I believe the last year(s?) of the 2.9 had a MAF.

 

For testing solid state circuits with a test light, we should use a high impedance LED type, not a incandescent lamp, lest we over load the solid state circuit & get a false/no light indication, or over load & damage the solid state circuit.

Same with multi-meters, we shouldn't use a low impedance analog meter, best to use a high impedance LCD multi-meter so we get accurate results & without overloading, or damaging the solid state circuit.

 

I went a head and bought myself a new computer, then returned it because it made the truck run like crap, got a new new one, and now that one runs just slightly better. Is there a specific way i need to install the computer?
What computer should I also be using?
Its a 1990 Ford Ranger Super Cab XLT with manual trans, federal emissions, 4 wheel drive, and a/c.
I have a E9TF-12A650-DA in the truck right now ( the original)

 

Did you ever verify your PIP operation?

 

I realized that the PIP signals the computer to fire both injectors and spark plugs during cranking. I pulled the plugs and tested them and found them all to fire while cranking.
The last place the injector isn't firing from is the computer.

 

If you are sure that it is your computer here is where I got mine,,, I had to send them all the information on my truck,,this info was found on drivers door tag.. I looked everywhere I could find online and this was by far the best price I could find.. They built it just for my truck by year,,motor,,trans and Vin number I think,,plus some other details if memory serves..They give all there computers a lifetime warrenty. It came updated and ready to install but I had to have it programed for my keys ( PATS) because of passive anti theft system.. But before 99 no PATS system to worry about.. Here is there info,,,,, Flagship One Inc. ,,, 21 Ryder Place,, East Rockaway NY 11518-1200,,, They have a internet site also,,, I have had no troubles what so ever and it works very well..

 

I went down to my local autozone and picked up a cardone computer, found out it was trash, got another one, found out it was trash, then finally got a blue streak computer which is able to get the truck to run a little better than before but still no start(started with ether again).

Something I was thinking about is the speed density of the engine. If I'm not mistaken, the engine uses manifold pressure and air intake temperature to determine how long the injectors should stay open for.
That being said, I wonder if the MAP is bad (I already replaced the Air Temp Intake sensor and both coolant temp sensors). I know they rarely fail, but what if during cranking the engine gets signal from every where but the MAP hence why the injectors don't fire?

 

My truck with the bad computer would only start if sprayed with either,,,then it would run but not correctly,,,,the computer was not getting or sending signal for the injectors to fire,,,i thought maybe it was the camshaft scyronizer or camshaft position sensor which is on top of the scyronizer,,,i replaced both with no luck,,,then got the flagship one computer and it solved the problem ..i wonder if it could be in your wireing harness,,,these old rangers can be a big pain sometimes,,,good luck to you

 

You must remember that the ignition system is separate from the fuel injection system.

The TFI module gets the PIP signal from the PIP sensor, and then passes it to the computer. The TFI/ICM can make a spark with a very weak PIP signal, but that doesn't mean the signal is good enough for the computer.

 

I understand but I figured since there is signal coming from the pip to fire the spark plugs there must be signal to fire the injectors as well.

I just realized my radio works only sometimes when the trucks running

 

Bad assumption to make. You could completely clip the PIP wire from the ICM to the computer, and still have spark.

 

Wait really? I always thought the PIP is what told the computer to fire the injectors and the spark plugs?

Found out that my accessories on the ignition switch don't work. Ill replace the PIP and the switch.

 

Once again, ignition system and the EFI system are separate. The ignition system is entirely self contained. It receives the SPOUT signal from the computer, which controls the ignition timing, and that's it. The ignition system can operate without any interaction from the computer at all - you could clip the PIP and SPOUT wire to the PCM, and still get spark.

 

John F: You are making so many one-line posts this thread is up to page 4, and I no longer remember if your engine starts and runs, or is unable to start at all.
Last thing I got from reading was that it will start, but not run properly.

If not, remove all the 'new and improved' parts you added, and get back to where it WILL.

The TFI module can run the engine with just battery + and ground. The timing will be fixed, but it will start and run w/o the computer functioning.
With all these pages of posts, and a plethora of short posts, the thread gets too long to keep up with when there are other threads that are much more succinct.
Does it start? If not, have you stepped back from your latest change? (Make only one change at a time, or you run the risk of causing more problems.)
A summary of changes made, listed one per line, perhaps with notes alongside, and the current 'condition' would make figuring out what's wrong much more likely. Unless you like dragging things out, that is.
tom

 

Sorry bout all the one liners
The original problem was a lack of fuel pressure I've fixed that a long time ago
The current problem is the injectors will not fire during cranking.

The truck will run as long as it gets help from a burst of ether. While cranking I get no injector pulses until after the key goes from start to on. If I get a shot of ether then the truck will begin to fire the injectors and run. While running, if I give it a quick burst of gas the truck will hesitate.

What I've replaced
Ignition module
Air temp sensor
Coolant temp sensor
Pip sensor
Ignition switch
computer