Vortec454/wont Start/nocodes

[KENNHON]

This got me stumped! truck was running finethen stumbled and quit [smoke came out thru airfilter]. It would not restart... used timing light---showed flashes[but NOT the way it should]. It has MSD-6AL spliced in. I checked gas guage[said 1/4 tank; put more in [5 Gals].

Then put OBDII scanner on it... NO codes displayed! truck has 134,000 miles. Fuel pump sounds likeit always does[replaced with 'lifetime -guarantee' Carter pump only 35,000 miles ago]. I replaced the crank-position sensor on a BMW a while ago['98 540 series-it wouldn't start].BUT that car showed PO387 code[which is CPS].

 

 

Why wouldn't the code come up[even if it were the MSD box-it still woould show PO350, if not functioning... I'm lost

[redvett]

I would start with the basics, ign/spark, fuel, compression. Do a compression test and check for the cat's being plugged.

 

This got me stumped! truck was running finethen stumbled and quit [smoke came out thru airfilter]. It would not restart... used timing light---showed flashes[but NOT the way it should]. It has MSD-6AL spliced in. I checked gas guage[said 1/4 tank; put more in [5 Gals].

Then put OBDII scanner on it... NO codes displayed! truck has 134,000 miles. Fuel pump sounds likeit always does[replaced with 'lifetime -guarantee' Carter pump only 35,000 miles ago]. I replaced the crank-position sensor on a BMW a while ago['98 540 series-it wouldn't start].BUT that car showed PO387 code[which is CPS].

 

 

Why wouldn't the code come up[even if it were the MSD box-it still woould show PO350, if not functioning... I'm lost

[Joe O]

I'd get rid of the MSD. I had nothing but trouble with them and will never purchase another. 30 year old technology and far over rated junk. Left me high and dry a few times. Had unit in my Camaro, damn thing runs better on stock HEI.

[96chevy7.4L]

The vortec 454's are bad about eating up ignition rotors. Sounds exactly like mine did when the ignition rotor burnt up. While apart because it is a PITA to get to..... replace the cap and the coil as they are not easy to get to. Just my opinion though. MSD's aren't bad they burn real hot and burn for 20 degrees of crankshaft rotation. Thus burning up rotors fast espeically if you leave the key on for any period of time before cranking the truck or while its sitting still be it listening to the radio or what ever.

[KENNHON]

this has me lost!.... engine was running fine at idle[temp 68 degrees]. All of a sudden, it 'stumbles' badly, then dies---smoke comes out air filter[have K&N box]. Refuses to re-start--- check all fuses[all ok-unless i missed some/any?]. Then put timing light on spark wire light flashed. then i dis-connected MSD system, still no start... then put timing light on coil wire-that's flashing like it sould... then pressure checked for fuel press. ---that's FINE.

Rented obd-11 scanner... no codes!.... then dis conn. battery [neg.]-wait one minute, re-conn. --nothing.... i took spark plug out to check for fuel on plug.... damp. but i don't think it's fuel related anyway.

Then started checking voltages.. 1st to hot feed to coil[ok-12 volts]. then CPS--ok 12 volts. where is CAM POSITION SENSOR??? where is Ign. Control Module???

 

 

BIGGEST question is WHY NO CODES!!!

[redvett]

Because its not always a computer detected problem as no ign,fuel,air,exhaust. Always do the basics first.

[KENNHON]

The vortec 454's are bad about eating up ignition rotors. Sounds exactly like mine did when the ignition rotor burnt up. While apart because it is a PITA to get to..... replace the cap and the coil as they are not easy to get to. Just my opinion though. MSD's aren't bad they burn real hot and burn for 20 degrees of crankshaft rotation. Thus burning up rotors fast espeically if you leave the key on for any period of time before cranking the truck or while its sitting still be it listening to the radio or what ever.

 

I ordered the MSD 8.5mm wires, and top-of-the-line NAPA cap and ROTOR.... GEEZ! you aren't kiddin about HARD to get! do u think i should get MSD[or OTHER] coil? i sent ya a message [thanks, and my trk specs]

[korbin502]

Have you done any mods lately? Programmer? Chip?

[96chevy7.4L]

Been down that road. Had a 96 just like and now a 99. When it does what you described its either an ignition rotor or the crankshaft postion sensor is going bad. The 7.4L vortecs are bad about burning up rotors. Bad part is there a PITA to get to. You have to unbolt the coil from the back of the upper intake plenum and then get the cap off. Those screws are philips and VERY VERY TINY. Do ti when the engine is completely cool and basically lay on top of the plenum to get in there. The distributor will not come out don't even try theres no room. Sorry to hear what happened but been there done that.

[96chevy7.4L]

The crank sensor is up in the front of the oil pan right near the harmonic balancer. Not hard at all to change one plug and a bolt that takes a 10mm socket (deep well socket that is). Hope that helps.

[96chevy7.4L]

The MSD coil or a Genuine AC DELCO coil are about as good as you can do.

[KENNHON]

Been down that road. Had a 96 just like and now a 99. When it does what you described its either an ignition rotor or the crankshaft postion sensor is going bad. The 7.4L vortecs are bad about burning up rotors. Bad part is there a PITA to get to. You have to unbolt the coil from the back of the upper intake plenum and then get the cap off. Those screws are philips and VERY VERY TINY. Do ti when the engine is completely cool and basically lay on top of the plenum to get in there. The distributor will not come out don't even try theres no room. Sorry to hear what happened but been there done that.

 

Mr. "99 chevy7.4L" was absolutely right---so was redvette [about codes]. with 134,000 miles i decided to rip off hood, tear out upper intake manifold, destroy old cap and rotor[they were TOAST!],jerk out the fuel rail, inj's-and the WORST job----dynomitin' the fuel press reg. out of its housin!!! i already have made up a new way the hard to get at parts will NOT be that way EVER again!!!

 

Who was the IMBECILE that designed the placement of these important pieces[ANYTHING can go wrong with elec. stuff-makin' it this tough must make most go to dealer!... I'm gonna flow injectors's[i think they are only 19 LB/hr???----i'll see if they are within 2% of each other; extrude hone intake while it's off[and get a nice polishing done---saw one on hot-rod---looks boss![already have chrome alt. and polished A/C compressor[i bet you guys already know what a JOKE the OE compressor is!!! there's a guy in Tampa that sells an upgrade for 190 bucks that will never quit! compressor blades are pinned]

 

BUT, THANKS AGAIN--- you rascals helped me AGAIN!