Hey guys I still have a problem. I have a 91 fbird 305 TBI and it won't start. Car cranks over but there is no fuel from the injectors and no spark coming from the coil. I have tested every sensor having to do with the Fuel injection and everything checks out. The fuel pump is working and pressure is within spec. Verified there is power going to the coil plus it is new. I have replaced wires, cap, rotor, distributor, module, and all vacuum lines. I have tested the pickup coil and ign coil and both are working. Had the module tested at AZ and it came up good. I think that's everything. I was told it could be a VATS issue. That if the VATS is bad the ECM will not send the appropriate signal to the injectors. Would that also stop it from getting a spark? How would you test injectors? Sorry I'm all over the place but I've been at this for weeks and it's getting a little un-nerving. Any help you can give would be much appreciated. Thanks!

Unplug the 4-wire connector on the distributor. It is now a stand alone ignition system. Trouble shoot until you get spark. Then re-connect the 4-wire plug to start the engine.

The ECM won't fire the injectors unless it gets pulses from the distributor. So until that is fixed the injectors won't fire.

A somewhat common issue is the two wire, 2 connector piece that goes from the coil to the ignition module. The wires tend to break internally where they exit the coil connector.

RBob.

from my experience the vats system cuts the STARTER circuit. at least on my 84 and 90. I have seen throttle position sensors cause no starts if it is reading WOT. it will usually only cut FUEL but let spark fire to clean fouled plugs. I think i'd start checking wiring if everything else checks out good. I really like ALLDATA.com its like 28bucks for a year for one car but will give you ALL the info you need as long as you know how to use it

good luck!

Funny you should mention that. I was at a junk yard today looking for a car like mine so I could get the ECM out of it. It just so happens there was one out there so I pulled the ECM and decided that while I was there that I would get all the pigtails on the engine that had broken clips on my car. This included the MAP sensor pigtail, The gray connector to the coil, the black 2 wire connector that goes between the coil and the module on the distributor, and the IAT pigtail. So I put the ECM in first and got the same thing, nothing. While I was racking my brain over where to go next I decided to throw on the little 2 wire connector since it was the only one I wouldn't have to splice and solder. Ya know what the bitch fired right up (Trombone playing sound here). To be honest I was so close to just converting it over to carb but I didn't want to give up and I'm glad I didn't. Let this be a lesson to all...When you think you've checked everything, check everything again and then check what you haven't checked. That was the one wire on the ignition system I did not check. Go figure

OK have an update here.

Well the problem occurred again. This time I have spark nut no spray from injectors when starting. If I spray starting fluid in the TB the car will start and run. It doesn't cut out or fall on its face when accelerating. Earlier today (or yesterday now I guess) I tried to start it and it wouldn't start. So I sprayed starting fluid into the TB and it fired. I ran it for about 20 mins then shut it off and immediately tried to restart it and it wouldn't start. The fuel pump is obviously working (it would seem) but the injectors do not prime so the car will start. Is this an injector problem, ECM, or possibly something else? Help please if you can so I don't get stranded right before work like last week. Good thing it not my DD anymore.

At key-on, engine-off the ECM runs the fuel pump for 2-seconds. To test for this can use a fuel pressure gauge. Then crank briefly and the ECM should restart the pump for another 2-seconds.

Another test is to crank the engine until oil pressure builds. That too will turn on the fuel pump. If the engine then starts it is the fuel pump relay being either bad or not being activated.

Although with the starter fluid being used it is the oil pressure switch running the fuel pump.

The ECM uses a small transistor to drive the fuel pump relay and they often go bad. Easy fix for it too as you can use a 39-sent off the shelf transistor to replace it (PN2907).

RBob.

Thanks for the help! Where is this transistor located? I also have another ECM in my shed I could use if the problem is the ECM. Thanks again.

https://www.thirdgen.org/forums/dfi-...swap-ecms.html

RBob.

Today when the problem occurred I noticed that the injectors were spraying but the engine would not start. I check the plug on Cyl.1 and physically it was in good shape but it was covered in soot. After the IAC adjustment it started but it had trouble idling for a while until I drove it for a bit then it seemed to be fine. It only shut off on me once (which it hasn't done before) when I went to back out of a parking space. As always when it runs it doesn't give me any trouble such as rough idle or falling on its face under heavy acceleration. It's just this random no start gremlin I keep having that will always happen at the worst possible times. I don't think its heat related as the engine never gets over 220 degrees even when sitting still and idling for long periods. The only other thing I've noticed from time to time is a slight gas smell. I couldn't tell you what kind of mileage I'm getting as I haven't checked yet. Anybody have any suggestions? I'm really stumped on this one. I'd like to get this figured out before I even think about upgrading the engine. As always any help would be appreciated.

Don't know what happened but that wasn't my entire post. Can't remeber everything I just typed but here is a list of everything I have done so far...

Replaced cap, rotor, wires, and plugs
Replaced distributor and module (module has been tested 3 diferent times and always tests good)
Replaced coil
Replaced and adjusted IAC
Replaced battery
Tested TPS (within spec)
Tested CTS (within spec)
Replaced fuel filter and gas cap
Replaced stock air cleaner with an open element
Tested injectors (within spec and have a perfect spray pattern)
Fuel pressure is 13 psi with KOEO (until of course the FP stops priming)

Whenever this happens the battery will die usually on the second attempt to get it started and it will be an absolute pain to get it jumped. The starter seems to be fine but from the test I performed on it I got these readings - Beginning Voltage 12.43/Ending voltage 9.98 Est Draw 340 amps. Not sure what is meant by ending voltage but the tester says its good. Anyone have any ideas on this? I'd like to get this licked before I even think about upgrades. Thanks in advance for the help.

Ok so it pulled the no start thing again last night. Usually when this happens I can give it a few hours and it'll start. Well it sat overnight and this morning it wouldn't start. So I took the ECM I had from the junk yard and put it in with my prom and it started right up and didn't give me any troubles. So we'll see if that's it. The only thing left to do if this happens again is to install the vats bypass from painless. That would be the only thing that could cause this now I think.