MudHippy

Long story short...I just installed a new flexplate on my 98 Monte Carlo 3.1L. Now when I start the thing it makes a quick "chirp chirp chirp" sound(sounds kinda like a loose belt...which it's not). It only happens immediately after the engine turns over(starts), just as soon as I release forward pressure on the key, right at the precise time when the starter drive gear is disengaging the teeth on the flexplate.

So...thinking the teeth on the starter drive gear were a little too worn, I went ahead and replaced it too(the whole starter). And...nothing...it's still doing the same thing. And I'm getting tired of giving myself headaches trying to figure out wtf is going on.

Anybody here got some ideas?

JasonYota

iTrader: (1)

So it only happens while the engine is turning over to be started? Not after its running?

MudHippy

Yeah. I turn the key to start for about 2 seconds. Engine starts. I let off the key, and then 3-4 quick "chirps". And then she runs smooth as silk...until the next time I go to start it.

MudHippy

I just googled it and found one other guy's thread on another forum saying pretty much the same thing. Which nobody even replied to.

http://g8nation.com/showthread.php?t=34691

Anyhow...it did have what should have been a stock flexplate on there(AFAIK). And the one I just put on it is aftermarket. Got it from NAPA, Balkamp part # 600-5160 to be exact. The starter was stock and was replaced with stock.

Blah blah blah...whatever...I'm thinking I'm about to go grease the damn thing and call it good.

MudHippy

I figured this thread would yield few, if any, ideas. It's not like it makes that much sense. Plus...if I can't figure it out...we're all screwed...basically. Hence the extreme rarity of a thread such as this. I decided to swallow my pride on this one though. I thought there might be a small chance I missed reading something somewhere about flexplates needing some kind of obscure installation procedure...or something...

After some closer inspection, however, I've reached a suitable conclusion. The manufacturer appears to have coated the teeth on the flexplate with a thin layer of something dark gray/blackish in color. Perhaps a rust preventative? I assumed the teeth I was looking at when I installed it were that color for a reason, and I probably shouldn't worry about it. Well...at this point I wish I would have taken a wire brush and stripped all that crap off first. Because it looks like it's going to take quite a few...dozen or so...starts before the teeth get scraped clean by the starter drive gear. Which, if I've guessed right, is going to be annoying as all hell for who knows how long. But shouldn't actually hurt much...

I'm chalking it up as one of those things. You know? The ones you should have known...but there's no possible way you could have...without finding out the hard way...

vital22re

iTrader: (2)

I don't know if I would agree with that. A coating? can the starter be shimmed at all? did the backing plate on the block get bent and is rubbing? Did you seat the torque converter properly?

MudHippy

All good questions:

1. I'm not 100% sure what/why it is, or if it makes any difference(or any weird sounds). It looks like the type of black coating that a lot of hardened OEM hardware has. And it does appear to be slowly "rubbing" off, as there's shiny metal starting to show on the leading edges of the teeth. Which looks normal, in comparison to the wear pattern on the old one.

2. I don't have an fsm, so I can't say for sure whether I could/should. But I'm not ruling the idea out.

3. Everything looks good there. Surprisingly the old flexplate that shattered stayed in one piece...ish, and didn't flop around too much(though was making a very loud, and frightful, knocking @ idle). I couldn't find any damage to anything else, except the torque convertor bushing(aka front pump bushing). Which got wallowed out since the TC was still "hopping" around quite a bit(up/down/side-to-side, more than in/out, apparently). No real big deal to replace that, which I did.

4. I'll tell you the truth on that...I think so. God I hope so. Mating the trans on this engine with what I've got is just short of a total nightmare. A majorly high ranking PITA for sure. And I've pretty much failed to do it "perfectly" yet. So...with any luck...yes...I finally got that much right.:fingerscrossed: The last time I tried it did cost me some splines off the tip of the oil pump drive shaft. Though I wasn't made aware of that until pulling it back apart this time. And it didn't make any difference...for the first 10k miles I drove it like that anyway...

So...I still don't know for sure what's really going on. All I do know for sure is it's pretty damn hard to judge by looking through the inspection plate opening with a flashlight. And if I have to pull this thing apart again I'm going to

vital22re

iTrader: (2)

In that case, ride it till it goes boom.

Terrys87

iTrader: (1)

Sounds like that is some close tolerances on space. The older chevys liked their shims but I haven't worked on one that new so not sure if they still do shims. I cant see your replacement plate being that much thinner to cause rubbing. I would look on the net and see if there is a trick to getting the TC seated in properly from the usual way of most TC. I have been finding a lot of information on youtube for things like that.

MudHippy

Did some research on the shimming idea. According to the manufacturers starter noise troubleshooting .pdf I just found, I need to add some to gain clearance. Needless to say, I'll be giving that a shot. So we'll see how that goes...

MudHippy

Fixed it!!!

2½ .015" shims did the trick. 2 full length(both sides) + 1 half length(engine side).

Thanks for the help guys!

JasonYota

iTrader: (1)

To be clear you shimmed the starter correct?

MudHippy

Correct.

I made my own starter shims out of some galvanized .015" sheet I had left over from my roofing job. Then did just like the pdf said(link in previous post). 1 full shim did nothing. 2 full shims sounded a little better. 2½(with the extra half on the engine side bolt), completely cured it.

Terrys87

iTrader: (1)

Thanks for letting us know you got it fixed. Now I know Chevys still like to use shims. I am sure I will run into it someday.

rworegon

I learned something new in this thread. I never have had a GM so this whole shim concept was new stuff.

Glad that is behind you MudHippy.