Car cranks but will not start. Fuel is there.

[kidwiththelaser]

I crashed my old laser, and then bought a talon shell, and swapped everything over.

I crashed the laser about 5-6 months ago, so it hasnt ran in awhile. Everything worked beautifully on the laser, so I know that everything I pulled off the laser is good.

Now heres my problem:

-The car will not start, it turns over but it will not start up. I know its getting fuel because there is fuel pressure at my FPR, and it should be getting spark because I pulled everything off of my running laser. And I know that it has good compression.

I think it could possibly be leaky ECU caps, but im not sure, im going to go check as soon as im done with this post. Or maybe I forgot to plug something in, what do the pros think?

thank you very much!

-Charlie

 

[ddavisaf]

Test the fuel at the injectors and make sure they're spraying.
Check for spark at the coil pack. Ohm out the primary and secondary coils, along with the plug wires.
Check the ECU caps like you said.

What numbers did you get from your compression test?

 

[GSX93DSM]

Check you resister box. I know my car wouldn't start when mine went bad. I was getting fuel and spark but no start. Hope this gives you ideas.

 

[98evoIIIpwr]

I have the same issue with my 98 talon I swapped the stock 7 bolt for an evo III motor. I cant get spark past the coil. I got fuel and the car turns over. I tested the coils and they seem good. I switched them out with new ones just to check and got the same thing. I wonder if its the same issue. I also used 3 different igniters or whatever you want to call it. That didnt solve the problem. Tried new wires and all that good stuff.

 

[ddavisaf]

Swap the firing order. 1 to 3 and 2 to 4
This can be done at the coil pack by switch the spark plug wires. Much easier than changing pins at the ECU.

 

[kidwiththelaser]

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Looks fine to me. Especially that lower right corner. But im far from an expert.

 

[ddavisaf]

You'll need to actually remove the three capacitors and inspect underneath of them.

 

[kidwiththelaser]

Test the fuel at the injectors and make sure they're spraying.
Check for spark at the coil pack. Ohm out the primary and secondary coils, along with the plug wires.
Check the ECU caps like you said.

What numbers did you get from your compression test?

How do I test the fuel at the injectors? Take them out and just aim them into a bucket?
Also how do I check for spark? like this?

http://dsmtuners.com/forums/attachment.php?attachmentid=33471&d=1088544507

I assume thats what you mean by "Ohm out the primary and secondary coils, along with the plug wires."

The compression was 142 across all 4.

 

[ddavisaf]

Great link. Yes. That's exactly what I mean.

You don't have to remove the injector, just the spark plug. You'll see fuel on the tips of the plug or on the piston.

 

[kidwiththelaser]

Great link. Yes. That's exactly what I mean.

You don't have to remove the injector, just the spark plug. You'll see fuel on the tips of the plug or on the piston.

Ok, thanks, when i put the ECU back together ill go do that.

But I took the ecu off the ecu case, and i looked underneith, and it looks like someone spilled a white liquid at the bottom of the ECU and it spilled up and dried. (The bottom being where the ECU conects to the harness). And theres also what looks like tiny bits of dried up orange juice pulp. Not quite sure if that means anything, but it seems weird. You can kind of see the dried up drips on the pic I just gave you guys of the ECU.

 

[ddavisaf]

Take a picture and PM steve. If it deals with ECU's, steve's your man.

 

[kidwiththelaser]

Take a picture and PM steve. If it deals with ECU's, steve's your man.

Ill do that, but my digi cam, just ran out of batteries.

thanks for all the help guys!

 

[ddavisaf]

Keep me up to date

 

[kidwiththelaser]

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Im going to PM these to Steve but, in case anyone sees these first here they are!

thanks guys!

 

[kidwiththelaser]

Keep me up to date

Will do!

 

[kidwiththelaser]

Well the cylinders looked pretty dry, maybe a little damp, but didnt look like there had been alot of fuel in there recently. When I took the plugs out I found oil on the plug in cyl #4.

Heres what plugs # 1 and 2 look like:

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And heres 3 and 4:

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I havent tested the coils yet, but Im off to my friends house to grab his multi meter!

thanks guys!

 

[kidwiththelaser]

Ok, I just tested the coil. On the primary coils I got between .8 and .9, and on the secondary coils I got 11.98 ohms on 4-1, and 11.89 on the 2-3. So thats good. I just put in some new BPR6ES plugs, and have brand new wires. So it should be getting spark. Must be fuel then.

 

[kidwiththelaser]

After re-checking the plugs, im not getting fuel into the cylinders, but it is getting to the fuel rail. So is their a way to check if my injectors work at all. I bought them used from a local guy who is trust worthy, but I have never used them myself.

 

[ddavisaf]

Test your CAS the same way you tested the coil pack. Your CAS tells your injectors when to fire. That and your ECU.

 

[steve]

The 1G DSM has two main circuits for the engine. The MPI circuit and the Ignition circuit.

The ECU is connected to both but powered from the MPI circuit.

Power for the MPI circuit comes from the MPI fusible link on the positive battery terminal to pin 10 on the MPI relay and should be present all the time even with the car off. Power for the Fuel Pump and the rest of the ignition circuit comes from the Ignition fusible link on the positive battery terminal and for the fuel pump winds up on pin 3 on the MPI relay.

The MPI relay has two actual relays inside, one for the MPI power and one for the fuel pump power. The FP side has two trigger inputs, the MPI side one input. MPI Relay pin 10 is the source for the MPI power and pin 3 is the source for the FP power. When one of the control lines to either relay is activated the relay switches the power from the source to the output pin(s)

The ECU receives backup power on pin 103 from fuse #19 (room) in the drivers footwell fusebox. This is used to maintain the RAM in the ECU's CPU and allow the ECU to power itself up. Like MPI relay pin 10 the backup power on ECU pin 103 should to present all the time even with the car off. In other words it's unswitched.

The ECU sits dormant in a powered down state waiting to see pin 110 (IG1 from ignition switch) go high (to battery voltage). When pin 110 goes high the ECU pulls pin 63 (MPI relay pin 8) low (to ground). This causes the the relay to activate and switches the MPI power from MPI pin 10 to MPI pins 4 and 5 providing power to the ECU on pins 102 and 107 along with various sensors, solenoids, injectors, ISC, and O2 Heater in the engine bay.

Shortly after battery voltage shows up on ECU pins 102 and 107 the reset circuit in the ECU wakes the ECU up and if it boots up successfully you'll get a heartbeat on ECU pin 1, the CEL will come on for about 5 seconds and then turn off, the boost gauge will display 0 (Stock ECU software on turbo cars) and the ISC on the throttle body will move in and out to rehome.

The next interesting condition is when ECU pin 108 (indirectly START from the ignition switch) goes high (to battery voltage).

The START signal also goes to the FP side of the MPI relay (pin 9) to power up the fuel pump, and to the ECU (pin 108) causing the ECU to do the things it needs to do the start the engine.

Once the engine is spinning (CAS is pulsing) the ECU pulls it's pin 56 (MPI relay pin 7) to ground and continues to hold it low until you turn the car off or the engine stops (CAS stops pulsing), to keep the fuel pump powered after you release the ignition.

The first thing you should do if your ECU doesn't power up (CEL on for about 5 seconds, the boost gauge displays 0) is check the two fusible links and the room fuse. Measure the fuses for continuity (0 ohms resistance) rather than look at them since looking isn't an accurate test. Then check for battery voltage at the ECU and MPI relay pins. Remember that the ECU doesn't get power on pins 102 and 107 until the MPI relay is activated by turning the ignition key to RUN or START. If the MPI relay doesn't activate try grounding its pin 8 and check that power shows up on its pins 4 and 5. If that works then either the ECU isn't seeing the IG1 signal or the ECU is damaged.

If battery voltage is present on ECU pins 102/107, 103, the ECU grounds are good, and the ECU still doesn't power up it's likely damaged.

Steve

 

[kidwiththelaser]

WOW!

thanks alot Steve!

I just went out to go check the fusable links, and the room fuse, and noticed that the MPI relay fuse wasnt even there!

So im going to go to the parts store and see if that was the only problem.

thanks so much guys!

 

[femmeDSM]

Steve to the rescue again

 

[kidwiththelaser]

^ yeah!

Ok, I just put in the new fusible link for the MPI relay. And now the ECU powers up.

But it still wont start, and im still not getting fuel into the cylinders.

Which pins do I check the resistance through on the CAS?

 

[kidwiththelaser]

Ok, I checked the resisitor box, and it had even resistance of about 12.2 ohms throughout each pin.
I checked the CAS and it too had even resistance.

What else could be causing this?

 

[kidwiththelaser]

When I start to crank the car over I hear a click coming from around where the ECU is. Could that be the MPI relay?