No Spark on Cylinders 1 and 4

[jumpman]

Please somebody help me out here, because I am fresh out of ideas.

It all started when I developed a leak in my valve cover. I replaced the valve cover.I had to use a screwdriver to jimmy the seal loose and I used the claw section on a framing hammer to remove the valve cover, but I don't think I nicked or damaged any sensors. And I also damaged the spark plug wire for Piston 1 (the wire separated from the contact), I attempted to repair it until I could order new ones.

I then replaced the valve cover and replaced the spark plug wires into their respective places and attempted to fire it up. Keyword being attempted. She kept cranking but wouldn't kick over. I removed each spark plug wire and saw that 1 and 4 weren't firing at all. From there the problem gets more frustrating and confusing,

I replaced the wires and still no spark. I switched the wires around on the off chance that the wires were bad and still 1 and 4 aren't firing. So I had a 1G coil pack lying around and installed it, thinking that may be the problem. It fired 1 and 4 twice and then no more. So I tried pulling my transister pack and installing it on my friends 95GSX, thinking that may be the problem, but his fired off just fine. Oh and I should mention that at this point my car threw a CEL and it was P0340 which is a cam sensor error. After all of that I ordered a 2G coil pack to replace the one I burnt out, thinking on the off chance that maybe I got two bad coils in a row. I installed it and 1 and 4 still won't fire.

So now I am completely out of ideas. Could some one please give me a point in the right direction?

Regards,
CMF

 

[my_gst95]

P0340 which is a cam sensor error

Did you get a new cam sensor? A bad 95 cam sensor could cause it not to fire properly. Here's a test, unplug the cam sensor harness (but leave the crank sensor plugged in) and try firing it up. It should start if that is the issue....

my_gst95

 

[jumpman]

Did you get a new cam sensor? A bad 95 cam sensor could cause it not to fire properly. Here's a test, unplug the cam sensor harness (but leave the crank sensor plugged in) and try firing it up. It should start if that is the issue....

my_gst95

Thanks man. I'll give it a try. One small favor though. Can you please snap off a pic of the location of the cam angle sensor harness (I lost my Chilton manual a couple of days ago) and post it up here.

Thanks,
CMF

 

[siceclipse]

Ok, Jumpmans car is at the shop right now, and his mechanic is almost stumped. He's now going to start from the beginning, the ignition and go to fuel next. If anyone else would like to comment and hopefully save Jumpman some $$$$ on diagnostic time it would be apreciated.

 

[DrHess]

It appears to be an "undocumented feature" of the ECM to kill spark to 1&4 (but not 2&3) if it senses that the cam and crank timing is not in sync. The ECM also won't tell you this when you read the codes. I had hell tracking this one down myself. Everything pointed to a bad power transistor, which the 96 does not have as a separate unit. The coil was good. If I switched the drive from the 2&3 circuit to the 1&4 circuit (little aligator clips, some paperclips or leads from the multi-meter in the end of the connector), I would get spark on the 1&4 coil. I figured the ECM was bad and located and tried a second one that gave the same result.

Given that the valve cover was recently off, I would suspect the cam timing sensor. If that is OK and you are real sure it is OK, make sure the cams are in time with the crank. If you are a shop, I will assume you can figure this out but the the benefit of the rest of the readers, as the 95-98 non turbo 2.0L motors do not have any timing marks, pull #1 spark plug and stick a long, dull screw driver down the hole. It should touch the top of the piston at least when the piston is near the top of the stroke. Remove the timing belt inspection cover. Put a wrench on the harmonic balancer nut and have your (wife, assistant, buddy) turn the motor over slowly in a clockwise direction while you hold onto the screw driver loosly. It is easier if you pull the rest of the plugs first. You will feel when the piston is at the top and stops, then goes back down. At the point it stops, the timing marks are lined up every other rotation. If the timing marks are off, that's your problem. If you see the cams jump by themselves, the tensioner/idler pulleys are likely toast, as is what happened to me. It is hard to see down in there to tell from the inspection hole.

Dr.Hess

 

[jumpman]

Thanks man. You have no idea how much I appreciate this.

If this works, I will buy you a beer next time you are in the NYC area (I am dead serious about this).

And just to clear any confusion, I don't work at a shop. I tend to work on my own car though, unless I don't have the time, or the repair is a pain in the butt, or if I run out of ideas. Then I take it to my mechanic. I've dealt with him for years. He has always been fair in pricing, and he does excellent work. He stands as the only mechanic that works on my car that I won't double check his work after he gives my car back to me.

I will definitely pass along the advice though. And I will keep a frosty one waiting for ya if this works.

TTFN

CMF

 

[2.4 turbo Hyped]

Is your power transistor working properly? When you only get spark on 2 cylinders this is a good place to look.

 

[siceclipse]

read the third paragraph again.