Reviving a 92 f150 that's been sitting for 2 years.

[zeky]

It was nice of the in laws to store the truck for you, while you were away.

 

[ram_man]

I found a very handy video from Eric the car guy and scanner Danner diagnosing no spark on the f150. I tested the module as they did I also stuck a spark plug into the wire going to the distributor and the. Hooked a ground wire from the spark plug to the battery and had spark . So coil tested good, as did the pick up. I then tapped the ignition module with a wrench and it fired right up. So tomorrow she gets new TFI then go for a proper test drive and see how she does.

 

[ripcord]

I'd buy a second TFI unit and put it in the glove box. No one makes a quality TFI any longer as they are all imported Chinese junk. Don't forget to use the heat sink goop on the back of it. Also, there are two types. The grey ones are mounted on the side of the distributor and the black ones are the type for mounting on the fender well.

 

[Lubener]

If the HP pump goes out, it won't run. The fact it is running indicates that pump is fine. In fact, I'd expect both pumps are fine, but confirm, as Lubener noted, by checking pressure at the rail. This should have a vacuum operated fuel pressure regulator (these are a return system) that will pull running pressure down during low load/high vacuum. Off pressure, if you repeatedly prime the pump to get rail pressure up, should be 45psi. Rail pressure should be 45 psi with the vacuum hose from the regulator removed as well. It'll drop into the 30's with the vacuum hose connected.

Also, it's not uncommon for the diaphragm in the regulator to fail. This will cause both a hard start (because the rail is bleeding down into the intake) and it may idle crazy because it's over-fuelling once running. That would be something I would check.

Just checked the fuel pressure specs. for the 300 I-6.
1987-1994 should be 45-60 PSI
1995-1996 should be 30-45 PSI.
Makes me believe 1987-1994 have three pumps and was changed to two in 1995.

If gas squirts out the FPR's vacuum nipple, the regulator is bad. No gas present, leave it alone, it's fine. The regulator keeps the pressure from going too high which is why pressure should go up when the vacuum line is pulled off.

 

[OVERKILL]

Just checked the fuel pressure specs. for the 300 I-6.
1987-1994 should be 45-60 PSI
1995-1996 should be 30-45 PSI.
Makes me believe 1987-1994 have three pumps and was changed to two in 1995.

If gas squirts out the FPR's vacuum nipple, the regulator is bad. No gas present, leave it alone, it's fine. The regulator keeps the pressure from going too high which is why pressure should go up when the vacuum line is pulled off.

I just checked the part #'s, the L6 got a different regulator (56psi) CM4763 than the V8's CM4764 (45psi) and that's 1987-1995 apparently. The vast majority of my experience is with the V8's.

And yes, on a failed regulator, as I said, if the diaphragm is leaking, it will both bleed down the rail and result in fuel in the intake because the engine will suck it in through the vacuum line straight off the back of the regulator. This is not an uncommon failure and easy enough to check for by pulling the vacuum line and checking for fuel.

The vacuum nipple on the regulator diaphragm is a somewhat elegant way of reducing fuel volume outside of the pulse width of the injectors. In low load situations when less fuel is needed, the ECM is calibrated to expect less fuel than would be commanded via pulsewidth which is likely due to the pintle-style injectors being unable to cleanly meter fuel at those short pulse durations. As you increase load, and subsequently decrease manifold vacuum, pressure will increase toward regulated. At WOT, you should see full regulator pressure at the rail, which is the same pressure you should see with the vacuum line removed.

The old 5psi Vortech supercharger kits as well as the nitrous dry kits for the 302 had a valve assembly that tapped into the regulator vacuum line. When under boost, the Vortech kit would divert some of that boost to the regulator, spiking pressure beyond stock. The nitrous kits worked the same way, using regulated bottle pressure to work the diaphragm in the regulator the other way, increasing fuel pressure and enrichment. Was a pretty smart way of doing it with minimal complexity, but of course you are still limited to the flow rate of the injectors at that pressure, so there were limits to both those kits.

Before the Tw33ker and other EEC-IV tuning devices, a "calibrated MAF" like a Pro-M or C&L would be used (I've owned both) and/or a Holley (or other brand) adjustable FPR to dial in your A/F on the dyno if you increased injector size to accommodate other upgrades you'd made. The adjustable FPR's were particularly helpful for the SD cars, less relevant if you had a MAF car (stock or converted) with an aftermarket MAF that was "calibrated" for your injector size. Later on the LMAF became very much "standard" with an SCT chip and dyno tune, which allowed for very large injectors to run perfectly.

 

[OVERKILL]

I'd buy a second TFI unit and put it in the glove box. No one makes a quality TFI any longer as they are all imported Chinese junk. Don't forget to use the heat sink goop on the back of it. Also, there are two types. The grey ones are mounted on the side of the distributor and the black ones are the type for mounting on the fender well.

Sometimes you can find NOS Ford TFI modules. I have at least one here that I keep "just in case". Later TFI's were remotely mounted on a heatsink and didn't fail with anywhere near the frequency of the distributor mounted ones. It's not a big deal to convert the dizzy-mount setup to remote using wreckers parts from an SN95 Mustang. And yes, the aftermarket ones are total crap, agree with you 100% there. I went through two and then found a couple of NOS ones, which worked great.

 

[ram_man]

Sometimes you can find NOS Ford TFI modules. I have at least one here that I keep "just in case". Later TFI's were remotely mounted on a heatsink and didn't fail with anywhere near the frequency of the distributor mounted ones. It's not a big deal to convert the dizzy-mount setup to remote using wreckers parts from an SN95 Mustang. And yes, the aftermarket ones are total crap, agree with you 100% there. I went through two and then found a couple of NOS ones, which worked great.

No joke on the TFI being junk! Bought one from Orielly's and it was bad out of the box . Died when you put it in gear ran rough ect. Took it back and got another and now she runs perfect. Took it for a drive through town tonight and she runs good. Transmission shudders a little but it did that when I sold it. It may eventually need a new transmission but if so that's a pretty easy job on these people old trucks all things considered. Engine runs strong as can be. It's so unrefined in every sense of the word but I love it. That's what makes old trucks feel cool, their rough and tough nature.