Ignition BS? (fixed)

[TYRODD]

So Ive been fighting all this nit picky bullshit on this truck for a few weeks now. I seem to have a pretty strange thing going on now. I started the truck a couple hours ago, tach flutter like a sonofabitch, so Im thinking "ignition". Strange thing is after a couple of minutes,the tach evens out, and then procedes to rise to 1500 at IDLE=vacuum. After a few more minutes, idle speed returns to normal.

I just replaced the IAC and cleaned the throttle body, which has caused a leak near the throttle spring. I am NOT throwing codes though. It just seems that my truck fixes itself temporarily, seems like a sensor maybe? It doesnt do this all the time. WTF? Cant find anything like this with the search feature.

Arge

 

[DanenGraham]

My truck will run fine, then when i get on it (WOT from a stop) it will throw a code 35 and 42. when they are both thrown the truck runs like crap, stalls bad idle. Ect ect... But sometimes it will only throw a 35 at start up once it warms up, and no 42 and will run fine like that, untill WOT from stop, then i get the 42 again.

Not really any help to you, and not really the same probem. But i havent been able to find any information as well. And would love to see what you find out.

 

[TYRODD]

I still think the problem is our leaky throttle bodys, I would imagine this would show up as a vacuum leak, but for some odd reason I cant throw a code 35. What stumps me is my wild tach. I would think if it were something like bad wires or my other problem of high idle due to a vac leak, that these problems wouldnt just go away intermittently . Ill double check my wires w/a spray bottle tonight.
Also Ive noticed the ty is a little doggy from a dead stop, not necessarily at WOT though, and it seems to go away after awhile. This shit sucks!

 

[TYRODD]

Ok, took it for a few WOT blasts after school tonight. On the first run, things were kinda shitty, but each preceding run got better and better. I still didnt throw any codes, and my idle was fine when I parked it. I guarantee that when I start it up tomorrow, the idle will turn homo. I wish I could zero in on this crap.

 

[gmcturbo]

ive been fighting a simillar prob for a while now... let use know what happens!

 

[Matthew Little]

ig

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What kind of coils are you guys running?

 

[DanenGraham]

I need to get another stock GM one, this one i got on here is just some off brand, and thats where i think i am getting the 42 from.

Your story sounds like mine Tyrod. Awhile back my truck started going to all hell, tach was jumping all around and truck was falling flat on its face, i went throug 5 coils, 5 IG mods, 2 distribs. and then found out that the tach wire was grounding out somewhere. So i cut that mofo off. Still need to run a new wire and find out what grounded it out.

 

[Daryl H]

I had the tach flutter when the battery was going bad.
Maybe after the battery gets charged up after a long drive it is less of a problem.

Got a multimeter?

 

[TYRODD]

Wow, not glad too see that others are having these problems, but at least we can help each other out! My motor is only 16k old, only 4k of which I have driven, Brand new from GM (long story). I know that my coil is still stock, I havent changed it, and I know that the prev. owner didnt, but then again he also had the luxury of not having to drive this thing everyday. Hmmm, coil wire grounding out eh, I HAVE installed a remote start on the ty in the last month or so, it required that I splice into the (-) tach signal wire. I cant say thats what caused this mess however. Everything worked fine until a couple weeks ago. I havent been using the R-start for a few days now, just in case.
Im thinking about ordering a new coil to dist. harness from GM, just to rule that out. I didnt get a chance to tinker on it tonight. Tomorrow I will install a new 02 sensor (It needs one regardless of everthing else)

Really, my truck doesnt run awfull when Im already moving (besides KR from the damn dirty intake), but its definitly not as great as it should be. like Ive said, it seems to stumble a little from a start, not a lot, but just enough to know somethings not right. Boost seems to be sagging, but like everything else, not all the time.
Everything points to ignition, but then that goes away and then I seem to get a vac leak, and then that goes away. MAP? ECM? I really would have no idea if it was some kind of sensor though, since of course I cant throw codes.

Ramble, ramble.......

 

[smeagol]

I've seen bad distributors cause what you guys are seeing.

ignition module/pickup replacement fixed 'em. If it doesn't fix it, it's worth replacing 'em anyways.

 

[TYRODD]

I replaced the dist. module about 3k ago, as well as cap,rotor. Maybe its them or another component of the dist. like you say. I have also thought about the battery being bad, that may explain why it seems to go away after I stomp on it a few times.

 

[TYRODD]

Okay, I replaced the 02 sensor last night, it had extreme antifreeze deposits on it (From 1st upper IC leaking, another long story). After I replaced it, I took the Ty out for a long cruise. The oxygen sensor definitly helped A LOT! My problems have seemed to disappear, not sure yet if it cured my Idle problem, Im not holding my breath, But I would recommend checking this out. This also might explain why My problem disappears when I drive the truck hard, as the heat produced might allow even a crappy o2 sensor to work.

 

[TYRODD]

GRRRRRRR!!! :evil: This week Ive replaced the coil (delco), coil to dist harness(delco), replaced the delco wires with spiro taylors, 02 sensor, and the f-ing thing is still a POS. Next Ill try a cap and rotor, and if that dont work, Ive got a 12 guage that will prolly do the trick :snipersmile: . Anyone figure something out on this problem, there is a few of us that have similar problems. This damn thing is nickel and diming me to death! (I guess that normal though). It pisses me off more to know the things Im spending money on are not working.
It still only has a "missing"/sputter problem off the line, at cruising speeds it has a noticible lack in power, and a random miss.

God,.. just gimme the answer!/A. Sandler, Billy Madison

 

[gmcturbo]

check fuel pres/volume, fuel filter, replace cap and rotor, replace vac lines, and check timing. if not that bring to a good technician and have him hook it to a scope/ real scan tool

 

[TYRODD]

Just replaced Fuel filter and cap/rotor. Still running badly. Ive now noticed that when in park, the sputtering and vibration is the worst at 1500. Also I noticed something interesting, I let the truck idle until at norm. operating temp, then disabled the EGR vac. line from the EGR itself, this made absolutely no change in the condition. What could this mean?...bad EGR?

 

[gmcturbo]

no that shouldnt change anything (i think)egr does most of its work at cruise (not idle)

 

[TYRODD]

Now that I think about the EGR, I already knew that .
I went cruising w/the vac line off, no trouble codes, made some "hiss" from the line not being capped of, but codes. I was actualy hoping it was the EGR though...It would give me a reason to put a block-off plate on it.

Im going to tinker on it and not fork out anymore $$$ until next week when I can have a GM master tech. check things out, he's cool and he knows his stuff.

 

[gmcturbo]

in the long run it pays to have a experienced tech check things out. i just replaced my distributor with the msd one. truck runs much better now. might also want to check compression btw...

mike

 

[TYRODD]

If it comes down to it being the dist. how much $$$ for aftermarket vs. delco? Randy (tech) will prolly recommend only delco, but I know thats not always the best route. I hope it aint the dist though, sounds like a pain as well as mucho $$$. Ill really be pissed because of all the dough Ive spent on parts that didnt fix anything :evil: .

 

[gmcturbo]

delco only offers parts to rebuild your dist. msd offers a plug and play one . they cost almost the same but the msd drops in out of the box. its also billet. a good t4ch with a scope can tap into the coil lead wire and check your secondary ignition. also can do a leakdown test of injectors.
the tech at work said fuekl volume should be checked by using a fuel pres gauge with a purge valve and it should fill a 1 pint bottle in 30 seconds.
also check your compression.