'99 Suburban With Cranking And Electrical Issues

[cwh]

I just bought this '99 suburban 3/4 ton 7.4L for the wife so I could park my Dmax for the winter. Can't park it until the burb is reliable for the wife.

 

Here goes. If the rig sits for a while it takes 5-10 seconds cranking to fire off. If it sits for a short period of time it fires off no problem.

 

Second issue is the interior lights. Driving down the road today and the interior lights start flickering. Could hear a relay from under the dash chattering away. I tinkered with the door switches and now it doesn't flicker but doesn't turn off either. The dome override will shut the interior lights off so it won't drain the battery down. How does the interior light circuit work. Anyway, any help would be greatly appreciated.

 

Thanks in advance,

cwh

[atboley]

with the long cranking you probably have a bad fuel pump, it will lose pressure after sitting and take a long time to build up... the interior lights is probably a door jamb switch, check all of them and make sure none of them are broken in half and that they are all touching the doors when they are shut...

[cwh]

Thanks,

I have a full tank of fuel right now so it'll be a while before I drop the tank to replace the pump. The door switches should be no problem. Does the door switch complete the ground path for the interior light relay? A loose wire intermittantly shorting to ground could possibly be the problem.

Thanks again,

cwh

[fourwheelinfool]

Cranking?

 

You're SURE you have good batteries? You should be able to hear your fuel pump working (whirrrrr) when you turn the electricital on, just before you start the engine. Sounds a lot like a dieing batts to me.

 

Lights may be a bad relay, I don't think that they're that expensive. May also be a loose wire. I doubt the switches are bad unless they're grimey.

 

As for electrical system, you oughta get a Haynes manual.

 

My $0.02

[cwh]

Cranking?

 

You're SURE you have good batteries? You should be able to hear your fuel pump working (whirrrrr) when you turn the electricital on, just before you start the engine. Sounds a lot like a dieing batts to me.

 

Lights may be a bad relay, I don't think that they're that expensive. May also be a loose wire. I doubt the switches are bad unless they're grimey.

 

As for electrical system, you oughta get a Haynes manual.

 

My $0.02

 

This morning I turned the key on twice to let the fuel pump double prime the system and it fired right up. I'm pretty sure the battery is good. As for the door switches I'll probably try a relay first and then start to replace switches.

 

cwh

[fourwheelinfool]

Good to hear you've diagnosed the problem. I saw some fuel pumps on ebay for a great deal not too long ago. I wish I had bought a couple.

 

Good luck. Let us know how the tank drop and cleaning went.

[atboley]

those door jamb switch dont really go "bad", what happens is the plastic that sticks out to contact the door breaks in half

or just enough that they wont contact the door enough, so every time you turn or go over a bump the door will move just enough to make the switch open... enough you cant tell if theres anything wrong with switchs, try and sit inside with all the doors closed and push and shake each one of the doors(even the rear cargo doors), when the lights flicker then you know which door to look at... the only other thing is it could be a remote control door lock reciver, somtimes they short out inside and will turn the lights on and off... but it will be one of those 2 things

[cwh]

Thought I'd give an update and the rest of the story. Shorty after the good patrons of this forum added some replys the wife had the suburban die on her. Restarted it once, got to a safe place and then wouldn't restart. Had it towed to our mechanic and sure enough the fuel pump went out. When they were doing the work they notice an antifreeze leak. Bad intake manifold gasket. When they had the manifold off they noticed a flat lobe on the cam. After a new cam, lifters, and timing chain they found that #3 cylinder had no compression. The bearing spun and double stacked the bearing and put the piston into the bottom of the head. My mechanic found me a used engine with good compression and good oil pressure. So after 6k for all the work (had them do a few other necessary repairs) the suburban is running well. Very frustrating to say the least. I did give the previous owner a call and let them know how much I was into it. Lesson learned... carfax and have a mechanic check it out prior to sale. The carfax showed mileage discrepancy... I would have passed on it if I would have carfaxed it prior to purchasing. Anyway, I learned my lesson and hope this helps someone else.

 

Thanks,

 

cwh