ok this is pretty strange, maybe somebody can help me figure this out.

My car wont start, it ran perfectly fine last week, now when i go to start it, it just cranks,

I checked my fuel pressure its at 45lbs the fuel pump is working like it should and is only about 6 months old.

I checked for spark a few different ways, maybe theres something im missing, first i took off the coil wire, put a plug in it and grounded it , cranked it and had plenty of spark, next i checked all the wires with a timing light, and they all were firing according to the light, so next i took out each plug and did the same timing light test with the plug in the end of the wire, and once again plenty of spark and the light verified this. I also put a spare coil i had on to see if anything changed, still did the same thing, so i dont think its a coil problem.

Next thing i checked was compression, which all cylinders were at 150psi after 5-6 cranks,and all of them were holding this pressure just fine.

I tried disconecting some things to see if it would start, such as the EST wire (brown/white that you disconnect to set the base timing), the MAF sensor, and neither yeilded any different results.

when it cranks, it spins like 4-6 times and then it gives a sound as if it almost might catch, but it does this consisently so i dont think this has 2 much to do with it.

Ok guys I need your help on this one, what am i neglecting to check? anyone had a similar problem? any help will be greatly appreciated!

thanks
Matt

 

Since you checked for compression and you know the car won't start when you give it starting fluid(right? Did you check to see that your injectors are spraying? ), I'd guess that your spark isn't strong enough from a bad component. I'm guessing you just grounded a plug or a wire and saw a spark so you thought it was fine? Or did you actually use a spark checker? What color is the spark?

 

thats what I was gonna say, check the wires, plugs, coli ect.
Just cause you "SEE" spark, does not mean it's enough to light it up.

 

Well if you have good spark and fuel pressure, then the injectors aren't firing, either blown fuse or possibly the ECM isn't seeing the refrence pulse from the ignition.

 

yeah i just grounded a plug, the spark is pretty bright white/blue, i dont have a spark checker, my next move will be to take the ignition module off and have it tested, or try one of the other ones i have, im also gonna try swapping out the ECM for another one i have, and check the pickup coil for continuity.

also after cranking for the compression test, there was a decent amount of fuel on the plugs, i dont know that this means the injectors are workin but i figured it would help in the diagnosis.

 

i had this problem with my bird last year after i replaced $300 worth of parts it ended up being my ecm you may want to try that first

 

87,

If you have a timing light, now would be the time to break it out. If you have spark, and wet plugs, you should have at least had some activity before the plugs got soaked. Install some dry plugs, but crank the engine a few revs after removing the old ones to clear out some of the excess fuel. Install the dry/new plugs and try it again. Check base spark timing to be sure you haven't slipped a timing chain, moved the distributor, or the EST hasn't gone "flakey".

 

You have compression, fuel, and spark, so i would second checking out what your timing is doing. And if the timing is good I would start looking into the ecm. It isn't throwing any codes or anything?

 

cold start injector good? any codes? buy a spark checker and do it right, just because you can jump .045 gap on a plug not under compression doesn't mean you have enough spark to light the A/F mixture

 

Well i took off the ignition module today and had it tested, it was bad. I havent put the new one in yet but ill let you all know if i have any other problems.

thanks
Matt

 

Thats a good sign if it actually tests bad. Too often a bad one will pass the check.