1990 Chevy Suburban

1990 Chevy Suburban questions and answers

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Q: how can i turn my 1990 chevy suburban into a cleaner more efficient vehicle?
its a 1990 chevy suburban gasoline 1500 2x4 and im not going to use my AC

A: Why are you not going to use your A/C? You've forgotten about your 4/40 air conditioner. The term means "4 windows down at 40 mph". All vehicles are equipped with it- at least the 4-windowed versions. Keep in mind, though, that the 4/40 A/C 'still causes extra gas consumption' because of the extra drag that reduces your vehicle's velocity. *The first thing you can do for your vehicle has more than one selling point: not only does it increase fuel efficiency but you will not have to replace it in 1 million miles. The K&N air filter is designed for very high airflow and only needs to be cleaned every 50,000 miles give or take a few depending on the conditions where you live. Searching your part number based on the info you gave me, I found the K&N site. There you can determine what you specifically need: http://www.knfilters.com/air_filter/Chevrolet_V1500_Suburban.aspx *Carburetors are the most complex of auto parts located above the motor. Since rebuilding one is extensive and costly, I recommend first using a fuel cleaner additive like B-12 chemtool. Keep also a can of carb cleaner spray in the glove compartment for the winter. If the butterfly valve sticks, you can just spray a small portion on it, then use your fingers to work it open. LUCAS also puts out fuel additives as well and if you use lower-grade gasoline I highly recommend using that on each tankfill. http://www.lucasoil.com/products/display_products.sd?iid=26&catid=8&loc=show&headTitle=%20-%20Lucas%20Fuel%20Treatment LUCAS makes an octane booster but keep in mind it isn't street legal (yet is sold in most aftermarket stores, go figure). http://www.lucasoil.com/products/display_products.sd?iid=50&catid=8&loc=show&headTitle=%20-%20Lucas%20Octane%20Booster *Look on your speedometer. Is there a circle or a highlighting around a particular mile-per-hour number, like 55? If there is anything like that, this means that your vehicle is designed to move at the best possible fuel efficiency for that speed. I recommend driving at that range. (Just not in school zones; I don't care that the sign had a larger number it said 'km'). *There is an item called the Tornado Max Air Flow System that cools and increases the amount of air leading to the intake, and I used one one my vehicles for the past few years. You can go to this site: http://www.realtruck.com/air_management_system_tornado_air/R141249P1C1T.html#order ..and enter your vehicle's information where it says "To find products for your vehicle, select your Make, Model, and Year." then choose one of the two that fits your vehicle: either [TOR-kc-60-c] or [TOR-kc-75-c]. Then take that information to eBay and get one a lot cheaper. Now I want to inform you that I saw a review once from a site that debunks the fuel saver ideas, saying that while they basically found no reason to debunk the fuel saving potential of the Tornado, it could cause a shaky intake. I have never experienced a shaky intake. You may just consider adding a new air intake system to your vehicle period. *Purchase spark plugs that are above OEM specification. I suggest studying up on platinum, double platinum, and iridium plugs. As a former counterman, your OEM brandmaker is AC Delco. They will also make higher grade plugs, but other brands are trustworthy as well, like BOSCH, a German-made plug. When studying the different plugs for your particular vehicle, keep in mind to find out the gap information for each plug, if the plugs you intend to buy require gapping at all. *ACCEL is a high-performance brandname that sells spark plugs as well as 'spark plug wires'. I suggest studying up on the differences between 8mm and 9mm wires, etc. *Check the consistency of your transmission fluid. This is a closed system that doesn't require changing near as often as engine oil, but should be checked for grit (by placing a drop of fluid between the fingers and spreading out) and odor (looking for a burnt smell). Replace this fluid and the filter immediately if you sense any of this. I recommend Royal Purple for your lubricants. Keep in mind that the torque converter holds a ton of transmission fluid and you may require about 22 quarts approximately on the drain (which should only be done professionally as special machines are required if you do not have this machine or others like it). http://royalpurple.com/ Another site to check out gives you other options for cleanable and reusable filters: http://gopurepower.com/ Basically, any time you desire to increase efficiency in anything, just consider first changing the filter before doing anything else. And keep the part numbers in a notebook in your glove compartment so that on future maintenance you will have a lot more time with information available. *BE VERY CAUTIOUS when considering any oil additive that cleans your engine! A lot of times the gunk caked in there on vehicles over 100,000 miles is actually sustaining its performance. Using a bottle of cleaner that truly does what it says it does may cause your engine to run worse than it did before. LUCAS oil additive is the best and only additive I will recommed for you. A 20% mixture with your oil on the oil change (substituting 20% of your oil for the stabilizer) will cause more oil to rest up in between the gears making for a lot less wear on start-up, and start-up is the worst damage that can be done to an engine.

Q: How to check the TPS on a 1990 chevy suburban?
I asked this question last night and got some good answers. It has 3 wires in a rubber boot. I took my meter and put the ground lead on the battery and put the red lead to each teminal in the boot. They all read 1.00. The meter was set on the 200m setting on the Vdc mode. I checked the TPS again and seems to be good thru the resistance reading. It is new. I assume the volt reading is not what it ought to be. The problem is that when I crank the car the idle starts low and goes very high and then very low. It does this for a long time.

A: well first i will need to know if your suburben is a throttle body type fuel injection, or a multiport injection system, engine size might help me some, and do you get a "check engine" light at any time???? judging by the year it may even be carburated, let me know and ill try to help

Q: Can I put a 700R 1995 2wd Chevy transmission in a 1990 4wd Chevy suburban?
1990 Chevy is a,350 engine, a 1500 Suburban, The 1995 is a 1500 Silverado.

A: nope

Q: will a transmission from a 1990 chevy sububurban interchange with a 1998 chevy suburban?
Will a Transmission from a 1990 chevy suburban ''Automatic'' fit in to a 1998 chevy suburban ''Automatic''? They both have a 350 5.7l

A: Physically yes,they will fit.The one out of the 98 uses PWM(pulse width modulation) torque convertor,and is also electronically shifted.I'm not sure of the year crossover from the 700r4 to the 4l60e.I beleive you have a 4l60e,if that is the case then you should just need a different torque convertor.If one is 4wd and one is 2wd you will need to change tailshaft's.you might need to go to vacuum modulation.

Q: need to repace bearing in rear differential in 1990 chevy suburban 2wd how do you remove it?
I have a 1990 chevy suburban 2wd i need to replace the to large bearings that you can view after removing rear plate from rear differential i do not know how to remove how do you remove axles because i can see that one of the bearings has disintergrated because the large gear wiggles every thing else looks ok i tore it apart because it developed a howl I have the suburban aready on jacks under rear end , i have snap ring pliers but i do not know if it has c-clips or is the axlie bolted in from behind brakes by bolts i have not removes the tires? I have the suburban aready on jacks under rear end , i have snap ring pliers but i do not know if it has c-clips or is the axlie bolted in from behind brakes by bolts i have not removes the tires?

A: Is it the inner bearing or the outter bearing? If its a matter of oil leaking out its the outter bearing (the inner is for protecting the diff from dust etc) to replace the inner you need to have it pressed out with a machine and then pressed back in - if its the outter its a matter of pulling the arm apart and popping the bearing out then putting a new one in and putting it all back together again - if your not a mechanic take it to one as there is a lot of parts to pull apart and put back together again and you dont want to get it wrong and cause an accident remember you might also like to check the break shoes are they covered in oil from the leak (if there is one) they might need replacing. - Best you see a mechanic as there are so many areas you can stuff up and cause an accident on the roads.

Q: What other vehicle (yrs, makes, & models) will a 1990 Chevy Suburban 5.7L V8 eng & 4x4 Transmission fit into?


A: Any same series full size Chevy pick-up or Surburban. Look at the body style and frame dimensions.

Q: I have a 1990 chevy suburban that runs like crap and has a dead spot?
Master tech of 40 yrs when it just sits there idiling it even runs like crap and when you stomp on it has a dead spot. Even when you put the pedal to the floor it wont get up and go. We put on new cap plugs wires and a fuel filter and air filter what is wrong with it?

A: advance the timing to 8 before top dead center. loosen distributor and rotate counter clock wise until engine sounds like it has no load. if you have no timing light

Q: I have a 1990 chevy suburban that runs like crap?
When it is sitting and when you drive it it runs like crap. When you step on it it wants to die. It has no acceleration at all. The check engine light is not on we put on new cap, plugs, wires,rotor, fuel filter, and still that did not help. What is wrong with it?

A: sounds like cam is bad

Q: Fuel Pump Has No power in a 1990 Chevy Suburban 5.7L Fuel Injected (K) motor?
I just replaced fuel pump, sending unit, filter, relay, and fuel line. Took truck for a short drive then died. After 2 minutes truck restarted and continued home and let run. Died after 5 minutes. The relay has power, and put 12 volts to new pump and old, they work. I am absolutely positive that there is no fuse for the pump and can't figure out why. When using a scanner it asks me to test the G (bottom left) terminal of the diagnostic socket, but there is no wire lead in the socket. I am starting to think maybe the computer's bad but I'm not sure. There are no trouble codes either. Has anyone run into a similar problem or have a suggestion on what to do next? This problem seems to come and go beacuse this is the original complaint, but in the begining I had power to the pump and now I do not. Any help or suggestions would be greatly Appreciated. - Thanks If there is a fuse for the fuel pump it's not labled as it is in my 89 Camaro. My father who's been a mechanic for over 30 years also told me there was a fuse until he looked for himself. I've already tested the tan and white wire(fuel pump) And the female harness is new(came with sending unit). There are alot of inline fuses in the engine compartment. But how would you explain this only happeneing sometimes? A bad fuse wouldn't work at all.

A: Talor245 is wrong your computer does not control the pressure that comes out of the pump. the fuel pump puts out a constant pressure wich is the regulated by a vacuum pressure regulator when vacuum is high the regulator lowers the pressure going to the fuel rail the injectors are hooked to because the vehicle would be at a lower rpm or load an would not need the pressure at this time. When you step on the gas throttle the engine loses the vacuum it had and then the regulator redirects more of the pressure to the fuel rail so the truck can get as much fuel as possible out of the injectors. He is right that the computer controls how much fuel the vehicle get by pulsing the fuel injectors in millisecond incraments. The more fuel the vehicle needs the longer the pulse are and the higher the fuel pressure will be. Not all regulators work this exact way some work on back pressure and have pressure on either side of them. They will be set up that as long as x amoun of pressure is on the side of the fuel rail it will dump the excss fuel back in the fuel tank if the pressur drops below the desired pressure it will allow a valve to open up and allow more fuel to come in wich will increase the amount of fuel pressure because fuel will come in quicker than it leaves. The rest of the answers you recieved were all right on the money. If you cannot find this problem I would suggest taking a test light and hooking it up the positive wire back at the fuel pump connector and the other to the ground side of fuel pump connector while the pump is still plugged in (it has to be plugged in so the vehicle will run you should still be able to see the light light up though). Then I would take a different test light at the same time and hook it up to the control side of your relay that would be the side that your ECM engine control module would control. again hook it up just like the fuel pump not in line but parallel make sure where you hook it is before the relay and not after hook one wire directly to the wire going to the relay and the other to ground of the vehicle you may have to get jumper wires to do these test. After I hooked up these two test lights then I would hook another up to the controled side of my relay. I would hook it up one end to the power supply side of the relay and the other to the bodies ground. With these three lights hooked up you should be able to start the vehicle up and watch these lights and see wich light goes out first. If the light that is hooked up to the ecm goes out first you know that either the ecm is faulty or you have some kind of connection problem probably due to corrosion or a stretched out female terminal. If the other lights go out first you will know that there is a problem in the controlled side of the circuit and you will want to look at all the ful length of the wire it is connected to before and after the relay if the light goes off before the relay mostlikely it is a faulty problem from the power source to the relay if it goes off after the relay most like it is after the relay assuming that the relay control cicuit is fine. The reason It is important to know what light goes off first is once the vehicle has quit running the computer will shut off the fuel pump after two seconds of vehicles engine has stopped turning. Remember electricity always follows the path of least resistance If it can go directly to ground without going through the fuel pump or whatever it is supposed to be powering up then it will. It could be a wire that has rubbed through and every once in a wile it hits the frame and grouns out or it could be when the vehicle gets hot the resistance in one of the connectors for the wiring harness builds up resistance and uses up an excessive amount of electricity there and robs to much power to let the motor run.

Q: 1990 Chevy Suburban?
I want to convert my suburban's tailgate to side by side doors from another suburban. How much trouble is this other than the hinge placement and door fit ?

A: Sounds like you are going to need to do some welding here. Not 100 % sure on this.... Just love those side by side doors though.... Hope it works out for you... It is a very cool look on them...

Q: I have a 1990 Chevy suburban that runs like crap just when its idiling and has a dead spot when u stomp on it?


A: Is the check engine light on? If it is, could be the TPS (Throttle Position Sensor). It tells the PCM that you've just accelerated and along with the MAP sensor, enriches the fuel intake. Give us more details. Master tech 40 yrs.

Q: firing order for a 1990 chevy suburban 5.7literengine?


A: 18436572

Q: compatable transmission for 1990 chevy suburban 2500?
I need a transmission 4 my truck it has the 400 in it now. It is not 4x4 and has 350 ci 5.7. Are there any other transmissions that will work for this truck ? THanks. The truck has only 1,2,D,N,R,P Image Hosted by ImageShack.us
sorry was trying to post a picture of what I compared it to. The picture is how to identify your transmission. and mine looks like the model TH400. Thank you for your comments.

A: being a 3/4 ton it is possible to still come equiped with th400 if it is it should have a trans pan thats 4 or 5 inches deep these where issued in heavy duty applications that where ordered by aggencies like hiway departments,and military . these trannies are are heavier duty than the stadard 700r4.my buddy bought a 90 heavy 3/4 ton 4 wheel drive that come with the heavy th400. it really depends on the vehicles GVW rating . if at all possible i would try to find another th400 if not a th350 will work with minor modifactions you should try to find a th350 that is not what they call a lock up tranny(lock up torque converter) they are a little stronger make sure to massure the trans you have form front of the bell housing(were it bolts to the motor)to the end of the tail shaft because th350's have two different tail housing lengths if you miss this youll have to change or modifie the drive shaft youll also have to move the crossmember(it think) this why I'd try to stick with the th400 hope i at least cleared up a few issues

Q: unsteady idle on 1990 suburban?
i have a 1990 chevy suburban. when you first start it idles fine but when it gets warmed up alittle to were it idles down it dont have a steady idle goes up and sometimes fealling like it wants to stall out but dont.it seems like it aint runnin on all 8 cylinders but i did a tune up new cap rotor plugs and wires. but no help.this is my first fuel injected truck and already i aint liken it. please help

A: You have a vacuum leak. Probably a little hose came off or broke somewhere on the engine. If not that, then there is an air leak somewhere on the intake manifold. Maybe you have a bad sensor and the computer is running the engine based on that. Is the "Check Engine" light on? If so go to auto-parts store, they can read the code for you and recommend a fix.

Q: Suburban won't stay running!!!?
Here's a brain melter for all you chevy guys. I have a 1990 Chevy Suburban 5.7L 4wd that constantly blows the ECM B fuse. First thing I replaced was the fuel pump relay as it only happened when the ECM is connected and the fuel pump relay was connected. Cranks but still no go. Found a burnt wire and replaced the wire that connected to the manifold. Started once let it run in park then turned it off. Started it again a few minutes later and when I shifted into reverse the fuse blew and the engine died completely. Traced all the wires from the ECM to their various places, disconnected the fuel pump power and the fuse still blows. Now it won't start at all just cranks, any ideas?

A: since you had a burnt wire on it to start with id start looking for the cause of that first,as long as any wire touches metal anywhere on it,its going to blow fuses,find the cause of the burnt wire,and you,ll find the short in it,good luck on it.