Need help on 2000 chevy pickup
Need help on 2000 chevy pickup Hey guys, my local garage has told me that i need a new engine, but when i did a leak down test all cylinders are within 6 % leak down. problem is that the truck isnt firing the two rear most cylinders, those plugs are black. I replaced the coils on those two is there something else that could cause just the two rear cylinders from firing? Was this a common problem for this year?Thanks in advance - Jason
On The Tree
Joined: Jan 2006
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From: Jersey
They're retarded...I'm assuming you've replaced or cleaned the plugs first. Check the coil for discharge by getting one of those little spark testers from your local parts store. I wouldn't recommend the 'Ol phillps screw driver method....these new coils have a pretty good bite
Before they have you blowing thousands...give me some background on the vehicle...'00 Chevy truck 5.3?, when did this happen, have you had any programming changed (tuning), is there a service engine soon light on. If so, scan the codes with the purchase of a walmart scan tool or take it to autozone for a free scan. See if the codes are set for ignition related components. If you have a Haynes/Chiltons manual or a friend with some automotive know how...get him to check for a reference signal from the plug on coil pack. ALSO.....check all grounds and connections on the individual coil packs and the main harness that is located at the center of the coil pack bracket...give them a quick wiggle. I figure if you getting carbon fouling...your getting fuel. Plugs are the cheapest....you've replaced the coils....the next thing inline is the connections and the reference signal. I would recommend NOT going back to that shop again...that's rediculous...places like that make me want to
To many crooked shops now days
Before they have you blowing thousands...give me some background on the vehicle...'00 Chevy truck 5.3?, when did this happen, have you had any programming changed (tuning), is there a service engine soon light on. If so, scan the codes with the purchase of a walmart scan tool or take it to autozone for a free scan. See if the codes are set for ignition related components. If you have a Haynes/Chiltons manual or a friend with some automotive know how...get him to check for a reference signal from the plug on coil pack. ALSO.....check all grounds and connections on the individual coil packs and the main harness that is located at the center of the coil pack bracket...give them a quick wiggle. I figure if you getting carbon fouling...your getting fuel. Plugs are the cheapest....you've replaced the coils....the next thing inline is the connections and the reference signal. I would recommend NOT going back to that shop again...that's rediculous...places like that make me want to To many crooked shops now days
I worked in an automotive shop for 7 years, and for them not to at least tell you what is wrong with the car is simply pathetic. Not necessarily a crooked shop, just under quailified. Your best bet is either gaining access to a scanner, or taking your car to a reputable shop with adequate tools and knowledge. You could very possibly have a very strange electrical problem, like a bad injector driver on the PCM or Coil signal. Those are strong motors and unless you ran it on highway without oil in the engine, then it will run for 250,000+ miles easy!
Last edited by autotrix; Nov 29, 2006 at 11:03 PM.
Thanks Guys,sorry i did'nt get back yesterday, Yes it is a 5.3 ,service engine soon light is on. I took it to autozone last night to get the codes.The first code that came up was PO300 Random/ Multiple Cylinder Misfire detected.The second code was PO442 evap emission control system leak (small) loose gas cap? I replaced the plugs,replaced the two rear coils,checked all the grounds.It still is misfiring on the back two cylinders.Could this be a ecm problem?Are there anymore checks that i can do at home ,or should i take it to a chevy garage?
Thanks
Thanks
On The Tree
Joined: Jan 2006
Posts: 115
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From: Jersey
PO442....Probably gas cap...PO300 is from the rear coils that are not firing. Could be PCM...but first grab a manual (nice to have anyway) and look up the coil pack wiring schematic. Get a meter and test the wire on the coil harness plug has the signal that triggers the coil. You can just do a continuity check between each run of wire. the colors on the wire will stay the same all the way to the PCM.
Test it from the coil to where the harness meets the other coils...(a rectangle connector about 1.5x.75in. in the center of the coil bracket assembly). Then if the wires check good there....move on from the coil bracket harness to the PCM pinout block...(I think it's the lower large 80 pin connector)...if you hold the PCM connector towards you with the 3 bumps on the bottom...(so you can't intall it upside down)...the pins are numbered from RIGHT to left 1-20 and 21-40 (Top row) and 41-60 and 61-80 (Bottom row). It's kind of goofy but hey Just remeber RIGHT to LEFT The pins are the IC Control outputs....the pin for #7 Coil is (27) (top left row) which has a RED Wire.....and the pin for #8 Coil is (66) (bottom left row) Purple/White. After you do this mess....and nothing is shorted...it will probably be the PCM. If you have a buddy with the same kind of truck/motor from 2000+ you could just swap PCM's. I hope this helps
Chris
Test it from the coil to where the harness meets the other coils...(a rectangle connector about 1.5x.75in. in the center of the coil bracket assembly). Then if the wires check good there....move on from the coil bracket harness to the PCM pinout block...(I think it's the lower large 80 pin connector)...if you hold the PCM connector towards you with the 3 bumps on the bottom...(so you can't intall it upside down)...the pins are numbered from RIGHT to left 1-20 and 21-40 (Top row) and 41-60 and 61-80 (Bottom row). It's kind of goofy but hey Just remeber RIGHT to LEFT
The pins are the IC Control outputs....the pin for #7 Coil is (27) (top left row) which has a RED Wire.....and the pin for #8 Coil is (66) (bottom left row) Purple/White. After you do this mess....and nothing is shorted...it will probably be the PCM. If you have a buddy with the same kind of truck/motor from 2000+ you could just swap PCM's. I hope this helpsChris
Originally Posted by autotrix
Your best bet is either gaining access to a scanner, or taking your car to a reputable shop with adequate tools and knowledge.
On The Tree
Joined: Jan 2006
Posts: 115
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From: Jersey
Your right Autotrix...I forgot about the BCM and other interfaces that might not like the donor PCM without reprograming (VIN)...If my last post looks greek to you....take it to a well known shop...ask around...couldn't hurt. I just wanted to throw the info out there. Hope it works out for ya
Chris
Chris
