I replaced my in-line pump recently due to a problem which as it turns out probably had nothing to do with the pump. Anyways, now with the key turned it doesn't whir like the old one used to, it just whirs every couple of seconds, obviously not building up enough pressure to start the truck. There is fuel in the pump and lines, but it's hardly pressurized. Two things: first, the new pump is significantly smaller than the one it replaced. Is this necessarily relevant? And second, the pump in the tank is new as well, and I can't hear that working either, although I'm not sure I should be able to. Any ideas on why this new in-line pump may be acting like this?

 

Need clarification. If eveything is operating as it should, the fuel pump is controlled by the main computer according to a very simple algorithm: 1) When the key is turned to "on," turn the pump on. 2) If the computer doesn't see PIP or TACH or similar that indicates the engine is turning over within 2 seconds, then shut the pump off. 3) When the PIP/TACH signal is present, turn the pump on. Hope that makes sense.

Your basic description of the problem sounds to me like it could be normal operation of the fuel pump (other than the low pressure generated). Have you put a fuel pressure gauge on it? What pressure are you getting? If you ground the fuel pump test lead in the self-test connector, what happens? Do you still get intermittent operation of the pump or do you get steady operation? With the test lead grounded, does it generate the required pressure (40 psi KOEO)? Have you thoroughly checked the wiring to the two fuel pumps?

Because the PIP/TACH signal is important in getting the pumps to come on, are you certain the problem isn't in the ignition system? I never did quite understand the specifics, but PIP/TACH are generated in the distributor or by the CKP and then passed to the main computer via the TFI module. TFI modules are known trouble spots on these. Another thing you might do would be to pull codes from the computer and see if the computer has any clues stored in memory that might help in diagnosis.

 

Why do I get the feeling that this is the particular rig in question:

http://norfolk.craigslist.org/car/248988349.html

I'm wondering if the fuel pump relay, a fuse, or the intertia switch is at fault. Also, could be that the fuel system wasn't re-pressurized after pump replacement properly? Is the fuel pressure regulator bad (pull the vacuum line on the regulator and check for fuel in the vacuum line)?

Anyhow, looks like it's for sale...

 

Haha, yep, that's the one. In fact it's going to be reposted again tomorrow. The relay, fuse, and inertia switch are all fine. Like I said in the ad, I'm really at the point where I don't have the will power/time/knowledge to keep going on this project. I've already replaced so much crap that hasn't solved the problem that, although I hate to do it, I need to throw in the towel. Thanks for your help, mrshorty. The TFI is brand new, and that's where I'm going to have to leave it. It seems like I must be close to getting this running, but I've run out of steam.

kernel-panic, if you want a good deal on a parts/project car, let me know!

 

I'm wondering if you got a bad TFI module (it happens) or if the computer is screwy. You could probably "hotwire" the fuel pump to get it started and warm it up then pull codes or something. By the way, I'm just over 10 miles from that intersection, and your ad didn't say if it was a 5-speed or auto... also, if you need help getting it running, I could probably help you figure it out if you'd like to keep it. On another note, I'm thinking I need to get some kind of spacers for my front suspension, it's sitting lower than the rear ... post-Explorer coil/leaf swap and I'm having tire rubbing issues, and all I have on it is 30x9.50-15s! But, so far so good:

 

I appreciate the offer, but I'll be out of town until Jan 2, and then we're moving to an apartment where I can't store a broken-down Bronco. I've been getting some emails on my ad, so hopefully I can at least work something out by then.

 

First off, did you remove the gas cap, while you primed it by turning the key to the on position, leaving it for a few seconds (you should hear the pump in the tank kick on or whirl), then put the key in the off position, THREE TIMES IN A ROW.

Let it sit for a minute, then try starting it without gas, if it does not catch keep pumping it quickly, then shut it off.

Repeat the above a few times. Don't kill the battery or starter with excessive cranking. If it does not start in five seconds, shut it off.

Disconnect both battery cables and let the truck sit for at least ten minutes.

Try starting it, if it does not catch right away, do the prime method again. Repeat the battery disconnect.

This method is what I have used to get tough ones started. Keeping if floored while cranking does no good as far as I can tell.

Now, the thing with the wire clip on the fuel pump in the frame rail is it is exposed to road water and salt and it can have a bad rusted connection. Take the connector off the fuel pump and make sure you are getting the 12 volts. Since the pump is in a strap with rubber on it, make sure the ground wire is okay too.


Not to rag on you, BUT, make sure you reconnected the in tank fuel pump and the connector is not loose. While there do a voltage and ground test too.

 

Uh, I'm a little curious as to why you'd want to pump the accelerator pedal on a fuel-injected engine? Not saying it wouldn't work, but that's a new one on me. Another thing, most resources I've read don't necessarily mention removing the gas cap (other than to relieve pressure), since I believe they are normally vented(?), but, they usually tell you to turn the ignition switch on and off at least 5 times to re-pressurize the system.

... Wondering if some of those e-mails about your BII are from people I know... someone in my 4wheel club messaged me about the ad and asked me if I needed another project!

 

So, do you???

 

zstr5000, don't give up yet. You don't have enough info to logic this out, so here is some to get you going again.
First you can run the pump right from the engine test connector. Put a pressure gage on the rail and see what you got, positively.
No, pumping the throttle does nothing for bringing gas. Operating the ignition switch a half dozen time is how the fuel system is primed again after service work is performed.
If you hear the inline pump each time, it is working but you can't tell what the pressure condition is without a pressure gage.
The PIP in the dist is the signal that turns on the pump, provides the EEC with timing pulse reference for ignition and fuel injection operation.
It is very possible to flood the engine while cranking with an ignition fault.
You have to establish that you have spark when cranking. If not, the TFI is suspect.
The TFI has two power inputs. One for cranking and one for running. These come from the ignition switch. One could be faulty.
Check these things out one at a time and you should begin to see what the fault is, then zero in on it.
How to run the pumps from the test connector: Look at the test plug end with the two single connection up. The bottom row will have 4 connections. The pump connection is the last one on your right. Place a ground on it with the ignition on. This brings up the fuel pump relay. If the pump dosn't run there is a problem from the relay back or there is no power to the pump circuit.
Good luck.

 

So did you sell it or fix it? Been a while since I thought of following up on this thread...