: Stalling in Reverse



DopeStar 156
04-02-06, 11:31 PM
Occasionally while backing up my 89 Fleetwood will stall while moving in reverse. It restarts just fine if I pump the gas once and will back up just fine after that. I'm curious as to why, no other gear has this problem. Any ideas?

N0DIH
04-03-06, 11:02 AM
Engine cold or hot? Or no difference?

Is idle speed ok? Should be around 500 rpm in drive.


Occasionally while backing up my 89 Fleetwood will stall while moving in reverse. It restarts just fine if I pump the gas once and will back up just fine after that. I'm curious as to why, no other gear has this problem. Any ideas?

brougham
04-03-06, 07:22 PM
It sounds like there's something not adjusted right with the carberator.

DopeStar 156
04-03-06, 07:49 PM
It makes no difference cold or hot. Once it did it after an hour long drive home from school and once after a three second drive from my grandmother's. The carb hasn't been touched since it was replaced back in the fall, maybe something's fallen out of adjustment since the weather changed? The idle speed is normal under most circumstances, it just seems to die out while backing up.

77CDV
04-03-06, 10:56 PM
Check the carb, esp. the auto choke. Could be sticking.

Craig

DopeStar 156
04-04-06, 12:04 AM
Check the carb, esp. the auto choke. Could be sticking.

Craig
Ok, could you tell me what to look for though? I'm a little rusty on carbs right now not having to deal with one for a while. Is there any particular reason this only happens in reverse though? It's never happened in Drive or any forward gear for that matter. Occasionally it would but that's only if it doesn't get enough time to warm up. Thanks.

Night Wolf
04-04-06, 12:32 AM
The fact it only happens in reverse is weird.

The enigne dosn't care what gear it is in...

though, due to torque, the engine will rock left, instead of right... perhaps its just enough to pinch a vaccum line or something...

N0DIH
04-04-06, 02:42 PM
Check the MAP sensor line, it is on the pass side fenderwell somewhere (at least on Olds it is) and see if the line is moving and creating a vacuum leak at the sensor, that will kill it for sure.

Check the motor mounts too. Pop hood, engage parking brake if you can, put in gear with foot firmly on brake, and torque up the engine, if the engine moves a LOT, then the mount is bad (do in DRIVE and REVERSE). Drive, left side, Reverse, right side. 95% only lunch the left side.

Also, you can sometimes feel it when you accelerate from a stop. It will thump just after you give it gas, more so when you give it more.

DopeStar 156
04-04-06, 03:25 PM
Motor mounts huh? Hmm, my transmission mount was discovered to be broken not too long ago. The only real blemishes my car has is the undercarriage is pretty rusted. Let's say I have a bad motor mount, how much would it run me to get that fixed?

N0DIH
04-04-06, 05:40 PM
If trans mount is bad, the motor mounts likely were the culprit, they are all a trio together. One bad will tax the others.

$10 for the part, 1 hour of labor in my book. All you need is a LONG extension, 3/8" drive, a 3/8" universal joint, 9/16" or 5/8" socket, matching wrench, 1/2" socket and 6 in extension, matching wrench. Hoist car, put wrench on back bolt of offending mount, long extension and socket on front, remove frame to engine bolt. Use jack to lift up engine (DO NOT HOIST ENGINE OFF OF BALANCER!!!), use oil pan with a block of wood. Once you clear it, get smaller wrench in on top bolts, and stick the short extension with socket in the lower control arm opening and you can find the mount to frame bolts. Remove.

Reinstall in reverse. You are done.

Honestly isn't a bad job on a Pontiac, but on my Cutlass, it was a pain. As Olds (like Chevy) likes to put the motor mount bolt in with a nut. Pontiac WELDS the nut to the mount, Olds and Chevy do not. If I ever find the engineer who did that I am gonna give him a peice of my mind!

I can pull a 455 Pontiac out of my T/A in 1 hour. It took me nearly that to get the motor mounts loose in my Cutlass!!

DopeStar 156
04-04-06, 10:59 PM
Being an Olds engine, would that be the same motor mounts then?

N0DIH
04-05-06, 02:45 AM
Yup, but hopefully the D body has more room, likely easier than the G Body.

DopeStar 156
04-05-06, 09:54 AM
It more or less feels like a vacuum problem, I didn't notice any eratic engine swaying when I futzed around with the hood open like N0DIH said to do.... This MAP sensor line, can anyone give me an exact on it's location? Also I wanted to ask, the automatic parking brake release since that's a vacuum operated thing, does that vacuum have anything to do with the engine or is that thing all separate? Mine leaks, I can hear it hissing all the time. Not so much when I'm accelerating but if I let off the gas I can hear it. Could that thing be robbing my engine of vacuum? It no longer works anymore but it used to. Should I look into replacing that thing first before I start messing around under the hood?

CoupeDevilleRob
04-05-06, 08:34 PM
I had a bad tranny mount in my car, it took literally ten, maybe fifteen minutes to replace. Made a huge difference in NVH too, the car runs like new after replacing the bad one.

Does your "Brake" idiot light ever come on? It doubles as a bad vacuum light. Mine used to come on if I was using my brakes a lot, like when parking. I replaced my auxilary vacuum pump and that solved it (I don't think your car has one).

My car would stall in reverse too. Replacing the ISC cured that. The old ISC was shot, putting it in reverse changed the load on the engine, ISC couldn't compensate and sometime it would stall. It doesn't seem like that's your problem though, so forget what I just said.

77CDV
04-05-06, 10:29 PM
I have to consult the FSM to remember exactly the where and how of the automatic choke. As to your parking brake release, it's all engine vacuum. In fact, you can use the parking brake release vacuum hose to check the engine vacuum, since it's a direct feed. Fixing vacuum problems in older Caddys is always recommended as so many systems depend on proper engine vacuum pressure. Bad vacuum causes myriad problems to pop up. I'll check the FSM when I get home.

Craig

DopeStar 156
04-05-06, 11:13 PM
So I need to get that fixed first and foremost, because it's quite a leak.....