Ok, I know I'm a newbie here, but I have been lurking and searching and I will continue to search while waiting for replies.

Here goes, Monday I bought an '89 RS 305 TBI for a song because it was having starting issues and they broke the column trying to fix it. When I unloaded it, I pulled the rod that the key usually turns and jumped across the starter and the car fired up and purred like a kitten. I even drove it around the yard with a busted column just to check out the tranny. Wednesday I swapped in a column from a wrecked '98 LS1 T/A. Most of the connectors connected up, except the wipers and of course the air bag, and I think the cruise. I went to start it after the swap and the car turned over, but wouldn't start. I started chasing connections and there is fire at the distributor and to the plugs. So next I started checking the fuel. Put on a new fuel filter(been sitting a while) and then checked the injectors. Only one of them was spraying fuel when cranking and it would run about 2 seconds then die. I checked the fire to the connectors and only one had power. I switched connectors and then only the other one sprayed. Are both of them supposed to spray when starting or just at WOT? I checked the fuses for the injectors and they are both good and there is power to the fuses. Please help with any info, even if it may seem obvious. I'm stumped because it ran before I took the busted column out. I'm new to the TBI, but not to cars. I was planning on going racing tomorrow to get some baseline numbers if I can get it started. Please help.

 

Time to break out the voltmeter (or at least a test light) and the repair manual with diagrams.

You already checked the fuses, good. Try swapping them. Did the problem move to the other injector? Fuse.

Test the positive wire (red resp. white) on each injector. With the key on, you should see 12V.

Test the actuation of the injector: with the key on, ground the negative wire (blue resp. green) and watch if the injector squirts. (you can ground the wire using a test light)

You can also swap the connections on the injectors. If the problem doesn't switch sides, it's either a bad injector of fuel supply on that side.

That should get you started.
Lou

 

I used a light on the injector connectors and one had power and the other didn't. So I switch connectors and the problem went to the other injector. So it must be a wiring/ECM problem.

 

Dang, I missed that one, oops.
So when testing the red wire and the white wire, only one had power? That would be the problem. They both should have 12V on them with the key on.

I'd try swapping the fuses and see if that does anything. It might be a fuse or a wire.

Lou

 

Must be a wire, because I check and swapped fuses and there is power to the fusebox. Where does the wire go between the injector and fuse box? The ECM? I'm at a loss.

 

Did you mean no power FROM the fuse box? If you probe the fuse holders for INJ1 and INJ2, does the test light light up?

The fused power for injectors should travel from the fusebox under the dash to the passenger side (so far, two pink/black wires), now the colors switch to white and red past the C207 (next to the ECM), then by the ECM through the hole in front of the passenger door, into the fender, up into the engine compartment, in the thick wireloom over the top of the HVAC box to the throtle body.

Lou

 

Thursday night I put the battery on the charger since it had gotten weak from all the cranking attemps. Friday when I got home I put the charged battery in, but the end of the hot connector was cracked, so I replaced it so as to be sure to have a good connection. I checked the power to the injector connectors before turning over and now they BOTH had power. I thought great it should run now. Re-connected injector connectors, turned the motor over and both sprayed for just a second and quit. Turned it over again and nothing. I pulled a spark plug off and now I had no fire, which I had before the injectors went haywire. I guess the ecm will not shoot fuel if there is no spark correct? I checked the coil and it was good and had power to one of it's connectors. The parts store said the cap and rotor looked good. When I checked the connectors at the distributor, neither had power and one of them did the other day when I did have spark. I traced these wires back to the passenger fender and into the interior. All of my fuses are still good and I'm stuck again. Is my ECM screwed up or what?

 

The spark is generated by the distributor and further advanced by the ECM if necessary. You can disconnect the timing connector (single wire connector by the firewall, on the passenger side - by the HVAC box) and that way the ECM will NOT have control over the spark. If you still have no spark, you might have a problem in the distributor or ignition module (inside the distributor).

Btw, the PINK wire on the connnector on the distributor should have power to it with the key on. So should the coil. If you don't have power there but the fuses are good, check the wiring. The power from the fuse goes through the C100 on the firewall (below the brake booster) to the coil and then to the distributor.

Hope this helps.
Lou

 

The pink wire on the distributor connector is the one that doesn't have fire now and did before. The coil does have power at the connector. These were both checked with the key on and also checked while cranking. So it must be a wiring thing and not an ECM thing?

 

ECM's don't go bad easily. They are designed to withstand some abuse. I wouldn't worry about the ECM yet.

The pink wire that powers the distributor comes from the coil. If the coil has power, check the second (outgoing) connector on it, it powers the distributor.

Lou

 

So both connectors at the coil should have power with the key on? I'm pretty sure only the one going to the distributor has power.

 

The pink wire on both connectors on the coil should have power with the key on.
The power comes from C100 to the coil on the first connector, then from the second connector (wired in parallel on the coil) it goes to the distributor. It's strange that you have power on the connector going to the distributor and not the first one.

You can pull off the other connector (with no power) and put a test light in the coil socket and see if it lights up. It could be just a bad connector.

Lou

 

Ok, now I have power at both coil connections and the two wire connection into the distributor from the coil is hot too. Should the 4 wire connector at the distributor be hot, because it isn't.

 

Yes, the pink wire on the distributor MUST have 12V (with the key on), otherwise you won't have spark.

Lou

 

The pink wire on the distributor has power. It is in the two wire connector that runs to the coil. There is a four wire connector on the distributor and none of them are pink and none of them have power. These are the ones I was wondering if they should have power.

 

Ah, I see.
The other 4 wires don't have 12V on them. They are signal/reference wires for timing control.

Lou

 

So if everything is hot that is supposed to be, then it must be in the cap or rotor? The parts store said he didn't think they were bad when he looked at them, but I guess I should try new ones anyway.

 

Before you start throwing money at it, you can keep troubleshooting the problem to find the source.

You can for example disconnect the center spark plug wire from the distributor and put it close to a ground. Crank. If you still have no spark, the problem isn't in the cap or the rotor.

You can advance the test by turning on the ignition and grounding the white wire on the coil. If you still see no spark on the center spark plug wire, it's NOT the distributor at all. It must be in the coil or wiring.

Hope this helps.
Lou

 

Guess it must be something in the wiring. B/C there is still no spark out of the coil into the cap. I know the coil is good because I put it on my V-6 truck and it fired right up. I guess something isn't telling the coil to fire.

 

Alright.
Now ...

Don't give up, you're almost there!
And I'm VERY curious what you find.

Lou

 

Been a while since I've been on the forum, but finally got some time to work on the car with a friend and we traced the problem back to the computer. We used a spare computer out of an 91 V6 5spd truck and the car started right up. This surprised me as I thought it had to have a 305 computer. We pulled the chip out of my computer and put it in the truck computer and it still ran fine. Now my question is, what is not going to function properly with the V6 truck computer instead of mine. I know the electric fan is not kicking on. Is this because of the truck computer or does the chip control all of this?

 

I think in order to get some action on the V6 computer query, we better start a new thread.

Eric