87 TC fuel injector test

[jubylives]

I've managed to get the car running. I took it to a shop and they told me to have the injection system cleaned and flushed. So I called a shop that can do that and they told me to make sure the injectors were all working properly by doing an ohm test. Can anyone point me to directions on how to test the injectors? My haynes book only has procedures to test ZCFI and SEFI but not the multiport. Any ideas?

jeremy

[gadget73]

your 87 has SEFI.

honestly, its highly unlikely an ohm test will tell you anything useful. Unless one of the injector coils is actually burned out, which is rather unlikely, it will not give you any indication about how well the injectors are actually working. How much money is this place gonna charge you to flush the injectors? You may want to consider just buying a good set and replacing them if you know the injectors are a problem. Its all but impossible to really get good results out of cleaning the injectors when they are on the engine. The best way to do it is to remove the injectors and have them rebuilt by a place that does that sort of service. They will flow test the injectors and verify that they are working properly and have a good spray pattern. Pumping injector cleaner through the rail will not tell you how well the injectors are actually working.

I'd also have to wonder if this place really knows mid 80s Fords. Lots of people just don't have a clue how these cars work, and will toss out random and expensive repairs without having any real idea if it will fix the problem you are having. Unless the car sat for years, I have my doubts that your injectors are the immediate cause of any problems. I've driven cars that sat for years and had gummed up injectors. They ran basically OK, but had a lack of power and lousy fuel economy but the car was driving down the road and running without any major issues.

[jubylives]

That makes sense. I'm really at a loss at what to do with the car. I'm trying to get it running in two weeks for my daughter's prom. It's just so irratic I'm almost totally at a loss. I've neveer been this stumped by a car before. He said he'd charge me $75 to get me a diagnosis and not do anything to the car without discussing it with me. I don't really have much left to replace on it it seems.

jeremy

[86VickyLX]

Run a code scan. When it's done flashing codes, press the gas pedal and release. The idle should go back up. The computer will then, in numerical order, drop a cylinder by turning off an injector. Anything that the computer finds to be less of an RPM drop than it expects will throw a code. It will be a code that corresponds with the cylinder that failed. If it flashes code 90, all cylinders are contributing equally. It's a good idea, to make sure there are no codes before this test is done.

[gadget73]

do that at least 3 times too. One scan isn't really enough to mean much. It has to run several times to indicate any sort of trend. You can re-start the test by blipping the throttle again after it gives you the codes for the balance test.