By Lena Thompson
Hello everyone! I am back.
I have been on hiatus since the beginning of the year, suffering from writer's block and other stuff (being single and loving it). The Engine Performance classes I wanted to teach in January were cancelled (low student count) and they had nothing available for me to teach throughout the summer (oh, bummer — not!). So, I've been busy enjoying my life, my summer (dancing on the patio at Como's), and not thinking about cars or trucks —√äexcept for when I am at my 40 hour-per-week job at one of the Big 3. Now, that I am back to teaching (Engine Performance I and II) my brain is ready to answer your pressing car/truck questions.
And for those of you who don't remember me, I've been in the auto business for over 20 years. I started as an auto technician, worked on a Technical Hotline, was a Field Service Engineer in Texas and later a Product Concern Analyst. Now, I manage a program for one vehicle line and am responsible for all serviceability issues. Basically, I write Technical Service Bulletins and work with Quality Engineers. I help identify issues the field cannot resolve and I ask them to release design fixes. Oh, the power! I love it!
So — let's get to the questions!
Dear Diesel Dyke,
I own a 1988 Olds 88 and the check engine light keeps coming on and going off. I really don't have the funds to get this checked out and wanted to know if it's something I should worry about. There is no driving concern. It starts and runs fine, but every now and then, this dang light comes on. What can I do? It has a lot of miles on it!
{ITAL Thanks,
Malika}
Dear Malika,
I would say it's probably OK to hold off on getting the vehicle fixed at this time. The fact that the light goes off is actually a good sign and tells me that some sensor is reading in and out of range. Most likely that sensor is the Oxygen Sensor. That sensor tells the computer how well the engine is running — too rich or too lean. When an engine runs too rich (too much fuel, not enough air) or too lean (too much air, not enough fuel), incomplete combustion occurs and this causes tailpipe emissions to go beyond "passable" limits and if we lived in a state that monitored tailpipe emissions, you would be forced to get it fixed right now. But, since we don√ït test here in Michigan, you can wait till you have the funds to get it checked out (if your global warming conscience is clear). Also, you might be able to take your vehicle to an Auto Parts Store. I hear that some offer free scan tool testing (pull codes). Have them retrieve the code and write me back in the future with that info and I can give you a more complete recommendation.
{ITAL Take care,
Diesel Dyke }
Dear Diesel Dyke,
I have a 1972 Gremlin with 69,546 miles on it. Her name is Linda. She has not been feeling well. She blows black smoke out of the tailpipe (really badÉenough to stain my garage floor) and the spark plugs are black, black, black (!) in every cylinder. She runs fine after I put new plugs in her, but then it starts to act up againÉmisses at idle and backfires when I accelerate. What do you think is wrong with her?
{ITAL Looking forward to your reply,
All Choked Up}
Dear All Choked Up,
First thing: the color of the smoke can tell us a lot about how an engine is performing. Basically, black smoke, means over fueling; blue smoke, means oil is burning; white smoke, means that coolant is burning. So, with the amount of black smoke you say is pouring out of your tailpipe, it tells me that the carburetor needs some serious adjusting. I suspect that the float is not adjusted properly and causing too much fuel to be dumped into the intake or the choke is stuck closed (the choke: chokes off the air to the intake manifold, so it runs rich during cold start). For both the float and the choke, there are specifications in the workshop manual. That spec should be checked ASAP. You can also check the choke yourself to rule that out, easily. If after the vehicle is at normal operating temperature, the choke is still closed, you have a problem with the setting or the bi-metallic winding. If the choke is open, then you have to remove the top half of the carburetor (six or eight screws) and check the float level drop (in hanging position) and the float level with the top of the carburetor inverted. Adjusting is done very easily by bending the float to the specified measurement. And by the way, these kinds of issues are exactly why we no longer use carburetors. They are susceptible to more mechanical issues and they donÕt meter the fuel very precisely. But I understand, Linda is probably a very cute little car and you'll want to get her ready for the Dream Cruise next year. She's probably worth saving!
{ITAL Ciao!
Diesel}
