Im gonna burn the damn thing.

[foxrider251]

Hey guys got quite the problem going on, i have a 1998 yukon 350 vortec with 270000 kms on it. from the time i bought it the thing had a slight misfire barely noticeable so naturally i did the fuel filter didnt help so a set of plugs and wires came next still didnt help, cap and rotor is where sh$t really went downhill. upon installing the cap and rotor it wouldnt start so we toyed with it and toyed with it and the rotor was 180 degrees the wrong way(facepalm) so then it ran fine...for 3 hours then it put me on the side of the road. next morning went to start it and thats when there was a full 8 cylinder misfire that literally developed overnight on its own. i have since done the fuel pump and spider injection assembly being the 2 most infamous issues with these gms and still nothing. so basically im now 1100$ in on parts 15+ hours of my own time screwing with the thing plus the 4 mechanics that have been helping me. oh and the one mechanic who owns a shop in town brought over his 7000$ mac tools scanner and found nothing wrong on the computer side of things. thanks for your time guys and any ideas are appreciated

 

[retorq]

LOL You have a slight misfire and you changed all that shit without trouble shooting it?? Your next step is a new engine bro.

 

[SunlitComet]

agreed. i think you have been going the wrong route trying to fix this issue. you need to start over with a systematic approach to trouble shooting. if you dont know the systems. i am really good at it but sometimes i have to really dig deep to find the actual cause.

 

[foxrider251]

SunLitComet, what exactly do you mean by systematic approach? i was just trying to do regular maintenance and then it exploded into this problem

 

[_Dylan_]

So, where are you at now? What is the current problem?

 

[SunlitComet]

and what maintenance were you doing when this started?

 

[Donnie Yukonie]

Well IMO it has to be an electrical Bug Obviously , since all those parts are new you have narrowed it down a little I think a new engine is Out of the question . whats the condition of the Distributor as a whole? are the teeth gone? Mechanically thats the ONLY thing I could see as being an issue My next step Personally would be looking at the ECM

 

[foxrider251]

well basically the problem now is that it will start sometimes and when it does itll run by itself for about 5 seconds, then you have to help it with the throttle. its ultimately undriveable when i tried it just about redlined on temp after a few minutes, we thought maybe the plenum gaskets but tryed spraying carb cleaner all around the plenum and no rpm jump, and as far as the distributor we havent pulled it out but it was working just fine before all this started so i cant imagine it just crapping the bed randomly. and for maintenance i was doing the spark plugs, wires, and rotor and cap

 

[_Dylan_]

the distributor could be worn and jumped time

 

[foxrider251]

i suppose, i should pull it out and take a look because if its not that it looks like everything is pointing towards ecm issues...

 

[retorq]

You redlined the temp after it ran for a few minutes? Something tells me that's not an ECM issue.

 

[Bigsteve04Ho]

Sounds like a head gasket blown

Sent from my Nexus S 4G using Xparent Skyblue Tapatalk 2

 

[SunlitComet]

you don't simply just jump a tooth and it just stays that way with no more issues on thee same part. at any rate there would have been a code popped for that.

---------- Post added at 10:23 PM ---------- Previous post was at 10:20 PM ----------

i would consider looking into getting some live data including gm specific data for iac data and cam retard setting.

 

[foxrider251]

retorq i should have mentioned that i had my foot to the floor for that few minutes trying to get the ***** to break 90 kmh. and it didnt redline but it was getting there so i shut it down, and where would i find that live data SunlitComet? sorry not trying to sound like an idiot stick but all this is way past my mechanical comfort zone im just trying to get this thing back on the road any way possible

 

[_Dylan_]

Your buddy with the mac tools scanner will be able to pull live data.

 

[retorq]

retorq i should have mentioned that i had my foot to the floor for that few minutes trying to get the ***** to break 90 kmh.....not trying to sound like an idiot stick ...

Whoa

 

[SunlitComet]

break 90 km. have you considered a partially plugged exhaust system? or week fuel pressure?

---------- Post added at 06:00 PM ---------- Previous post was at 05:59 PM ----------

and yeah your friends scanner should do fine.

 

[foxrider251]

i was pissed off so i tried just matting it onto the highway, and as far as fuel preussue we should be able to eliminate that seeing as how it has a new fuel pump, new spider assembly and a fairly new fuel filter

 

[raptorforme93]

Is it just me or should it still not almost overheat like that even when floored, which I also wouldnt do with your engine conditions. Did you check the coolant levels and oil to see if it looks all milky??

 

[foxrider251]

yeah i know it wasnt the best thing to do, gotta learn to control that temper lol and yeah i checked the oil and coolant for any signs of a head gasket issue (ive had a chevy 350 with a bad headgasket before) but nothing. it will only heat up when you put throttle into it as soon as you let off it cools right off. its also now just started idling at 2000 rpm by itself and will do so until i shut it down. tried several times and does it everytime so basically its booked in to go get looked at in the next couple days. this godamn thing is all over the place and i just really dont want to damage anything internally engine-wise because she still is my baby after all and i love driving it not doing an unneccesary engine jobs. guess ill stop being cheap and get the pros to figure it out :/