Running in 4 cylinders!!!
#1
Senior Member
Thread Starter
iTrader: (2)
Join Date: May 2002
Location: Hollywood, FL
Posts: 504
Likes: 0
Received 0 Likes
on
0 Posts
Car: '88 Black GTA, T-tops, digital dash
Engine: 5.7 TPI w/custom chip
Transmission: 700R4
Axle/Gears: 9 bolt 327 posi
Running in 4 cylinders!!!
Hello, my 305 TPI is runing with only 2,4,6,8 cylinders working, the whole driver's side is not working. I do have ignition in the spark plugs but it runs very rough and when I unplug the injectors on that side, nothing happens for better or worse. When I unplup the spark plug wires one by one, there is spark but no change either. Is there some kind of "shared ground" on those 4 injectors? I have no SES light on or codes advisory. It's been parked but I start it once a week or so. I didn't start it for a couple of weeks 'cause of the hurricanes here in FL but it didn't get damaged by water or anything like that. A couple of days ago I started it and it worked fine, the whole 8 cylinders were working fine but it started to act up again. I started it a couple of hours ago and it is still in 4 cylinders. Please help me! Sorry for the long letter.
Thanks, David
Thanks, David
#2
Member
Join Date: Jan 2004
Location: LONG ISLAND , NY
Posts: 328
Likes: 0
Received 0 Likes
on
0 Posts
Car: 86 T/A
Engine: 2000 TPI 5.7L vortec L31
Transmission: 700R4
Re: Running in 4 cylinders!!!
Originally posted by Davidgou
Hello, my 305 TPI is runing with only 2,4,6,8 cylinders working, the whole driver's side is not working. I do have ignition in the spark plugs but it runs very rough and when I unplug the injectors on that side, nothing happens for better or worse. When I unplup the spark plug wires one by one, there is spark but no change either. Is there some kind of "shared ground" on those 4 injectors? I have no SES light on or codes advisory. It's been parked but I start it once a week or so. I didn't start it for a couple of weeks 'cause of the hurricanes here in FL but it didn't get damaged by water or anything like that. A couple of days ago I started it and it worked fine, the whole 8 cylinders were working fine but it started to act up again. I started it a couple of hours ago and it is still in 4 cylinders. Please help me! Sorry for the long letter.
Thanks, David
Hello, my 305 TPI is runing with only 2,4,6,8 cylinders working, the whole driver's side is not working. I do have ignition in the spark plugs but it runs very rough and when I unplug the injectors on that side, nothing happens for better or worse. When I unplup the spark plug wires one by one, there is spark but no change either. Is there some kind of "shared ground" on those 4 injectors? I have no SES light on or codes advisory. It's been parked but I start it once a week or so. I didn't start it for a couple of weeks 'cause of the hurricanes here in FL but it didn't get damaged by water or anything like that. A couple of days ago I started it and it worked fine, the whole 8 cylinders were working fine but it started to act up again. I started it a couple of hours ago and it is still in 4 cylinders. Please help me! Sorry for the long letter.
Thanks, David
#3
Senior Member
Thread Starter
iTrader: (2)
Join Date: May 2002
Location: Hollywood, FL
Posts: 504
Likes: 0
Received 0 Likes
on
0 Posts
Car: '88 Black GTA, T-tops, digital dash
Engine: 5.7 TPI w/custom chip
Transmission: 700R4
Axle/Gears: 9 bolt 327 posi
Thanks Vortec, could it be a bad conection in the computer?
#4
Senior Member
Join Date: Jun 2000
Location: Tuscaloosa, AL
Posts: 998
Likes: 0
Received 0 Likes
on
0 Posts
Car: 91Z, 91RS, '84 Jimmy
Engine: L98, 355, L98
Transmission: 700R, T56, 700R4
The injectors are all grounded through the ECM. Each bank has it's own fuse...check them both. INJ1 should be the fuse for the 1,3,5,7 bank and INJ2 should be for 2,4,6,8. If the fuses are both good, you probably have a wiring problem like a loose connection in the harness. Check for voltage at the dead injectors with the key on...if +12v is present then the power side wiring is good and you'll need to use a test light to check for a ground pulse signal from the ECM (engine must be running.)
#5
Senior Member
Join Date: Jun 2000
Location: Tuscaloosa, AL
Posts: 998
Likes: 0
Received 0 Likes
on
0 Posts
Car: 91Z, 91RS, '84 Jimmy
Engine: L98, 355, L98
Transmission: 700R, T56, 700R4
If the other bank is firing normally then it isn't a bad computer. There are 2 wires to drive the injectors (one for each bank,) but there's only one transistor in the ECM, and it runs all 8 injectors. The only way the ECM could be the problem is if it has a bent pin in the harness conenctor.
#6
Senior Member
Thread Starter
iTrader: (2)
Join Date: May 2002
Location: Hollywood, FL
Posts: 504
Likes: 0
Received 0 Likes
on
0 Posts
Car: '88 Black GTA, T-tops, digital dash
Engine: 5.7 TPI w/custom chip
Transmission: 700R4
Axle/Gears: 9 bolt 327 posi
Originally posted by TheGreatJ
The injectors are all grounded through the ECM. Each bank has it's own fuse...check them both. INJ1 should be the fuse for the 1,3,5,7 bank and INJ2 should be for 2,4,6,8. If the fuses are both good, you probably have a wiring problem like a loose connection in the harness. Check for voltage at the dead injectors with the key on...if +12v is present then the power side wiring is good and you'll need to use a test light to check for a ground pulse signal from the ECM (engine must be running.)
The injectors are all grounded through the ECM. Each bank has it's own fuse...check them both. INJ1 should be the fuse for the 1,3,5,7 bank and INJ2 should be for 2,4,6,8. If the fuses are both good, you probably have a wiring problem like a loose connection in the harness. Check for voltage at the dead injectors with the key on...if +12v is present then the power side wiring is good and you'll need to use a test light to check for a ground pulse signal from the ECM (engine must be running.)
Trending Topics
#8
Senior Member
Thread Starter
iTrader: (2)
Join Date: May 2002
Location: Hollywood, FL
Posts: 504
Likes: 0
Received 0 Likes
on
0 Posts
Car: '88 Black GTA, T-tops, digital dash
Engine: 5.7 TPI w/custom chip
Transmission: 700R4
Axle/Gears: 9 bolt 327 posi
Ok, I'll go and check those fuses now. I'll let you know in a few minutes. Thanks again.
#9
Senior Member
Thread Starter
iTrader: (2)
Join Date: May 2002
Location: Hollywood, FL
Posts: 504
Likes: 0
Received 0 Likes
on
0 Posts
Car: '88 Black GTA, T-tops, digital dash
Engine: 5.7 TPI w/custom chip
Transmission: 700R4
Axle/Gears: 9 bolt 327 posi
Thank you so much guys. It's fixed!!! I checked the fuses and they were both fine. I actually interchanged them and same thing. I took the #1 spark plug and it seemed fine. So I started thinking about the computer. So I tapped under the dash where the computer is located and it worked perfectly fine. I am guessing that moisture probably got a hold of the computer connections, but it's working fine now. I'll take the covers off one of these days and check and clean all connections there. Thanks again!
David
David
#10
Senior Member
Join Date: Jun 2000
Location: Tuscaloosa, AL
Posts: 998
Likes: 0
Received 0 Likes
on
0 Posts
Car: 91Z, 91RS, '84 Jimmy
Engine: L98, 355, L98
Transmission: 700R, T56, 700R4
When you go to check it, check the terminals in the wiring harness connector as well. If one of them is bent or backing out it can cause the same problem.
Thread
Thread Starter
Forum
Replies
Last Post
NinjaNife
Tech / General Engine
27
08-23-2015 11:49 AM