20 Most Recent 1988 GMC C1500 - Page 8 Questions & Answers

Faulty fuel pump.Check your fuel pressure it should be 9-13 psi with engine running.

You could possibly have a fuel injector that is sticking open in that cylinder.The only way to check this is to install a fuel pressure gauge and turn the key to the on position and check the pressure.It should stay between 60 to 66 psi and hold for at least 10 minutes or more.If it goes down the you could have an injector leaking or leaking internally in the tank.I checked service bulletins and found one for the fuel pulsator in the tank getting ruptured from the high percentage of ethynol in the gas.The bulletin number is 66-63-09.The part number is 25175836.This pulsator is updated to handle the high percentages of ethynol.Hope this helps.Good luck.

4.3L, 5.0L, 5.7L, 6.5L DSL Turbo VIN F or 6.5L DSL Turbo VIN S ??????????

Finding free repair manuals on vehicles is almost imposssible. Even finding downloadable repair manuals are hard. I have found that ebay motors has used copies for not to bad a price or ordering them on cd from the dealers.

Some fault codes or check engine light turn on there?

The most common reason for stalling on this engines is the fuel pump. You should have around 45-55 psi fuel pressure. If you can set up the gauge so you can see it and drive the truck at the same time, watch the gauge and see if the pressure dropsout when the engine stalls. You my also want to check the grounds on the back of the heads on the engine, a loose ground can also cause the engine to stall and shutoff.

Are you check wires at/from coil harnesses? Brokes could cause this effect. Also, keep in mind that a CKP (Crankshaft Position) sensor can cause a stall and it may not set a code. Most of the time when a crank sensor goes bad, the engine will stall and not restart until the engine cools down. It could be a wiring issue, a bad connection or loose connection. Try running the engine and wiggling the wiring around the sensors and grounds to see if the engine stalls or studders.

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The assembly sequence in which you set the crank gear dot at 12 o'clock and the cam gear at 6 o'clock (for timing chain installation) and then rotate the crank 360 degrees to bring the IP drive gear on the front of the cam to 12 o'clock for installation of the IP driven gear at 6 o'clock? That is the so-called "connect the dots" process to properly time a 6.2 diesel. -------- Click this link below for more details:-- http://howtobyme.blogspot.com/2011/09/1989-gmc-diesel-62-timing-gear-diagram.html ---------- This will help.Thanks.Helpmech.

There should be 2 rubber blocks in the wire harness down by the starter. These are fusible links and one kills power to the truck, the other kills power to the engine. Cut them out and splice the wires back together, one at a time of course. Old age will do them in on occasion, moisture gets in there. Use some "heat shrink tube" to cover the splice. It works much better than tape. Hope this helps.

The short answer is yes. Rear ends are made in a variety of gear rarios depending on what you want to do with the truck. If you want to haul heavy stuff around most of the time then you are loking for a gear ratio in the area of 4.10 to 1. If you occasionally put a load in it and do a lot of empty driving you would want a ratio about 3.00 to 1 or lower. They will all affect mileage.

To find out what your truck has there should be a tag on it but it's probably rusted off by now so jack up the rear end and remove the cover. Have a drain pan to catch oil. Use something like White Out to mark a tooth and count the teeth on the big (crown) gear and do the same with the small(pinion) gear that drives it from the driveshaft. Divide the small number into the big one and that is your gear ratio. If you are looking for better mileage go to a smaller ration. The closer you get to 1:1 the better mileage you will get but you will lose grunt on take off. If you want help moving a loaded truck go away from 1:1. Hope this helps.

Can test in THIS LINK: Enter a VIN Number to begin HERE.

Official GM car and truck VIN decoder cards: http://service.gm.com/dealerworld/vincards/

Get complete VIN info on your GM car or truck that looks like this:



Hope helps.

Hi.

Below you get all the parts breakdown for GMC Sierra 1500, including steering column assembly:

1500 SIERRA

Here diagrams for all 1989 GMC trucks.

If you need to take apart the steering column you will also need wiring. below the color codes and wiring tips:

GMC SIERRA 1988-2005 VEHICLE WIRING

Regards.

Ginko

Brake light switch. If I remember correctly, the third brake light works off a seperate circuit from the other brake lights so part of the switch could be bad.

Keep in mind, the spark plug wires can be placed in any position (depending on the spark plug wire length) in relation to where the number 1 spark plug terminal is located. In other words, once you assign a port on the cap to number 1 cylinder the rest will follow the 1-8-4-3-6-5-7-2 firing order.

The knocking is a motor and gears that move the fresh air/recycle flap - it is up behind the dashboard behind the glovebox
the problem is that the gears wear and become misaligned
the flap then can not open fully, its doesnt reach its end stop which switches the motor off
so the motor keeps going the and the gears keep clicking over.---------- Remove the dash assembly then the glove box and inspect the blower motor and its gears.This will point towards the problem causing this noise.The blend door actuator motor needs to be inspected.That is what makes a thumping noise when the key is on or off.------- This will help.Thanks.Helpmech.

rt side from under truck all 350 is same