1991 Chevy Cavalier oil pressure and idle

Tiny
BACKWORDZDOG
  • MEMBER
  • 1991 CHEVROLET CAVALIER
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 200,000 MILES
Hello I recently have had a problem with the oil pressure it goes up and down often its gettin worse the car revs up to almost 80kph without touching the gas sometimes and somtimes its normal the check engine light goes on sometimes too it died today waiting in a drive thru and didnt start easy but went to a few places and came home and it was fine can you please help me thanks alot I just picked up new plugs will this help? Does my car have a computer diagnostics system that needs to be reset?
Friday, September 19th, 2008 AT 3:09 PM

15 Replies

Tiny
MERLIN2021
  • MECHANIC
  • 17,250 POSTS
Cross these two terminals as shown, then turn the key on. Count the flashes, a 22 will flash as 2 flashes then a short pause, then 2 flashes, if more than one code is stored, the pause will be longer. The codes will display three times and end with 12. Write them down and post here. This connector is right under the middle of the dash...


https://www.2carpros.com/forum/automotive_pictures/62217_GM_DLC95_Older_20.jpg


Post the codes here.
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Friday, September 19th, 2008 AT 5:34 PM
Tiny
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I dont know how to cross the terminals is there any way of telling whats wrong even if its just a guess of whats likely wrong?
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Wednesday, October 22nd, 2008 AT 11:47 PM
Tiny
MERLIN2021
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If you can change plugs, you can run this test. But if it's been a while since your last tune up, Plugs filters and an oil change to start, without the codes, we are GUESSING.
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Thursday, October 23rd, 2008 AT 4:45 PM
Tiny
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I changed the plugs and wires a few weeks ago and added fuel treatment the car ran good for about 3days and now I have the same problem to the point where somtimes I have to hold the pedal to the floor and rev it hard to get it started
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Thursday, October 23rd, 2008 AT 7:37 PM
Tiny
MERLIN2021
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All you need is a paper clip, plug it into the terminal as shown in the picture, turn the key on, and the SES light will flash the codes. It's real easy, a caveman could do it! TPS voltage may be off, if you need a guess instead!
Image (Click to make bigger)
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Friday, October 24th, 2008 AT 5:12 PM
Tiny
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OK I did it I crossed the two terminals it flashed once then a short pause then flashed twice then a long pause then just kept repeating this
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Monday, October 27th, 2008 AT 6:18 PM
Tiny
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Is the tps the small one with two small bolts on the fire wall with the snap on connector also with a vacuum hose or is it the larger one that is to the right of the smaller one on the fire wall
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Monday, October 27th, 2008 AT 7:03 PM
Tiny
MERLIN2021
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TPS is on the side of your throttlebody, not the firewall. I thought you said the check engine light came on? A 12 code means nothing is wrong. If the oil and check engine lights just flickered as the car was about to stall they are not your problem, a vacuum leak, fuel delivery problem, or ignition problems will cause these symtoms. We now would enter testing with meters, are you up to this?
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Tuesday, October 28th, 2008 AT 2:02 PM
Tiny
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Yes I am up to it and the check engine light came on twice in the last week for about 30 seconds each time while driving it. Today I drove the car since I did that check and it seemed to run a little better I may just be hoping for the best. Last week I noiticed it start running different when I moved the heat control from def/floor to defrost or just on off I know that in the summer when id use the a/c the engine would drag but maybe there is something there thats not right? Anyway your the boss whats next?
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Tuesday, October 28th, 2008 AT 3:06 PM
Tiny
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You may have a vacuum leak, get a can of spray gumout, spray the vac lines and maniflod area, when the idle changes, youve found the leak! You want the engine running and spray on the outside but do direct the stream onto the hoses, if it is a vacuum leak, the engine idle will change speed, then you have detected a leak, repair the vacuum leak and see how it runs! If that doesnt do it, you may need a new idle air control valve, it's bolted to the throttlebody
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Tuesday, October 28th, 2008 AT 5:06 PM
Tiny
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Its still crappy it started all lumpy but the check engine light didnt come on its definitly a fuel problem
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Tuesday, October 28th, 2008 AT 7:08 PM
Tiny
MERLIN2021
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Test this way and post the pressure results. Toll can be rented at autozone for free, or puchased by clicking on the link at the bottom in my signature file.
https://www.2carpros.com/car_repair_video/test_fuel_injection_pressure.htm
Go here and checkout our video.
https://www.2carpros.com/affiliate/uid/merlin2021_1
Tools available here!
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Thursday, October 30th, 2008 AT 3:36 PM
Tiny
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I found the code its a one flash then 5 flashes so its 15 please help
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Tuesday, November 25th, 2008 AT 1:30 PM
Tiny
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I found the code its a 15 please help
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Tuesday, November 25th, 2008 AT 1:34 PM
Tiny
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I havent seen your last few posts I am going through it now im gonna check what you told me too
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Wednesday, November 26th, 2008 AT 12:46 AM

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