knock wont leave me alone

[GN1]

damn car keeps knocking at 8 p. of boost 15 deg of knock

here is what i have done so far i changed all the sensors except the cam sensor and the crankshaft sensor. ive also changed the coil pack and the ignition module. ive also changed spark plugs. fuel pressure is correct and so are all the other readings on my scanmaster. last night i changed plugs and tryed launching car knocked 15 deg. at 8 p. boost my o2 milivolts were 144 but my air/fuel ratio gauge read rich dont know which one to go by . or if i might have a cloged injector.

the only mods to the car are fuel pressure regulator, cold air kit, 340 walbro fuel pump and torque strap. IM READY TO SELL THIS CAR DRIVING ME CRAZY!!!!!!!!!!!!

 

[suicide six]

First and easiest,try car with tq strap disconnected.Check condition of knock sensor if this one wasnt changed,also check the tq on sensor.It may have been just cranked down by someone other than you.What condition or how old are plug wires?Knock could be chip related also.too much timing,poor fuel quality.What is your static pressure on regulator w/vac line off?Change fuel filter.Try some of these.

 

[GN1]

I Have Newfuel Filter Tried Torque Strap Off And Still The Same Knock The Fuel Pressure Is Coorect

 

[suicide six]

Knock Problem Check List
1. Start-up knock? Normal and usually caused by the starter engaging the flex plate. Usually sets off 1-3 lights.
2. Possible bad ECM or ESC module. Test with good working units.
3. Exhaust rattle – check the down pipe, tail pipes, and have engine tie down strap
4. Boost creep especially top of 1st gear on 1-2 shift.
5. Lean air/fuel mixture.
6. To low octane gas – bad pump gas – try some race gas
7. Too much timing in chip for fuel used. Try different chip.
8. Try cooler spark plugs – use only AC Delco (R43-TS or R42-TS)
9. Gap plugs to .035
10. Check torque converter bolts to make sure they are tight
11. Loose harmonic balancer. Make sure torqued to 200 ft/lb Is keyway secure?
12. Check internal engine noises like timing chains (roller), lifters/rockers, etc.
13. Damaged knock sensor
14. Check fuel pump pressure and volume
15. Proper torque on knock sensor – 14 ft/lb
16. Check Alternator voltage: 13.8 - 14.5v
17. Check computer power wire - they can break internally.
18. Troubleshoot the computer connector power wires and ground wires.
19. Swap coil pack, wires, plugs w/known good units.
20. Swap MAF with known good unit.
21. Check battery ground connection @ block (clean/inspect).
22. Check/change battery cables (both).
23. Are there MAF leaks in the inlet tube?
24. Are there vacuum leaks. Use carb cleaner or WD-40 & spray everything. Does the rpm change?
25. Disconnect the main injector harness - inspect, WD-40. Check for moisture in main connector.
26. Disconnect the coil-pack connector - inspect pins & spray w/WD-40.
27. Is the cat still installed? Is it good?
28. Have you performed a leak down check?
29. Do the rockers open/close? Do we have a wiped cam lobe?
30. Is the boost/vacuum steady @ idle?
31. Is the engine over revving? Should be 4,800-5,200 rpm
32. Carbon in cylinders? Clean with GM engine top cleaner
33. Inter-cooler dirty? Clean inside inter-cooler and fins
34. Oil in intake tract?
35. Check for exhaust leaks, cracked header
36. Battery good?
37. EGR valve in working order?
38. Check that no cables, wires, etc are touching the knock sensor
39. Blown head gasket? Compression test. Should be around 150.
40. Injectors flowing/working correctly?
41. Check vacuum line to fuel pressure regulator for cracks
__________________

 

[SouthernCal GN]

OK, take a deep breath, and start with the basics:

144mv is another way of saying 'I want to kill my motor'! The fuel pressure may be fine at deadhead (no load), but what happens when you put a load on it? You should get a rise in FP coincidental to boost- have you verified this?
How do you know the fuel pump is a 340- did you change it, or were you told it was a 340? Have you changed the fuel filter? Hotwired?

Injectors- original or upgrades? Chip- original or upgraded?


Yes, I see the list of mods you've done, but I never assume anything about these cars- somebody had it before you........

and


Yes, I'm a dolt......I should have just said,' Yeah, what suicide said!!! '

 

[SouthernCal GN]

Also- how are you checking boost? Is your gauge accurate- are you sure that that isn't actually 18 or 28 psi?

 

[GN1]

Yes All The Mods I Did Them My Self I Whent Out And Bought All The Parts And Installed Them My Self I Know That The Gauge Is Not Aff Because Its An Aftermarket One And Everything On This Car Ive Done My Self No Aftermarket Injectors Or Chip

 

[GN1]

And The Fuel Pressure Does Go Up Accordingly With The Boost

 

[TurboBuRick]

Mabye MAF is taking a Crap

Stock MAF still?

 

[suicide six]

Try changing you O2 sensor,esp if 144 reading was at WOT.If youre between 40 to say 43 static FP,you should have the fuel needed as long as it raises equally with boost.Go thru list I posted doing easy things first.Borrow a good maf if possible.

 

[GN1]

The Maf I Just About A Week Ago Its An Ac Delco Rebuilt The O2 Sensor Was Also Jus Replaced With A Good Gm One From Kirban

 

[TurboBuRick]

I'm with suicide six.

Barrow a MAF that is working on another car.

I have also had new o2 sensors that where bad. It' s not a heated one is it?

 

[GN1]

No Its Not Heated Im Wondering If The Injectors Might Be Clogged Since I Was At Wot And The O2 Milivolts Were Only 144 And My Sp Is Good

 

[TurboBuRick]

TPS working right?

Did you check TPS #s Set at .42 at idle

Check #s while pressing the pedal. Whats tps say at wot on the scanner?
You can check this with the key on motor off.
Did you do this yet?

 

[GN1]

Yes All The # Are Correct

 

[TurboBuRick]

Well........... Try the easy things first.

Cloged injectors, I dont know. I guess its possible.

You where also able to verify FP under load?

Do you have another chip you can try?

 

[jhanson1750]

clogged injector problem can SOMETIMES be identified with either an infered thermometer check each tube right at the exhaust flange, or the poorboy way, cold motor start it and have a spray bottle with water in it start LIGHTLY spraying the exhaust and the clogged injector will do one of two thing get hotter quicker if spraying a little OR stay cooler longer if not spraying at all (total obstruction) Either way good luck. I found a small shop here (houston tx) that cleans injectors. Flow bench for comparison and clean with hexain if needed.

 

[suicide six]

Rebuilt MAFs are troublesome,try a friends along w/new O2 sensor.

 

[GN1]

after working on the car for about 6 hours last knight found out the injectors were very dirty and the ignition module and the coil pack were out i feel relieved

 

[Lhorn]

How does a lowish alt. voltage affect knock? Mine is reading in the 12's. I'm also getting knock at about 10 pounds of boost and haven't been able to figure it out yet.

That's a very helpful list suicide.