Very strange no spark problem. I searched Need Help

[93jdmlaser]

I have read all the no spark threads I could find and could not come up with an answer. Heres the problem- Engine cranks over great but will not fire. The trans broke 4 months ago and has not cranked until last weekend and it has had this problem since then. I installed a new tre trans, pte 50 trim, denso 660s, sx afpr, vpc if it matters.
This is how everyone else problem is but I check all I could.
1) I used a timing light and checked the wires goin into the coil pack. It pulsed so from what I read the power transistor must be working.
2) I put the timing light around the 1,2,3 spark plug wires and it flashed but did not flash on the 4th wire.
3) My afpr guage is reading 43psi.
4) I used my logger when cranking and I am getting inj. pulse so I think that rules out the ecu and the cam angle sensor.
5) Ignition relay on the battery is fine.
6) Logger is reading hz so the vpc is fine.
7) The resistance across the 1-4 coil pack is 12.1 and 2-3 coil pack is 12.4.

The engine will not fire at all except one today it idle for less than a second and back fired so I turned it off and it would not even fire again. I have no idea what else to check and I am confused about why wire 4 gave off no pulse with the timing light on it. I will be putting new plugs in but I dont think they caused this. Any ideas please post.

 

[luv2rallye]

First make sure you visually really have a strong spark at the plugs. Timing lights are triggered on weak as well as strong fields. Remove each plug, reconnect wire, hold plug threads against block (with glove) and have someone turn over engine and verify that strong spark is really there. Weak spark in all plugs is a weak coil.

 

[93jdmlaser]

I did just what you said tonight. I pulled all the plugs out and put them in the wires and let them hang in the wires. First time I cranked it wires for cyl. 2,3,4 fired ok and 1 didnt. Then I switched plugs and all 4 fired. The 2 and 3 plugs were about 2 in apart and the spark jumped from 2 over to 3. I stopped then and when I went to do it again none of them fired at all. I did noticed that my battery volts dropped to 8.1 when it was cranking it. I used a timing light to check the power transistor pulse to the coil pack and it was fine. Is there any reason my coil pack would work one time and just stop working after that?

 

[qtxdevilz]

i would just try a new coil pack...i live in philly...let me know if you need some help...

 

[luv2rallye]

I SAID you need to hold the threaded part of the spark plug AGAINST ENGINE METAL. Use a clamp to hold it or connect it using a jumper cable. Only do one plug at a time and don't let the others dangle or you may electrically damage the coil or cables. Keep the others disconnected (unless you can guarantee to have them all clamped to engine metal).

 

[Hammer_Gaidin]

When you changed over to the 660s did you adjust your tune any? Or your fuel pressure? Maybe you're just running so rich that it doesn't want to fire...

 

[93jdmlaser]

I put another old coil pack in and jumped the car and it started. Finally it runs again but not very well. I had to put my vpc gain on -10 and afc at -25% to get a decent idle. The car is sooo rich. I step on it and you can smell feul and see it smoke. Its getting better as I lean it out. I put my logger on it and I got an engine coolant temp. reading of -59*C and it stayed there. I think this is why its running bad. Any idea on this problem?

 

[Hammer_Gaidin]

I would say borrow someones wideband to check your a/f. As for the coolant...maybe the sensor is bad.

 

[93jdmlaser]

I took my volt meter and there are no volts coming throught the wire to the sensor so are there any fuses that can cause this or are the wires just broken somewhere?

 

[bfdahl]

I put another old coil pack in and jumped the car and it started. Finally it runs again but not very well. I had to put my vpc gain on -10 and afc at -25% to get a decent idle. The car is sooo rich. I step on it and you can smell feul and see it smoke. Its getting better as I lean it out. I put my logger on it and I got an engine coolant temp. reading of -59*C and it stayed there. I think this is why its running bad. Any idea on this problem?

defiantly check that sensor! and check your logger for codes, If you have more than one really wacky input reading this is a strong indicator of a ECU going bad!
and you will need a propper coolant temp reading to get proper tuning!

 

[93jdmlaser]

There is no voltage goin to the wire so I am not sure if it is the ecu of just a broken wire. I know I need it to tune. What pin numbers do these 2 wires go back to so I can check for continuity?

 

[luv2rallye]

There is no voltage goin to the wire so I am not sure if it is the ecu of just a broken wire. I know I need it to tune. What pin numbers do these 2 wires go back to so I can check for continuity?

The DSM Backup Manual shows the '91 2.0L turbo engine coolant temp sensor connected to ECU pins 20 (yellow/green signal wire) and 24 (green/black internal ECU ground). The '90 is probably the same.