1989 Z24 Motor Problem

[Demoman]

Hello I have a 89 Z24 with a 2.8 and a 5 speed.

The car doesnt want to rev over 3000 rpm
and i get no responce when the throttle is all the way open.
i cant get the rpms over 3000 when i am driving eather.

when driving if i put the pedal to the floor its like the motor locks up or something. With the the pedal to the floor i pressed on the clutch to try to get it to rev up and even with the clutch pressed the motor didnt rev up at all!

the clutch and tranny both work excellent.
The only way to drive it is with the pedal barely pressed and it climbs up real slow but not over 3000 rpm.




Any Help on this would be Greatly Apperatated.

Dave

[Three_Fingers]

Check fuel pressure between the fuel line and the throttle body, Pressure should be 9-13 psi.
28-42 psi for multi-port and sequential systems. There should be a schrader valve on the fuel rail for connecting a fuel pressure gauge on the SFI and MPFI motors (Exc. 1993-3 2.0L).

If pressure is OK, check O2 sensor and MAP sensor.

Sounds like you may have a fuel starvation problem due to either insufficient fuel flow or a sensor malfunction. Your "Check Engine" light on?

[Demoman]

I just put a new O2 senser in it and it never helped, where is the other sensor located?

The check engine light comes on only after about an hour of driving then goes off when i let off the gas.

Could you give me more details how to check the fuel pressure.





Dave

[C_Sephiroth]

Could possibly be a knock sensor

[Three_Fingers]

The MAP sensor is usually located on the side of the air cleaner on a small bracket thereabouts-or right nearby somewheres.
It's about the size of a matchbox toy car and it has three wires and a small-diameter vacuum line going to it.
either way it's right there near the intake plenum somewheres.
You're lucky...Your car is still OBD1, which means you can use a highly sophisticated, precision test instrument to troubleshoot your ECM! A "Paper clip".
Connect the paper clip (straightened out and bent in half to make a jumper wire) to the A and B terminals on the ALDL connector under the dash (left side near the steering column, usually, and turn the key to "ON" without starting the engine.
The check engine light will illuminate very briefly then go out.
It then will flash code 12 (Flash....flash..flash..........flash....flash..fl ash..........flash....flash..flash-three times, like that).
Code 12 means that the ECM is alive and has passed it's self-diagnostic routine.
Any other code after that is a trouble code.
Usually the first code you see is the problem (some problems cause multiple codes as the system tries to compensate for a screwed up sensor, etc...it's like dominoes).

Each code is repeated three times and you'll hear various engine controls cycling-your cooling fan may come on..It's just the ECM checkin' stuff out.


Oh, BTW...don't forget to remove the jumper after the test...it makes the engine run like crap..or in your case it might either improve or not run atall..but take it out anyways.
codes for '89 all except turbo are:
12-ECM OK and passed self-test
13-Oxygen sensor circuit (open circuit)
14-Coolant temp circuit (hi-temp indicated)
15-Coolant temp circuit (Low temp indicated)
21-TPS voltage high
22-TPS voltage low
23-Manifold Air Temp low
24-VSS circuit problem
25 MAT sensor high
32-Digital EGR circuit
33-MAP sensor voltage High(Low vacuum)
34-MAP sensor voltage low(High vacuum)
35-Idle Air Control circuit/valve problem
41-Cylinder Select Error (bad MemCal)
42-EST (spark timing) circuit problem
43-ESC (spark control) problem
44-O2 sensor lean exhaust indicated
45-O2 sensor rich exhaust indicated
54-Fuel pump circuit low voltage
51-MemCal error-bad MemCal
52-CalPak error-bad CalPack
53-System over-voltage
61-Degraded O2 sensor
62-Transaxle gear switch circuits (problem)
66-A/C refrigerant pressure low

If you don't have a schrader valve in your fuel system, you'll have to plumb a fuel pressure gauge inline between the fuel line and the throttle body/rail.

Take a fuel pressure reading with the key "ON"-engine off.
Then take another reading after you start the engine.
It should not drop more than a couple pounds.

[Demoman]

I did the ECM Check and the Fan kicked on like you said

also the Shift UP light turned on

I held it on for a good 60 seconds and this is what it did

( FLASH ..... FLASH FLASH. about a 3 second pause FLASH.....FLASH FLASH... pause again and this just repeated.)



Dave

[Demoman]

Also what does the schinder valve look like .. my 2.8 is a Multi Port
















Dave

[amac209]

plugged exhaust will do the same thing. can be checked with a pressure gage in the O2 sensor hole or with a vacuum gage. try unhooking it at the catalytic convertor and going for a burn.
good luck

[Demoman]

Ya the exhaust isnt plugged its pushin just fine..










dave

[Three_Fingers]

OK, You let it flash code 12 three times and then it repeated again?
If this is the case-then there are no trouble codes stored in the ECM-then the problem is either too intermittent or it's a straight mechanical problem that the computer can't "see". (It only knows what it's sensors tell it).

The Schrader valve is on the exposed end of the fuel rail in front-right in the "notch" in the intake plenum on the right as you're looking under the hood from the front.
It's a "tire stem valve" with a shiny metal cap on it that unscrews.
This is where you connect your fuel pressure gauge.

Youcan check rail pressure (regulator bad or good)-a failing fuel pump/restricted pump intake sock/pinched return line will also cause fuel demand problems.

Best thing if none of this helps-take it to a shop and have the tech hook up the scanner to it and drive it 'til the condition appears.
It only costs about an hour's labor.

[Demoman]

I took it too Midus and there computer told me that there wasnt no power to the knock sensor. so i am going to change it out where is it located.



dave

[dejaybrian]

so did you get your car fixed and was it the knock sensor, My car only revs to 4 grand and its an auto, 1997 Z24 2.4L... I got a sensor on order so well see what happens on Tuesday...

Let me know if you got yoru care fixed..