Wondering if anyone has any suggestions. The motor has done this since it has been built. When I get the boost up to about 26 lbs. it is giving me about 4 to 6 degrees of detonation. o2's are always a little fat at around 820's to 830's. Fuel pressure around 51 to 53 psi (line off.) I'm running a RA106 chip. I've tried coil packs, a hemco, different throttle body, mass air, even ran c-23 last time out. The car did this with 55lb. inj. and now with 72's. All my mods are in my sig. Any suggestions???? Thanks
Still have knock w/c16&c23??Help!
- Thread starter QuickSixx
- Start date
Dusty Bradford
Well-Known Member
- Joined
- May 24, 2001
Can you actually hear it detonating? With that much knock you should be able to hear it. I ran mine this past weekend and showed a 29 degree spike and 10 degrees all the way down the track but I never heard it. At what point of the run are you seeing the knock? It sounds false to me looking at the info.
Part way through 2nd gear and 3rd. Like I said it is usually between 4 and 6 degrees. You can't hear or feel a thing in the car. The car doesn't do it till I get up around 26psi. But when it starts showing detonation I'm afraid to keep turning the boost up. ?????? I think the car has much more in it but it won't happen till I can fix this. Thanks
Dusty Bradford
Well-Known Member
- Joined
- May 24, 2001
I can't see how it is real detonation if you can't hear it. I looked at everything and took a chance and unplugged my knock sensor. If I were you I would turn the boost up a little more and see if the knock got worse or if you could hear it. It sounds crazy but there is no easy way to find out what is causing it. As much fuel as your putting in it with that high of an octane and with Red's 106 which is probably around 19-21 degrees of timing there should be little chance of detonation even at 30 psi of boost. If it still knocks and you can hear it I would look at a faulty injector. You can still be rich on the 02's but have one cylinder lean and knocking.
With that combo have you ever run TSS in BG?
With that combo have you ever run TSS in BG?
- Joined
- May 28, 2001
KNOK??
I would be looking at the turn on point of the second pump.. assuming it's working
Fuel pressure at 53 base is ALOT, considering 2 pumps...Does FP rise as it should when going to 26psi?
IMO, turning the boost up to see if knok gets worse is an invitation to the DOTCC.. Better to turn it DOWN a bit and see if the knok goes away. Also, knok is NOT always audible.. don't be fooled there... Unplugging the sensor sometimes provides a fatal sense of security.. again DOTCC...
I would:
1. Turn the boost down until the knok is gone.
2. Turn the FP down to about 42 line off.
3. Ascertain that the 2nd pump is even working and at what PSI of boost it comes in.
4. Put the GA,[ A good one!] on the W/S and make a couple WOT blasts and check to be sure you have rising FP to match boost rise.
What do you have on the engine for an air cleaner??
What is injector duty cycle at the knok point??
Is the exhaust system dumping thru a dump pipe?
Plugs and plug gap??
Stock MAF?
HTH,
I would be looking at the turn on point of the second pump.. assuming it's working
Fuel pressure at 53 base is ALOT, considering 2 pumps...Does FP rise as it should when going to 26psi?
IMO, turning the boost up to see if knok gets worse is an invitation to the DOTCC.. Better to turn it DOWN a bit and see if the knok goes away. Also, knok is NOT always audible.. don't be fooled there...
Unplugging the sensor sometimes provides a fatal sense of security.. again DOTCC...I would:
1. Turn the boost down until the knok is gone.
2. Turn the FP down to about 42 line off.
3. Ascertain that the 2nd pump is even working and at what PSI of boost it comes in.
4. Put the GA,[ A good one!] on the W/S and make a couple WOT blasts and check to be sure you have rising FP to match boost rise.
What do you have on the engine for an air cleaner??
What is injector duty cycle at the knok point??
Is the exhaust system dumping thru a dump pipe?
Plugs and plug gap??
Stock MAF?
HTH,
Thanks for the replies guys. Dusty, I have never been to B.G. but I would like to if I can get the car to run right. Chuck, I checked to make sure the second pump was working with compressed air. It is working but I do not know when it is coming on during a run. What psi should it come on?? I also checked to make sure I'm getting voltage back to the pumps and I'm getting about 13.8 back there. ( It is hotwired.) How much should the fuel pressure rise during the pass? I figured the motor is so fat that fuel pumps would not be the problem. But I will check. Air cleaner is 4"K&N, not sure of duty cycle of inj. ( had direct scan on the car but had some problems ) , plugs are R42ts gapped at 35 and it does have stock mass air. Thanks
- Joined
- May 28, 2001
More ideas??
Q6, I wouldn't be surprized if you are not getting a rich nock..
The engine is making max cylinder at max torque, the rpm range most likey close to the points in the run you describe... Too much fuel could be the cause.. Use of C16 or better would, no doubt, be high enough octane for what you are doing, so the knok is most likely not octane related.
Another item worth mentioning could be MAF drop out...
I would most certainly get that DS working before I leaned on this engine again...DS is fast enough to catch the drop out...
As for when the second pump comes in.. You need to know this.. I've seen ALOT of cars in your ET and speed range run the number w/ a single 340.. mine included.
Are the two pumps powered w/ 2 power wires to a relay, or is there 1 wire feeding the two all the way to the relays??
There is no set boost level to trigger the 2nd pump.. each combo is on it's own. I would think not less than 15psi..
As for the FP .. The regulator MUST be boost referenced. One pound of FP rise for each pound of boost. In your case, w/ the base FP at 53#, then 26# of boost should be 79# of FP...That's alot.
GET the gauge on the windshield and find out what's going on..
I would put the plug gaps to .032
Make a WOT w/ DS and the gauge.
I would try 1 item at a time. start w/ a reduction in boost..that's safest!
Read the scan
make a decision.
go to next item.
read the scan.. You get the idea...
Learn to pull the plugs and look too!
I would find out where the 2nd pump comes on..use a regulator on shop air and a gauge...
HTH,
Q6, I wouldn't be surprized if you are not getting a rich nock..
The engine is making max cylinder at max torque, the rpm range most likey close to the points in the run you describe... Too much fuel could be the cause.. Use of C16 or better would, no doubt, be high enough octane for what you are doing, so the knok is most likely not octane related.
Another item worth mentioning could be MAF drop out...
I would most certainly get that DS working before I leaned on this engine again...DS is fast enough to catch the drop out...
As for when the second pump comes in.. You need to know this.. I've seen ALOT of cars in your ET and speed range run the number w/ a single 340.. mine included.
Are the two pumps powered w/ 2 power wires to a relay, or is there 1 wire feeding the two all the way to the relays??
There is no set boost level to trigger the 2nd pump.. each combo is on it's own. I would think not less than 15psi..
As for the FP .. The regulator MUST be boost referenced. One pound of FP rise for each pound of boost. In your case, w/ the base FP at 53#, then 26# of boost should be 79# of FP...That's alot.
GET the gauge on the windshield and find out what's going on..
I would put the plug gaps to .032
Make a WOT w/ DS and the gauge.
I would try 1 item at a time. start w/ a reduction in boost..that's safest!
Read the scan
make a decision.
go to next item.
read the scan.. You get the idea...
Learn to pull the plugs and look too!
I would find out where the 2nd pump comes on..use a regulator on shop air and a gauge...
HTH,
Dusty Bradford
Well-Known Member
- Joined
- May 24, 2001
I agree. It looks like knock from being so rich. He says it only starts knocking when it gets to 26 lbs though so it could be something else like MAF dropout as Chuck said.
The best thing is definately DS so you can see what's going on.
The best thing is definately DS so you can see what's going on.
Dusty Bradford
Well-Known Member
- Joined
- May 24, 2001
I think your pumps are just fine but it is good to know if you have the right fuel pressure at WOT.
I wouldn't recommend unplugging your knock sensor just yet. My situation was a little different since it seemed that the knock sensor was bad. It was spiking to 29 degrees for about 8 frames and then holding 10 degrees for the entire run.
The safest thing would be to drop the fuel pressure a little and see if anything changes. You could turn the boost down but it seems your very rich. With your combo at 26lbs. you are way over fueled which is why I personnaly would turn the boost up to better match the fuel and watch DS for changes, but that just me and my car. You have enough fuel with your setup and Red's chip for mid 10's easy and your not using it so turning the fuel down should help if the problem is rich knock.
MAF dropout is caused by flowing a lot more air than the stock MAF can read so it is resetting itself causing your MAF reading to drop very low for a very short period of time which can cause problems. But I would think Red's chip would have MAF lockup to prevent this.
I wouldn't recommend unplugging your knock sensor just yet. My situation was a little different since it seemed that the knock sensor was bad. It was spiking to 29 degrees for about 8 frames and then holding 10 degrees for the entire run.
The safest thing would be to drop the fuel pressure a little and see if anything changes. You could turn the boost down but it seems your very rich. With your combo at 26lbs. you are way over fueled which is why I personnaly would turn the boost up to better match the fuel and watch DS for changes, but that just me and my car. You have enough fuel with your setup and Red's chip for mid 10's easy and your not using it so turning the fuel down should help if the problem is rich knock.
MAF dropout is caused by flowing a lot more air than the stock MAF can read so it is resetting itself causing your MAF reading to drop very low for a very short period of time which can cause problems. But I would think Red's chip would have MAF lockup to prevent this.
