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Will not rev up

Tiny
GARY KENNETH GRASSER
  • MEMBER
  • 1991 MERCURY CAPRI
  • 1.6L
  • 4 CYL
  • 2WD
  • MANUAL
  • 121,123 MILES
My car started losing power, starts, idles, will not rev up. Replaced fuel filter, plugs, wires, rotor and cap. It acts like it is in limp mode.
Sunday, April 15th, 2018 AT 2:53 AM

14 Replies

Tiny
MIKE H R
  • MECHANIC
  • 3,094 POSTS
Check the fuel pump screen in the gas tank, with the stuff they put in gas nowadays they will clog up and let enough gas through to just keep the vehicle running at idle
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Tuesday, April 17th, 2018 AT 11:31 AM
Tiny
GARY KENNETH GRASSER
  • MEMBER
  • 10 POSTS
Thanks M.H. This is a car I am buying and I have three, lol. So I took fuel pump off Mr. Red and other stuff, idle and air controls, because other research calls for it. Thanks for your post. Any other thing I should look for besides house leaks?
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Saturday, April 21st, 2018 AT 10:08 AM
Tiny
STEVE W.
  • MECHANIC
  • 13,443 POSTS
What does it do when you open the throttle, just quit or does it rev to say 1,200 rpm's and just stay there and not rev higher? Does it act different in gear vs. Out of gear?
If it has been setting a while I would also test for a plugged exhaust system. If it is the turbo version check that the turbo is free. A locked turbocharger would choke the engine.
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Sunday, April 22nd, 2018 AT 10:22 AM
Tiny
GARY KENNETH GRASSER
  • MEMBER
  • 10 POSTS
Hey Steve, thanks for your time. At full throttle its at 1,000 rpm's. The guy I got it from may have played with idle control screw, help on that. I have replaced coil/air intake box, TPS, BPA, exhaust is hot! So separated catalytic converter and it seemed to gain rpm's, oxygen sensor and other sensors today.120,000 on this engine, no smoke and before BPA broke the engine sounded great at five, six grand. May call Priest for exorcism today.
Thanks again everyone, I have four now, and just found another in a field way out in the country. Saving them from extinction is now my life mission apparently, lol. Gary
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Monday, April 23rd, 2018 AT 9:03 AM
Tiny
GARY KENNETH GRASSER
  • MEMBER
  • 10 POSTS
It is a non turbo. Will not move in gear. Changed computer, no change. What is going on?
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Monday, April 23rd, 2018 AT 11:23 AM
Tiny
STEVE W.
  • MECHANIC
  • 13,443 POSTS
Hot exhaust = partly plugged or blocked converter. There is a simple test using a pressure gauge in an O2 sensor port to check for excessive back pressure. You pull the forward most sensor and put a pressure gauge (I use a fuel pressure / vacuum gauge) At idle you don't want to see anything over 1.5 psi then rev it up, the reading shouldn't show much over 3 psi at 2,000 rpm.

Then there are these tests.
https://www.2carpros.com/articles/how-to-test-a-catalytic-converter

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Monday, April 23rd, 2018 AT 1:11 PM
Tiny
GARY KENNETH GRASSER
  • MEMBER
  • 10 POSTS
Thanks again Steve, since I do not have a pressure gauge, I am switching out catalytic converter. I replaced sensor on firewall, and it revs now as high as I push it. Idle to that takes some five to ten seconds though, and idle is 500 and shuts off without giving it throttle. I suspect cat also, looking for sawzall as I type. The parts car I am using ran fine so it is just piece by piece, ugh! Nice day finally in Washington state though. I really appreciate your input and time. I love these cars and am going to be a master mechanic on them no matter what, lol. Keep you posted, first a cold beer.
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Monday, April 23rd, 2018 AT 1:46 PM
Tiny
GARY KENNETH GRASSER
  • MEMBER
  • 10 POSTS
Also, disconnected sensor on upper exhaust. No difference in idle?
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Monday, April 23rd, 2018 AT 1:48 PM
Tiny
GARY KENNETH GRASSER
  • MEMBER
  • 10 POSTS
Getting some backfire, not bad just there. Have not replaced distributor thingy that causes problems yet either though. Sorry for lack of terms. Switching back and forth to download manual is difficult. Is there a ballpark spot for idle screw? It does not affect idle anywhere I place it?
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Monday, April 23rd, 2018 AT 1:53 PM
Tiny
STEVE W.
  • MECHANIC
  • 13,443 POSTS
Idle speed is not really adjustable, the screw is basically there to prevent the throttle plate from fully closing. I would also check it good for vacuum leaks, even a small one after the throttle body will cause a lot of problems.
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Monday, April 23rd, 2018 AT 10:49 PM
Tiny
GARY KENNETH GRASSER
  • MEMBER
  • 10 POSTS
Replaced main engine relay, nothing. Put old relay in. No start but engine light now stays on when shut off. Did not make it to catalytic converter. Will check for leaks tomorrow, also look for 12ga. Rounds. Thanks Steve.
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Wednesday, April 25th, 2018 AT 1:02 AM
Tiny
STEVE W.
  • MECHANIC
  • 13,443 POSTS
Engine light on with the engine shut off, that is different, you did check to be sure the engine is still there? It might have seen the reference to the lead poisoning and skipped town.

With that issue I would possibly suspect the ECM is having issues. That could cause all the problems you are seeing.
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Wednesday, April 25th, 2018 AT 11:22 AM
Tiny
GARY KENNETH GRASSER
  • MEMBER
  • 10 POSTS
Hey Steve, switched out ECM from Mr. Blue, Mr. White is slowly getting every sensor and relay from blue, which ran great. Could only get 0.12v on TPS, checked Mr. White 2 and TPS said.03 and it runs like fast. Mr Reds TPS says a perfect. 07 and it beats Mr. White all day. Dug out welder, putting Mr. Blues catalytic converter on white tomorrow, thanks as always for the time and help, fuel pressure sensor? How many sensors do these have?
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Saturday, April 28th, 2018 AT 1:22 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 47,513 POSTS
It does not have a fuel pressure sensor on this car. Let us know what happens with Mr. White.
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Tuesday, May 1st, 2018 AT 11:11 AM

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