1990 TBI Silverado No fuel or spark!?

benjiboy · 03-06-2007, 10:21 PM

Had the truck since new always been extremely dependable. Two days ago go to start it up in the morning, it runs for 10 seconds then dies. No sputtering just dies. Now it won't start and I'm pretty sure it isn't getting any spark and looks like no fuel either.

I'm pretty decent with cars and had a TBI Camaro but mainly deal with speed density stuff now and need some ideas to start.

I've ruled out fuel pump and fuel filter. I pulled the codes and got nothing but this was after I unhooked the battery to see if this was just some fluke electronic problem; will try to start it again and then pull them again tomorrow. Fuses are all good.

Is this a relay or module somewhere?

Thanks in advance all

-Ben

bradrhale · 03-07-2007, 05:59 AM

do you know for a fact that it is not getting any spark and fuel?? if both of them went out at the same time, it might mean something is wrong with the computer.

benjiboy · 03-07-2007, 12:41 PM

Its not getting any spark checked with two inline spark checkers and I can't see any fuel being intorduced into the motor when trying to start and giving it gas.

I was thinking ECM is a defenite possibility but didn't know if there was anything much easier to check out first.

thanks!

bradrhale · 03-07-2007, 04:21 PM

i think that would be a near dead giveaway. cant think anything else that would kill spark and gas.

benjiboy · 03-07-2007, 06:55 PM

I might just have to go to the boneyard and grab one this weekend.

Addressing the two seperatly what would need to be checked...

FUEL:
Pump
Throttle Body
Fuel Filter

SPARK:
Dizzy
Coil

Anything else I can get on the list...relays are a big one here I don't know much about on this truck.

bradrhale · 03-08-2007, 06:05 AM

lots to check. fuel wise, everything you said plus your injectors. i have seen one not fuel because the wire was hanging off the injector. plugged it up and started fueling again. also fuel pressure. TBI takes a higher pressure than a naturally aspirated engine. as for spark, check the coil wire. i have seen these break down too. spent two days trying to find the problem when i picked it up and it came apart.
i am assuming that you have power to everything inside your truck??

benjiboy · 03-08-2007, 08:53 AM

yea everythings got power

436'd skylark · 03-08-2007, 09:33 AM

The problem is not the computer. The ignition system used on those trucks is very primative. The computer can be unplugged, missing or whatever and the truck will still spark, just no advance. If you lost both fuel and spark the problem is either the pick-up coil or the module for sure. Assuming of course the harness is in good shape- power to the coil, and the two and 4 pin connector at the module are good, as in not green or broken. I'd pull the distributor and replace both. In order to replace the pick up coil, the distributor shaft must be removed from the housing. its a fairly easy job just make sure to set the timing afterwards. If you want to make it real simple, just replace the module. Likely it will fix your truck, but if not dig into the distributor and replace the pick-up coil. That is really common on those. WooHoo, first post. Joe

benjiboy · 03-08-2007, 01:28 PM

thanks for the reply. you are referring to the HEI control module in the dizzy cap right? this is a small cap dizzy with the remote mount coil.

436'd skylark · 03-08-2007, 01:42 PM

yeah I'm refering to the module in the cap. Start there.

03-06-2007, 10:21 PM	#1
benjiboy Junior Member Join Date: Mar 2007 Posts: 9	1990 TBI Silverado No fuel or spark!? Had the truck since new always been extremely dependable. Two days ago go to start it up in the morning, it runs for 10 seconds then dies. No sputtering just dies. Now it won't start and I'm pretty sure it isn't getting any spark and looks like no fuel either. I'm pretty decent with cars and had a TBI Camaro but mainly deal with speed density stuff now and need some ideas to start. I've ruled out fuel pump and fuel filter. I pulled the codes and got nothing but this was after I unhooked the battery to see if this was just some fluke electronic problem; will try to start it again and then pull them again tomorrow. Fuses are all good. Is this a relay or module somewhere? Thanks in advance all -Ben

03-08-2007, 01:42 PM	#10
436'd skylark Senior Member Join Date: Mar 2007 Location: Buffalo Ny Posts: 629	yeah I'm refering to the module in the cap. Start there. __________________ Joe 89 K2500 Chevy, Wee-Oh-five 285K miles, completly rebuilt needs a motor, bad 1962 IHC Scout All Wheel Drive (Scout speak for locking axles) 152 ci, dana everything else

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03-07-2007, 05:59 AM	#2
bradrhale Moderator Join Date: Apr 2006 Location: Texas Posts: 3,620	do you know for a fact that it is not getting any spark and fuel?? if both of them went out at the same time, it might mean something is wrong with the computer.

03-07-2007, 12:41 PM	#3
benjiboy Junior Member Join Date: Mar 2007 Posts: 9	Its not getting any spark checked with two inline spark checkers and I can't see any fuel being intorduced into the motor when trying to start and giving it gas. I was thinking ECM is a defenite possibility but didn't know if there was anything much easier to check out first. thanks!

03-07-2007, 04:21 PM	#4
bradrhale Moderator Join Date: Apr 2006 Location: Texas Posts: 3,620	i think that would be a near dead giveaway. cant think anything else that would kill spark and gas.

03-07-2007, 06:55 PM	#5
benjiboy Junior Member Join Date: Mar 2007 Posts: 9	I might just have to go to the boneyard and grab one this weekend. Addressing the two seperatly what would need to be checked... FUEL: Pump Throttle Body Fuel Filter SPARK: Dizzy Coil Anything else I can get on the list...relays are a big one here I don't know much about on this truck.

03-08-2007, 06:05 AM	#6
bradrhale Moderator Join Date: Apr 2006 Location: Texas Posts: 3,620	lots to check. fuel wise, everything you said plus your injectors. i have seen one not fuel because the wire was hanging off the injector. plugged it up and started fueling again. also fuel pressure. TBI takes a higher pressure than a naturally aspirated engine. as for spark, check the coil wire. i have seen these break down too. spent two days trying to find the problem when i picked it up and it came apart. i am assuming that you have power to everything inside your truck??

03-08-2007, 08:53 AM	#7
benjiboy Junior Member Join Date: Mar 2007 Posts: 9	yea everythings got power

03-08-2007, 09:33 AM	#8
436'd skylark Senior Member Join Date: Mar 2007 Location: Buffalo Ny Posts: 629	The problem is not the computer. The ignition system used on those trucks is very primative. The computer can be unplugged, missing or whatever and the truck will still spark, just no advance. If you lost both fuel and spark the problem is either the pick-up coil or the module for sure. Assuming of course the harness is in good shape- power to the coil, and the two and 4 pin connector at the module are good, as in not green or broken. I'd pull the distributor and replace both. In order to replace the pick up coil, the distributor shaft must be removed from the housing. its a fairly easy job just make sure to set the timing afterwards. If you want to make it real simple, just replace the module. Likely it will fix your truck, but if not dig into the distributor and replace the pick-up coil. That is really common on those. WooHoo, first post. Joe

03-08-2007, 01:28 PM	#9
benjiboy Junior Member Join Date: Mar 2007 Posts: 9	thanks for the reply. you are referring to the HEI control module in the dizzy cap right? this is a small cap dizzy with the remote mount coil.