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Strange fuel injector electrical problem.

I've got an 87 ranger with a 2.3L fuel injected 4 cylinder engine. I've been having some serious driveability problems with it and last week removed the throttle body and the valve cover to check the operation of the valve train. While I had access to the fuel rail/injectors I swapped the injector on cylinder 4, which I suspected was not functioning properly. The repacement injector is known good and I only disconnected/reconnected the electrical connection to that one. After every thing was put back together the truck wouldn't start or even kick like it might be thinking about starting.

The battery is fully charged and cranks the engine over just fine. The compression is OK and there is good spark. The distributer roter points right at tower 1 on the distributer cap when the number one cylinder it TDC. I assume from that that the timing is at least close to correct. I just tested the ignition module this afternoon and it tests out good.

When I put a stethoscope on the fuel injectors while the engine is cranking over I hear nothing on the injectors for 1 and 4 cylinders. 2 and 3 have very light and rapid clicking. Much more rapid that would be expected at the engine cranking speed. The clicks are nowhere near as solid as I've heard in the past when putting the stethoscope to the injectors with the engine running. I'm assuming this is the problem and is causing a no fuel condition. Any idea what could be happening here?

Thanks in advance for any help.

Jon Splane

Reply to
Jon Splane
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On Sun, 31 Oct 2004 18:50:45 -0800, Jon Splane rearranged some electrons to form:

Bad fuel pump? Clogged filter? Bad fuel rail pressure regulator? You problem may not be electrical at all. What made you think that injector 4 wasn't working?

Reply to
David M

David,

It makes sense to me that if there is no fuel pressure in the fuel rail the injectors would be very quiet; as I would guess the pressure is mainly what closes them so positively. With the probe of a stethoscope against them I hear nothing at all from 1 and 4 amd a very audible but too rapid clicking on 2 and 4. Perhaps all four are silent and the clicking has another source. There is no valve noise with this engine.

The regulator is nearly new. Clogged filter or fuel pump is possible. This truck ran very poorly, but ran when I started working on it. The last couple time I started it it started a little hard, but ran OK for the first half mile or so at least. The sudden onset of the problem makes me think electrical (including pump). The clicking I hear on 2 and 3 injectors make me think electrical. I think a clogged filter wouldn't develop sitting in the driveway.

RE: cylinder #4; I had a miss or very weak cylinder evident at idle for about the past 6 weeks. This appeared suddenly; one day it was fine and the next day a pronounced rough idle. The problem has stayed pretty much the same since it started. Pulling plug wires while the engine was running seems to indicate cylinder 4 as the source. Hard to be positive because the computer corrects the idle so rapidly when you remove a wire. The spark plug, wire and distributer cap appear good and are fairly new. Compression in that cylinder is only 120 dry and a couple pounds more wet, but I don't think that would cause a miss. My conclusion was a possible injector malfunction.

If it doesn't rain too much tomorrow I will try to get the fuel filter out. It isn't easy with this vehicle which has a "lifetime of the vehicle" filter that is quite difficult of access. I will try to check the pressure at the fuel rail also. In West Oregon where I live it rains 3 days out of 4 this time of year, so may not happen.

Jon

Reply to
Jon Splane

On Mon, 01 Nov 2004 00:25:21 -0800, Jon Splane wrote: [...]

I have a 1990 BroncoII, which is quite similar to the Ranger. The Helm manual covers both and the Aerostar, with many pictures and procedures labelled as applicable to both the BII and Ranger. The Helm manual also claims that the fuel filter on my BII is a "lifetime" filter. The guys at the parts store say that isn't true. Maybe your '87 is close enough to my '90 for this information to be applicable.

I replaced the filter last year; here's what I learned : the purolator replacement cost around $7 or $8, purolator's packaging recommends replacement every 12 months, and the job is extremely easy to do. The filter is located on the inside of the driver's side frame rail, right about where the t-case is. Mine is missing the shield the manual says should be there. After depressurizing the system, remove the old filter by pulling the plastic clips off. Use a flathead screwdriver or pliers. The fuel lines snap off very easily. (be careful because the fuel in the lines and filter will then spill on the ground) The new filter snaps into the lines, then the retainer clips snap on through the slots in the lines. The new filter includes new clips. (I like these "snap" lines and clips. A friend's Saab and another friend's Volvo bolted the lines to the filter, and that was much more difficult to work with)

HTH,

-D

Reply to
Derrick Hudson

Well I removed the "lifetime" filter today after a struggle to get the shield off. There was no filter element in the housing canister. It appears I've driven this truck 20,000+ miles without any filter in the fuel system except presumably a stainer in the tank. Who knows how long the previous owner drove it this way. It looks like all the injectors and the high pressure fuel pump and the pressure regulator are all suspect at this point.

Jon

Reply to
Jon Splane

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