My son just bought his first vehicle, 1994 jimmy. He finally got it started and lots of smoke coming out of exhaust. It drives good, but to reverve he has to floor the gas pedal. Help please

Possible head gasket but it would still run but overheat lots of smoke from exhaust or you have a leak from transmission or oil lines in radiator. If too much sludge is running in your engine jackets, may be seizing engine. Those are worse case scenarios. But always start with obvious protocol why it is not starting. Spark, charge, fuel, oxygen. You may have a simple fix with old contaminated antifreeze. Antifreeze needs to be replaced every two years.

go through it with a new tune up. when exhaust is under water it turns into a suction and sucks water into the motor fauling out lots of stuff

Hi,
is it a diesel or gas engine?
Usually excessive blue smoke on start up indicates oil is getting into the combustion chamber. It could be piston rings or valve seals.
Quick check, drive it within operating range and speed. Either use the rear view mirror or get someone to drive it and you follow in another vehicle. Accelerate, then take your foot of the accelerator. Blue smoke under acceleration indicates piston rings / pistons. Blue smoke on deceleration or the "over-run" indicates worn valve guides / seals.

White smoke can indicate coolant in the combustion chambers / leaking cyl head gskt, or incorrect fueling. If brake fluid gets into the combustion chamber it will generate a lot of white smoke from the exhaust. However, that would entail a leaking brake master cyl and a leaking brake booster.

Good luck.

Your head gasket is leaking and you'll have to take your car to your mechanic, the wihte smoke is coolant leaking into theengine cylinders, check you radiator it's problably low.

that your car runs really rich (more gas than it needs) then the excess comes out in a smoke from your exhaust. check to see if it spews out a lot of smoke next time you run it.

yes that has 4.0 liter and it hold 9 quarts with filter change use 20w50 thats what the factory calls for

If 1994 Suzuki equip with air condition then please check the A/C compressor clutch.

The compress clutch can lock up on a defect ai/c pump and cause the belt to smoke.

Please check for a fail a/c pump first and get back to me.

An fair A/C pump can be bypass via an a/c pump bypass pulley (as picture below)

Too late to check now... you've got a blown head gasket. When the gauge starts to give you any indication that something's not right you must shut it down or this kind of thing happens. Could have started as a bad water pump, hose etc. With low coolant from that (or anything else) continued operation will kill the whole thing!...Sorry!!

it seems that the engine blew. the rings, rod bearings, main bearing etc. Sorry but it sounds like that. Especially the smoking at the exhaust. take it back to the one who sold it to you.If possible.