Engine light coming on for awhile and then going off for awhile.

[briand069]

Seeing as how the engine was replaced, many connections have been disturbed. I suppose it's possible you have other main harness connectors that are dirty/loose. I'm not sure where your PCM is, but check the connectors there as well. Also, one thing that comes to mind is a bad diode in an alternator that allows ac current to leak into the electrical system can cause odd error codes to appear. Try taking it to a parts store that does free electrical testing and see what happens. Otherwise, you'll have to bite the bullet and take it to a shop or dealer.

Brian

[robertbassin5]

I have a 1999 chevy truck with a rebuilt engine 4.3L V6. Engine light coming on for awhile and then going off for awhile. The engine has about 3000 miles on the rebuilt engine. But I keep getting codes P0174, P0171, and P0327. The problem that I am having is that the engine light will come on for awhile and then it will turn itself off for awhile. Can''''t figure out why. My cuz works at Firestone and he ran all the checks ( Smoke test, fuel pressure check). Cause there are no vacuum leaks, fuel pressure 59 to 60 psi.,MAF sensor new, and the O2 sensors were changed last December. Like I said all these problems started after the engine was replaced and the reason it was replaced cause it spun a rear main bearing. Right before the motor went out I was pulling a boat with cruise control on, when I was approaching an overpass the motor raved up like it does with cruise control on, but when I got to the top of the overpass the motor didn''t slow down like it should have so I had to stop it myself. An that''s when the motor spun a rear main bearing. The repair shop said that gas got into my oil and caused the oil to thin out due to the fuel regulator going out. Any ideas??? Will driving with the light on with these codes damage my motor?

[Scrapper]

did you reset comp. when it was doing this? and did you get another moter or rebuild that one? because if you rebuilt the old and never put new crank in or have it turned that can be a problem.you can go to HTTP://WWW.OBD.COM/PO325 see if they got the codes...

[Scrapper]

did you reset comp. when it was doing this? and did you get another moter or rebuild that one? because if you rebuilt the old and never put new crank in or have it turned that can be a problem.you can go to HTTP://WWW.OBD.COM/PO325 see if they got the codes...

[robertbassin5]

Well first of all the day the motor went out the engine light never came on at all. Now to answer your question when I first got my codes the computer has been reset maybe at least 5 times and for the motor the old one shot so we had to purchase a long block to put in the truck. I am not getting a code of P0325. So how can everything for the codes that I am getting work fine before the motor went out and now its telling me there something wrong with them. Oh yeah by the way I have a 2007 chevy truck with a 4.3L and I have already swaps some parts like (MAF sensor and the tubing from the air filter to the throttle body area) with no change in both trucks.

[MT-2500]

Originally Posted by robertbassin5

Well first of all the day the motor went out the engine light never came on at all. Now to answer your question when I first got my codes the computer has been reset maybe at least 5 times and for the motor the old one shot so we had to purchase a long block to put in the truck. I am not getting a code of P0325. So how can everything for the codes that I am getting work fine before the motor went out and now its telling me there something wrong with them. Oh yeah by the way I have a 2007 chevy truck with a 4.3L and I have already swaps some parts like (MAF sensor and the tubing from the air filter to the throttle body area) with no change in both trucks.

Your fuel pressure is low and you have lean running codes for bank 1 and bank 2.
Does that not tell you something?
Get some good repair info and go thrwe the repair flow charts for the codes.
A factory repair manual. Or
http://www.alldata.com/products/diy/index.html

MT

[j cAT]

I see your still not giving us much to work with....no o2 sensor readings no KS sensor readings,no vacuum readings just slightly low fuel pressure..60psi.


since you have no more money to get these readings and have a pro look at it other than free cuz service...perhaps trade in or just ignore these lights...

also earlier I suggested to check all the ground wires how many did you remove and clean....???

[ErickTR]

9 times out of 10 its a Oxygen sensor. It pops on and off when the gas to air mixture changes in side the exhaust tube. You could change it but its not really a problem unless it stays on. A bad one can effect your gas mileage.