Poor fuel mileage + backfiring + steering wheel slack
10-03-17, 03:51 AM
#1
Junior Member
Thread Starter
Join Date: Jan 2017
Location: Kauai, Hawaii
Posts: 8
Likes: 0
Received 0 Likes
on
0 Posts
Poor fuel mileage + backfiring + steering wheel slack
Aloha,
I have a 1985 GSL-SE on the island of Kauai. It was rebuilt about 8k miles ago and has stock internals. SR motorsports flywheel, exedy clutch, racing beat header and exhaust. Emissions were deleted but I put the BAC valve back on. It starts great, idles at 800 rpm with A/C on or off. Runs fantastic.
Issues: it backfires extremely loud after decel at low rpms and then apply gas again. Gunshot backfires. With the A/C on, it backfires less. I was hoping the when I put the BAC valve back it would help, but it didn't. When it backfires, the tourists duck and cover their heads like a fire drill .....
Poor fuel mileage: I've been getting a consistent 13 MPG for city driving. (shift at 4k-5k rpm, cruise at 3k rpm, redline once every few days) New fuel filter, fresh tune up, timing set correctly. Running rotella T6 ... idemitsu premix 1/2 oz per gallon. Not sure if OMP is working correctlly.
Steering wheel slack: replaced idler arm and put poly bushing in. Still have lots of play in the steering wheel, almost a couple inches either side. Looks like the someone tried to tighten the box before. Anything else i can do?
I have drag raced it twice. I want to post in the drag racing section, but no can because i dont' have enough posts. I ran a 16.08 best time so far 1/4 mile. Wanting to improve.
Thanks for reading
Been a rotary nut for many years.
Cheers
I have a 1985 GSL-SE on the island of Kauai. It was rebuilt about 8k miles ago and has stock internals. SR motorsports flywheel, exedy clutch, racing beat header and exhaust. Emissions were deleted but I put the BAC valve back on. It starts great, idles at 800 rpm with A/C on or off. Runs fantastic.
Issues: it backfires extremely loud after decel at low rpms and then apply gas again. Gunshot backfires. With the A/C on, it backfires less. I was hoping the when I put the BAC valve back it would help, but it didn't. When it backfires, the tourists duck and cover their heads like a fire drill .....
Poor fuel mileage: I've been getting a consistent 13 MPG for city driving. (shift at 4k-5k rpm, cruise at 3k rpm, redline once every few days) New fuel filter, fresh tune up, timing set correctly. Running rotella T6 ... idemitsu premix 1/2 oz per gallon. Not sure if OMP is working correctlly.
Steering wheel slack: replaced idler arm and put poly bushing in. Still have lots of play in the steering wheel, almost a couple inches either side. Looks like the someone tried to tighten the box before. Anything else i can do?
I have drag raced it twice. I want to post in the drag racing section, but no can because i dont' have enough posts. I ran a 16.08 best time so far 1/4 mile. Wanting to improve.
Thanks for reading
Been a rotary nut for many years.
Cheers
Last edited by beetz; 10-03-17 at 03:54 AM.
10-09-17, 04:06 PM
#5
Sucker for Punishment
When were your plugs replaced? If your OMP is working, you're mixing your fuel and you aren't redlining every time you get in the car then I wouldn't be surprised to find that the spark plugs are severely fouled. Too much oil will take out plugs really fast man. Take plugs out and hit them with a wire wheel and see if that clears up the issue. There aren't too many things that cause backfiring.
EDIT: I redline every time I get in my car and it never sees anything under 3k unless I'm sitting at a red. I also mix and my OMP if functioning properly. If I putt putt for let's say a whole oil change(5000miles) my plugs will be pretty nasty. Driving it hard keeps the plugs cleaner. Mind you my engine is running flawlessly and it's timed perfectly -zero backfiring.
EDIT: I redline every time I get in my car and it never sees anything under 3k unless I'm sitting at a red. I also mix and my OMP if functioning properly. If I putt putt for let's say a whole oil change(5000miles) my plugs will be pretty nasty. Driving it hard keeps the plugs cleaner. Mind you my engine is running flawlessly and it's timed perfectly -zero backfiring.
Last edited by Rotary Alkymist; 10-09-17 at 04:19 PM.
10-19-17, 05:33 PM
#6
Junior Member
Thread Starter
Join Date: Jan 2017
Location: Kauai, Hawaii
Posts: 8
Likes: 0
Received 0 Likes
on
0 Posts
Thanks for the reply rotary alkymist
The plugs were replaced 2500 miles ago, about 9 months ago. I'll have a look at them and do as you said.
I have a question about the O2 sensor. I thought replacing it might help with gas mileage. I have what looks to be a RB road race header. I can't seem to find the O2 sensor under the hood. Is it possible it is not installed because of the header? Where is the exact location of the sensor? Do I have to get underneath the car to see it?
The plugs were replaced 2500 miles ago, about 9 months ago. I'll have a look at them and do as you said.
I have a question about the O2 sensor. I thought replacing it might help with gas mileage. I have what looks to be a RB road race header. I can't seem to find the O2 sensor under the hood. Is it possible it is not installed because of the header? Where is the exact location of the sensor? Do I have to get underneath the car to see it?