20 Most Recent 1990 GMC S-15 Jimmy Questions & Answers

Without knowing what car it is ...make. model and year this is a very vague question. A quick and dirty educated guess sounds like your timing has jumped ... if it's a timing belt, open the cover and check the timing marks ... or if it runs put on a timing light and look where the timing is ... sounds like it's firing after top dead center.

Check for a bad connection at the blower motor resistor these are well known for getting hot and melting the connector on the resistor.You can find it mounted on the heat duct on the passenger side with 2 screws.Make sure the ignition and fan switches are on when you perform the wiggle test on it.

you need a haynes repair manual you can buy at any auto parts stores

Without more information, I would recommend checking your vacuum lines for breaks, cracks(dryrot), etc. This problem can effect the air-fuel mixture of the engine; causing rough running and high fuel consumption.
One simple way to check, is to start engine and spray vacuum hose's with some type of spray. windex works good, so does wd-40,
The premise is, the rubber hoses are for vacuum, or sucking. If a hose is defective the spray will be **** thru the rubber and enter the air/fuel management system.
Using windex (a water based solution) will cause the engine rpm to decelerate, where as, using WD40 (a petroleum based solution) will increase engine rpm. safer to use windex (it's non-flamable).
With engine running spray the hose's, if you notice a change in rpm / engine sound, then replace that hose. I would recommend changing all rubber hose's as the truck is over 10 years old.
Another possible cause is bad spark plug wires, one way to see if there's a bad wire is to run engine in the dark and look for small spark(s) comming from the wires.
if this dosen;t help then we need to have more infomation to resolve your your problem

i would check the fuses, and also check the signal light [ blinker ] relay , normally they are under the instrument panel. " the fuse box, should be located under the instrument panel on the drivers side down toward the firewall area, not to far from brake pedal.

Seals. Try some transmission seal conditioner. Tranx is good. Mine took a couple of days to clear up.

Did you replace the fuel filiter there is a big problem with the fuel pumps on these vehicles how long ago did you replace it and you repair the wireing problem to the pump

U forgot to bleed the BRAKE MASTER! When ur bleeding the brakes, make sure ur engine is RUNNiNG. I f u haven't got any BLEEDiNG tools that sucks all the fluid in ur car, try Bleeding first the master, 2nd will be the front wheel brakes, and the REAR brakes! If everything FAiLS go to ur nearest garage and have them fix it! Drive slowly, using ur engine and hand brake! Hope that helps u out!

Get you one of those carburator/throttle body cleaner and spray the throttle. ( Where the gas pedal cable is connected on the engine, that is where the throttle is). You would have to remove the intake hoses attached to it then work that throttle manually as you spray cleaner to it. This should get rid of the gas pedal getting stucked and maybe the low idle problem as well.

Firing end of rotor under number one spark plug wire on distributor cap.

maybe I miss understood your request, but I do not recall ANY vacuum lines directly connected to the transmission or transfer case.

Vacuum is used by the ECM to determine load, so I included those here.

If you need something else please let me know ASAP

check all your fuses 1st especially the one for crank at the bottom of the fuse as you open the door drivers side dash panel on edge of dash

also check for fuel pressure in the back on driver side there should be a black cap much like that of a tire cap remove it and with the key in the on position depress it to see if any gasoline disburses {{Keep you eyes shielded or throw a towel over it

also when you turn the key do you hear a slight humming noise if not recheck all the fuses for being good and not blown if you do hear a humming noise this indicates your fuel pump is working ...also note even though it is working you may not be getting proper fuel pressure to the engine ..if it is off so much as a mere few lbs of pressure it will not start ..i would then suggest a fuel pressure test ...on another note check all the vacuum lines and wires ensuring they are not dry rotted or laying on the engine causing a short

check for spark pull a plug wire and use the end of a Phillips screwdriver but {make sure} YOU do not touch the metal end or you'll get a shock of yer life but hold the plastic/wood end of the screwdriver while inserted into the wire and hold near ground on the engine block / have someone turn the engine as you hold it about an inch or so away and see if an arc is present ..if so that's good if not then you have a firing issue again recheck the fuses all of them .

please let me know what you find out after checking these areas 1st it may be quite simple as the fuse ..i hope for you it is that easy

but check for the humming noise as well when you turn the key

Hello,
Sounds like you could have thrown a rod, or cracked a piston. Could even have spun a cam bearing if you used the old cam during a rebuild. What you can do is see if you have any oil pressure. If you have good oil pressure then your cam bearing is fine. After that, you'll have to drop the oil pan and see if anything has blown up inside the motor.
This has nothing to do with the sound, but its always good to check. Check to see if you have spark. Take a spark tester and crank the motor over and see if the tester shows any signs of spark. If you dont have spark, see if you getting any spark from the coil the same way you checked the plugs. If no spark there either you will need a new distributer.
If the motor wont spin over at all like its locked up, your motor may be blown. You will have chunks of metal in the oil in the oil pan once you drop it. Also, you can see signs of wear if the oil is a metallic looking substance. Hope this helps.
-Steve

Hello,
I would check for a spark leak through the coil wire to the dipstick as it happens comonly. If thats not the problem check the PU coil and module. There are some parts stores that can check the module as there is no self diagnostic for it. The Pick Up coil can be checked with an ohm meeter or mv test if you crank it over while testing it should produce a mv oscilating from positive to negative.

Roy

look up above your brake pedal and you'll see a brake switch - this controls your brake lights and it probably needs to be replaced

It would probably work, but I'm sure that it is not legal. It could cause a fire in an accident. I must recommend that you use the correct refrigerant.

If you do decide to use propane, post a comment and tell everyone how it worked.

Thanks,

Tim