Question about 1989 Chevrolet S-10 Blazer

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4.3 starts lean and sometime rich

Changed idle air plunger . when runnin rich at low rpm i unhook one injector and got it home , help

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  • 13 Answers

Sound like it could be a faulty cold start solenoid/relay. can't tell you what the resistance should be off hand but I would start with the cold start cicuit of your injection system.A good workshop manual will guide you as to the testing steps to follow.

Posted on Jan 19, 2013


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SOURCE: 1989 Chevy K5 Blazer uneven idle

I had this probelm, we found that the throttle body gasket was letting air in through a tiny pin hole, new gasket fixed it. You have rebuilt yours, maybe check the seal. Be sure and use a new gasket.

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SOURCE: 1990 chevy truck with 454 v8 idles too high

One thing is to leave the IAC adjustment alone, you have a vachum leake betweent the mais air flow sensor or a intake leak.

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SOURCE: 2000 Malibu will not idle

It sounds like either and O2 sensor (primary or bank one) or it may be a MAF sensor have the car checked at an auto zone parts store for stored computer trouble codes, this chech is free and should point you in the right direction instesd of just replacing parts you may not need.

Posted on Sep 21, 2009

Testimonial: "Thanks, I needed some place to start checking, the OBD is reporting zero codes.(forgot to put that in my question.)"

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SOURCE: 95 gm 5.7 stumbles bad at low rpm

have you tried to spay the base of throttle body & intake to see if throttle body base gasket is is good or sucking air

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SOURCE: fuel injectors??? when cold start up good high

Do you have any check engine lights on? If so, what codes? This could also be the signs of a bad coolant temp sensor thinking the engine is cold all of the time. Does it get to the normal operating temperature? On this model, do you see electrical connectors at fuel injectors or is it a big, bulky, black manifold? If it is the big manifold, the injector are inside and mechanical. This is where it gets expensive! The entire manifold must be removed in order to get to them and these have common failures. Let me know what you see and I will be happy to help pinpoint the repair.

Posted on Oct 26, 2010

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1 Answer

Tracker idle problem

sure, when unplugged the MAF , the PCM goes to limp home
and mimics the dead or missing MAF.
one reason, of many
is the AFR is lean, with maf present
then you remove MAF and the mimic goes horrid rich. (normal effect)
this huge rich hides the true cause of horrid lean.

see? 2 wrongs, make a right in this case.

its a 97, why are you scan too free.
connect it and see it fail. and why?
see all sensors. here. same engine, same all.

air leaks on this engine cause, lean.
a dirty mAF causes, lean. (clean it with carb spray 1foot away never close up)
clogged injectors cause, lean.
low fuel pressure causes lean.

if you put all the parts back and scan it
you'd see that.
you'd see the 0xysensor (Front) stuck lean B1S1. bank 1 sensor 1
ignore B1S2.

try a new oxysensor front. first. so the scan tool can see true facts.

on a good engine, the 02 swings at idle
if that fails , i jump over that like at tick on a hound dog.
finding car parked and idling hot AFR issues, is easy with any scan too.
the EFI must be in closed loop at idle, hot, MUST.
is it>?
does the maf read right at idle, ?
1.5-4.0 grams per second
or MAF output pin volts of. 1.7-2.0 volts
if the voltage is good ITS NOT THE MAF, its LEAN AFR.

if you gun the throttle
the maf goes higher.
3v or 20grams/second.

here is me driving see MAF hit 55 grams/ a second.
Hills. do that.
the more HP the more Grams /per second, until max engine torque is hit. and RPM max HP.

here is live data plot of a 96 MAF

the blue line is THROTTLE ANGLE> im driving aggressive as heck.

if the maf tests good, its not the MAF>
its easy to test.

Jun 17, 2014 | 1997 Geo Tracker 2 Door

1 Answer

How do I fix a code P0171 (too lean)?

code p0171 refers to system too lean bank1===causes intake/exhaust leak-AIR system--MAF/VAF sensors---fuel pressure/pump/regulator---injectors---HO2S. To understand the fuel mixture there is a direct ratio between the air and the fuel and it is 14:1 air to fuel . Anything either side is too rich or too lean. manifold leaks/vacuum hose leaks--Mas air flow sensor, Volume air flow sensor all tell the CPU what the ratio is so any unit not performing will throw out the ratio. If the fuel pressure is too low or high the injectors do not squirt properly at the rpm required

Nov 30, 2013 | 2000 Pontiac Grand Prix

1 Answer

1995 f-350 runs rich and won't idle?

If this is a gas engine, check for air leaks on the intake manifold and every vacuum line and switch you see. Use a pump spray water bottle and with the engine running, spray around seams and such.

A change in rpm or stalling will indicate the leak.

What is probably happening is the air leak is making the system run rich to balance the air/fuel ratio. This would make more fuel dump into the engine where it is not needed.

Another possibility is a loss of the signal from an O2 sensor. The O2 sensor sends a signal to the ECM to set the fuel demands and let the engine controls know that the fuel ratio is rich-normal-lean to adjust to optimum running condition.

Now if this is a Diesel, the hard to start condition would be due to an inoperative glowplug timer or worn glowplugs. If this is the mechanically injected model, the injector pump is timed to get the fuel into the cylinder either earlier or later to change the fuel ratio. Your diesel injector pump would need to be retimed. It will help across the board.

Please rate my info and let me know how you solved this.

Mar 03, 2013 | 1995 Ford F350

1 Answer

97 wrangler 2.5 running rich

this is a MAP , speed density EFI fueling system,,,,
not misfiring.
in no order,
  1. map reads, low all the time cause rich, (low means low vacuum that is real) the ECU sees that and adds huge fueling.
  2. fuel pressure way too high bad PFR.
  3. injector leaking i do an injector leakdown test, or balance test, like the book shows. (and has 3 causes)
  4. front 02 sensors struck lean , forced ECU to go RICH. Any exhaust (its air sucking in) leaks, cause the 02 to go nuts or stick at 0v all the time. and RICH will happen. unplug it , get better?
we use simple tools to find this.
is vacuum at 19 inches HG at idle.? hot? sealevel #s/
???? clean the map yet?

Sep 08, 2012 | 1997 Jeep Wrangler

3 Answers

Mil on fault code p2188 help please

2188 rich at idle,Ive seen the injector creat this fault by not having the ability to atomize fuel properly are you willy to put a bottle of fuel injector cleaner in the fuel tank. This vehicle is equipt with a air ratio when it fails system goes lean, try this first but dont wait too long rich condition can destroy the catalytic convertor

Apr 21, 2011 | Mini Cooper S Cars & Trucks

2 Answers

Rough idle under 1000 rpm

There are a lot of causes for this problem. Common ones are: Low fuel pressure, dirty injectors, valve seating issues, leaky ignition wires, or a sensor that is fooling the computer to either lean the engine out or make the mixture too rich. . If it is a high mileage car, have the tuneup done, and then check the fuel pressure. If low, check the filter, then change the pump if filter change doesn't do it. . If that doesn't do it, do a top-end cleaning (or have it done) to clean the throttle body, injectors, and valves. . If the problem started suddenly, look for pump pressure problems, then ignition. Run the engine codes for bad sensors. . If the problem slowly got worse over a few months, do a top-end cleaning.

Nov 25, 2009 | 2004 Buick LeSabre

2 Answers

Jaguar xj6 4.0 1990. showing fault code fuel 14, fail 14. what does this code mean ?

2 airflow sensor out of operating range 3 coolant temp sensor out of operating range 4 oxy sensor indicates full rich 5 throttle potentiometer/airflow sensor... (low throttle pot signal with high airflow sensor signal) 6 throttle pot/airflow sensor...... (high throttle pot signal with low airflow sensor signal) 7 throttle pot...idle fuel adjustment failure(idle speed??) 8 intake air temp or shorted circuit to sensor 11 Throttle pot at idle: Throttle pot idle trim out of normal range 12 Airflow meter: MAF signal out of range 14 Coolant thermistor: Resistance out of range or static during engine warm up 16 Air thermistor: Resistance out of range 17 Throttle pot: Out of range 18 Throttle pot/Airflow: Low throttle pot signal at high airflow 19 Throttle pot/Airflow: High throttle pot signal at low airflow 22 Fuel pump drive: ECU output to fuel pump relay 23 Fuel supply: Engine running too rich 24 Ignition Drive: ECU output to ignition Amp 26 Air leak: Engine running too lean 29 ECU self check 33 Injector Drive: ECU output to injectors 34 Injector: Looks for Injector dribble 37 EGR Drive: ECU output to EGR switching valve 39 EGR check sensor: EGR not working (normally pipe blocked) 44 Lambda (O2) sensor: Poor mixture control rich or weak (or misfire) 46 Idle speed Control valve: ECU output to Coil AB 47 Idle speed Control valve: ECU output to Coil CD 48 Idle Speed Control Valve: Stepper motor grossly out of position 66 Air pump: ECU output to air pump relay 68 Road speed sensor: Seen speed < 5km/h at high engine airflow 69 Drive/Neutral switch: Seen cranking in "D" or high airflow in "N" 89 Purge Valve drive: ECU output to purge valve
this is all I could find

Nov 09, 2009 | 1990 Jaguar XJ6

2 Answers

Hi, I have a 2006 Altima with 31,500 miles. Recently, the engine start shaking when car is Idle but I still feel the shake when driving or at red lights. My second problem is a weird loud (humming) noise...

You don't need to change the spark plugs since it has only 31.5 K. The plugs should last 60K. There is a an adjustment at the gas cable end at engine to increase the idle a little bit. You can increase rpm at idle to 600 RPM. Since your RPM at idle is low that why it is shaking at idle, red lights. Let me know it it is shaking at high speed ( 2500 RPM)

Sep 13, 2009 | 2006 Nissan Altima

1 Answer

I have 3 codes that showed up in the computer of my 1995 Ford Windstar

Here is the first half of the codes look till you find the one you have
111 System PASS.
112 ACT sensor circuit grounded.
113 ACT sensor circuit open.
114 ACT sensor is out of Self-Test.
116 ECT sensor is out of Self-Test.
117 ECT sensor circuit grounded.
118 ECT sensor circuit open.
121 TP sensor is out of Self-Test.
122 TP sensor input is less than Self-Test minimum.
123 TP sensor input is greater than Self-Test maximum.
124 TP sensor input voltage is greater than expected.
125 TP sensor input voltage is less than expected.
128 MAP vacuum hose damaged or disconnected.
129 Insufficient MAF input.
136 HEGO sensor circuit indicates system lean (Right HEGO).
137 HEGO sensor circuit indicates system rich (Right HEGO).
139 No HEGO switching (Front Side).
141 Fuel system indicates lean.
144 No HEGO switching (Left Side).
157 MAF sensor circuit open.
158 MAF sensor shorted to power.
159 MAF sensor is out of Self-Test.
167 Insufficient TP input change.
171 Lack of HEGO switching (Rear Side).
172 HEGO sensor circuit indicates lean. (Rear Side).
173 HEGO sensor circuit indicates rich. (Rear Side).
174 Check for diluted engine oil.
175 Lack of HEGO switching (Front Side).
176 HEGO sensor circuit indicates lean. (Front Side).
177 HEGO sensor circuit indicates rich. (Front Side).
178 Check for diluted engine oil.
179 Fuel system at part throttle lean adaptive limit, system rich (Rear Side).
181 Fuel system at part throttle rich adaptive limit, system lean (Rear Side).
182 Fuel system at idle lean adaptive limit, system rich (Rear Side).
183 Fuel system at idle rich adaptive limit, system lean (Rear Side).
184 MAF sensor input voltage is greater than expected, in range.
185 MAF sensor input voltage is less than expected, in range.
186 Closed loop injector pulse width longer than expected.
187 Closed loop injector pulse width shorter than expected.
188 Fuel system at part throttle lean adaptive limit, system rich (Front Side).
189 Fuel system at part throttle rich adaptive limit, system lean (Front Side).
193 Flexible Fuel sensor circuit failure.
211 PIP circuit failure.
212 Loss of tachometer/IDM input.
213 EEC SPOUT circuit open.
214 CID circuit failure.
215 PCM detected coil 1 primary circuit failure.
216 PCM detected coil 2 primary circuit failure.
217 PCM detected coil 3 primary circuit failure.
218 Loss of ignition diagnostic monitor signal-left side.
219 Spark timing defaulted to 10 degrees, spark output circuit open.
221 Spark timing error.
222 Loss of ignition diagnostic monitor signal-right side.
223 Loss of dual plug inhibit control.
224 PCM detected coil 1, 2, 3 or 4 primary circuit failure.
225 Knock not sensed during dynamic response test KOER.
226 Ignition diagnostic monitor signal not received.
232 PCM detected coil 1, 2, 3 or 4 primary circuit failure.
238 PCM detected coil 4 primary circuit failure.
241 Ignition control module to PCM ignition diagnostic monitor pulse width transmission error.
244 Cylinder Identification circuit fault present when cylinder balance test requested.
311 Secondary air injection system inoperative during KOER self-test (bank #1).
312 Secondary air injection system misdirected during KOER self-test.
313 Secondary air injection system not bypassed during KOER self-test.
314 Secondary air injection system inoperative during KOER self-test (bank #2)
326 PFE sensor circuit voltage lower than expected.
327 PFE sensor circuit voltage below Self-Test minimum.
328 Exhaust gas recirculation valve position sensor closed voltage lower than expected.
332 Insufficient EGR flow.
334 Exhaust gas recirculation valve position sensor closed voltage higher than expected.
335 PFE sensor circuit voltage out of Self-Test range.
336 PFE sensor circuit voltage higher than expected.
337 PFE sensor circuit voltage above Self-Test maximum.
338 Engine coolant temperature lower than expected (thermostat test).
339 Engine coolant temperature higher than expected (thermostat test).
341 Octane adjust service pin open.
381 Frequent A/C clutch cycling.
411 Cannot control RPM during KOER low RPM check.
412 Cannot control RPM during KOER high RPM check.
415 Idle Air Control system at maximum adaptive lower limit.
416 Idle Air Control system at upper adaptive learning limit.
452 Insufficient input from VSS.
453 Servo leaking down.
454 Servo leaking.
455 Insufficient RPM increase.
456 Insufficient RPM decrease.
457 Speed control command switch(s) circuit not functioning.
458 Speed control command switch(s) stuck/circuit grounded.
459 Speed control ground circuit open.

Jan 15, 2009 | 2001 Ford Windstar

2 Answers

87 Supra idles rough and dies out

check timing and set idle to 650rpm

Dec 15, 2008 | 1987 Toyota Supra

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