I am working on a new to me 1990 Ford F250 with the 300 in it, manual transmission, AC. The truck sat for an extended period. Sometimes it wont start, always when it won't start the fuel pump relay is chattering/clicking, the tach jumps up and down and the check engine light blinks all at about the same rate. Sometimes it will start and then after running awhile the engine stalls and does the same thing with the relay. Other times the engine will run and idle for 30 minutes.

I was told it was a ground problem. I replaced the negative battery cable, cleaned the L/R grounds on the radiator columns, cleaned the L/R grounds on the firewall, cleaned the ground on the L fender as well. I also replaced the positive battery cable. No real change in the problem. Did I miss checking some?

Another (possibly unrelated) couple of issues are that the battery drains very fast when cranking, and at idle the truck is drawing more power than the alternator is providing (the battery voltage drops over time). I took the Alternator and had it tested off vechicle, it passed all the tests. If I rev the engine up over 1000rpm, the battery seems to charge ok. The truck has a brand new (2 day old) battery in it, whichw as fully charged before being installed. I can crank the engine two to three times before it needs charged again. With the engine cranking and the battery fresh I get about 11 Volts at the battery, for the second crank it is down to about 9.8 Volts while cranking, by the third crank it drops to about 8.4 Volts while cranking.

I tried searching for similar problems but did not find any. If these are already addressed please point me to the thread(s).

Thanks!

 

Get 2 bottles of heet and 2 of iso heet and some fresh gas to absorb the water in
there and dilute the old gas!! Any fuel over 90 days is turning bad and give you more
headaches then you want since it can mimic many problems. I would check out the
relay since if the contacts are corroded it can do a bounce and give you trouble.
If You can do a code read and see what comes up it could clue you in.
I would pull all the connectors apart and with a strong flashlight look and see if there
is any corrosion and use a contact cleaner to spray it out and reconnecting and
disconnecting a few times can get them a better contact.

 

With the check engine light blinking along with all the rest of it, I would guess it to be the ground from the computer to the body. I don't remember where it's at on this model, but find the computer and look for it. That would explain the relay chatter, not running, and possibly the charging issue.

 

Thanks!

I hooked up a scanner to the EEC port on the left (drivers) side in the engine compartment. It kept coming up "Unable to communicate, check connections, try again?". I took the EEC connector apart (one lead at a time) and cleaned each one thoroughly. I put it back together and the same problem, still can't communicate.

I found the EEC (I think!) its below the radio in the center of the truck. I will try tracing back the wires. I *think* it connects to a rectangular connector through the firewall, which has a ground lead that comes right off the connector and goes straight up to the left fender well area somewhere and bolts on. I cleaned it under the hood in my ground cleaning rampage. I will try cleaning the connections inside the cab and see if that helps. I assume it is a connector at the firewall as well as at the back of the computer. I will try cleaning both and see what happens, will report back.

It occured to me that I have not cleaned the ground straps where they connect to the engine block. On inspecting things I noticed there is a ground strap on the left frame rail under the rear of the engine that is not attached at the other end it is about 8" to 12" long or so. I don't see an obvious point that it was attached. Of course I was laying on my back, in the dirt, looking up, I could have missed the obvious. I will take a closer look and see where it may have orginally attached.

Thanks again for all the help so far, I hate intermittent problems... As soon as I get the chance I will try cleaning and see what happens. Will report back on whether it solved it or not (and where the problem was if it is fixed!).

Rich

 

IF it can't connect then it is more than likely an issue with the computer. Either no power, or its shot. Is the ground cable end a clip on type, or a does it have an eyelet for a screw?

 

The ground cable has an eyelet for a screw. Also it has two wires going from it to the connector on the firewall. One looks to be about a 12ga or so black wire, the other is a much thinner stranded wire with no insulation. Both go to the rectangular connector just to the right (looking back from the front, it is towards the drivers fender well) from the large round connector on the firewall with tons of wires in it.

Rich

 

Rich
I have been chasing the same problem off and on for quite a while now. I have changed the ignition switch ( thought I had it there) both fuel pump and EEC ( Electronic Engine Control) EEC relay--this small relay supplies power for the computer as well as the fuel pump relay. I have also untaped the wiring looking for bad grounds.
The problem has diminished some but is still there. It is intermittent so I can't get it to happen with any regularity. The problem seems to be worse when the weather is damp. I was a service tech for 35 years and ran into this type of problem(intermittent)many many times. It was almost always a bad connection/corroded or relay contact. The trouble was finding it. Sorry -not much help. I have the Ford wiring diagrams and have studied them and can't find any reason for the problem. The chattering pump relay seems to hold the key. The problem may lie in the circuit that causes the pump relay to shut off after you turn the key on and do not start the engine.

 

That grounding cable sounds like the ground for the computer. It just needs to be put in a very good grounding point. I hope that solves your problems though.

 

Didn't have time to pull the connectors this evening, but while making sure I knew where the computer was I noticed something new. There is a door chime! It is very faint, but with my head under the dash I can hear it. Not sure if it is just a faulty chime, or if it is a related electrical issue but it sure is faint sounding. Also, one other thing most likely unrelated is that the temperature gauge does not work. The other gauges all work, though you have to tap the dash to get the oil gauge to read the first time.

Is there any problem with my running a wire directly from the negative battery terminal around to the bolt where the computer ground is just to rule out any chassis/frame grounding issues?

Rich

 

No, there wouldn't be an issue with that.

 

I cleaned the connector to the computer, no change. I also jumpered from the negative battery terminal directly to the ground on the computer, and from the positive on the battery directly to the power on the EEC and to the red/green on the EEC relay (effectively bypassing the ignition switch run terminal and ruling out a bad ignition switch).

No luck. The EEC relay does not click in and out like the fuel pump relay does. The check engine light definitely flickers when there is a problem. I checked the fusible link at the starter relay, it seems good too.

Sometimes the fuel pump runs for about 30 seconds and shuts off, other times the relay chatters and yet other times the fuel pump just runs continuosly.

I checked with the junk yard, they want $100 for a computer, and its a you-pull, so I have to go out and see if they even have one. Sure hate to spend the money if its not the problem. Going to try the Scanner again, forgot to try it after cleaning the EEC terminals. I'll report back with what happens on that front.

 

What kind of scanner is it? Some brands, like snap on, have a "wiggle" test on them. You set the test, and start wiggling connections, and it will look for a change in outputs. Just a thought.

 

Thanks for the input. It is an Elite AutoScanner Pro from Actron. It works well on the son-in-laws lincoln and on GM and Chrysler products. First truck it has been used on though.

The only code was 067, which it says "clutch interlock switch circuit open".

I tried the wiggle test. I wiggled all the connectors I could find under the hood. Then when I gave up and sat down in the cab it went off like the fourth of July. Turned the ignition off and back on, reset... wiggled everything and nothing. I am thinking about pulling the EEC computer and trying wiggling it to see if maybe it has something loose or wrong inside it. I really think this has to be an electrical connection issue, just running out of ideas where to look.

 

Oh, almost forgot. I can only run the fast test. When I run the slow test less than a minute in to it every time the relay starts clicking and eventually the scanner shows an error communicating with the EEC computer.

 

I have the same problem with my 1990 ford bronco, including the door chime. Have you been able to narrow down the problem yet?