a prospective purchase today, an 87 EXI with 272,000 KM on it. It is cheap because it doesn't run. The seller says that the last two days it was driven it sputtered and would not start at all on the third day, it has been sitting now for two months. Turned the key and can hear the fuel pump run; loosened the banjo bolt at the fuel rail and fuel sprays from this location as pump is running; fuel pump is pumping fuel, but not sure at what pressure. Took out No. 2 spark plug and had seller turn over engine as I held plug to ground, the plug fires so there is spark. The plug is dry and not wet with fuel. There is spark and there is fuel at the rail but nothing seems to be getting injected. I did not try starter fluid into the throttle body to see if it would run that way. A couple of questions. Is there a minimum pressure that is required to activate the injector and second question, since there are wires from each injector, what initiates the signal for the injector to open at the right time? It does not appear to be an easy/cheap fix and the condition of the car is such that it is not worth spending much money on.

[Dr_Snooz]

If you're getting fuel and fire, then you're looking at a timing problem, like a broken timing belt, or an air problem, like a clogged air filter. If you're convinced it's the injectors, then take a look at the injector resistor. It's a big silver box above the driver's side fender. Review the test for it in the manual on p. 12-61. The only other thing I can think of is maybe the injector ground wire has come loose or gotten corroded. Unfortunately, someone else is going to have to tell you where it is. I don't know.

[omianan]

Thanks for that info Snooz. If I go back for another try at getting this started, it will not be till next weekend but will take my testing equipment with me this time. I would also like to try the starter fluid sprayed into the throttle body to see if it will fire that way. At least that would tell me if the timing is more or less okay. It appears that the injector resistor is connected to the ECU and the Main Relay. If the resistor checks out within specs, then it is getting expensive after that. Will post what I find out after next weekend.

[ecogabriel]

The ECU fires the injectors based on the inputs from the CRANK and CYL sensors in the distributor (lower half, where is closer to the engine).

There is probably a minimum pressure under which they may not inject fuel.
I read about a trick to see if the injectors indeed fire by putting a screwdriver to the injectors' body and holding one's ear to the screwdriver's handle. With the engine cranking you should hear the clicking noise they make when they open and close.

I wonder what may happen if the fuel pressure regulator -at the end of the fuel rail - goes bad and stuck open; fuel pressure may not build up. You may also try pinching the return hose and see what happens. If the guy selling you the car tells the truth, maybe it is not too complicated to fix after all.

[obdriver6]

Try spraying starting fluid. If it starts then it either the pressure is too low or injectors are not working.