What's new
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.

need some guidence

BIG*RED

BIG*RED

1/2 ton status
Joined
Mar 14, 2003
Posts
1,094
Reaction score
0
I have a 1993 gmc suburban. It has been acting up lately and being that this is my first go around with fuel injection and obd I computers I am not sure how to proceed. It has the 5.7 with 4l60e.

ISSUE 1. while driving under any accleration be it gentle or hard it pings, once I get up to speed and maintain speed it no longer pings. but if i so much as give it just the slighest gas it will ping. I have replaced the spark plugs, the plug wires, the cap and rotor. I unhooked the brown with black stripe wire and checked the timming which is at 0. according to the sticker under the hood thats where it shoud be, and when I reconnect the wire the timing advances like it should.

ISSUE 2. every time I come to a stop in gear (stop light, stop sign), my idle drops to about 150-200 rpms, the oil guage drops to around 25, the volts drop to around 10. If I pop it into neutral the idle goes up to about 750-800, oil pressure goes to 35-40, volts go to 12-13.

anyone experience similar things and can give me some guidence? point me in a direction to start? I would appreciate it.

Thanks!
 
Sounds like you might be running way lean. If what you say is true about your timing, then yes way lean. Lean enough to pre-detonate. Yikes!

Check for vacuum leaks. Second thought, the timing could not be correct. There is just no way for it to be pinging with that much timing going on there. There has got to be more going on there than just a fuel issue.
 
If you want to waste a lot of time, effort, and money, by all means start replacing parts without doing any diagnostics.

If you want to fix the problem, pull the codes from the computer. It will most likely tell you what the issue is for $0.00 and less than five minutes of effort. Follow the link in my signature to the buyers guide, scroll down, and find the OBD document. You may have a faulty coolant temp sensor or O2 sensor, or any number of other easy to fix items.

If that yields no codes, then check for proper fuel injector operation and flow, as well as proper fuel pressure.
 
sheoldeblaze said:
I have a 1993 gmc suburban. It has been acting up lately and being that this is my first go around with fuel injection and obd I computers I am not sure how to proceed. It has the 5.7 with 4l60e.

ISSUE 1. while driving under any accleration be it gentle or hard it pings, once I get up to speed and maintain speed it no longer pings. but if i so much as give it just the slighest gas it will ping. I have replaced the spark plugs, the plug wires, the cap and rotor. I unhooked the brown with black stripe wire and checked the timming which is at 0. according to the sticker under the hood thats where it shoud be, and when I reconnect the wire the timing advances like it should.

ISSUE 2. every time I come to a stop in gear (stop light, stop sign), my idle drops to about 150-200 rpms, the oil guage drops to around 25, the volts drop to around 10. If I pop it into neutral the idle goes up to about 750-800, oil pressure goes to 35-40, volts go to 12-13.

anyone experience similar things and can give me some guidence? point me in a direction to start? I would appreciate it.

Thanks!
Click to expand...

How do you know what rpm it's running at? I have NEVER seen a V8 motor even run at 200rpms!!!! 600 is pushing it at a minimum......your engine should be running an idle at around 800-900 rpm.
 
mudbuggy said:
Jesse,

How much of your diagnostic can be used for a 350? Is it basically the same (with exception of the ci)?
Click to expand...
As mentioned, the engine and most likely all of the TBI system are nearly identical across the 1989-1994-ish years. Just check the engine light codes and go from there. Seriously, don't over think this, it's too simple - the computer can tell you what the problem is nearly 95% of the time. Get a piece of wire or a paperclip and jump the ALDL terminals and read the codes! :D
 
sounds like fuel pump,fuel pressure,or injection issues.changing out the fuel filter would help a lot.i bought mine barely running and changed the fuel filter and all is good now.a bunch of brown crud came out of the filter and lines so i took air and blew out the lines as well to clean the whole system.than ran some lucas injector cleaner and all was good.
 
I'll say it again, check the codes.

Sure, changing the fuel filter won't hurt anything, but it may be a waste of time and money if that's not the problem! In addition, it may mask the true symptoms of your issue.
 
Jessie James said:
I'll say it again, check the codes.

Sure, changing the fuel filter won't hurt anything, but it may be a waste of time and money if that's not the problem! In addition, it may mask the true symptoms of your issue.
Click to expand...
by all means,check for codes.i wasnt sayin anything against what you were sayin.i was just givin a cheap and easy thing to check.cost ya ten bucks and if anything,it should jump up your fuel pressure a lil bit.
 
You must log in or register to reply here.

Latest Posts

Top Bottom