Hello everyone - Just wondering if someone here can point me in the right direction with my 1990 Eldorado Touring Coupe.

About a month ago I was coming home and since this is my wife's car and she never drives it hard, I decided to get on it at a red light - To my surprise the car jumped and took off just like it did when it was new (I have owned it since it was new). But when the engine cranked up to about 4500 or so she fell flat on her face and forced me to limp home.. Anyhow, I thought that I blew the timing chain but after a little digging into it (car has 105,000 miles) it turned out being a blown fuse for injector bank B. I replaced this fuse and the car was back to normal.

Well, in the back of my mind it puzzled me as to why a fuse like that would blow but after 18 years, all things do get weak and I put it off to a "tired" fuse after 18 years in service. Not so lucky, as I expected, the car is now running like it has a really bad miss - When it's cold it seems to run good for about 30 seconds, then starts coughing and missing and when I took it out and jumped on it it blew the fuse again for bank B. I measred the resistance of all the fuel injectors and get readings from 1.5ohms to 1.5K ohms. Not any two of the injectors read the same on any of the 8 cylinders. I checked the fuel pressure at an idle and I have 35psi.


Not sure if any of the experts here have ever had a similar problem or can help me with my diagnosis - Thanks in advance
Shawn Mink
Michigan

 

What size engine does it have?

 

Sorry - The engine is a 4.5L

 

1 ohm is pretty much a short circuit i would replace that one..

Here is a chart I got from alldata on my car (90 deville with 4.5l) should be the same.

 

Thanks for the info... I'll check them all again and see if I can determine anything else.. Seems odd to me that none of the 8 injectors read the same.. The 1.5K ohm was using a digital fluke meter - I got readings in the 14-20 ohm range when using an old simpson 260 - I'll check them again and see what the real readings are. Appears that my digital meter was giving me some false readings on the initial check... Thank God I never chucked the old simpson 260!

 

for a trial-and-error method you could disconnect a few of the in question injectors crank it and then plug em in one by one and see which one(s) blow the fuse.

Its also possible for a short further upstream.. so trace the wires are far as you can and look for wear/possible shorts also.

 

Unfortunately it was going to be a real pain to pull wires at the injectors one at a time but because of the harness that ties them to the main wiring harness, I was able to again measure the resistance of each of them - I had readings as low as 1.5 ohms and not one of the eight was within the specs from the chart above. i bit the bullet and bought a set of injectors, installed them last week and the car is once again running like she used to! Thanks for all of the help.. This is the first time I have ever seen a fuel injector fail, let alone all of them being out bad like they were!

 

Hi Shawn. Same car, different city in MI . . . Grand Rapids.
I just had the same situation only I'm not as smart or experienced as you are. I had to have a garage diagnose the problem for me. They put the car on this sophisticated electronic gadget. Two of the injectors showed dead short, the others were all over the place. The shop owner, a friend of mine, told me he's seen this before. He told me to just take it easy for a while (no street racing) and try to take the car on the highway for an hour or so a couple of times at cruising speed. He used the term "lazy injectors" apparently meaning that the car has been used so long at slow, city-driving speed that they don't operate well at higher speeds. I'm a little afraid to go that far from town lest the car breaks down. So I opted to go back and forth on a 12 mile stretch of x-way near home (with a littl' plastic box of 7.5 amp fuses). I've done the trip once last week without blowing a fuse. Gonna try it again this week.

The other option is to simply change the injectors. I have been told that the injectors that GM used are inferior to the same size, same spec injectors Ford made. I've found an excellent reconditioned injector source. If you want the name, email me privately and I'll give you all the info.

Love my Eldorado. I'll drive it until one of us dies.