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post #1 of (permalink) Old 01-26-2000, 02:23 PM
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Fule Pumps Help!

My last post was related to 2 trouble codes and a high idle. Problem solved. The EGR Valve gasket some how got bent up during installation. I cleared the codes and it passed smog with flying colors. Now on to my current problem.
I went 4 wheeling for the first time in this truck this past weekend. Not to bad of conditions, just a little mud. The truck being stock except for 31 inch tires did great. On my way home a few hours away, the truck began to stumble and die like it was running out of fuel. Not the case. At the same time my check engine light came on rapidly. I drove like this down the highway a few miles, and it dies on me, and didn't want to restart for a couple hours. I got it started, and continued on home. It didn't make it. I managed to get it to a friends house to figure out what is wrong. I checked my codes again and they are as follows: The same 2 before 32 and 67. I think they were there from before and I forgot to clear them.
Code 53: TP circuit above maximum voltage.
Code 54: ACT Sensor circuit open.
Code 64: ACT sensor grounded or input reads 254 degrees F.
I replaced the ACT Sensor (Air Charge Temperature) and it started to run good. I decided to head home and it completely dies on me and doesn't want to restart at all. I finally gave in and had it towed home. At home I discovered a big problem. No check engine light coming on at all when KOEO. And both fuel pumps remain ON with the key off. I guess the reason it won't start is it's getting way to much fuel. I don't know if it is computer related, or the fuel pump relay. The relay is only $11 at Ford. But the computer is about $120. Any help will be greatly appreciated. Thank You.


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post #2 of (permalink) Old 01-28-2000, 11:12 AM
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Re: Fule Pumps Help!

I'm not sure what year vehicle you have but will assume it is fuel injected. I can't give you very many answer. Your fuel pumps should indeed go off with the key. Probably need that relay. Must be stuck on. You can check it with a ohm meter to see if the contacts are closed. The fuel pumps should run all the time when the key is on. The fuel pressure regulator takes care of how much fuel is reaching the injectors. Some quick troubleshooting when it won't start. Check for a spark at the spark plug wires. If you have a spark the problem is most likely no or not enough fuel. Get a fuel pressure gauge to put on your fuel rail bleed valve or one made for checking the press. Maybe your regulator is not working properly. That's all my ideas at the moment.

[img]/wwwthreads_images/icons/cool.gif[/img] MG48 - 88 Bronco
post #3 of (permalink) Old 01-28-2000, 12:27 PM
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Re: Fule Pumps Help!

You should check the Fuel Pressure: it should be about 39psi with the KOEO. I think that it should be about 30psi with the engine running. If the regulator is bad, then your pressure will be way too high. Regulators are pretty cheap, by the way. In case you didn't know, the fuel pumps are controlle d by the fuel pump relay, which is controlled by a signal from the EEC Module. The Pumps should be on when the engine is running and off when you shut off the key. I hope this bit of info helps. Good luck!

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post #4 of (permalink) Old 01-28-2000, 01:33 PM
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Re: Fule Pumps Help!

I am sorry, I didn't make myself clear. It is a 1988 Ford Bronco, with the 4.9 L, and 5 speed. I going to get the relay today, and see what happens. I still have no explanation of why my check engine light doesn't come on anymore KOEO. I will also be checking my fuel pressure also. I will keep you posted

post #5 of (permalink) Old 01-28-2000, 02:11 PM
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Re: Fule Pumps Help!

Fuel pressure is at least 10 pounds higher on the I6 than on the V8's. No fuel should actually make it into the intake manifold itself, until the computer pulses on injectors (which won't happen until you crank). However, as mentioned above, the Fuel Rail will pressurize with Key on, engine off, as the pump will run for a second or so.

post #6 of (permalink) Old 02-08-2000, 01:59 AM
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Re: Fule Pumps Help!

No check engine lite means no EEC power, or no ground. Key on should produce VREF of 5 volts at tp sensor. You should get a book to trouble shoot the EEC system. Ford tech.

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