Fuel Injection

[katsi]

Everyone, I have a friend who just purchased an 81 fuel injection in really great shape. Problem is that we can not get it to fire. The fuel pump was replaced as it was not working but what is the next in line to check? When the hose to the throttle body is removed and the intake fogged, she will fire for a few seconde before she runs out of fuel. I know you guys will get this car back on the road. He signed up but is really anxious about working on it so I am posting the question for him now. Tomorrow he will introduce himself to you guys. Thanks.

[narfire]

I believe the way the FI works is that when you crank the engine at start, the flap in the afm will open a tad. That sends a signal to the double relay and then to the fuel pump to turn on. I'll check it is flowing by disconecting the cold start valve hose with a cup underneith to catch the fuel if it is working.
If you can download Brad's electrical schematics for the year, I'm going by memory here, I saw a post sometime ago there is a wire to the double relay that has an inline fuse. Check that. Ron Luxmore is a FI guru,perhaps he'll chime in here as well.
With the ignition on, poke the flap with a screwdriver carfully and see if you can hear the fuel pump. Direct conect the fuel pump?
After all that I suppose you do have spark as it ran momentarily when fogging the intake.

[RRoller123]

Brad Artigues' Fuel Injection manual is excellent and should help diagnose get you in the right direction! You can download it at his web site.

[redcars]

The fuel pump will not run when the hose to the throttle body is remove as the air is not holding the AFM arm open. When you have the hose off the AFM and the ignition on move the flap in the AFM. when you do this the fuel pump should turn on.

Good Luck

[rlux4]

It does sound like you're not getting fuel seeing as it will fire with the fogging. That's good, you have spark, timing and compression. Being as it's a new pump we'll assume it's good. The fuel pump get's a signal from two sources to run, 12 volt from the ignition switch through an inline fuse to the dual relay. This 12 volt is sent to the dual relay after the flap in the AFM is opened, either by hand as narfire says, or in normal cases by the intake of air when the engine is cranking. First drop the relay tray under the glove box and find the dual relay. Then with the key "on" check for 12V at the brown with white stripe wire. If no power it's either the ignition switch or more likely the fuse on that line. The inline fuse holder is up in the rat's nest of wires behind the main fuse panel. The wire there is still brown with a white stripe. If the fuse is good it may be the holder itself not making good contact with the fuse. I replaced mine with a normal AGC type inline holder because it was so erratic. If those are good you'll next check that the contact in the AFM for the fuel pump is closing when the flap moves. To do this you'll need to carefully pry off the black cap from the top. If it's never been removed you may need to use a razor knive to cut the silicone adhesive from it. There's a little lip on the side, just carefully put the blade up between it and the body of the AFM and work your way around. Be carful, the black cap is brittle.
Once you've got the cap off you'll be able to move the arm that's attached to the flap by hand. As you move the arm look in the upper right corner of the area and you'll see contact points. Are they making contact when the arm is moved?
Try these steps and let us know if it solves the problem.
Brad's manual is great, I learned what I know from it and tinkering with the FI components. Also, if these steps don't solve the problem here's a manual to trouble shoot the dual relay. It's less likely, but possible that it's bad.
http://www.wcmotors.com/personal/Fiat%2 ... agnostics/
Ron

[So Cal Mark]

remember that the pump ground is at the left taillight, not too uncommon to find it loose or disconnected

[SchaefSpider]

Thanks guys! I appreciate all the input. My friend that was helping me fog the engine knows FI very well and (incidentally) owns a toyota MR2 'spider'. So he was manually opening the flap on the throttle body. We can hear the pump come on, and pressurized fuel is coming through the fuel pressure regulator. we were going to pull out the injectors, but suspected there may be electrical issues as opposed to 4 simultaneously clogged injectors...but she has been sitting for at least a year. That said, before I do anything else mechanical, I am going to see what's going on with the wiring. Ill let yall know as soon as we get her rolling! Then there's the stopping issue...LOL! Thanks again to all!
Bob

[BEEK]

if the car has been sitting for a while , it is possible for all 4 injectors to be stuck, as the fuel has evaporated leaving sticky deposits. sometimes you can excute the injectors with 12v and break them loose if they are determined stuck

[SchaefSpider]

good news! she started. i was troubleshooting the wiring issue under the dash and just as the instructions said, "turn key to on position", while i seatched for the inline fuse. found it, tested it. not it. although there is a brow and white candy-stripe wire that goes to nothing-which had me a little confused-any takers on that? maybe a picture would be better. Anyway, i just figured id crank it over for no other reason than to listen to it; lo and behold she cranked over. i guess the fuel line needed to pressurize and push out the air.

now its just a matter of fluids and tuneup!

[rlux4]

The brown with white strip wire for the fuel pump has a straight white stripe on it. If the one you found doesn't go to the dual relay it's possible a PO has bypassed the dual relay and has the fuel pump wired to come on when the key is turned on. Does yours do this? The factory set up is a safety issue; if the engine stops turning, as in an accident, the flap in the AFM closes and stops the 2nd signal needed to power the fuel pump. Fuel stops flowing reducing the chance of an engine bay fire. Did you drop the relay tray? If so, does the brown with white stripe wire at the dual relay look the same as the one going nowhere?
Here's a pic of the dual relay with the wires annotated posted a while back by... I can't remember. The brown with white stripe wire is just above the red wire. (The white with black stripe wire is labled incorrectly)

Ron

[SchaefSpider]

ah, there ya go! The dual relay has been bypassed and the fuel pump DOES come on when the key is turned on. In fact, nothing is hooked up to the dual relay. so we're getting somewhere. ok, it starts, ilde is low. no big deal. after fresh plugs and wires and fluids we can address the idles issue. still think I have fuel delivery issues but for now I'll be systematic in my approach of one thing at a time. BIG THANKS to all for your insights!

The cowel from the AFM to the throttle body is cracking (particularly where the forward vacuum hose come in). I electrical taped the crap out of it, but im sure at some point I may need a more permanent fix.

[wikkid]

You can use Shoe-Goo very effectively to seal all cracks in the big rubber intake piece. Check at your local hardware store, in with the glues.