Salvaged Silverado Trouble

ALWAYSTRUCKIN

MEMBER
CHEVROLET SILVERADO

Hello I salvaged a 2003 chevy silverado from a dealer. It was/is in excellent shape and only need aesthetic body work things done to it to repair it from a auto accident. Before buying it, the dealer guy hooked up a battery to it and put on a MAF sensor and the truck ran smoothly with all systems goo. So I bought the vehichle and towed it home (no plates). It has 103800 miles on it. The engine size is a 4.8 liter. I bought all aftermarket body parts for it, such as the hood, grill, etc. The ONLY mechanical things I need to do to it was hook up the mass air flow sensor, install a new driver side air bag and buy a new radiator. Before I connected the MAF sensor, I would turn the truck on and it would idle or run perfectly. If I put it in gear, it would cut out. The Dealer said it was because it needed a MAF to keep it going. So a friend of mine gave me a mass air flow sensor from a 2002 chevy tahoe with a engine size of 5.3 liter. I installed everything except the air bag, put all the front body pieced on the car and the MAF and new radiator. I went to start the truck and it starts perfect, but when I put it in gear, the truck loses power and cuts off. I would turn it on and try to switch the gear to neutral right quick, but it would turn off, even if I tried to rev it simultaneously. Some of my electrcial went hay wire immediately. When I step on the brakes, the two turn signals lights come on. If I have the truck Idling in park, it will cut off if I turn on the head lights switch. I could not even move the vehicle out of Park without is shutting down. Months later, last week, I let it idle a while and went to move it to get my boat out. It moved perfectly when I put it in drive and reverse. I was like wow. I drove it around the block a while. But it immediately loss power when I turned on the head lights switch also all my gauges went to zero. If I switch the lights back off, the truck powers back up. Also when I step on the brakes or push the horn (where the air bag should be) the turn signal lights come on. I do not now where all this is coming from. At the dealership, the truck drove around perfectly, but he didnt turn on the headlights because it was during the day. Is it because of the improper MAF sensor I installed. I thought it may be the Body control module so I uninstalled it from the dash board to replace it, but I haven't replaced it yet because I wanted to get a second opinion before thinking my project is a bust. I purchased this truck for $2,800 after finagling the dealer down from $3,900. I assumed I would have to only put maybe $1,000 into it, but if I have major trouble, I fear my cost saving investment may be going belly up.

I just want to know whats up. I dont even know where to begin with all my electrical going haywire and the truck loosing power.

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Saturday, July 7th, 2007 AT 7:57 AM

16 Replies

SERVICE WRITER

MECHANIC
9,123 POSTS

It's not a bust, worse case scenario is a shop troubleshoots it.

Not sure how much I can, but will try. Are any codes in the computer by chance?

It sounds like there is maybe wires not hooked up right or a wire harness corrossion problem, ground etc.

I would start by tracing the headlight wiring circuit and see what it uncovers. On the lower left of the radiator support there is a ground that ties in with the headlights, since you were there, check this first.

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Saturday, July 7th, 2007 AT 11:40 PM

ALWAYSTRUCKIN

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Hello Paul, I will retrace my steps tomorrow. I thought it was a headlight wire, so I checked them and I thought they all looked fine and I grounded the wire by the radiator to the frame.

As I do not have a code reader, for my year of car, 2003, can I turn my engine key on/off rapidly 3 times and have the error codes read digitally somewhere on my dash? Or something like that? I will have to find someone with a code reader.

Again, I will try to retrace my steps since this is the main area I was working in rebuilding the truck and hopefully the simpliest solution is the solution. I know a dealership is going to have field day with this so they are my last last last (never) option. I will give you more details of my findings in a later post.

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Sunday, July 8th, 2007 AT 1:46 AM

ALWAYSTRUCKIN

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Do you think this is the cause of the truck losing power when I switch on the headlights and the gauges zeroing out? Do you think this has anything to do with the improper MAF sensor?

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Sunday, July 8th, 2007 AT 1:53 AM

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The MAF should be put in that is correct. If it isn't determining the right air flow it very well can create a drivability problem.

Regardless I still think there is a wiring problem of some sort. I'm not the greatest electrical guy by any stretch, but I "think" that that gauge going down is a ground problem, maybe a chafed wire for example. Look at the diagrams I sent to you. Turning headlights on should shut down the truck unless something is being electrically interfered with as I see it.

I certainly didn't mean taking it to the dealer. There are very good independent shops out there and would be glad to help direct you to one in your area if you get to that point. Say it cost $300 to diagnosis, better than scrapping the project.

You'll need a code reader, no special tricks. I don't know that you'll have codes, but would expect something. I'll look at the dash cluster diagram and see if anything in common is there.

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Sunday, July 8th, 2007 AT 6:32 AM

ALWAYSTRUCKIN

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Where is the diagram you sent, I don't see it?

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Sunday, July 8th, 2007 AT 6:45 AM

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Gotta go work outside before it gets too hot. Check your email and your PM. Let me know.
Servicewriter43@hotmail. Com

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Sunday, July 8th, 2007 AT 7:10 AM

ALWAYSTRUCKIN

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12 POSTS

Okay Paul, have a good time at er. Talk to you later. FYI. When I was grounding the wire to the frame, I noticed that (long story why I did this, messing around with battery) I touched my indicator testor pen to the frame to make sure it was ground. I noticed the tester pen it up. I did it again and again. I said something must be touching the frame to make it hot/live. I tried to find any loose wire I could that was in contact with the frame. So again, I will retrace my steps today, but we may be getting close. If the ground wire is connect to a live frame, its not really ground now is it. I tried to overlook what I was seeing with my tester pen because I couldnt find anything, but I guess not. Later dude. I will get back at you.

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Sunday, July 8th, 2007 AT 7:30 AM

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Did you the the diagrams in your email?
Send me an email, so I know-got a few more that may help.

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Sunday, July 8th, 2007 AT 8:16 AM

ALWAYSTRUCKIN

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Yes, Paul, I got the diagram. Thank you. I am going to print it off and look at it today. I am waiting for my bestfriend to get back from church so we can get at it. He has more experience than me at this.

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Sunday, July 8th, 2007 AT 9:38 AM

ALWAYSTRUCKIN

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Hello Paul,

It took me a minute to study the schematics. I am learning as I go. This task looks very daunting. Okay, this is what I know, maybe you can lend some advise. The truck frame is not hot, it is grounded (good news). But the ground wire under the radiator on the left is also ground, without being connected to the frame. When I use a tester pen, I connect it to the red battery terminal and touched the ground wire, it lit up. (Note: When I have been driving the truck, the ground wire has not been attached to the frame.)

To try to see what side of the truck to start with, I cut the right side ground wire to see if both black wire were still reading negative, they did when I touched them. (Note: Before I cut the wire, the right side lights were acting up and/or wouldn't work. After I cut the wires, the lights on both sides came on normally. I cant explain this.)

So I do not know where to begin, left or right. I will begin on the left side though, tracing the ground wire backwards, because that was the side hit during the original accident. I tried to go up under the truck to see if any of the cords anywhere were noticeably pinched or crushed, but nothing stood out. Working left to right. I began just unwrapping and rewrapping the cords beginning on the left side of the truck. I called it due to darkness and the home run derby.

QUESTION #1: Is there anything I can get to read the cords that I can touch the wires and it leads me to the one that is touching he ground wire it is wrapped with.

QUESTION #2: How would you begin knowing the above. Do you think my approach is logical?

QUESTION #3: Why do you think the ground wire that connects to the frame is negative without being connected to the frame? It is suppose to be hot. Correct?

QUESTION #4: Do you agree the problem has to be somewhere in the headlight connections because when I turn the lights on the power to the truck cuts out. Then when I turn them back off, the power picks back up in the truck.

Any advise you can provide would be appreciated. Thank you

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Monday, July 9th, 2007 AT 9:23 PM

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Good Morning Tynetta,

Looks like we are both doing some learning on this one. Electrical isn't my strong point, but will try to help. So, don't take what I say as gospel.

I'm going to have to do a little digging myself to help.
As far as ground goes. The test light lit up for you because it completed a circuit.

Don't cut wires unless you are replacing them. When you reattach them, there are good connectors to use and ones that will come back to haunt you. I'll get back to you on that later. You can back probe connectors, that is use a tool ( I seen paper clips used for this) to get into the terminal connector and tocuh the wire to get a reading. There are special tools if you choose,

for example. I would be careful about what wires you touch to what as components can be damaged from this. I'd like to elaborate, but I would be saying more than I know.

"(Note: Before I cut the, the right side lights were acting up and/or wouldn't work. After I cut the wires, the lights on both sides came on normally. I cant explain this.) "
My thoughts are that there are wires touching or pinched, misrouted etc. On the lighting circuit and. Another circuit that that is causing the stalling because of the wiring problem. I "think" by removing the ground wires, causing the light to work right, means another circuit and the lighting circuit are sharing grounds, but when both circuits are put into service, such as by stepping on the brake or by turning on the lights, the circuit gets shorted.

With those grounds disconnected does the stalling still happen? There has to be a problem with the lighting circuit and another as I see it.

"QUESTION #3: Why do you think the ground wire that connects to the frame is negative without being connected to the frame? It is suppose to be hot. Correct? "

I "believe", the ground is just the return path for the electricity. You have 12.6 volts going into a component (hot), it goes into the component and then seeks ground. I'll ask a few questions at work today and see what I can't learn/teach :shock: :)

I'll get back tonite with what I learn.

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Tuesday, July 10th, 2007 AT 4:27 AM

ALWAYSTRUCKIN

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Morning back at you Paul,

I will not cut anymore wires. Very frustrated yesterday and really didnt know where to begin, but I will not do this anymore.

In regards to you question does the car still cut out after I cut the wire when I turn on the lights. I do not know. I had taken out the battery and some parts off the front. I was doing all my testing/work by having the battery sitting off to the side utilzing jumper cable. I tried to start it in that position, but truck requires to much power to start without battery connected.

Okay, have to rise and fly. I am a civil engineer and I use to hang around EEs in school (a many moon ago). Boy if I knew then what I know now, I would have married one just for this truck alone. Hahahahaha.

C you later.

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Tuesday, July 10th, 2007 AT 4:44 AM

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It looks like the part numbers are the same for the two different trucks regarding the MAF sensor.

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Tuesday, July 10th, 2007 AT 7:16 AM

ALWAYSTRUCKIN

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That is good news. The part numbers are the same. Thank you again for all your help. I am still blow anway, honestly, that someone that I have never met is thinking about "my" problem. Take care. I am looking at the website info you sent regarding the electric instrumentation.

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Tuesday, July 10th, 2007 AT 10:32 AM

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MECHANIC
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My pleasure :wink:
Glad you feel that way, sad summation for society today huh? By helping you, I learn too. In this industry no one knows all. Strangley I got more out of helping someone I don't know.....are you really a girl?? 8)
The website has given me a good tool to use as well.
I think using a digital volt meter is the best way to go about this. The battery should be hooked up. I think we should focus on finding how much power is getting to the switch and how much leaves the switch. As the voltage comes from the battery (12.6), it will lose a little as it goes along. every connector will eat up .1 v roughly the lights will eat up a major portion of the voltage or other components on the circuit. after the componet is a ground and the left over voltage returns back to the negative terminal of the battery through the body grounds.

Nice bike BTW, Kawasaki? I just bought an 82 yamaha maxim 1100. I hope to get it going by fall. :shock:

The blackish sludge is what was brake fluid. :cry:

I posted this in the moderator forum hoping someone with electrical skills might jump in and teach us both something. If not it will get solved one way or another.

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Tuesday, July 10th, 2007 AT 2:34 PM

ALWAYSTRUCKIN

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Hey Paul, GOOD NEWS.

I thought I had solved the problem, I can't say I applied to much smarts, just stumbled into it I thought? Remember when you asked "Does the truck still cut out since I cut the wire" and I didnt know since battery was out. Well, splice the cut wire back together. Unwrapped and re-wrapped all the wires I could get to without taking the 2 radiators back out. Still didnt see anything. So put the battery back in, grounded the ground wire under the core support and plugged back in all the lights to see what happened. The problem didn't occur anymore, I drove the truck for a while and she seemed fine. All the light work when engaged, just regular. MAF seemed fine. All systems go.

So my theory was, when I was putting the front end back on, I had to drill new offset holes to get some of those aftermarket parts on. I even had to do that for the core support. So I thought maybe the wire were so jammed in that corner that something was touching something to cutting power to the truck when engaging the lights.

I then put back in the windshield wiper fluid holder (whatever the name of that thing is) and tightened up that corner, but, all thing considered, I thought I had just bunched the wires in that corner to tight. That seems so simple, but everything was working properly.

So, driving, driving, driving on the road again, seeing place that I never been, . Truck shut down. I had to drive it back home in the dark.

I think I am going to sell this truck to a guy I work with. "Man's gotsta know his limitations".

Thanks for all your help. You are awesome. I still dont have enough points to post feedback on you, but you are awesome and anyone who reads this post should know that. You went above and beyond.

Later Paul

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Wednesday, July 11th, 2007 AT 9:29 PM