QuestionQUESTION: Hi Howard, I read all your other answers on the subject of starting but my problem is a little different. The old girl spins over and is very slow to fire. When she eventually fires she runs real rough with intermittent misses on one or two cylinders. However, once she warms up she runs like a clock. I put a new battery on her which seems a little weak so it's probably not a Deep Charge/cycle battery which may possibly have something to do with the prolonged cranking? The horrid missing when cold has got me beat. Any ideas of where to look? I appreciate your time and thank you in advance for any advice you may offer.
Kind regards
Michael Chorney
Murray River in South Australia
ANSWER: Hi Michael,
The need for a deep charge battery has the symptom of spinning fast enough but not fire at all.
You seem to have a different problem. Any time a car is brought in to me in a dealership with your problem I need to run some tests first.
Compression test first. (throttle open) You need to see from 130 to 170 PSI on all cylinders with little difference between cylinders. If it don't pass this test, it is no use proceeding.
Fire is second. Most people don't have a scope so you will need to run a rough test this way. Take a extra spark plug and widen the gap to about .040" and take each plug wire off of it's plug and put it on your test plug and lay it on the head so you can see the gap. (DO NOT REMOVE ALL OF THE PLUG WIRES FROM THE PLUGS AS YOU RUN THIS TEST)The reason is that you must never let the ignition try to fire a plug wire with it not attached as the spark can then jump to the primary of the ignition and do damage.
Have some one spin the engine just a few revs and watch the spark. You want to see a thick blue spark (not in sun light) If it does ok, check the ignition timing.
If it does not pass this test it is no use proceeding until it does.
Fuel is last. First test the cold start injector for a power and a ground (when the engine is cold and in the start position) If it gets power and has a ground in this condition remove the injector (two screws) and point it into a small glass jar and hit the starter and watch the spray. (take precautions for fire as you are spraying raw fuel)
The cold start valve (injector) is powered in the "Start" position and is grounded by the Thermal Time switch in the coolant rail (the large one usually at the front) The Thermal Time switch grounds the injector to operate it until either the coolant gets warm or the electric heater in the switch disconnects it.
A preliminary test of the cold start system is a simple test. When the engine is cold and you are sure it will not start easily, just spray some starter fluid into the intake when starting. if it starts just fine on starting fluid then you know to proceed with the cold start tests.
If all this is correct then you need to start testing the injectors. Most people don't have a test bench that you can view the spray pattern of each injector to see if they are good and a scope to view the voltage pattern of an injector so you may need to try other methods. By shorting out a spark plug wire as a "Cylinder Kill" test to locate which cylinders are not firing when cold. (DO NOT PULL A PLUG WIRE TO KILL TEST A CYLINDER)
Once you have identified the dead cylinder/s switch the injector from that cylinder/s to a known good cylinder to see if the problem stays on that cylinder or transfers to the good cylinder. This way you know you have a injector problem.
If you determine that you do have a injector problem seek out a shop who has an injector cleaning system to first try cleaning the injectors.
An injector that produces a stream like a garden hose does, may run ok hot but fails to atomize the fuel for cold running. This is usually caused by varnish that builds up on the pinal valve of the injector, not necessarily a bad injector. Injector cleaner added in the fuel tank may clean it off in time but is usually a long process and sometime don't do the job.
Howard
---------- FOLLOW-UP ----------
QUESTION: Howdy Howard. Thanks for the great advice! I did as you said and got a great result.
Please assist me with yet another little problem:
I had my steering rack exchanged and the new one is a little different. After a wheel alignment my steering wheel is now upside down as the steering column connection to the rack can only be put on in one position due to the through bolt indent on the rack. I need to take my st/wheel off and turn it 180 degrees but I don't know how to remove it. Advice please.
Kind regards
Michael Chorney
Murray River South Australia
AnswerRemove the center pad by removing the Phillips head screws in the back of the steering wheel then unscrew the large plastic nut in the center and then you will have access to nut on the shaft. However, I don't remember what the trip device for the turn signals looks like so before you do all of that check where the canceling is on the steering and if it is aligned with the steering wheel you will need to go down to the floor/fire wall "U" joint and remove it and rotate the wheel to get it in alignment or take it off at the rack and set it straight. As I remember the one at the floor was the easier one to do it. It has been many years since I did one.
Howard
