89 5.7 one side engine not firing
#1
89 5.7 one side engine not firing
i just switched my 5.7 from one trans am to another. now im having a problem the passenger side of the motor is not firing.It has spark from the cap to plug.the fuel injectors are getting voltage.The engine idles fine but just dosent have a lot of power.any suggestions???
#2
Member
iTrader: (2)
Join Date: Aug 2006
Location: Collegeville PA
Posts: 443
Likes: 0
Received 2 Likes
on
2 Posts
Car: 91 Z-28
Engine: 360TPI
Transmission: PA Racing 700r4
Axle/Gears: 3:73
Re: 89 5.7 one side engine not firing
If the engine is running and idling fine, why would you think half of it is mis-firing??? I'm sorry but that makes no sense to me... Check all your vacuum lines and make sure you didn't leave anything disconnected...
#3
Re: 89 5.7 one side engine not firing
i did notice there wasent hardly any vacum at the pvc valve.but when i take a plug wire off the cap on the passenger side the engine dosent change.but when i take a wire off the drivers side the engine loses power like it should
#4
Supreme Member
Join Date: Mar 2008
Location: CT
Posts: 1,549
Likes: 0
Received 1 Like
on
1 Post
Car: 86 T/A, 83 Z/28
Engine: 5.0 TPI, 350 2 X 4 bbl
Transmission: 4 speed auto, 5 speed manual
Axle/Gears: 3.23 posi, 3.73 std
Re: 89 5.7 one side engine not firing
Well if you truely have lost your passenger side i suspect a fuel injector issue. If your sure youve got power than you probably have a bad wire back to the ECM or the ECM has failed. Use a noid light to see if the injectors on that side are firing.
#7
Supreme Member
Join Date: Mar 2008
Location: CT
Posts: 1,549
Likes: 0
Received 1 Like
on
1 Post
Car: 86 T/A, 83 Z/28
Engine: 5.0 TPI, 350 2 X 4 bbl
Transmission: 4 speed auto, 5 speed manual
Axle/Gears: 3.23 posi, 3.73 std
Re: 89 5.7 one side engine not firing
yea it does kinda matter the 305 injectors are 19 pound and the 350s are 24s i believe although it shouldn't cause this problem no.
Trending Topics
#10
Supreme Member
Join Date: Mar 2008
Location: CT
Posts: 1,549
Likes: 0
Received 1 Like
on
1 Post
Car: 86 T/A, 83 Z/28
Engine: 5.0 TPI, 350 2 X 4 bbl
Transmission: 4 speed auto, 5 speed manual
Axle/Gears: 3.23 posi, 3.73 std
Re: 89 5.7 one side engine not firing
Well it might be and it might not be. The problem with putting smaller injectors on is even if they max out with 100% duty cycle they may not be able to supply enough fuel. If that will happen i cant say for sure never tried it but it should atleast run well enough for u to decide for yourself how big of a deal it is.
#14
Supreme Member
Join Date: Mar 2008
Location: CT
Posts: 1,549
Likes: 0
Received 1 Like
on
1 Post
Car: 86 T/A, 83 Z/28
Engine: 5.0 TPI, 350 2 X 4 bbl
Transmission: 4 speed auto, 5 speed manual
Axle/Gears: 3.23 posi, 3.73 std
Re: 89 5.7 one side engine not firing
Well the way injectors work is like many electrical things the work when there is a complete circuit from +V to ground. In this case the 12V is supplied to the injectors and to control the injector the ground is switched on and off. This brief period of time when the injector is grounded is considered the "pulse" like a heart beat. The "injector pulse" is in this case would be in reference to the ECMs rapid grounding and un grounding of the injectors ground again like a heart.
#15
Moderator
Join Date: Jan 2000
Location: Mercedes Norte, Heredia, Costa Rica
Posts: 20,981
Likes: 0
Received 9 Likes
on
8 Posts
Car: 1984 Z28 Hardtop
Engine: 383 Carb
Transmission: 4L60
Axle/Gears: 3.54 Dana 44
Re: 89 5.7 one side engine not firing
It's the electrical pulse that actually fires the injectors. All the injectors on each side are wired in a chain. If an entire side fails, it's because of a problem in the wiring for that side, or because one of the two injector drivers in the ECM has failed.
#16
Supreme Member
Join Date: Mar 2008
Location: CT
Posts: 1,549
Likes: 0
Received 1 Like
on
1 Post
Car: 86 T/A, 83 Z/28
Engine: 5.0 TPI, 350 2 X 4 bbl
Transmission: 4 speed auto, 5 speed manual
Axle/Gears: 3.23 posi, 3.73 std
Re: 89 5.7 one side engine not firing
Also seeing as how you just replaced the injectors with used ones did you ever ohm them out? If you had a bad one it could be shorting out the whole bank. Usually there are other symptoms as well but just a thought.
#19
Supreme Member
Join Date: Mar 2008
Location: CT
Posts: 1,549
Likes: 0
Received 1 Like
on
1 Post
Car: 86 T/A, 83 Z/28
Engine: 5.0 TPI, 350 2 X 4 bbl
Transmission: 4 speed auto, 5 speed manual
Axle/Gears: 3.23 posi, 3.73 std
Re: 89 5.7 one side engine not firing
behind the dash on the passenger side. If you remove the plastic interior cover underneath the dash on that side and look up under the dash you wont be able to miss it.
#21
Re: 89 5.7 one side engine not firing
plug into injector connect and check for flashing light cranking or running....indicates injector driver/circuit integrity. i agree w/ rolling thunder probably shoted injector winding pulling whole bank down
#22
Member
iTrader: (4)
Join Date: Jan 2004
Location: henderson, nv
Posts: 130
Likes: 0
Received 0 Likes
on
0 Posts
Car: '86 TA 305 F, '89 GTA 8
Engine: F 305 TPI, 8 350 TPI
Transmission: 700 r4
Re: 89 5.7 one side engine not firing
350's had 22lb injectors.
I had similiar issue.
Turned out to be 3 clogged injectors on passenger side.
You need to verify with noid light, if inj. are getting power.
I got loaner set from Auto Zone.
Pull off Inj wire from Inj. then put Noid light onto wire.
Then start car and see if light flashes a pulse.
I had similiar issue.
Turned out to be 3 clogged injectors on passenger side.
You need to verify with noid light, if inj. are getting power.
I got loaner set from Auto Zone.
Pull off Inj wire from Inj. then put Noid light onto wire.
Then start car and see if light flashes a pulse.
#23
Member
iTrader: (2)
Join Date: Aug 2006
Location: Collegeville PA
Posts: 443
Likes: 0
Received 2 Likes
on
2 Posts
Car: 91 Z-28
Engine: 360TPI
Transmission: PA Racing 700r4
Axle/Gears: 3:73
Re: 89 5.7 one side engine not firing
Did you ever change your prom in the ECU when you did the engine swap??? The car would still run if you didnt, just not at its peak...
#24
Supreme Member
iTrader: (2)
Join Date: Mar 2002
Location: San Antonio TX
Posts: 2,516
Likes: 0
Received 3 Likes
on
3 Posts
Car: 1990 G92 IROC Z Miniram
Engine: 388cu 6.4 Liters
Transmission: G-Force T5
Axle/Gears: 3.73 Gears
Re: 89 5.7 one side engine not firing
First thing first. Make sure that all the ground wires are grounded in back of the engine. 3 on passenger side and 2 or 3 on driverside.
A stock L98 has 22lbs injectors.
Why did you change injectors anyway?
Did you swap the 350 into the car that had a 305 in it? If so, the you need to swap the chip.
Question, what years are the cars? 87-88 MAF, 89 MAF with VATS, 90-92 MAP with VATS. swapping ECMs or chips may not work depending on the years.
A stock L98 has 22lbs injectors.
Why did you change injectors anyway?
Did you swap the 350 into the car that had a 305 in it? If so, the you need to swap the chip.
Question, what years are the cars? 87-88 MAF, 89 MAF with VATS, 90-92 MAP with VATS. swapping ECMs or chips may not work depending on the years.
#25
Junior Member
Join Date: Aug 2010
Location: Tucson, Az
Posts: 91
Likes: 0
Received 0 Likes
on
0 Posts
Car: 1992 Trans Am Convertible
Engine: 305
Transmission: 5 Speed manual
Re: 89 5.7 one side engine not firing
I am having this problem with my 92 305, just wondering if you fixed this and what it was?
#26
Member
Join Date: May 2010
Location: Houston Area
Posts: 463
Likes: 0
Received 0 Likes
on
0 Posts
Car: 1989 IROC-Z
Engine: 355, 6.0 (LQ4) soon
Transmission: 700R4
Axle/Gears: Borg Warner 2.77 for now
Re: 89 5.7 one side engine not firing
Try checking the fuses, theres 2 fuses that are in the box. I don't know if each one does a seperate bank or not, try the easy stuff 1st.
#27
Junior Member
Join Date: Aug 2010
Location: Tucson, Az
Posts: 91
Likes: 0
Received 0 Likes
on
0 Posts
Car: 1992 Trans Am Convertible
Engine: 305
Transmission: 5 Speed manual
#28
Member
Join Date: May 2010
Location: Houston Area
Posts: 463
Likes: 0
Received 0 Likes
on
0 Posts
Car: 1989 IROC-Z
Engine: 355, 6.0 (LQ4) soon
Transmission: 700R4
Axle/Gears: Borg Warner 2.77 for now
Re: 89 5.7 one side engine not firing
I also noticed when I changed the plugs one time that the even bank plugs were black and the odd bank was almost white. I thought they weren't firing, did the usual checks and everything was working right, come to find out there was a piece of rubber blocking the crossover tube, this is on a HSR set-up using braided hose, but its something to check out. I've seen where fuel filters fall apart and clog little holes before so thats something to think about.
#30
Member
iTrader: (2)
Join Date: Nov 2013
Location: Freehold NJ
Posts: 297
Received 0 Likes
on
0 Posts
Car: 87 Iroc 5.7,67 SS Camaro,90 Formula
Engine: 355 AFR Superram LPE 219
Transmission: 700r4 3000 stall 4spd 5 spd
Axle/Gears: 3.27
Re: 89 5.7 one side engine not firing
did this ever get fixed and what was the problem?
Thread
Thread Starter
Forum
Replies
Last Post