Two more annoying problems

[mike561]

1st, im getting a check engine light only if i sit at idle or in park after about 2 min, when i get the car moving again it goes out, i jumped the terminal and looks like im getting a code 14 which i belive is coolant sensor detecting overheating? The temp guage reads normal however. I'll replace the temp sensor and see what it does.

2nd I notice when i step on the gas only from a complete stop the engine sounds like it shuts off for a split second (incorrect timing?). Im thinking of turning the idle up just a bit also, however i think it may be time for a tuneup soon, new plugs, wires, dist cap, and fuel filter.

any input on both would be great.

[Scrapper]

have you changed or checked fuel pump pressure? if it's good on fuel pump i think you better tune it up first because one sensor throws other sensors off as well. if you can take it to autozone when check engine light is on they can scan it on ther machine and 90% it's right.

[mike561]

Well now if i stomp on the gas a few times at a complete stop the engine will actually stall, but start right back up. i have to press on the gas slowly for a normal acceleration, it only does this in drive. ive read around and symptoms point to a fuel pump issue?

[mike561]

anyone????

[J-Ri]

Originally Posted by Scrapper

have you changed or checked fuel pump pressure?

[JFLO]

Originally Posted by mike561

well now if i stomp on the gas a few times at a complete stop the engine will actually stall, but start right back up. I have to press on the gas slowly for a normal acceleration, it only does this in drive. Ive read around and symptoms point to a fuel pump issue?

not an expert but sound like fuel pump pressure might be low and idk if your car has a throttle positonm sensor or not but if it does that could b it or fuel filter

[caffeineaholic]

I'm not an expert either, but I would think that it could be overheating while sitting for several reasons (other than fuel pump -- which I would think is not related?) My '85 caprice will overheat if it sits idling for too long.

I'm not sure but I think the brakes have something to do with the engine vacuum (I think the master cylinder is hooked up to it) I do not know how it works yet as I am still learning about cars but perhaps pushing on the breaks affects the amount of vacuum and can therefore cause it to stall if something is wrong...

Which car is this? Is this your '83 caprice? Also, I saw that you posted this topic last week, are you still having these issues?

-Good luck.

[mike561]

yeah this is on the 83, i checked the codes that im getting and it came up as a tps sensor and temp sensor problem. the coolant sensors are new, so im thinking next is to replace the tps sensor and see if that helps, than reset the ECM. if thats not it then i may replace the fuel pump after

[j cAT]

Originally Posted by caffeineaholic

I'm not an expert either, but I would think that it could be overheating while sitting for several reasons (other than fuel pump -- which I would think is not related?) My '85 caprice will overheat if it sits idling for too long.

I'm not sure but I think the brakes have something to do with the engine vacuum (I think the master cylinder is hooked up to it) I do not know how it works yet as I am still learning about cars but perhaps pushing on the breaks affects the amount of vacuum and can therefore cause it to stall if something is wrong...

Which car is this? Is this your '83 caprice? Also, I saw that you posted this topic last week, are you still having these issues?

-Good luck.

when idling and you step on the brake pedal then the engine surges idles erratic this is usually the brake booster...leaking...this is the large metal disk where the brake fluid res. is located,,you should also get a hard brake pedal feel...there is a large vac hose going to this brake booster and even a check valve to hold vac...in this booster...when engine is shut down so that you will get a good brake when engine stalls..

these engines require the many feet of vac line replaced,,this usually takes care of idle problems...

however most don't do this then ,,they screw with the carb adjustments and F up everything....

[mike561]

I know theres that direct vac line wit the filter that screws into the back of the carb, then goes to the booster. is this the line you are talking about that i should look to replace first or should i just replace the booster AND line?

[caffeineaholic]

I would think you should check all vacuum lines if you haven't recently. I've replaced almost all of mine at a very cheap price (Autozone) I usually buy several feet for numerous different sizes that I need.

It is possible to check your TPS sensor to see if it is functioning correctly but you need a multimeter. I learned that mine is not working correctly by testing it, also, I would suggest getting a Chilton or Haynes manual if you don't have one already; it's worth the price.

Furthermore, I would suggest getting a pressure/vacuum gauge from Autozone or some auto store so that you can read the engine vacuum and check to see if accessories are leaking, that the engine vacuum is at the correct level, and etc. (I think they are under 20$).

EDIT: Forgot to mention that you can also check fuel pressure if you get that gauge.

[Blue Bowtie]

Presuming this is on your "current" 1983, the fuel pump pressure is almost irrelevant. The car should have a mechanical fuel pump, E4ME (feedback) carburetor, electronic timing advance, and several TVS units for vacuum control.

As long as there is fuel in the bowl, fuel pressure really doesn't matter. If this only occurs at idle and it runs normally under load, the fuel pump is not the problem.

There is likely a lean condition on throttle tip-in, which can be due to a low fuel level in the bowl, poor accelerator pump operation, lean idle mixture, curb idle too low, incorrectly connected vacuum hoses on the TVS, AIR, and EVAP controls, and/or restriction in the idle circuits.

[j cAT]

Originally Posted by Blue Bowtie

Presuming this is on your "current" 1983, the fuel pump pressure is almost irrelevant. The car should have a mechanical fuel pump, E4ME (feedback) carburetor, electronic timing advance, and several TVS units for vacuum control.

As long as there is fuel in the bowl, fuel pressure really doesn't matter. If this only occurs at idle and it runs normally under load, the fuel pump is not the problem.

There is likely a lean condition on throttle tip-in, which can be due to a low fuel level in the bowl, poor accelerator pump operation, lean idle mixture, curb idle too low, incorrectly connected vacuum hoses on the TVS, AIR, and EVAP controls, and/or restriction in the idle circuits.

I have experienced a fuel pump of this vintage fail by slowly reducing pressure/capacity...the pump don't totally fail it slowly reduces the amount of fuel available..

the other problems may be a hole in the supply line to pump,worn pump arm/cam, plugged restricted inline/carb filter at connection to fuel line...

if there is vacuum leaks the engine can no longer suck the fuel out of the carb ....then the lean condition...

adjusting the carb without testing/insuring the vacuum lines are sound is not very smart...

one thing that would also be suspect if all the lines are not leaking would next be ,,,,the carb to intake gasket...

[mike561]

I did replace all the vac lines and caps on the carb, as for accesory lines such as the ones that come out of the intake manifold, those have not been replaced but look solid. Im gonna have a shop look at the carb adjustments and ill test the tps sensor.

[Blue Bowtie]

I have experienced a fuel pump of this vintage fail by slowly reducing pressure/capacity...the pump don't totally fail it slowly reduces the amount of fuel available..

I've seen the same thing, but it has usually manifested itself as a problem sustaining fuel at higher RPM and under load, and not at throttle tip-in. Even if the bowl level is half-full in the QuadraJet, a functioning accel pump will allow the initial shot for tip-in, then the engine falls on its face - Almost like premature opening of the secondaries from an incorrect pull-off or windup adjustment.

Not to hijack the thread, but I've also recently had three camshafts fail by losing lobes. One of them actually wore off the fuel pump lobe. I have NEVER seen that before, but it stands to reason now that auto engine oils no longer have EP additives. Older, flat tappet engines and those running mechanical fuel pumps need that protection, and probably should all be running truck oils just for that reason. BTW - All three of those have been Crane cams, so their billets are now suspect in my book. Since they have recently sold out to another company, the jury is still out, but I'll let everyone else experiment while I use someone else's cams. Howards and Comp are still looking pretty good.