no start troubleshooting

[DGC]

Need help from the experts. Started engine on Father's Day weekend and ran fine for 4 minutes (shut down because did not want coolant temp to go above 143 and trigger ecm.). Just wanted to check for leaks and loose stuff.
Tried to do the same next weekend and got no start. I have been following the no start tests available at vortex-buick and find no issues. Here's what I've done.

1. Originally thought it was a fuel pump issue. With the help of BlackBandit discovered the fp relay was switched with ac relay. With new fp relay (and
no longer needed new ac relay) now have 2 sec pulse at ign and cranking fuel pressure at 20 lb.

2. SES at prestart ign continuous on. ALDL tests for 12 and no other codes.

3. Double checked cam sensor. Used my leakdown tester with a balloon to make sure I'm at TDC of compression stroke. Advanced crankshaft to 25 degrees atdc (added mark to balancer for 25 atdc). Reinstalled new cam sensor with sensor gap at 4 o'clock position from front of car and +7 volts to 0 off terminal "B" of cam sensor places cap leads at the 4 o'clock position as well.

4. +12 from pin "P" of 14 pin connector to ign module. Also get +12 at both ECM fuses in fuse panel. Fuses good as well.

5. +12 to pin "C" of ign module connector triggers injectors (pretty neat design with all injectors firing at once).

6. Jumper B and C of cam sensor harness followed by jumper B and C of crank sensor harness triggers injectors as well. +12 at terminal A of crank sensor harness.

7. 0.025 inch clearance on both sides of all three blades for crank sensor.

8. Checked/replaced coil pack.

From what I can determine all the electronic/fuel tests appear to pass the no start protocol. Seems that the ign module is all that's left, but I'm looking for suggestions about what I forgotten, ideas about what to do, or ways to determine if it is the ign module.

Hope to get her started before next Father's Day....

Thanks,
DGC

 

[williamsGN]

is it the same as this one ?

No Start Diagnosis - Page 1

 

[DGC]

yes, the same one. there are additional charts for further testing. btw i used
my timing light to check spark.

 

[Daniel Jost]

Ok check this, the module will put out spark regardless of if the ecm is functioning or not or for that fact if its even connected.. did you check the basics? Do you have spark? It will be there no matter what if the cam and crank signals are there and the module/coil are good. The way it sounds you have power to it for sure. If you have spark, it should fire right off if you ether it and crank it. Sounds like you also have good ecm power since your fuel pump functions at key on. If it fires after spraying brake clean into the tb after you assure it has spark I would check for injector function, they might have lost their constant 12v.

Get back to us, Dan

 

[278cikiller]

hard start

if the fuel is at only 20psi when cranking it wont start ,don't you need 28psi to get these bad boys going.

 

[Daniel Jost]

It should actually be around 38-45psi after the fp prime.

 

[BlackBandit]

You should have +12 at coil module pins M and P.

If you put the window of the reluctor in crank sensor and key on you should see voltage at coil module pin F. If you don't have voltage here and you have power to the crank sensor the sensor is most likely bad. If the signal is there then it should also be at ECU pin B5. If it's at module F but not at B5 the ignition module is bad.

ECU pin A11 is the signal from the cam sensor. If you don't get the cam signal here it's probably the module. (I'm assuming this because you know the cam sensor is sending a signal but you could always ohm out the wires)

How did the epoxy look when you swapped the coil pack?

 

[DGC]

More information. Getting +12 at pin "P" and "M", but nothing at pin "F". Looks like the crank sensor. Pulled the 8mm cinch bolt and removed 2 13mm bracket bolts. Everything is free but have not yet found the 'magic" crankshaft position to slide the pedestal out. Looks like the centering pin is ~1/32 inch too long. Checked blogs and seems that should be doeable without removing harmonic balancer. Any suggestions for getting this out? Made full 360 turn (carefully) of crank and no go. buickvortex-etc "how to" says need to position sensor in interrptor ring. But still no go....

Thanks for the help,

DGC

 

[BlackBandit]

After that cinch bolt is loose you can remove the sensor by sliding it out. It should slide toward the connector side. It will be tight but wiggle it and it'll go. You DO NOT have to remove the balancer. You don't even have to take the bracket off.

Edit: You do have to have the sensor in the window of the ring.

 

[aminga]

The REF high on B5 only has a signal when the IGN module syncs. The Cam signal on A11 may be the same.

Start the car and turn it over until you get spark. Leave ign on and then test for voltage.

 

[DGC]

Its out!!*!*. The middle ear of the OE sensor was taller than the two outer ears. Thus clearance prevented removal. Carefully ran a hack saw to trim a little off and out is came. Clearly engine builder installed sensor before balancer. Anyway, sensor was loose in its plastic support, so a new one is hopefully going to get her running. Looks like the OE ac-delco sensor ears are all the same height.

Thanks again for the help.

DGC

btw, how does a Michigander make his way to San Diego? I'm was raised south of Ann Arbor but landed in DC...

 

[BlackBandit]

came out for the Navy. Still trying to get back michigan way. You might try reinstalling that sensor. I'm prwtty sure the reluctor ring is supposed to to pass through the slot farthest from the connector side.

aminga. If it's missing on module pin F then it's the sensor (assuming power and ground are being applied to the sensor) because that's where the sensor sends the signal before it's passed to the ecu.