cgk60

My 90 f-150 wouldn't start, had the distributor module replaced, still would not start, ended up being the computer.

PollyRDH98

Getting it towed in the morning. Been working on it and testing things nearly every day for 2 weeks, so it's too much for me to do. I thought about the computer module, but it seems like the relays wouldn't kick on if that were the case (I could be wrong.)

I don't want to pay $70 for a new ECC if that's not what it is. Oh well, at least I learned a lot about that truck in the process.

Good old Bill

Please excuse me for being so slow with your responces, my excuses are not relevant.

You need to get fuel to the fuel rail at the schraeder valve, this is, I believe before the computor takes over. (Statement subject to change at any time). Find a tank that has access to the electrical connections and power that pump up with jumper wires, follow the pressure to the rail, disconnect where necessary to see fuel pressure. No fuel pressure to rail means an engine will not run.

Please send me a Private message, its a whole bunch easier for me to follow up with people, my memory and visits of this and another forum get lost.

PollyRDH98

No need at all to apologize for slow responses. I'm just glad this forum exists and for all the expert advice/suggestions everyone is putting out there.

Don't know how to jump the fuel pump. I guess that code 556 Fuel Pump Circuit Failure can be pretty vague in that it can be an issue anywhere from the pump itself to any of the electrical controls for the fuel system? It seems that it tells me what I already know - that I'm not getting fuel pressure in the system. Considered going to buy a pressure gauge, but since I'm not getting spray @ the schrader valve, then there is little or no pressure.

Both fuel tanks are registering on the gas gauge, but I read that there could be enough power coming out of the pumps to control the gauge even if there isn't enough to power the pumps. Would be quite a coincidence though if both pumps went at the same time.

Before towing in the morning, I'm going to crawl under one more time to get a look at the line and check that filter I put on. Would it make any sense at all to disconnect the filter and put a container underneath to see if fuel is pumped out when the key is turned on?

Warlockk

That is exactly what I was going to recommend. I seem to recall you said you hear the fuel pumps running. If so that means they are getting power. Check for fuel flow at the filter. If you don't hear the pumps running, you can check for power to the pumps using a DMM or test light. The wires run to the fuel sender on top of the tank. If you get no fuel at the filter from either tank and you know the pumps are running, you have some bad pumps, pickups or an issue with the fuel lines.

PollyRDH98

I pulled the fuel filter and no fuel pumped out when I turned on the key.


Decided to just have it towed. If it is a fuel pump issue, I won't be able to get into that. Read a lot of threads that said the Ignition Control Module can cause similar problems, but couldn't figure out if it would cause fuel pump not to engage. If it is the ICM, I don't want to get into pulling the distributor to work on that. Also, if I did all that and it still didn't start, I'd be forced to take a sledge hammer to the whole thing!

Anyway, I'm already annoyed with the owner of the shop I took it to. While it was still on the tow truck, he has basically "diagnosed" it as a faulty pump. Told him that both pumps were working and now both are not. Both pumps still register the volume of gas on the gauge, which is different in both tanks. He looks away while I'm talking and smirks. "Fuel pump" is all he says. He then said the switch could be broken and the one and only tank that is registering could have lost the fuel pump. I've added fuel to both tanks over the couple of months that I've had the truck and when either of them get low or near empty, I switch the tank and keep on driving and put gas in only when both tanks are low.

Yes, I understand both "could" have gone at the same time, but that's not very likely. If he calls and says it's a bad pump, I'm probably going to have it towed elsewhere just to be sure.

Warlockk

I would be skeptical of both fuel pumps failing at the same time. More likely the tank switch failing to activate the right tank. Or being stuck on the one bad pump while still reading the fuel senders from both. Another likely suspect is the power relay for the pumps. Make sure they tell you what's wrong before they do any work. If your suspicious make them show you how they diagnosed the problem. And don't forget to ask for the bad parts before they throw them out. Get a warranty in writing listing everything they did not just fixed fuel problem.

PollyRDH98

Apparently it was the tank selector switch. Both fuel pumps are still in good, working condition. So, somehow the fried switch caused an electrical failure to both tanks. I guess this shop did what they needed to do to track down the problem. Cost around $120, and I figure it would have taken me another 2 days to really pin down the problem, so it was worth it to me.

Thanks again, all for your assistance and suggestions. It was a great help, but I have to know when to call in the pros!

Polly