I have a 97 Chevy 3500HD w/454 vortec I bought the truck not running
and after checking it out found the pick up was bad replaced that and
it started up but ran very rich After checking it out now I found the
cylinder 1 fuel injector was running like a fuel pump all the time I
replaced that and it seemed to be clearing up so I drove it around the
block to clear it out only to get worse It coded p1435 so I pulled the
distributor cap and found the rotor button mount was loose from the
distributor so I replaced that now and no more code and it seemed to be
running ok but after 2 minutes or so it started again to load up very
bad and backfire I think the timing chain is ok but is there anyway to
check witout pulling it apart?
I didn't want to pay for all the injectors yet if I don't have to I did
do the tune up and same thing I was just working on it and found it was
out of gas so now it starts but still runs very rich misses and stalls
at idle.One thing I noticed when I had the plentum off #1 and #8
injectors when you turn the switch on ran as long as the fuel pump are
they supoposed to?If not any ideas why?
Shades (at dot) wrote:
On 26 Jul 2006 13:19:40 -0700, firstname.lastname@example.org wrote:
Did you do a resistance check of it and of MAP sensor too? 454's are
pretty sturdy internally and not know to have internal weaknesses of
the than valve guide seals (oil consumption)
What should it be on both of those sensors?I unhooked them because I
thought the obd2 would override and use a default sense of them but it
ran the same.Do you know what the map would read at like 2k rpms on a
obd2 trouble shooter computer?
On 26 Jul 2006 15:07:02 -0700, email@example.com wrote:
What is the static ohm reading of them with engine off and cool. Check
TPS ready too as to what idle resistance is and if the change is
smooth throughout range.
No I knew what you meant I'll have to check on those Whats the best way
to check the tps?It shows up good on the computer 0 at no throttle and
smooth to 100% And for the timing thing I did turn the distributor 180
and it was right before for sure
When I have the obd2 system tester hooked up it reads that the ignition
adv (deg) is 28.0 and bounces around a little I have two other chevy
trucks here both w/vortec but ones 4.3 and the others 5.0 and they both
read -18 or so and the more throttle you give them the less they read
Does that sound like a problem?Also how about lobes on the cam being
wiped?Thanks alot for the help so far by the way
On 27 Jul 2006 11:10:27 -0700, firstname.lastname@example.org wrote:
Timing is not the same from engine to engine as it varies with engine
load and size. Typical it should be atound 20 degrees at a idle (plus
or minus 5 degrees) and it will vary a lotwhen you drive. Crusiing at
60 or so light throtle it may be 30 to 35 degrees or more at times.
You are not looking for it to be constant but you are looking for it
to be predictable. WOT it should be around 25 to 28 degress or a bit
more at 4000 RPM. It would help if you could graph it while driving
and watch the see if the spark is erratic. I had a problem with my
2000K3500 that drove me a bit nutz. It would develop a funny idle at
time and then steady out. It never thru a code and dealer under
extended warranty said all was well. I finally found the problem. It
had a flakey crank pos sensor because at times it would through
erraticing timing data but not enough to code. Never likely would have
found it without a live data graph.
I found out the #1 and #8 injectors are running all the time I checked
and it has a full time ground to both of them rather then the
pulsating.I think it's the ecm but I'm not positive but thats what it
seems They're not grounding when it's unhooked so it almost has to be
On 31 Jul 2006 08:08:55 -0700, email@example.com wrote:
Okay, I just pulled up the schematic on that engine in and all of the
the injectors are tied together on the power side to a 20 amp fuse
called ECM 1. They are fired by the ECM grounding them. I uploaded a
schematic to the members only tech referance area of my forum.
Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here.
All logos and trade names are the property of their respective owners.