This is a 90 coupe that I put a replacement engine into. It was running pretty good, probably used up about 10 gallons of gas test driving it over a couple of days as I was working out the kinks.

I was working on getting the radiator fan/fans working and then just when it looked like I got them working right, the car died, and hasn't started since.

I didn't measure fuel pressure, but if I press down on the valve on the fuel rail, I get fuel squirting up.

I checked for spark by pulling a plug and leaning it against the alternator bracket while cranking the engine and it looked like it sparked once right at first, but then no more spark.

So I started troubleshooting the distributor. The batt wire had 12v, so I took the cap off and using my haynes book I started measuring resistance between various leads on the coil. It looked like the coil was the problem, but I have so much trouble with false information in my haynes manual that when I went to buy the coil, I tested it's leads with my multimeter before buying it and it was the same as my old one.

So I went ahead and bought a ignition module. I put it all back together and tried to start it, but still nothing. I pulled the spark plug again and looked for spark and it didn't look like it was sparking, but it was pretty far from my eyes when I was just leaning through the drivers side window and trying to see spark 5ft away, so I put a couple of alligator clips from the negative post to the plug so it was only a couple of feet away and I did see spark.

It was very tiny white spark, but it was there.

Also, now when I try to start the engine either the courtesy lamp or fog lamp relay are clicking off and on over and over real fast while the engine is cranking.

While I was shorting pins A and B on the ALDL connector to put it in diagnostic mode and make the cooling fans come on, I did accidently short the two pins that are kitty corner, I think one of them is for testing the fuel pump, and the one right next to it I don't know what it's for. Could I have fried my ECU or something?

The car was running and then just died even though it looks like it has spark and fuel.

Also, I DO have my braided ground strap connected from the engine to the frame, and right now if I try to flash codes, I just get code 12 over and over.

Any ideas?

 

Oh by the way, it just occurred to me that maybe my injectors aren't firing. I had some spares from my old engine so I unplugged one of the ones that I have installed and plugged it into one of my old injectors and cranked the engine while holding the injector but I could not feel any kind of vibration or pulsing. Are you normally able to feel an injector when it's operating, or is the vibration too subtle?

I did check both Inj1 and inj2 fuses and both were fine. If I have fuel to the rail AND spark I would think that about the only thing left would be the injectors.

 

No one?

 

Code 12 is normal. It means there are no codes.

 

You need to do some testing with a bit better equipment than your eyes and feeling in your fingers. Engines need hot spark, spark at the right time, fuel and air and in the correct ratio and cylinder pressure in order to start and continue running. You say spark quit, find out why, no spark, engine will never run. Use a timing light during cranking to measure timing. Bring a grounded wire close to the boot of an unplugged spark plug wire and crank, you should see a snappy at least 1/2 " spark. Measure the fuel pressure with a gauge, they are about $12 at a parts store. It should be 35-42 psi and it should hold up for at least 1/2 hour with the ign off. Rapid pressure drop indicates leaky injector/s or a defective check valve in the fuel pressure regulator. Use a noid light (available at parts stores) on an injector on each bank while cranking, you should see it pulse. You can make your own noid light with an LED (light emitting diode) and a series 680 ohm resistor and you will have to connect it to an injector plug with the correct polarity. If you get spark, try spraying starter fluid into the MAF and if it starts and quits, you have a fuel delivery problem. Last, measure compression. Post your results for more help.

 

Thank you for your reply. I will make a noid light with a led and see what that does.

Earlier today I tried pulling each inj fuse and then when I pushed it back in I stuck a wire in the left side at the same time which went to my DMM. When grounding the other lead I get the expected 12v when the key is on. Then, if I watch the voltage it drops to the expected 9v or so while the starter is pulling current.

I did this on both fuses, then plugged them both back in and then just tried to start it like normal and thing actually fired up for a second, and now i'm back to nothing again.

One thing I am a little concerned about is that if I connect my DMM to the positive battery terminal, and then connect the other lead to a injector plug, I get 12v on both connections which tells me that they are being grounded, which does not make sense. One of the terminals should be 12v from the fuse, and the other one should be grounded by the ECU when it pulses. With the key off I show that both terminals are grounded because I get 12v between either of the connectors and the +12v. But if this was the case one or both of my fuses should blow, right?

 

OK, I made a NOID light, it lights up on the battery, but no flashes in the injector plug. I tried both ways just in case. Anything I can do to fix no injector pulses besides buying a new ECU? I wonder if one of my injectors is bad and is some how grounding out in the fuel rail.

I will try to unplug all the injectors except for the noid light and see if that fixes anything.

Edit: If I unplug the other injectors, I get nice bright flashes, but as soon as I plug one in, the flashes are visible, but just barely. With 2 or more plugged in the flashing is not visible. At the moment i'm thinking that the mosfet that drives the injectors in the ECU is bad and is unable to supply enough current. But on the other hand it did fire up for a sec earlier today.

Edit2: I jumped a wire half from a plug wire and left a 1/2" gap between it and ground and I did get a good spark. What gets me is how 99% of the time, it won't run, but it has started up twice since all this trouble began, which tells me it's some kind of intermentent problem.

 

Ok, you have some more symptoms. Since the engine started for a second or two, it must have adequite spark, but test for it anyway. The injector plug supplies 12v on one pin when the ign sw is in run and the other pin goes to the ECM whose power MOSFET pulses that pin to ground to make the injector spray fuel. The noid light across an injector plug should stay the same brightness no matter how many injectors are plugged in. The noid light sees 12v pulses across all the injectors on that bank because they are all in parallel. There is a fuse from the ign switched 12v on each bank of injectors.
Your battery might be discharged. You can tell the state of charge by measuring its no load voltage, 12.0 v, discharged, charge your battery up overnight with a battery charger. 12.9v or higher, fully charged and linear in between (ex. 12.45 v, 50% charged). When cranking, the battery voltage should not drop below 9.0 volts or your battery is discharged, battery cable connections need cleaning, or the battery is at the end of its life. Older batteries will usually only charge up to about 12.8 v overnight which is ok. No relays should be clicking during cranking!

 

I found the problem, it was the ground. I thought the ground was one of those 5 grounds that bolt to the bell housing, ends up it's the ground that bolts to the frame underneath the heater hose and ac lines. The bolt/hole was stripped. I unwrapped my main harness and traced the ground wires until I found out where they go. Fires right up now and runs good, but now I have a overheating problem, it looks like the water pump is leaking, going to go out now and trace the water leak down.

Thanks all for the help.