Question about 1989 Toyota Pickup SR5

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My air fuel mixture screw at the MAF is supposed to be set and caped off by the factory... but the previous owner drilled out the cap and messed with it. which way do i turn it to make the truck run more rich?

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You are sure that this is your problem? First check this:

In here, more details about:
- TOYOTA-Electrical-and-Engine-Control-Systems-Manual (page 415 and next; in page 418, fig. 2-42 schematic about Idle Mixture screw adjust).

Adjust and regule the screw with the engine turn on.

Posted on Sep 03, 2009

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Posted on Jan 02, 2017

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I have a 2002 Blazer and it is hard to start we replaced fuel pump,fuel filter,crank sensor unit , oil line ,oil pressure Gage, did Tune -up Rotor button ,rotor cap wires spark plugs


by not running the fault codes first , you have missed the real faulty sensor that is causing the problem
nothing of what you replaced is linked to hard starting, like , ambient temp sensor ( used to report the air temp for the setting of the rich mixture need for starting)
baro sensor ( used for reporting the air density used to set the mixture setting
Maf/ Vaf sensors ( again used for mixture settings)
heated oxygen sensors ( used to adjust the gas composition by reporting the results to the ECM

May 06, 2017 | Cars & Trucks

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What is the factory setting for the fuel mixture screw on a toyota 1.8 litre 2Y engine


most fuel mixture screws are set initially by turning it all the way in and then backing out 21/2 turns. This should allow start and idle and final adjustment can be done to fine tune it. Check that the idle solenoid is working as it will shut off the idle circuit if it is not

Nov 01, 2014 | Cars & Trucks

2 Answers

My 94 Toyota Camry LE is running really rough and stalling.


The previous owner has screwed things up by changing the air intake and eliminating the air temp sensor. The car's computer depends on a series of sensors to determine what fuel mixture it should command, and now it can't do that properly.

When the car is cold, it knows from the coolant temp, and it sends plenty of fuel, but when hot it is getting the mixture wrong.

Restore the air intake to original, with the correct sensors, as it should run OK.

If not, then go looking for a vacuum leak or an air leak in the air intake hose and plenum somewhere.

Mar 05, 2017 | 1994 Toyota Camry

1 Answer

Set low idle dodge 6 cyl. 1981


If you are refering to curb idle, there should be a stopper on your throttle linkage that bumps onto a screw. turn the screw in or out to adjust idle. Often times a simple cleaning of that area will restore idle to its proper place. Some penetrating fluid and an old toothbrush to remove crud that has built up over the years around the throttle linkage. The idle mixture screws are plugged off by steel caps at the factory, part of the EPA's whizz bang solution to air pollution. They can be drilled out but care must be taken not to hit the screw heads. Hope this helps.

Nov 05, 2011 | 1981 Ford F 150

1 Answer

How do i get more power from my 1975 cadillac eldorado engine ,also shes running too lean so need the mixture screws adjusting,are these in or out also the air filter is new thanks


The air/fuel mixture screws are usually capped off and the adjustment might not be possible, but if the air/fuel mixture screws are exposed then turning them in will lean out the fuel mixture, and turning the air/fuel mixture screws out will en-rich the fuel mixture.

With the engine fully warmed up and at normal idle speed adjust the air/fuel mixture screws one at a time, and turn each air/fuel mixture screw in until the engine just begins to mis-fire, then back out the air/fuel mixture screw one and a half turns to two turns to achieve a smooth idle.

Be certain that the air and fuel filter(s) are not plugged up (there might be a fuel filter inside of the fuel pump as well as the fuel filter/stone at the fuel inlet to the carburetor) and keep in mind that the minimum octane requirement for that engine is 91 octane, and 92 octane is the average octane rating for the premium higher grade fuel, so a bottle of octane booster added to a full tank of fuel will greatly improve the way the engine idles and performs.

That engine should have an electronic HEI (High Energy Ignition) distributor with the large distributor cap and with the ignition coil inside of the top of the distributor cap, and keep the tune-up parts in good condition and replace them when they wear out. The tune parts would consist of the distributor cap, ignition rotor, spark plugs, spark plug wires, and the spark plugs should be gapped at .045 in.

For better performance from your El Dorado a 1 inch spacer under the carburetor will really help a lot if the hood clearance will allow it, and you will need to set the ignition timing to 10 degrees before top dead center, and adjust the accelerator pump on the carburetor for maximun pump efficiency so that as soon as the throttle is opened there is two healthy squirts of fuel from the accelerator pump, and they should squirt as soon as the throttle is opened, and if the throttle can be opened and the accelerator pump does not squirt fuel at the same time as the throttle is opened, then there will be a lag or stumble from the engine on take-off and a severe loss of engine performance. (The accelerator pump must pump fuel into the carburetor at the exact same time as the throttle is opened)

For better performance check the adjustment of the secondary throttle linkage, and let me know if you require assistance with any of the proceedures.

Be sure that the vacuum lines to the EGR valve are correctly routed and that the EGR valve is not operating at idle.

Also, that engine has a plastic timing gear that was used for the camshft timing gear, and I would seriously suggest that it is changed before trying to get any performance from that engine.

Other than those modifications, the engine would need a better camshaft and the catalytic converter removed to increase the performance of that engine.

Here are some images to help assist you.


Fuel Pump Filter:

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Rochester Carburetor Secondary Adjustment:

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Jul 10, 2010 | 1976 Cadillac Eldorado

1 Answer

Diagnostic warning light.....diagnostic done at kia dealer... no obvious but told it might be mixture problem as they had seen same before. Any ideas?


Hi.

Mixture problems can be caused by a number of factors and faults. A computer module, the PCM, determines the mixture using data from different sensors. Re-circulated gas is also used to determine the mixture.

If the problem only happened at cold, then check the MAF (mass air flow) and (IAT intake air temperature) sensor, and also have the vacuum system tested for leaks, hat can affect the mixture and make a difference, particularly when idling.


If the problem reported by the error code was mixture related, then a common cause is often the EGR valve, that regulates gas re-circulation. In this case the engine will be running rough at idle and when driving.


More problems that can return mixture related codes can concern:
Fuel injector problems (voltage , leaking injector, dirty injector). In that case more codes may be returned. Excessive or insufficient fuel pressure due to fuel lines, pump problem, or bad fuel pressure regulator. Gas recovery system, vacuum leaks and EGR valve. Air leaks from air intake mainfold (after sensor), or defective MAF, IAT. If sensors are faulty, then you will get more codes. If the car recently runt out of fuel, or if the fuel cap is defective you can also get an error related to mixture. Exhaust leaks before reaching the O2 sensors. Timing problem.


If the only problem was a mixture related problem, then wait to see if the code comes back. The engine warning light will turn on. In that case check for additional codes and report the code here.

Things are different if there are more codes. Also there are differences if the mixture is too rich or poor.


Regards.

Feb 04, 2010 | 2004 Kia Rio

2 Answers

99 boxter p1128 and p1130. replaced air mass sensor. no vaccum leaks


Remove the MAF sensor and carefully clean the sensing diodes with some solvent and a q-tip. These codes are commonly caused on this car by a dirty MAF that does not see the air entering the engine so fuel is not added by the computer. Then the computer sees that the mixture is lean by looking at the exhaust gas oxygen (sensor) content and it sets a code because it can't trim fuel delivery to the correct level as the MAF signal has more authority.

Jul 07, 2009 | 1999 Porsche Boxster

1 Answer

1980 Trans am original 4.9 engine. I messed up fuel and air screw


Screw each one in all they way, and then back them out two and a half times, then start it up and then ajust each until it runs smooth.

May 12, 2009 | 1979 Pontiac Firebird

2 Answers

22R Carb at high altitude


Yes, Colorado is much higher in altitude. Do to higher altitude the barometric pressure is less than sea level by a long shot. Lower barometric pressure mean that less air is entering your engine. Which in turns mean that your engine is now running richer than it was at a a lower altitude. So I recommend checking you engine timing, and adjusting your carbs air/fuel mixture. yes this means that you may need to rejet. but first there is a screw on your 22r's carb that you must adjust to lean the air mixture just right. I have had a stock 22r carbortor before and never had to rejet it. i probibly should have but it ran fine at sea level and all the way to about 10000 ft. after 10000 feet i had to lean the fuel mixture to even alow the engine to run. This screw that you must turn is hidden due to toyota not wanting you to tamper with it and burn your engine to the ground by running your engine to lean. it has a metal plug on the passenger side of the carb about the size of a pencil eraser. you must drill that out and then you can adjust the air fuel mixture. Clock wise is to lean the air fuel. and Counter clock wise is to richen the air fuel mixture.A good rule of thumb is to turn the air/fuel screw all the way clock wise and then back out about 2 and 1/2 turns. That is the factory adjustment. you may only need 2 turns out. Best of luck i hope you get it running perfect. Try this adjustment first then if it still runs rich then think about rejetting.

Here is a picture of what i am talking about.

#1 is the air/fuel mixture, #2 and #3 are cold and warm idle screws.
#4 is a A/c idle adjustment.

5ff308f.jpg

Sep 04, 2008 | 1987 Toyota Pickup

4 Answers

2005 mustang gt


replaced fuel filter yet ? have you checked fuel pressure and the fuel regulator

Sep 03, 2008 | 2005 Ford Mustang

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