walt355

Ive been fighting this since I got my car back togather 3 months ago. Was pretty random but it is getting more common. The car cranks over but doesn't start. Has a good clean spark but little or no light on the injectors. I have swapped PCMs and done the resiter trick on the VATS, even though VATS is tuned out and the security light goes off after about 3 seconds and doesn't come back on or flash. Sometimes A battery charger on the battery helps it to start. And suggestions will be appreciated and checked out. Im out of Ideas. I have checked all power and grounds going to the PCM and the Plug/harness and all is good, However I am going to go back over the grounding spots 1 more time. The injectors Do have a good 12V going to one side of them. Thanks

timnfxr

The weak spark may be due to low voltage during cranking due to the weak battery. That's probably why the battery charger help.

Have you checked the fuel pressure at the Schrader valve?

Skedaddle

Did you scan it for codes? The Opti codes may not turn on the SES light.

You indicate good spark, but "little or no light at the injectors". Did you test with a noid light?

4586

I just went through that scenario..in my case it was a pinched fuel return line. A fuel pressure check would reveal that problem..make sure to check pressure while cranking.

Scanning it "might" help to pin point a trouble area.

walt355

IT has a good battery and cranks like a champ, However The battery is in the rear Pass wheel well. I need to hook up and see what kind of voltage drop I have.
I have scanned and no codes, Using a noid light on the injectors
Fuel PSI is good and doesn't drop below 40 while cranking. It has a guage mounted outside the windshield.
I read a post yesterday about a guy on here had a lot of the same symptoms. He found a faulty ignition switch. Had good spark but no injecter pulse. Im going to look into this. I thought opti but is should have neither spark or injecter pulse, And once it starts it runs good. Am I right on this? Sometimes you can go out to the shop, hit the key and its ready to go, sometimes it wont hit a lick.

4586

I finally determined it was a fuel problem by spraying car starter into the intake while someone cranked it...could actually keep it running with small bursts.

Keep in mind..too much fuel pressure and it won't start either (I know), it might drop to 40psi after the pump cycles off..but monitor the initial pressure when the pumps first starts before dropping.

Injuneer

If you had problems with the Opti cam position sensor, you would likely have codes.

timnfxr

It very well may be an excessive voltage drop from the rear mounted battery and the 12v distribution block in the engine bay. That's why it runs fine once it starts, because then the alternator is providing the proper 13.5 to 14 volts.

walt355

I agree Fred, It gives no codes.
It may be too much voltage drop, But even with the charger it doesn't start every time. Ill try to get out and hook a meter at the J block to see houw much voltage drop is acutally there. I would assume anything above 10Volts while cranking should be suffecent. Am I correct on this?

timnfxr

Yes, approx. 10.5 volts is normal when cranking. Just measured mine at the distribution block: 12.5 VDC before cranking, 10.6x VDC during cranking, 14.5 VDC when running.

walt355

That may be my/a problem. I checked it yesterday. First the battery with the key on only has 11.4 volts. cranking it drops to 9ish, at the terminal while cranking it has upper 8 volts. The battery is about a 950amp battery which is why I think it cranks so good at 9 volts, plus it has a massive welder cable going to the front. noid light will light 1 good time, second time is real dim, then does not light anymore( even with opening the throttle blade)As usuall 5 minutes fo charging and it starts good, even started this morning. I think I will do a slow trickle charge for a while then remeasure. If no good ill try a new battery and see what happens

Injuneer

I had slow starting with my aftermarket ECU, and I just assumed that's the way it was. But I changed out the starter and it was like a brand new car.... just touch the key and it started instantly. I think my headers had toasted the starter, and the CVR Pro-Torque unit can be rotated to move it away from the headers. Old unit was drawing too much power and hurting the system voltage.

walt355

Im going to try this next. I haven't messed with it in a while but gonna try to get it in the shop this week and see if I can figure it out. First thing Im gonna check is the ignition switch. Ive read that some have had trouble with either the contacts arcing or the conector arcing. However the starter would make a lot of sence for the major current draw.

walt355

Ive been screwing around with it some. Will a large Semi batter (1100)CCA it will crank and start. With this massive battery it only drops to 10.3 volts which is a pretty good drop for this size of a battery. I ordered a new Remi LT4 started and should be here Friday. Hopefully by his weekend ill know something. Next weekend is the last test and tune and would like to get a single digit pass before winter

walt355

I may have fixed it. Put a New ford battery in it the other night and it is working so far. Hope this fixes it