Car stumbles in all RPMs

[drifter420]

OK.. car seems to stumble misfire @ all RPM.. most notable under heavier accelaration when OD kicked in. Was thinkin it might be bad fuel and or possible Alt having a blown phase. Talked to a buddy via email and he mentioned that a blown phase on the alt will more likely result in no charge then intermittent issue * reason I was thinkin it might be alt was cause when I was parkin underground @ work, I notice the my fog would dim a lil during the stumble *.. it made sense since most caps, and diodes blows thats that.. He suggest to check for bad ground ( and not just at the battery source also ).. my question is how would I check for bad grounds? Especially under the coil packs and such.

I'm going to run 2 bottles of gas line antifreeze on my home after work, and do some checking of ground in the dark ( and snow !!! ). I won't have access to a code reader till friday evening, so want to troubleshoot further in the mean time. My question is if it's the MAF or IAT sensor.. would it throw a SES light?

97 Bonneville SSEI..

Thanx

 

[buddy-lee]

Don't overlook a most obvious source of stumbling and bog, on cars with HEI, and that's a bad sparkplug wire-it only takes one- having blown itself insulator & leaking to ground, to cause the symptoms you describe(most likely). A bad coilpack could create havoc as well and should be considered, no less.

Good luck.

[ November 08, 2004, 06:15 PM: Message edited by: buddy-lee ]

 

[drifter420]

Thanx.. how would I check coil packs and such? After this gas tank I will try a different pump $10 to see if its bad gas or not.. I will also get my ECm/PCM watever it's called read.. I heard that the standard code reader may not do it.. so I may have to take it to a shop to see. If thats not it.. I will replace the plug wires.. hope it's ju

st bad fuel

 

[Gary Allan]

I was about to scoff at your alt theory and assign this the most likely causes that were mentioned. That was until I remembered that my mother's 88 Corsica had a hesitation whenever coming off idle. It had been there as long as she had owned it. Once I was servicing it for something (antenna I think) and I noted that the battery had some low cells (one of the former "servicable" sealed batteries. I topped them off to the proper level and charged the battery and the hesitation went away for about 3 days.

The root cause was a lame belt tensioner that was fine in terms of belt squeal and such ..but never kept the battery fully charged. The magnetic drap on her 2.0 4 banger was too much and when you took it off idle ...hesitation.

Easy test for the plug wires. Go to a self serve car wash at night.... spritz the engine. If it lights up like a lightening storm under the hood ..you've found your problem.

 

[drifter420]

Humm.. when I was tinkering under the hood a lil out in the cold and snow.. I notice the belt tensioner's bearing is starting to go.. but again not enough that I can see the belt slippin or squeaking. I never thought of the water idea... but I"m just worried it will screw up other electronics there? Thankfully I just thought of using my GF's plug wires as she has the same engine just not supercharged.. and if it runs fine.. then I know thats it.. if not.. I'm sure you'll see me here more

 

[drifter420]

more thinking.. I"m going to pull each wire off the coil tower and see if the stumbling becomes rythmetic or still stumbles sparidically.. that will at least narrow it down to which cylinder plug,wire, coil pack might be the cause..

 

[Matt_S]

quote:

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Originally posted by drifter420:
Thankfully I just thought of using my GF's plug wires as she has the same engine just not supercharged.. and if it runs fine.. then I know thats it.. if not.. I'm sure you'll see me here more

---

Yeah, but you'll have one PO'd girlfriend in the process. "Uh, yeah, honey, I think my plug wires are making the car run bad, so I'm just going to swap them out with yours instead." I bet that'll go over well. Seriously, though, if these are the original wires, they're overdue for replacement anyway.

 

[tmorris1]

Could be fouled injectors also. This happens about once or twice a year with our 98 Montana.

 

[drifter420]

so if I do the ignition test and it didn't yield any results.. then I will look into that along with the pcm.. but how'd you diagnost a fouled injector?

 

[kenw]

"I"m going to pull each wire off the coil tower and see if the stumbling becomes rythmetic or still stumbles sparidically.. that will at least narrow it down to which cylinder plug,wire, coil pack might be the cause.. "

excellent idea. if it gets worse, that's not the problem pack (or wire or plug). If nothing changes, that's the culprit.

One way to check wires is to run it in the dark. VERY DARK. look for small faint blue arcs from any plug or HV wire. Use a WOODEN stick to nudge the wires around a bit to see if you can make it arc.

good luck

 

[Matt_S]

quote:

---

Originally posted by kenw:
"I"m going to pull each wire off the coil tower and see if the stumbling becomes rythmetic or still stumbles sparidically.. that will at least narrow it down to which cylinder plug,wire, coil pack might be the cause.. "

excellent idea. if it gets worse, that's not the problem pack (or wire or plug). If nothing changes, that's the culprit.

One way to check wires is to run it in the dark. VERY DARK. look for small faint blue arcs from any plug or HV wire. Use a WOODEN stick to nudge the wires around a bit to see if you can make it arc.

good luck

---

Yes, that and a spray bottle will help, too.

 

[T-Keith]

Scan the car for codes, before anything else. Most auto parts stores will loan you a scanner or even do it for you.

If that doesn't turn anything up, look for vacuum leaks, bad spark plugs or bad wires.

 

[drifter420]

quote:

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Originally posted by T-Keith:
Scan the car for codes, before anything else. Most auto parts stores will loan you a scanner or even do it for you.

If that doesn't turn anything up, look for vacuum leaks, bad spark plugs or bad wires.

---

Unfortunetly due to the fact that I live in a hick town, they're trying to charge me from $50+ and the only other source is my bro.. but again that won't be till friday eveing.. so in the mean time I just want to do some troubleshooting in the meanwhile. Vacuum leak maybe possible but I"m going to shoot at ignition system first.. then I will harass you all after that for vacuum leak.. injectors PCM and such help. Will keep you updated tomorrow

 

[drifter420]

K.. it was just wire for cylinder 5 not being open and dead. Tried it on another coil/cylinder and it was still dead.. but the other wire would fire cylinder 5 now. Whew.. thought it was going to be soemthing major.. Thanx for all the info guys. Now wat recommendations for plug wires would you suggest? OEM is a lil pricey from GM.. for the same amount I can get aftermarket thicker wires and or for less but I don't want cheapie Crappy Tire brand either.

 

[kevm14]

It might need a coil or three, in addition to wires and plugs.

 

[BlazerLT]

My friends Bonny did the same thing.

It was the coil pack.

 

[drifter420]

Sorry... update.. got new set of wires.. Beldens' 7MM with lifetime warrenty.. car seems to run fine and smooth again. How would I check coil pack out of curiousity??

 

[ZR2RANDO]

What's wrong with using a std timing light , clipped over each wire one at a time to verify each wire is firing. If you find one that is not firing, swap it with a good one and see if it starts firing, that should help with chasing down probs huh?

 

[kenw]

quote:

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Originally posted by ZR2RANDO:
What's wrong with using a std timing light , clipped over each wire one at a time to verify each wire is firing. If you find one that is not firing, swap it with a good one and see if it starts firing, that should help with chasing down probs huh?

---

because it may be doing fine where you clamp it, but "leaking" spark farther down the lead. Leaks can happen under the plug boot, etc.

 

[ZR2RANDO]

Dang, thought I had the perfect idea..at least it would verify coil delivery..

I have noticed a "nose-over" feeling when wires were breaking down, hope that helps.
I learn stuff here all the time, thanks.

Rando