problem: acceleration difficulty/ local mechanic
I have a 74 2002. Stock engine and single carb.
Been running fine for a few years. Lately it begins to lose power at I accelerate for brief moments 1-2 seconds at a time.
Fuel filter? thoughts anyone?
Any good 02 mechanics in the NC triangle area?
Lots of possibilities...give more
specific information to help narrow it down. When was the last tune-up, and what was done? Any changes in gasoline? Changed fuel filter? Vacuum lines cracked or loose or vvac loss anywhere? How old is the carb and has it been serviced ever? Timing checked lately?
Re: Lots of possibilities...give more
Right: here is what I know:
I did adjust the timing about a year ago. Perhaps I should try that again. It idles fine.
I replaced the fuel filter about two years ago. Hoses are OK.
I don't think it is the original carb. Single barrel,down draft. dont remember size or make. K and N filter about two years ago.
I have replaced the points with electronic ignition.
I suspect I have a valve issue with a little blow by on decel. Cant remember the compression values when I changed the sparks about 2 years ago. All were about the same.
Did have a 4 speed tran placed. Was an automatic.
Hope that helps a bit. Thanks for your thoughts.
I would start with a regular tune-up,
but be sure to check or replace all vacumm hoses. When you say "loss of power," how would you describe it? Can you tell if it is fuel, ignition, clutch slippage, or a compression problem? If the car is parked and you rev the engine, can you hear the engine "stumble" at a particular rpm? It't still hard to tell what's wrong without more information (and without seeing it in person). Keep coming back, and someone here will help. It's not the most active forum, but it's a good one.
Re: I would start with a regular tune-up,
I will do as suggested. It really feels like you are lifting your foot off the gas for 1-2 seconds while acceleratig in 4th gear...
It happens about 5 or so times in a row then I usually slow down.
Cuts out in 4th gear at what rpm range?
I'm also wondering about any frayed, corroded, or loose wires to your coil or electronic ignition. Do you still have a condensor since you changed to the electronic ignition? So, keep the information coming. It's difficult to figure if this is "external" or "internal." Internally, it could be weak valve springs allowing a valve to float, losing compression. Does this happen if you accelerate slowly or quickly or always? Only in 4th gear? At what rpm range would you begin accelerating, and at what rpm does it loose power? Do you accelerate by pressing the pedal to the floor and waiting for the car to catch up, or do you generally press or your gas pedal in a progressive but even motion or "tromp it" hard? Try a steady but moderate rate of acceleration and see at what rpm it cuts out. Does power come back on after passing through a particular rpm range or peter out until the rpm drops again? Do the same with an aggressive rate of acceleration. Keep the information coming; there are many more skilled people on this forum than I, and someone will help you figure this out. We've all had this sort of thing happen, and it's a hit or miss topic. Could be a simple thing like a lose wire, or it could be mechanical...we might even get some debate going on what it could be.
Re: Cuts out in 4th gear at what rpm range?
I will do a little more testing this weekend and let you know if I can dig up any other details.
I will check all 4 gears. Unfortunately it was converted from an automatic and I dont have a tach in place yet. Is that difficult to do?
Obviously I am not a mechanic just like to fiddle around and try to solve these little mysteries.
Thanks for your effort!
No tach? I hadn't thought of that. (long post)
I didn't know the AT models had no tach. It would be simple to put one on. You can pick up an inexpensive one from most parts stores or from JEGS or Summit, or you can get extravagant. It will have wiring instructions, which will be pretty straightforward. I imagine the tach wires are already in the wiring loom. You can find them with a wiring diagram. You might want to complete the trans installation by finding the instrument panel with the tach so it will look stock, but there is another fun job. Do you have a decent shop manual? It sounds like you will become a much more experienced mechanic soon.
Just to get a relative rpm range, if you wind it out pretty well without trying to blow it up, say on the highway, you might be shifting at 4500 to 5000 rpm. In moderate driving you would probably shift somewhere around 3500 to 4000. If you baby it, you might be shifting at 2500-3000. It depends on your driving style, but power doesn't come on much below 2000 in higher gears, so you might be able to guess at your rpm as a relative figure, since you don't have a tach. You can get a simple clip-on tach for tuning and secure it well according to directions just to drive it around a bit. Anyway, my 76 cruised at about 3500 at 55-60 in 4th, I think, if that might help you guess a little. I seldom reved it over 5000 because I bought it from a "little old lady" literally, and it had not been driven much or very hard, and only had 85k, but I was taking it easy to sort of break it in to more demanding driving. I think my son, who was driving it everyday to work, and while he is careful about cars and is not a "hot rodder," might have pushed it a little too hard, and since it used a little oil to "lightly lubricate the exhaust," may have let it go low on oil and dislocated a rod, so, to end this run-on sentence, ended the life of the m10. We bought it in 2002 and drove it practically everyday for four years until it busted. I bought it with the contingency plan that if it broke I would swap a newer engine in, but I wasn't anxious to do that, because I'm up to my neck in other projects along with work. Right now I'm doing an m42 transplant over the next-as quickly as possible-as long as it takes me-this summer.
Oh, how about your AIR system? I forgot, because mine was disfunctional, and not required by law in Indiana, was subsequently bypassed and artfully removed.
Anyway, keep checking on particular conditions, but it would really help if you could find someone in your area who could see this in person. See if you can find a local club or someone on the forum. Most '02 owners are pretty cool and helpful folks. Otherwise, you will need to get a good mechanic or get a good manual, a timing light, compression guage, a voltmeter, and spend some time hangin' out bonding with your baby in your garage. At least the older ones are fairly simple. That's how most of us have learned. Beer helps. Have a great weekend! Good luck. Jim
Re: I had this problem.....
Lucky for me it was a race car, so the interrior was all out. What I found was a fuel delivery problem.
My engine is totally stock, with original mechanical fuel pump. There is a clear plastic (and now very old) tube that runs from the fuel tank through the interior under the passenger side carpet, against the side of the floor/side of car. This tube as it ages, can get hair line cracks in it. because I have no carpet in mine, I was able to see bubbles flowing through it upon acceleration.
Running a new fuel line (I went with braided SS covered) from tank to fuel pump did the trick.