QuestionHi Mr. Finston:
I read a couple of your respones and I am sure you can help me with my problems.
Problem #1:
I have a 91' Dodge Shadow America 2.0 liter engine. When I first start the car and drive the temperature gauge rises rapidly and pins itself at the highest possible temperature. Then a few seconds later (2 or 3 sec.) the needle on the gauge drops and reads normal. In addition, when I turn on the heat it does not blow as hot as it should.
Problem #2:
When I stop at a light or drive in heavy traffic the car idles very low, then when I think it may stall the engine revs (it surges). In other words, the car seems to prevent itself from stalling by raising idle and then letting it fall. This "surging" will continue until I drive with my foot on the accelerator. This only occures after driving the car for about a half an hour (the engine is hot/temperature gauge at normal temp).
Recent repairs:
1) I recently install new plugs, cap, and rotor
2) Replaced vacuum hoses near and around intake manifold, PVC? valve
3) Did not replace little check valve that connects to back of fule injector (auto part store did not have it)
a) This little plastic check valve, how do you know which way it must be installed? (one side blue other side clear).
4) New alternator
Last year:
new gas tank, 2 new gas filters, new computer
Had same problem before and after repairs.
Thank you for your time. I look forward to hearing from you soon.
Anthony
AnswerHi Anthony,
I suspect that you have either a 2.2 or 2.5L engine, not a 2.0L, correct? You can look on the underhood sticker to tell which one, it is listed in the upper corner of the sticker. In either case the problem with your temperature gauge and your heater is, I believe, due to air trapped in the thermostat housing and in the heater core. This probably happened when the system was last drained and refilled without doing it according to a very specific protocol. So I would recommend that you redo the job at least partially to remove the trapped air. You don't have to drain it all, just get it down to below the level of the thermostat housing which has a vent plug in the top of it which you can remove to inspect whether the fluid is out of the box where the thermostat is housed, between the 3 and 4th cylinder spark plugs.
There is a plug in the top of the thermostat
housing (8mm allen head) that has to be considered when you are
dealing with the cooling system or you will trap air in the housing or
the heater. Here is the way to do drain and refill:
Start the engine and put the heater control slider in the Heat
position (this opens the water line to the heater). (A/C should be off
of course)
Shut off the engine
Open the radiator drain valve and watch to see that the water drains
first from the coolant recovery bottle. Then remove the radiator cap
and let about another quart or so drain out. (You can collect the
coolant in a pan for reuse if you choose).
Then remove the plug from the top of the thermostat housing and let
the water drain out of that housing, use a flashlight to observe level
(you don't have to drain any further if you are just trying to remove
trapped air, otherwise complete draining).
Close the drain.
Start refilling thru the radiator cap opening
When the coolant level rises into the thermostat housing and up to the
top of the plug hole, stop filling and put in the plug (put some
never-seize compound on the plug threads).
Continue filling thru the radiator cap opening until radiator is full.
Put on radiator cap.
Fill the coolant recovery bottle to the "max" line on the bottle.
In theory you will have now a air free cooling system. At least if
there is any trapped air it will work its way out more quickly if you
follow this procedure exactly. This may lower your operating
temperature and also eliminate the intial rapid rise of the gauge, and make the heater work properly.
On the idling problem, the engine does try to maintain its idle speed but it is having trouble doing so. There may be a coded fault message stored in the engine controller that will tell us what the controller believes is the cause of the problem:
Try using the ignition key: turn it "on-off-on-off-on" and leave it "on" (doing this quickly, no longer than 5 seconds). By "on" I mean just the normal position when the engine is running, not the cranking position. The 'check engine'light will remain on when you leave the key in the "on" position with the engine still not running. But then watch the 'check engine' light to begin flashing, then pause, flashing, pause, etc. Count the number of flashes before each pause and keep track of the numbers. Repeat the readout and verify the counts are correct. Then group them in pairs in the order that they came out, thus forming two digit numbers. You may notice that the pause is shorter between the digits of a given number, and longer between the numbers themselves. Then send me a 'follow-up' question telling me the results of your readout. By the way, 55 will be the last number (two groups of 5 flashes each) and that is the code for "end of readout".
I have the troubleshooting manual for several engines and we can look up the possibilities of what is wrong based upon what fault codes you show. When you write back tell me which engine you are driving.
There is also an essay on fault codes at the site:
http://www.allpar.com/fix/codes.html
which gives the meaning of the code numbers. But then you need to get specific info for what exactly might be the diagnostic tests or parts to replace to complete the repair.
It may also be the case the the egr valve is sticking ajar at idle rather than closing which will cause a faltering idle condition. I'll describe how to check and correct that if the fault codes don't appear to be helpful.
On the check valve, I don't believe there are any check valves in the fuel lines, but rather in the intake manifold-based vacuum lines that operate on negative air pressure. If you will describe where the hoses that come to either side of the valve come from/go to I can then know better how to advise you.
Roland
