chevy 4.3 v6 not running right

Technical Discussion Forum

Moderator: Sitewide Forum Moderators

Post Reply
chadbostwick
1st Gear Member
Posts: 2
Joined: Mon Apr 12, 2010 8:36 pm
antispam: NO
Please enter the middle number: 7

chevy 4.3 v6 not running right

Post by chadbostwick » Sat May 01, 2010 12:57 pm

so i got the wiring figured out, thanks for the tips. But now the engine idles good but is sputtering and popping and some times backfiring. checked plugs, wires, vaccum leaks. Wish the harness had tho OBD plug, that would make things easy though. Any suggestions?

User avatar
jhitesma
7th Gear "No Brakes" Member
7th Gear "No Brakes" Member
Posts: 7791
Joined: Thu Nov 09, 2000 9:57 pm
Please enter the middle number: 5
Location: USA
Contact:

Re: chevy 4.3 v6 not running right

Post by jhitesma » Sun May 02, 2010 9:55 am

I don't know much about Chevy EFI but do you have enough of the harness left that you may be able to hook up a MIL light and pull error codes that way?

On my 2.3 Ford I just hooked a volt meter up where the check engine light should have been and then cycled power to get it to read out the codes. Helped me figure out what was wrong very quickly.

User avatar
GlamisSandDuner
Duner Connection Moderator & Coordinator
Duner Connection Moderator & Coordinator
Posts: 774
Joined: Wed Oct 10, 2007 10:45 pm
antispam: NO
Please enter the middle number: 7
Location: East County (San Diego), Ca.

Re: chevy 4.3 v6 not running right

Post by GlamisSandDuner » Mon May 03, 2010 6:56 pm

chadbostwick wrote:so i got the wiring figured out, thanks for the tips. But now the engine idles good but is sputtering and popping and some times backfiring. checked plugs, wires, vaccum leaks. Wish the harness had tho OBD plug, that would make things easy though. Any suggestions?
Assuming that a 2004 4.3L Vortec still uses a distributor, then I know on the s-10 you have to set the base timing which I believe GM refers to it as the "spark or cam angle" with the scan tool hooked up to the OBD II diagnostic port while the engine is just off of an idle. I know that these engines had big problems with the fuel injectors, but it usually showed up at idle. Since it is idleing OK, I would say it should be a spark / timing related issue if the compression of the engine is good. Did you move the distributor since you got the engine and installed? If so, try to line up the ghost mark on the distrubutor housing with where it was set before. Also put a new cap and rotor in it, they were pretty bad about eating rotors if memory serves me correctly and a new set of plugs and wires wouldn't hurt either. Hope this helps.
'05 TRX450R
I work to support my duning habit!
aSa Duner Connection Moderator & Coordinator

User avatar
jhitesma
7th Gear "No Brakes" Member
7th Gear "No Brakes" Member
Posts: 7791
Joined: Thu Nov 09, 2000 9:57 pm
Please enter the middle number: 5
Location: USA
Contact:

Re: chevy 4.3 v6 not running right

Post by jhitesma » Mon May 03, 2010 8:05 pm

I'd be pretty surprised to find a 2004 that still had a dizzy.

It could be a fuel delivery problem if it's not able to get enough volume of fuel for anything but idle. Could be a clogged filter.

Could also be temp or airflow sensor issues for idle to be ok but the rest to have problems. But so many things to look for it really helps to have some level of diagnostics. Without them working on an EFI setup is really hit or miss and not a lot of fun. Is there enough of the harness left that you could try and hook the ODB port back up. Shouldn't be too hard unless it was cut off right at the computer or something.

dude2420
1st Gear Member
Posts: 1
Joined: Fri Feb 12, 2010 4:55 am
antispam: NO
Please enter the middle number: 7

Re: chevy 4.3 v6 not running right

Post by dude2420 » Wed Oct 19, 2011 5:52 am

The first thing I would check is make sure that you are getting the proper fuel pressure. If you do not have a gauge some of the part stores willlend out a fuel pressure test kit. I have a friend that runs a Chevy 4.3 with the mercury mpfi manifold and we had a similar problem and we found out his pump was only outing out 25-30 psi.

Post Reply

Return to “SandRail • Jeep • OffRoad Vehicle”