Conversions & Swaps LSX Engines in Non-LSX Vehicles
Sponsored by:
Sponsored by:

another new conversion, no spark

Old Mar 31, 2008 | 09:18 PM
  #1  
los bastardos's Avatar
Thread Starter
Teching In
iTrader: (1)
 
Joined: Jun 2005
Posts: 42
Likes: 0
Default another new conversion, no spark

and I'm out of ideas.

Here's what i've done:

car cranks, but doesn't start. No backfires, no puffs, just a smell of fuel in the air

tried:
unplugging the MAF
jumped all 8 injectors to make sure they clicked, I also pulled the rail and put paper towels under each to make sure it squirted some fuel when the engine turned over
fuel at the rail is 58PSI, solid
checked +12v at the pinks while cranking
checked +12v constant to the oranges, when cranking
the fuel pump is run directly to the battery so it has power during crank
replaced CPK
tested +12 and ground at CPK, wiring is all in good condition
tested +12 constant and ground to ECU
double checked the vac lines, no leaks
checked ground and +12 to coils
the CPS is plugged in
confirmed no spark with a plug
new plug wires




I put a cam in the engine while it was out, I lined up the dots and cranked the engine around like 20 times to make sure it stayed in and every other rotation it came back around and lined up so I think that's OK, it's a small cam and I have comp 7.4" rods in it, I guess the compression check will tell me if the valvetrain is OK. I doubt it's anything to do with my problem.

anything else to look at? I'm quickly running out of ideas. All I can think is it's time to ship the ECM off to someone to try on their car, but I don't know.

VATS was supposed to have been eliminated but I have no way to know it got done.
Reply
Old Mar 31, 2008 | 10:21 PM
  #2  
ssduane's Avatar
TECH Apprentice
iTrader: (3)
 
Joined: Jan 2008
Posts: 394
Likes: 0
From: San Diego
Default

I'm still working mine. DO you have spark when cranking, is the plug sparking? Pull out and ground on exh manifold to see. Is the wiring done right? Is left bank inj wire on the right bank and vice versus? Drivers side should be 1-3-5-7, I think.

Just a thought, or two.
Reply
Old Mar 31, 2008 | 11:09 PM
  #3  
los bastardos's Avatar
Thread Starter
Teching In
iTrader: (1)
 
Joined: Jun 2005
Posts: 42
Likes: 0
Default

No, I get no spark at all.
Reply
Old Apr 1, 2008 | 07:07 AM
  #4  
sho-me speed's Avatar
Closed ex-Sponsor Account
iTrader: (55)
 
Joined: Apr 2005
Posts: 506
Likes: 2
From: Ozark,MO
Default

Just because you have voltage at the CPS or CKS doesn't mean they are any good. Had a CPS go out and it did the same thing yours is. I would fet a new CPS before i sent my computer off.
Reply
Old Apr 1, 2008 | 07:59 AM
  #5  
los bastardos's Avatar
Thread Starter
Teching In
iTrader: (1)
 
Joined: Jun 2005
Posts: 42
Likes: 0
Default

I'll order a new one and give it a shot
thanks!
Reply
Old Apr 1, 2008 | 08:56 AM
  #6  
Rodder's Avatar
TECH Resident
iTrader: (2)
 
Joined: Jun 2006
Posts: 802
Likes: 0
From: Roswell, GA
Default

How are you checking spark? With a spark plug laying on the valve cover, or with a timing light? The timing light won't fire if your plugs are fouled. And your plugs are more than likely fouled by now if you've been cranking it over a bunch with no spark. Pull your fuel pump fuse until you figure out the spark problem. Replace the spark plugs, too.
Reply
Old Apr 1, 2008 | 09:52 AM
  #7  
exodus's Avatar
TECH Fanatic
iTrader: (15)
 
Joined: Jan 2004
Posts: 1,078
Likes: 0
From: Forreston, IL
Default

sounds relly stupid, but I had the same issue a while back, and it turned out to be a shorted o2 sensor. the back of the sensor hit the frame upon install of the exhaust, and was shorting. This may or may not apply, but just throwing it out there as an option. I would have never found it without john's help from speartech.
Reply
Old Apr 1, 2008 | 11:27 AM
  #8  
los bastardos's Avatar
Thread Starter
Teching In
iTrader: (1)
 
Joined: Jun 2005
Posts: 42
Likes: 0
Default

Originally Posted by Rodder
How are you checking spark? With a spark plug laying on the valve cover, or with a timing light? The timing light won't fire if your plugs are fouled. And your plugs are more than likely fouled by now if you've been cranking it over a bunch with no spark. Pull your fuel pump fuse until you figure out the spark problem. Replace the spark plugs, too.
with a plug, I haven't cranked it that much and they look good, they're brand new plugs.
I guess it could be bad plugs :dunno:
Reply
Old Apr 1, 2008 | 11:29 AM
  #9  
los bastardos's Avatar
Thread Starter
Teching In
iTrader: (1)
 
Joined: Jun 2005
Posts: 42
Likes: 0
Default

Originally Posted by exodus
sounds relly stupid, but I had the same issue a while back, and it turned out to be a shorted o2 sensor. the back of the sensor hit the frame upon install of the exhaust, and was shorting. This may or may not apply, but just throwing it out there as an option. I would have never found it without john's help from speartech.
you never know but I don't have any o2 sensors plugged in and the wiring looks good.
Reply
Old Apr 1, 2008 | 02:00 PM
  #10  
andrew69_04's Avatar
TECH Resident
15 Year Member
iTrader: (148)
 
Joined: Dec 2006
Posts: 848
Likes: 1
From: Crete, NE & Berthoud, CO
Default

sounds like a bad sensor if all your power wires and grounds are correct. did you double check the 3 grounds on the back of the driver side head?
Reply
Old Apr 1, 2008 | 02:21 PM
  #11  
los bastardos's Avatar
Thread Starter
Teching In
iTrader: (1)
 
Joined: Jun 2005
Posts: 42
Likes: 0
Default

Originally Posted by andrew69_04
sounds like a bad sensor if all your power wires and grounds are correct. did you double check the 3 grounds on the back of the driver side head?
I'm sorry, yes I did check them. I grounded them with the intake bolts under the assumption that those, connected to the heads, would be a good ground. I traced it with my DMM to be safe and it seemed to be a pretty good ground.

I ordered a cam pos. sensor, maybe mine got jacked. I don't know if a bum MAF will prevent spark, I figured it wouldn't but I dunno.
Sure hate to pull that intake again just for one dumb sensor.
Reply
Old Apr 2, 2008 | 07:25 AM
  #12  
exodus's Avatar
TECH Fanatic
iTrader: (15)
 
Joined: Jan 2004
Posts: 1,078
Likes: 0
From: Forreston, IL
Default

move ground wires from the intake bolt to a bolt on the backside of the head
Reply
Old Apr 2, 2008 | 12:14 PM
  #13  
los bastardos's Avatar
Thread Starter
Teching In
iTrader: (1)
 
Joined: Jun 2005
Posts: 42
Likes: 0
Default

I'll try her, thanks! Or to test I'll just jumper it over to the - term.
Reply
Old Apr 4, 2008 | 08:17 PM
  #14  
los bastardos's Avatar
Thread Starter
Teching In
iTrader: (1)
 
Joined: Jun 2005
Posts: 42
Likes: 0
Default

new cam sensor did the trick, thanks guys
Reply
Old Apr 5, 2008 | 01:14 PM
  #15  
exodus's Avatar
TECH Fanatic
iTrader: (15)
 
Joined: Jan 2004
Posts: 1,078
Likes: 0
From: Forreston, IL
Default

glad to hear you got it fixed
Reply


Thread Tools
Search this Thread

All times are GMT -5. The time now is 08:09 PM.