97 C2500 Rough Idle/Vibrating at acceleration under 2k RPM+Gas Ground Help ! NO 56K - Page 2

rg3918 · 10-02-2009, 02:59 PM

Thank you for the comments - how do I check the CAM RETARD ? - data does not show on scanner right?

Below is a key shot which I think shows where I am having the issues - I read a tech note stating that the 02 sensors should be checked at WOT - so I looked for my snapshot of that and found the following:

DTC_CNT 0
FUELSYS1 OL
FUELSYS2 OL
LOAD_PCT(%) 99.2
ETC(°F) 194
SHRTFT1(%) 0.0 0% Good I think
LONGFT1(%) 0.0 0% Good I think
SHRTFT2(%) 0.0 0% Good I think
LONGFT2(%) 10.2 *** HMMMMM ? Related to low voltage below ?
MAP(inHg) 28.4
RPM(/min) 4148 High RPM's
VSS(mph) 63
SPARKADV(°) 21
IAT(°F) 54
MAF(lb/min) 26.529
TP(%) 100.0 Wide open throttle
O2S B1S12--B2S12--
O2B1S1(V) 0.895
SHRTFTB1S1(%) 0.0
O2B1S2(V) 0.890
O2B2S1(V) 0.755
SHRTFTB2S1(%) 0.0
O2B2S2(V) 0.090 RELATED TO 10% FUEL TRIM ?
OBD Not OBD

Wyley87 · 10-02-2009, 03:49 PM

just fyi that ground you got gos to the frame

rg3918 · 10-02-2009, 03:58 PM

thank you - It was hanging from the frame, so I assumed it went to the filler neck, i rigged it to the filler neck with a clamp for now, didnt change anything though..

mudseeker · 10-02-2009, 07:41 PM

i found some old screen shots of my truck before i replaced my bad cat.
sounds like you have a bad cat on bank two, if i am correct in thinking this truck has a cat for each bank.

leolkfrm · 10-02-2009, 07:50 PM

next to what looks to be the breather for the filler is either a pressure or return line, it is also kinked, this is not good, it may be time to think about new fuel lines. I had a dealer put a fuel pump in my 91 and they kinked a line, and could not figure out why my 454 would not perform as it should, found the same thing

rg3918 · 10-07-2009, 01:08 PM

A few things have happened since the last post.. I checked the compression on all the cylinders - lowest was just under 180 and the highest three were 190 - so thats good (I'm running 20w50).

I didnt know it at the time, but I cracked a sparkplug putting them back in, and yesterday morning, the initial stuttering/slight miss that Ive been trying to resolve amplified - it happened throughout the rpm's and would hesitate and buck.. I quickly found the problem - blue sparks flying around the spark plug! But - this made me think more about the ignition being the problem. After many more hours of reading through forums, I came to the conclusion that I needed to check my distributor shaft and gear..

Today - I pulled it out and WOW! See pics below.. I think I found my problem. I ordered a new distributor assembly from a parts wholesaler for $59 - and will know in a couple of days if its all resolved.. There is alot of slack in the gear, and you can see just how thin the teeth have gotten - they are as sharp as a razor blade!

Interesting - there was no gasket around the neck of the distributor shaft.. so this is not the first time it has been replaced (I think).. Also could have been a cause of the damage by having it seat too low..

What do you all think? This could cause a slight miss that wouldn't show up on a scanner right ?

My next question would be - what does this drive off of - and could that be worn too after 185k miles..

Crmzendrgone · 10-07-2009, 02:02 PM

The cam drives the dist. gear. The Jeep 4.0L straight 6 actually has a recall for that exact problem for 05 production dates bla bla. I know this is not a jeep but that looks like the cause to me.

I know the recall involved changing the oil pump do to debre getting in the oil. So might be something to think about if you start to have oil pressure issues. Just useless info I guess but never hurts.

leolkfrm · 10-07-2009, 02:34 PM

look down the hole and you can see the gear on the cam, you will need to turn the oil pump shaft back a bit so things line up, and yes there should be a gasket

mudseeker · 10-07-2009, 08:31 PM

that thing should have thrown a cam correlation code for that much wear!

bradrhale · 10-08-2009, 05:51 AM

shoulda, coulda, woulda. my grandfather had a slight idle problem with his that brought up a p0300 code. the problem: the MAF had gotten unplugged. go figure.

10-02-2009, 03:49 PM	#12
Wyley87 Senior Member Join Date: Jul 2009 Location: Arlington, Tx Posts: 663	just fyi that ground you got gos to the frame __________________ 96 GMC C1500 305 2WD K&N FIPK C.A.I. Rebuilt Motor and Trans Mobil 1 15w50/Mobil 1 Filter 05 Nissan Xterra 4.0 V6 Royal Purple 5w30/Mobil 1 Filter Cost money to go fast...How fast do you wanna go?

10-02-2009, 07:50 PM	#15
leolkfrm Senior Member Join Date: Mar 2008 Location: N.Y. Posts: 4,927	next to what looks to be the breather for the filler is either a pressure or return line, it is also kinked, this is not good, it may be time to think about new fuel lines. I had a dealer put a fuel pump in my 91 and they kinked a line, and could not figure out why my 454 would not perform as it should, found the same thing __________________ 4 wheels move the body 2 wheels move the soul B.W.A.I

10-07-2009, 01:08 PM	#16
rg3918 Full Member Join Date: Sep 2009 Location: Northwest CT Posts: 15	Possible Fix Finally - Updates (Distributor Wear) A few things have happened since the last post.. I checked the compression on all the cylinders - lowest was just under 180 and the highest three were 190 - so thats good (I'm running 20w50). I didnt know it at the time, but I cracked a sparkplug putting them back in, and yesterday morning, the initial stuttering/slight miss that Ive been trying to resolve amplified - it happened throughout the rpm's and would hesitate and buck.. I quickly found the problem - blue sparks flying around the spark plug! But - this made me think more about the ignition being the problem. After many more hours of reading through forums, I came to the conclusion that I needed to check my distributor shaft and gear.. Today - I pulled it out and WOW! See pics below.. I think I found my problem. I ordered a new distributor assembly from a parts wholesaler for $59 - and will know in a couple of days if its all resolved.. There is alot of slack in the gear, and you can see just how thin the teeth have gotten - they are as sharp as a razor blade! Interesting - there was no gasket around the neck of the distributor shaft.. so this is not the first time it has been replaced (I think).. Also could have been a cause of the damage by having it seat too low.. What do you all think? This could cause a slight miss that wouldn't show up on a scanner right ? My next question would be - what does this drive off of - and could that be worn too after 185k miles..

10-07-2009, 02:02 PM	#17
Crmzendrgone Senior Member Join Date: Apr 2009 Location: Arizona Posts: 3,167	The cam drives the dist. gear. The Jeep 4.0L straight 6 actually has a recall for that exact problem for 05 production dates bla bla. I know this is not a jeep but that looks like the cause to me. I know the recall involved changing the oil pump do to debre getting in the oil. So might be something to think about if you start to have oil pressure issues. Just useless info I guess but never hurts. __________________

10-07-2009, 02:34 PM	#18
leolkfrm Senior Member Join Date: Mar 2008 Location: N.Y. Posts: 4,927	look down the hole and you can see the gear on the cam, you will need to turn the oil pump shaft back a bit so things line up, and yes there should be a gasket __________________ 4 wheels move the body 2 wheels move the soul B.W.A.I

10-02-2009, 02:59 PM	#11
rg3918 Full Member Join Date: Sep 2009 Location: Northwest CT Posts: 15	Thank you for the comments - how do I check the CAM RETARD ? - data does not show on scanner right? Below is a key shot which I think shows where I am having the issues - I read a tech note stating that the 02 sensors should be checked at WOT - so I looked for my snapshot of that and found the following: DTC_CNT 0 FUELSYS1 OL FUELSYS2 OL LOAD_PCT(%) 99.2 ETC(°F) 194 SHRTFT1(%) 0.0 0% Good I think LONGFT1(%) 0.0 0% Good I think SHRTFT2(%) 0.0 0% Good I think LONGFT2(%) 10.2 *** HMMMMM ? Related to low voltage below ? MAP(inHg) 28.4 RPM(/min) 4148 High RPM's VSS(mph) 63 SPARKADV(°) 21 IAT(°F) 54 MAF(lb/min) 26.529 TP(%) 100.0 Wide open throttle O2S B1S12--B2S12-- O2B1S1(V) 0.895 SHRTFTB1S1(%) 0.0 O2B1S2(V) 0.890 O2B2S1(V) 0.755 SHRTFTB2S1(%) 0.0 O2B2S2(V) 0.090 RELATED TO 10% FUEL TRIM ? OBD Not OBD

10-02-2009, 03:58 PM	#13
rg3918 Full Member Join Date: Sep 2009 Location: Northwest CT Posts: 15	thank you - It was hanging from the frame, so I assumed it went to the filler neck, i rigged it to the filler neck with a clamp for now, didnt change anything though..

10-02-2009, 07:41 PM	#14
mudseeker Senior Moderator Join Date: Feb 2006 Location: michigan Posts: 7,155	i found some old screen shots of my truck before i replaced my bad cat. sounds like you have a bad cat on bank two, if i am correct in thinking this truck has a cat for each bank.

10-07-2009, 08:31 PM	#19
mudseeker Senior Moderator Join Date: Feb 2006 Location: michigan Posts: 7,155	that thing should have thrown a cam correlation code for that much wear!

10-08-2009, 05:51 AM	#20
bradrhale Senior Moderator Join Date: Apr 2006 Location: Texas Posts: 9,536	shoulda, coulda, woulda. my grandfather had a slight idle problem with his that brought up a p0300 code. the problem: the MAF had gotten unplugged. go figure.

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