I have an '86 Regal with the 307-4V and 52K original miles. It has recently started sputtering and backfiring under normal acceleration. I was told it could be a clogged up catalytic converter so I removed it (since there are no smog tests or inspections of any kind here in Kentucky) but that didn't help. I also took the belt off the smog pump. I replaced the spark plug wires but that didn't improve the situation either. I was told it could be a loose vacuum hose but I couldn't find any. On Tuesday I'm supposed to take it to a local garage to have them look at it but I'd like to try to fix the problem myself if possible. Does anyone have any suggestions as to what the problem could be? Thanks in advance....:beers2:
I wouldn't go there right away. I had that exact car and same engine. Believe it or not, that engine has a roller cam and lifters. I'm thinking you would have some serious valve train noise and that would get your attention. That engine has the full complement of pollution control and lots of vacuum hoses. I'd put a vacuum gauge on it, and see what it is pulling in vacuum, fully warm, in Park/Neutral. It should be 20". If it is less, I'd start looking for vacuum leaks. Could also be a stuck EGR valve. BTW, I really hated that engine. I called it the gutless Cutlas engine. It was the slowest V8, I have ever driven. My 98 Riviera would run circles around that car.
Thanks for the replies. I guess I'll buy a vacuum gauge tomorrow and see what happens. I'm not real impressed with this engine either. It might get 10 mpg going downhill with the wind behind me. I would have preferred the V6 with the 2 barrel. I'll check the vacuum tomorrow and let you know what happens. Also, where is the EGR valve? Thanks again.... :beer
My 86 Regal got great gas mileage. I managed 23 MPG on the open road, and about 18 MPG mixed driving. The EGR valve is at the back of the intake. Really, you can't miss it.
Larry, you're absolutely right - if they're roller lifters, there should be a lot more trouble happening if the cam or a lifter was at fault. Devon
isnt this what happens when the timing chain goes......maybe im way off base but i only had one go and it was similar symptons......also agree maybe cam,marty
Can I eliminate any or all of the smog crap since there are no smog tests or inspections here? Couldn't I just stick a screw into the lines going to the EGR valve? I've already removed the cat and taken the belt off the smog pump so is it still going to work anyway? :blast:
The EGR valve gets carboned up. It can be stuck open which would cause a rough idle, hesitation, sputtering, etc. You can unbolt it from the intake and clean it up. See if the valve moves freely. Test it with a vacuum pump.
On the 307 Olds motor, the EGR valve is on the drivers side (left) side of the intake. Check your ignition wires also. The 307 Olds motor is a gutless wonder, but there long lasting smooth running engines. Also, leave all the polution stuff alone, you'll likely make it run worse, just check all vacuum lines and replace as needed.
I agree with the others, you should get well over 20 MPG! I have a 88 Caddy that weighs a TON and it gets 23 MPG at 70 MPH and 20 MPG at 85 MPH. This is with an Olds 307 the same as yours pretty much. I was getting 12 MPG when I got the car and just did plugs wires, cap, rotor, intake gasket, air cleaner, set the timing, free flowing exhaust, nothing major.
I've seen more rigs develop problems from a worn cap and rotor than I can count. It is VERY often overlooked, as most folks go right to plugs and wires. Plugs and wires won't help a thing if the spark can't get out of the distributor. If the contacts look crusty, scrape the crust layer off with a screwdriver. Also check the tip of the rotor. If that helps, replace the cap and rotor. If not, you can rule it out at no cost.
X2. I've seen the cap melted in the area of the center contact. Get the best quality cap and rotor you can.
Is this the EGR valve in the middle of the photo? I removed the rubber hose and stuck a screw in it and took the car for a drive when the engine was cold. It ran a lot better until the engine warmed up and then it started backfiring again. Is that any kind of a hint?
No, that is a choke unloader for the carburetor. The EGR valve is larger, and is mounted directly to the intake manifold.
Is this it (see photo)? I took the hose off and stuck a screw in it but it still backfires when I accelerate. I drove it down to Advance Auto and the guy there said I should have an OBD-1 test run on it which takes 2.5 hours and costs $225. Is that a good idea? Do you have any other ideas what could be causing the backfiring problem?
Is your check engine light on? If not then the computer is not throwing any codes anyway. I am not even sure if your car has an OBD1 port or not.... Have a look at this video it shows where the port is located if you do have one. If you do have an OBD port you can use a paperclip to check your codes instead of paying them $225! No offense but I would have the car looked at by a mechanic, you seem a little new to this and we would hate to see you mess up the car worse than it is. Disconnecting and plugging things is not the way to trouble shoot an engine. http://www.youtube.com/watch?v=4cfKVal4gAo&feature=related
The check engine light is not on. I have an appointment with the local garage for Tuesday morning so I'll let you guys know that evening what happened. Thanks again for all the info.... :TU:
I bought 30 feet of vacuum hose this morning and spent a couple of hours replacing all of the old ones. I only had a foot and a half of it left when I was done so I guessed pretty well on the length. Unfortunately that was the only thing that I did right because it still backfired when I took it for a drive. I'm done messing around with it and will take it to the auto repair shop on Tuesday.... ou:
