firebirdgirl_87

Hello everyone!
Well thought I'd post my problem.
The dealership can't figure it out!
Here's the short version: Car runs and drives great when cruising down the highway, but when I come to a light and have to stop it surges like it want's to go and then shakes a little and mostly dies. I can start it right up and go, but it's starting to **** me off!
It only does this when the car is warmed up.

Work done:
Injectors cleaned, tested (from the dealer)
NO SES light
New plugs, rotor, cap , wires
New ignition module

Blah, lots of stuff

The only problem they can find is that the screws that hold the ignition module down are broken off on the distributor. (They want to replace the distributor. Seems like it would be easier to drill out the screws and put new ones in) Could the screws make a difference???

Other than that it all looks and tests fine.
Well if anyone could help, please!! Let me know.
Thanks
firebirdgirl:bs:

89RSOwner

Sounds like maybe it's your Idle circuit. There are two different (in gear) Idle speeds. And if it's not high enough, it will do as you are desribing.

TomP

Welcome to the board! Yeah, the screws could cause a problem, and fry the new module. The module uses the distributor base as a heat sink. The module could be overheating (since it's not attached to the distributor). A heat sink grease, usually a white lithium compound (radio shack, $5), is applied between the module and distributor for heat transfer.

But... common "overheated module" problem goes like this: Car runs great when cold. Car gets hot, stutters, and stalls. Then, the car will not start until the module cools again. Doesn't sound like your problem. I'd suspect the mass air flow sensor as being bad. Try unplugging the MAF and see how the car drives. A MAF can go bad and not turn the service engine soon light on.

And yeah, it'd be easier to drill the screws out. You could also buy a distributor from the junkyard; I bought one a few years ago for $15. Sounds like they don't want to drill the screws out.

firebirdgirl_87

Thanks guys for the replys,
I guess I'll get my friend, and see if we can drill the screws out and put new ones in an d see if that solves the problem.

I have a newer MAF (2yrs old) so I hope thats not the problem, wouldn't that throw a code though?

firebirdgirl_87

Never heard of an idle circuit? Could you give me more info?

It's strange because if I put the car in park it keeps running, but when it's in gear at a stop light it dies...maybe it just hates stop lights! Ha! Ha!

So maybe thats the problem, or maybe torque converter?

89RSOwner

WoW! [flirt] I just noticed your full nick, and a woman with a ejoyment/knowledge of third gens? *swoon* now thats one i'd bring home to momma![/flirt]

As for the problem you have, i had a similar problem with my 85 Z-28. MY cold/not in gear/idle was correct. However my hot/in gear/idle speed was not. Upon getting hot and needing more RPM's to keep the motor in gear, it would die. Let the thing out of gear? fine. I just took mine in and had them set my idle(s) to what my mechanic at the dealership suggested. Worked great.

redraif

Hey another girl on the board. I knew there were a few of us floating around. Sounds like our cars are twins. 1987 red 2.8L. I have t-tops. You? Though mine is not stock anymore.

Ok, ok about you prob. TomP is the man. Listen to him. My car was having similar probs and it was the dist needing a rebuild. That and we suspect the timing had walked. After the rebuild and a timing tweak, the car was amazing again. Makes me almost sad we are going to trade the 2.8 for and V-8 soon. So I would say get those screw holes fixed up and see if it helps. One step at a time. Fix the obvious problem first and then start digging.

Mass air is a good suspect. Mine acted like that when there was a crack in my Mass air sensor case. But with it being so new & not coding... check your Air temp sensor. Mine was going, but did not code at first and the car ran like crap. It had a little fight with and Armadillo and a truck on the hwy. (I had a custom cold air set up that stuck a bit below the car and an armadillo ran out in front of me. I hit him and he and the filter flew, taking my ATS with it. A truck hit the fliter after that.) The sensor was dying on the trip, but never coded. The cars idle was way bad, like it was dying. Surging all over. Worse the hotter it got.

After that I would check the idle control components, mine were replaced early on & I still had the symptoms, you are describing.

Dale

iTrader: (12)

The screws that hold the IM down!!! MAJOR PROBLEM!!! The IM has a magnit on it, and so does the shaft, it tells the puter the rpms its turning, if its bounching around, its not getting a good reading. Seems you have done a very good tune up, and elminated that. Also check the vacume, see if you have a leak. I have had probs with my truck that it had vacume leak, idle in park/nutural fine, in gear at light, cough cough, sputter, sometimes died. Also get a fuel pressure check, from my readings these cars tend to have fuel pump probs 20-25 years old. If you fix the IM w/o pulling it, check your timing after your done!

firebirdgirl_87

Hello redraif,
Thanks for the info. And nope my car has no t-tops. But same yr. and color! Is that a pic of your car? Your right it's not stock any more!

Yep, just a girl who loves her car, and love's the challenge of trying to keep it running and keeping it looking good. And boy is it challenging some times...like now.
I guess I'm going to start from the beginning and fix the mounting screws and go from there.
Looks like it could be a few things.

Right now when I come to a stop I just put it in neutral, and it doesn't die on me. Seems to be working out so far. Hopefully this weekend I'll have time to work on it, and with some luck figure out what's wrong. I do have an '87 factory service manual, which has helped me out alot in the past.

So hey, I'll let you all know what I find out, and thanks for all the help.

TomP

Red, thanks for the compliment; I've always done my own work, and know how frustrating it can be to pay a mechanic tons of cash when they either work on the wrong thing, or can't figure out the problem. An armadillo? LOL! If I saw one of those on a road in new jersey, I think I'd have a heart attack. 'Fact I bet the whole state would be in an uproar!

Dale, are you sure the module has a magnet in it? As far as I knew, the only magnet was on the reluctor. That's the 6-pronged disc that sits stationary on the top of the distributor. It's got 6 magnets. It spins in the middle of 6 stationary pole pieces (look like fingers). The pick-up coil (white disc, if it's old, looks like a brown disc that's falling apart) senses the magnetic pulses from the pole pieces. When the magnets in the reluctor line up with the metal pole pieces, there's a magnetic pulse- and the pick-up coil picks that up. (sounds funny!) I believe the ignition module just reads the pick-up coil, reads the computer (for the timing), and decides when to "fire" the spark coil.

'Fact, those pole pieces and reluctor tips don't need to be perfectly rust-free. They don't (and shouldn't!!!) make contact, no electricity jumps between them. Only thing electricity jumps between is the top and side of the rotor (not from the bottom!) and the inside/outside of the cap. 'Course, the pole pieces/reluctor shouldn't be covered with a 1/8 inch of flaking rust, but they don't need to be 100% shiny.

FBG, like Red said, an MAF can go bad and not set a code. Try the test I mentioned in my first message of this topic. Glad to hear you have the GM service manual! It'll cover the distributor, but here's some info in an old message: https://www.thirdgen.org/techbb2/sho...threadid=63110 And another message, https://www.thirdgen.org/techbb2/sho...threadid=61335 Hey I bet in another day, someone will ask how to rebuild their distributor. Seems to always happen after I dig up old messages with the <a href="search.php?s="><img src="images/top_search.gif" alt="Search" border="0"></a> button. Hell, here's one more message, https://www.thirdgen.org/techbb2/sho...threadid=62305 If you do a search for distributor rebuild (remember to choose the V6 forum) you'll find a million more.

TomP

Oh and FBG, have you looked in your GM book at section 6B? Unless GM changed the section numbers between my '86 book and your '87 book, that's the spot for the driveability charts... like "car surges", or "car stalls". You could walk through one of the charts and see what's up.

Dale

iTrader: (12)

I was informed it senses the magnits on the shaft. So it may not have a magnit inside it, but it works off a "magnetic pulse". And thats how it knows the timing/rpms. Otherwise I see no point at all that it be built into the distrib. Either way it goes, that has got to be fixed!!!

TomP

I'm 99.9% sure the pick-up coil is the only thing that senses the magnetic pulse. Two wires run from the pick-up to the module. I actually asked about remote mounting the module a long time ago on the tech board, nobody had any reasons for it or against it. I'll see if my GM manual mentions anything. Heck, for an older 4-pin HEI module, an MSD box replaces the module completely! You remove the module from the distributor, and plug the MSD 6-series wires into the distributor base. Then you mount the MSD box wherever you want to.

firebirdgirl_87

WOW, you guys and gals really know your stuff!

Yep, the dealership pretty much screwed me out of way to much cash, and didn't fix a damn thing. So guess it's up to me and this board to figure it out.

Tom I'll test the MAF to see if it's working right and check out those articles. Thanks.

Dale I agree with you too about the screws, I'm sure they are there for a reason, so it wouldn' t hurt to make it right.

Just wish it would throw me a code or something...I'm thinking a vac line somewhere also. The car is 15 years old and they are starting to look real bad all flakey and old.
I should just take the time and try to replace all of them, probably would solve alot of the problem.

Is there a diagram somewhere that shows the routing of all the vaccum lines, on the 2.8 V6??? That would help.

Well thanks again board.

Dale

iTrader: (12)

If it has the orginal hood, it should be on it. Might want to try and look at a haynes manual, or chiltons manual.

1991rsblue

i have the same problem, i have a91 rs with a 3.1 and i figured it out finally!!!! my problem was a combo of my TPS too low but not low enough for the computer to triger the code and my torgue converter wasn't shifting my gears down fast enough, so when i pulled up to the light or stop sign i would die. i put a new torgue converter in and chainged the tranny fluid and filter raised my idle about 25 rpm and it runs like a charm. my advice to you with the IM is drill out the holes and make sure your IM is touching your distributor withe the white goop in between them. When your cars stalls the rpm's should go wacky if the IM is bouncying around. if it doesn't then most likely not it. just trying to help let me know.

1991rsblue

oh yeah i forgot to mention, if you have a vacuum leak it should affect it when your at idle not just when you come up to a stop sign or light. Vacuum lines work all the time when the car is on. They have diffeent amounts of vacuum to them but if that was your problem you would have rough idle and shaking all the time not just a stop signs and lights.

redraif

All my lines were dry rotting bad. I don't think I had any leaks, but it didn't hurt. I had to one by one just lay a new line by the old and cut it to size and then swap. I never used the manual. I replaced mine with red aftermarket hoses and they look great. They were good quality silicone hoses from NOPI. I got a kit that had 3 different sizes.

1991rsblue

that was the same thing i did, but did it help you out???

redraif

I changed mine because I could not touch a thing in my engine bay w/o my hands coming out black. Mine we rotting. They we leaving black sooty stuff everywhere. Apparently mine had not begun to leak yet, so I did not notice a difference when I swapped out the lines. Just the bay was way cleaner. Then I attacked the crusty wire looms (for aesthetics only)

Now my mother has a "carborated" 2.8L in her 6000LE wagon. She had some drivability issues and we took a look and it was her vacuum lines. We swapped them and it seemed to fix the prob.

It can't hurt, is my point. If they are original, they are due for a swap.

redraif

Thats why I started to do my own work. I was working with one mechanic at a chevy dealership that was very fair and helped me anyway he could. He did alot of stuff off the books, cause he felt most of it was a ridiculous $.

Problem was the car was not throwing a code and it was taking too much time to try and haphazardly replace things. Brent then advised me to do one of 2 things. Get a manual and start replacing things, or let the drivability guys take a wack at it. He did however admit to me that the drivability guys could find it, but he did not think I wanted to spent that kind of $. He said it would be cheaper to replace the engine. Thats when I met Joe and he said he would help me and teach me how to do all the pitally crap myself.

So we attacked it. It took a good solid year, but we got it going right.

firebirdgirl_87

Yep, my vac lines are rotten and really need replacing. Going to do that hopefully after I fix this stalling problem.

The more I talk with people who have had simular problems the more I agree with rsblue. Could be both the tps and the torque converter.

The car had always idled rough but it never really bothered me. And I agree with redraif just start replacing all the old solenoids and sensors with new ones. Because I think alot of the rough Idle problems are caused by worn out parts. Plus hopefully It will run for awhile with out any more problems!

Going to read up on the TC more and see if that could be the stalling problem.


This isn't rocket science or is it?

Thanks

FAST RS

I had that problem before it happens when you step on the brake and your aroudn 20 MPH and under. I reset my computer that kinda helped also check the hose that goes from your powerbooster to TB. When ever i work on the driver side of the car by the powerbooster it seems to do that then it goes away after a week or 2.

LT1guy

iTrader: (1)

If you haven't already, I'd check the TPS voltage. I don't have the manual here with me at work to see what its supposed to read, but thats a possibility as well. If Tom or one of the other guys doesn't post it I'll find it whenI get to Shannon's tonight. Also, you may want to clean the throttle body and IAC...not a bad idea on any injected car.

Do you have a Pull-A-Part type salvage yard near where you live? If so you might be able to get a used MAF there for cheap, if it is indeed bad. We have picked up spares of almost everything...MAFS, relays, weatherpacks (they're bad about breaking), etc...for next to nothing.

devianb

hey firebirdgirl_87. Its nice to see another female Fbody driver. It seems that everyone has given a different answer to your problem. With GM vehicles the problem could be any number of things. There's a thousand different parts just in the engine bay and they all eventually wear out over time. I know this doesn't help you, but it explains why even a dealer can't find out what the problem is. I hope you find out what it is. Its that kind of stuff that makes me want to junk my car and get a new one.

TomP

I've gotta do that with my charcoal canister hoses- they're doing the same thing yours were (leaving black on my hands). If there's a vac leak, though, it's not enough for me to feel it. I replaced all my wire loom after I totalled my car- the original stuff all snapped into a million pieces! I wound up buying a big friggin' kit from JC Whitney; came with a few miles of wire loom, all different sizes, including the hard-to-find 1" diameter loom for the main engine harness.

6000LE, eh? Does that car have the trans am seats? Two-tone bucket, separate head rest, map pocket on the back of the seats. I had those seats in my Firebird, and they rotted to hell. I could never find duplicates in another f-body. Finally it came to me to start searching other GM cars. I found my exact seats, with the colors reversed (where I had light gray, these had dark gray, and vise versa), in a Pontiac 6000 wagon SE. I knew they'd fit since they were already in my car. I had to swap the seat rails off the bottom, and put the tilt-forward mechanism from my seats onto the wagon's, and punch holes through the headrest for the seat belt guides. (Yep, I guessed correctly, there were threaded holes hidden underneath the fabric.) I posted about my "find" on the body/interior board, and found out those seats were the Trans Am optional seats- no wonder I never found them in a yard! Got 'em for $15 each.

AFrikinGoodTime

I would suggest to just leave the MAF hooked up and tap on it near the connecter area with the handle part of a screwdriver while the car is running. If the engine fluctuates when you tap on it then it is going bad.

If there is any kind of lope to the idle then you most likely have a vacuum leak. put a gauge on the rear manifold T-fitting (small side) and it should read at least 16 in. of vacuum while the car is running.

redraif

JC rules. That where I got 75% of my looms. They did not have red 1 inch ones. Had to get those from NOPI.

Mom's has the burgandy bench seat. We did see the exact seats your were refering to in a 6000 at pull a part. Grand Ams and Grand Prixs come with them too. I can just never fine a silver drivers seat in perfect condition. Mine have the extra bolsters under your legs. You see the low trim level seats alot though. I would love a set in black. Tough luck finding them in anything.