General knock under any load

[sweet97]

I've got a set of 450's you can use, just give them a good cleaning. I might have an EGR also though you should be able to get on locally quite easy along with a 1G mas, they go for $40. You're 1/2 to 2/3rd's of the way there!
PBOGLIO will give you straight advice but you are trying to "fix somethng that is a major problem with bandaids", that and I have seen him get CRANKY when he tries to help and guys want to change his advice!! As a favor to me for lending the inj's go along with his plan so we can both learn from it. Mark

 

[ucancallmedebo]

well i was checking some of my old/new logs and it seem at most all of my knock starts at about 40-50% TH at 2500-3500 rpm at around 28 deg timing.by what PBOGLIO had said this is transitioning into heavy th and timing should be much lower and like 21dg max. if no EGR causes part th knock and then transitions into advanced timing and lean knock. i am lean right? sounds and looks like prob, i am going to lood into geting an egr at the junkyard. and work on the timing issue. i could lower fuel press and increase afc to same affect to make the ecu see more air and bring back timing,but this only works assuming that my mass/safc,550,ecu are in good tune. i bet a most of the people who run a 2g mass on 1g have there EGR. this is likely why i cant get a constant baseline to judge my car with. thanks 4 the help i had no idea my timing was really that advanced.

 

[sweet97]

The EGR keeps cylinder temps down. That can stop part throttle knock if the extra heat without an EGR is causing knock. I think you still have another problem causing the high timing. The EGR would not cause that would it? I do think I remember PBOGLIO stating that once knock begins under partial throttle it often continues into WOT until you back off to the point before the knock started. The EGR is certainly a start and I have good directions for the vac lines for the EGR along with the pics at Tabo you will be able to get the EGR functioning. If you get to a point where you want to try 450cc inj's we can work something out that will not cost you except a minimal fee for shipping & insurance.
While at the yard check into a1g mas or on the classifieds here as they are quite plentiful from guys who have gone to 2g's themselves. Follow PBOGLIO's course of action without cutting corners and he will work with you through the issue. I will do what I can as a brother who wants to learn and who has his own knock issues! Mark

 

[sweet97]

OK. What PBOGLIO said in reply #39 was that part throttle knock WILL often take the pulled timing into WOT so havin an EGR that prevents the knock in the first place will prevent timing being pulled at WOT so run an EGR!
You are getting part throttle knock so hence the EGR is necessary. You are also getting a high amount of timing
which is being caused by something else so PBOGLIO gave you the advice to go back to EGR, 450's, 1g mas and no safc to start from scratch and get the motor running correctly as it should stock and then start adding the performance parts. Mark

 

[ucancallmedebo]

what would be the most basic way to get my EGr working again.without care to emissions,just the bare minimum setup to get combustion temp back down.is this possable or does all of the emissions stuff have to go back together? thermal vacuum valve, emission canister,purge control valve> are these all nessasary? one more question, does the CAS give the ecu a baseline for timing or is the ecu gonna do what it wants in regards to airflow it sees regardless of what the CAS is set at. I have heard that if a harmonic balencer is going bad it might not be possable to set accurate base timing. If this is true i could think i have base at 0 but it may really be a +10. I am just trying to think out all of the variables.

 

[sweet97]

Thermovalve and EGR are all you need. I can direct you to pics and written instructions as I was going to do mine also. As I see it the thermovalve simply allows the EGR to only operate when the engine is at operating temps, then it will allow the EGR to open.
If you set your base timing and then continue to check it for a few days and it does not change position I would say the balancer is OK. My base timing jumps about some but new plugs and wires are going in first. The Scanmaster I told you about gives the timing so I can watch what it is doing as I drive. I can also just watch it at idle to see fit is steady. I know someone who recently changed a bad balancer, I'll get his story on why he suspected it. I can say it did not solve his off idle phantom knock.
I have a 255 Walbro to install as I found that fuel is a problem. I have a wideband a/f meter and my motor likes a 10.5-11.0:1 a/f and on my last run thrugh the gears and high rpm's I had no knock until high rpms and I caught knock and the a/f in the 12.xx:1 range. I have an AFPR here to go along with it.
Since I am in the snow capitol of New York State I will not be driving my car until mid April. I do want it top notch by then. Mark
PS: CAS/ECU can only do so much, that's why backing the base a couple degrees helps limit knock.

 

[ucancallmedebo]

does anyone know if it possable to get a chip which would help with the part throttle knock without adding back egr? custum timing to take in account the higher combustion temps at part throttle. also,does anyone have a good description on what the CAS effect is on timing at all times and engine loads.

 

[Turbo442]

ucancallmedebo,

I have a similar setup to you on my 90 AWD. Here are some suggestions.

1. Verify your cam timing is correct. I know its a pain in the ass but make sure the timing belt is installed and tensioned correctly per the vfaq or service manual. Your cam could be off one tooth and still run.

2. Make sure the honeycombs are installed in your 2g mas. With a stock 2g mas, 550's, and fuel pressure set at 37 I can leave my SAFC at lo +0 hi _0 and the car will run pretty well.

3. It sounds like your base timing is set corectly at +5 btc while grounded. Good.

4. You say you only have a small boost leak at your tb shaft. I fixed my tb so I have zero leaks but I agree with you, thats not the problem if your intake can hold pressure for 30 seconds.

5. For what its worth my EGR is blocked off as well.

6. Why dont you try some 100 unleaded and see if the knock decreases or goes away. If it does not I would start trying to find a source of phantom knock. (motor mounts rubbing, harmonic balancer, downpipe running)

7. I mounted my B&M fuel pressure gauge in the cockpit with a kit I picked up from napa designed for an oil pressure gauge. It worked perfectly with the fuel pressure gauge including all of the fittings. They had copper line kits and teflon line kits for around $12.00 ea. You may only want to do a temporary setup, high pressure fuel in the cockpit is dangerous.

I was recently suffering from severe knock as well and high EGT's. I tried everything I could think of like you are doing. Like you I kept thinking I was too lean. Actually it turned out I was too rich. My fuel pressure was 40 psi at idle. Just 3 psi was all it took to put things completely out of wack. As long as you run 17 pounds of boost or less you should have plenty of fuel available with the 550's. I would consider setting your afc to +0 hi and lo and turning your fuel pressure down to 36 and see what happens.

 

[ucancallmedebo]

if one of my cams was off a tooth how bad would it run at idle. after fixing the boost tee leak my idle smooth significatly.,but any way from the day i bouth the car vacume at idle is about -10 hg. i beleive the car has webcams. the cams i am told are not degree'd. could this cause a prob this bad without adjustable cam gears. lately on the logger i and get the car to idle at 750+-10 for up to 10 sec at a time without much change. if it was off a tooth would it be possable to it to run this smooth. The mass has the honeycomes and the adjustment screw still has silicon over it..That vacume at idle seems pretty low considering how well it runs and the motors compression. I can take the oil fill cap off and the dipstick out and the car runs about the same "very little blowbye". I got my walboro yesterday and will install it tomorrow, i will make a log to see if i can get the 02's over .85 at 10psi.If I can't than i got other issues besides timing.

 

[Mike000]

Thermovalve and EGR are all you need. I can direct you to pics and written instructions as I was going to do mine also. As I see it the thermovalve simply allows the EGR to only operate when the engine is at operating temps, then it will allow the EGR to open.
If you set your base timing and then continue to check it for a few days and it does not change position I would say the balancer is OK. My base timing jumps about some but new plugs and wires are going in first. The Scanmaster I told you about gives the timing so I can watch what it is doing as I drive. I can also just watch it at idle to see fit is steady. I know someone who recently changed a bad balancer, I'll get his story on why he suspected it. I can say it did not solve his off idle phantom knock.
I have a 255 Walbro to install as I found that fuel is a problem. I have a wideband a/f meter and my motor likes a 10.5-11.0:1 a/f and on my last run thrugh the gears and high rpm's I had no knock until high rpms and I caught knock and the a/f in the 12.xx:1 range. I have an AFPR here to go along with it.
Since I am in the snow capitol of New York State I will not be driving my car until mid April. I do want it top notch by then. Mark
PS: CAS/ECU can only do so much, that's why backing the base a couple degrees helps limit knock.

Can you please give some info on the pics and written instructions to get the egr going again. Part throttle knock is killing me. I have a feeling 3g lifters will cure it, but I want to see if this helps first.

 

[sweet97]

Sure! www.taboospeedshop.com has the pics under their techtips and vacuum line removal section for both 1 & 2 g's. They have before and after pics of the vacuum lines if someone should care to remove theirs. Helps to put it back together too.
What we need is to be sure we still have the thermovalve and the EGR valve. Refer to the pics.
1. from the front nipple on the thermovalve run a short line into a "T" or "Y" fitting so we can split the line into 2. One runs to the 3rd fitting on the throttle body. That's 3rd towards the back from the front marked
"A1" on my 1g. The other goes to the rear nipple on the EGR valve.

2. We repeat the one to 2 lines like we did above again only from the rear or inner nipple of the thermovalve so that one can run to the 2nd nipple/fitting back on the top of the Throttle body which on my '93 is marked "E".
The other line goes to the front nipple on the EGR.

That's it. What i have written here is my description on what I see on the pic at Taboo. If you have any questions feel free to ask. I will double check these directions against the pics in the AM as I am headed to the sack! Mark

 

[ucancallmedebo]

just installed the walboro, peice of cake after fitting was broke loose. anyway i checked and i think my thermovalve is gone. the egr is there but the only thing i could find was the factory boost control valve. tough luck huh. I started her up, 45 psi at idle,not surprised. I backed the timing back 5 more deg, like -5 now and took it for a spin at 10psi. basicaly anything under 3000 where the motor is lugging i get what feels like rich knock a lot. doing 1st,2nd,3rd runs it shows great improvement in knock counts. my 02 has not changed and know is even lower, it must be running so rich it is killing the 02 sensor? moved afc to 0 hi and low. here is the new log

first gear

RPM NK 02 TH TM
1687 0 .01 41% 26
1937 0 .01 41.4 26
2187 4 .05 41.4 28
2531 4 .74 41.4 27
2812 3 .74 41.4 27
3093 11 .74 41.4 29
3406 10 .68 41 26
4156 10 .76 40 24
4593 13 .78 37 25
4937 13 .82 33 22
4625 0 .85 10.9 27

second gear

RPM NK 02 TH TM
2781 0 .01 42 30
2900 4 .41 43 29
3187 7 .09 43 27
3700 6 .41 99 24
3900 6 .74 99 24
4100 5 .76 99 24
4250 5 .78 99 24
4531 4 .78 99 24
4750 4 .80 86 24
4968 3 .80 85 23
5350 2 .80 81 25
5937 1 .78 96 28
6156 1 .78 95 29
6281 0 78 91 28
6437 0 .78 80 28
5843 0 .76 10.9 41

third gear

RPM NK 02 TH TM
4156 0 .00 49 38
4218 0 .76 50 29
4281 3 .78 51 27
4343 7 .80 58 23
4406 6 .78 77 24
4468 6 .78 79 24
4531 5 .80 79 24
4843 4 .78 75 23
4968 3 .78 65 23
5062 3 .78 62 25
5125 2 .78 61 25
5218 2 .78 59 25
5250 1 .80 39 26

my heavy throttle drivability has gone up but the 255 is overruning at lower rpms.anyone else have this prob with stock regulator.will aftermarket AFPR fix this. my timing is stilll high but much better. the -5 est on timing makes the car idle rougher.turning up the boost will bring my timing down "ecu sees more air" but i dont want to hurt the motor either. should i try a run at 15 psi or wait till i can get lower timing where i am at. i dont see it is possable to be runing leaner as far as 02 is concerned with double the fuel volume. The pump was factory.
My EGT has risen during cruise and part throttle, is the result of more fuel+lower base timing.

 

[sweet97]

The thermovalve screws into the thermostat housing. A higher EGT could come from less timing but yours still seems to be high. More fuel would cool the temps unless it was burning in the exhaust /02 housing/turbine.
Check aain for the thermovalve. Probably only a few dollars from the dealer. All it does is not let the EGR operate until the ungie temp is up to normal. mark

 

[ucancallmedebo]

just a thought but by running 10psi is the ecu seeing so little air than in conjunction with my 2g mass that it is making my timing worse"to high", than it would normaly be with just 2g mass. the car used to be really fast at 18psi. It felt like it pulled timing less. Upping the boost still would not fix anything at part Throttle where boost would be lower anyway but I feel I am going in the right direction. I ordered an AFPR today cause 45psi at idle is way high.

 

[sweet97]

02 voltage should be .85 minimum under boost/wot. Strange you are running rich and still ow readings? mark

 

[ucancallmedebo]

with this set up i am getting minimal knock between 5-6k rpm and 02 is like .78 . Surely I am not to lean or i would be getting knock,or is a .78 at 10psi enough fuel.

 

[sweet97]

Road Race Enginering has less than .85 under Wide Open Throttle dangerous and over .92 conservative. I have a wideband a/f meter and my '93 likes to be in the 10.5-10.9:1 range to stay knock free which is in the .92+ 02 volt range. Why your 02 will not read higher is the mystery especially if you have gotten the knock down. I believe 10 counts to be the high edge for me and I shoot for 7 counts. Mark

 

[ucancallmedebo]

tommorow i might pull my 02 to check it as sometimes at top of third i see EGT at 1650+.
Considering the good condition of my plugs it would seem i have to be rich to get EGt 's that high, especialy combined with retarded timing. Does temp this high fry 02 sensors. My 02's have always sucked from day 1 with this jewl so my prob likely lies with something draging my 02 volts down. I might try checking the resistance of the wires running to and from the 02. Anyone know a easy way to do this?

 

[sweet97]

High EGT's are a sign of a lean condition. A lean motor runs hot, that's what causes the damage along with knock. Again that is why my EGR will be operating as soon as my silicone vacuum hose gets here next week. Mark

 

[ucancallmedebo]

I turned my boost up to 12psi today and re sodered every crimp connection under dash/computer/mass I could find..Idleing at 750 or so my hz on the karmen is saying 67 or so.. .It used to say about 53?.mmm Its warmer than it used to be so it really should show less air,anyway. I took it out and did some logs, I have'nt got my AFPR yet so i set 2-3-4 at like neg 5 on high and low to compensate to the 255 a little bit. It ran a little better. In second i still get knock with the high timing but by third with the highter 1650hz the ecu is seeing timing is like 23 or so. Really no knock once i get her into third. . I plan on getting eprom ecu and stage 3 dsmchip for timing and the afpr for my rich knock down low. I am looking around local for egr,so that should help some of my initial part th knock. I have my base timing at -5 and the car idles at 650 like this so when I get my timing curve back to spec I should be able to bring it back to 2-3 deg for a more decent idle. I seem to be making good progress and would like to thank everyone for their replys to my Q's. I'm not out of the woods yet and will update apon installation of new goodies.

 

[cfisher]

I know you shouldn't normally tune off o2's at all but year really lean. Do just one 3rd gear log from 2K-7K and floor it the whole time. Your throttle is all over the place but try and seriously add fuel and get the o2's to around .85/.90 andd see how it runs. It won't hurt anything by richening it up but your going the other way and from what your o2's say doesn't look good. Also, reset your ECU and start over. It just did wonders for my car.

 

[sweet97]

Debo check out your turbine housing after a run. I found with my timing set around 0-+1 degree of base timing that the late timing is causing the turbine to be glowing orange as perhaps some of the burn is a tad late and blowing out the cylinder? Anyone else have an opinion on this retarded timing issue? Thanks, Mark

 

[ucancallmedebo]

with the timing at 0 or so the egt seem pretty high. hopefully with the chip i can put it back at 5-8 degs. As far as 02 with my timing backed off i am getting 0 knock in third with 02's around 80-82 WOT? with high on +10 or 0 02's are basicaly the same? maybe low 02's are normal 4 my car. I dont really know what is in the motor,piston wise, supposed to be big rod though,but is it has lower compression pistons than 7.8 i should be able to run lower 02's without knock. Has cometic head gasket to. if it is thicker than stock my comp/ratio may be even lower. I got like 160 with compession tester in #1 cyl,this was after about 10 revolutions of the motor. I forgot to hold throttle open though ....how much would this affect the reading? or would i just have to turn it over more. The motor has basicaly no blowbye as it has less than 5k on rebuild. My vac at idle is like 8 ... This no doubt contributes to a higher base pressure at idle with stock regulaor, will be fixed soon though. Cruising in say 4th i has get vac around 20-23 apon decel so I think my gauge is reading correctly. Basicaly if I should have vac around 18-20 on stock motor this means my fuel press is higher than normal while in vacuum bacause its not taking as much fuel press out on the factory FPR. I have heard that even 3psi of extra fuel pressure over stock can throw everything out of whack.

 

[sweet97]

02's are just a measure of oxygen, unburnt fuel. You are showing lean. Can you try another logger? Retarded timing will raise engine heat. I also have a wideband and a scanmater so I see 02's, knockand a/f all together. my '93 with the same compression as you(which makes no diff. for 02's) likes a 10.-10.9:1 a/f, 02's in the .90+ range and I get no knock. Mark PS: like one guy said raise the fuel and see what happens to your 02's.

 

[ucancallmedebo]

well gentalmen,I finaly got my ecu with chip stage 3. apon installation found a short in the fuel pump,"in tank no doubt", loose pin at ecu, detonation wire completly disconected after installation becuse the wire was sodered into the plug. went to junk yard and enjoyed splicing a new 20+ pin plug . Ater all is said and done and everything is fixed i took the jewl out for spin. The studderbox is amazing, timing is back to spec, she runs pretty quick now. I was messing around and idle with the logger and the safc and noticed apon startup than my 02's took forever before they began to cycle. No AFPR yet "backorder", so i adjusted afc to about -8 at 1000 rpm. they started to cycle normaly. OK. well lets see how rich she can run. i steadly increases safc at idle until about +30. This was the most it would handle and still idle. Looks like I can get any higher than a .91 on the logger. This must be the richest my 02 will read. Lowering the % on the afc till about .78 or so and it would start to cycle again. I really need to get that AFPR.. I did drive around for about 30 min and still get some knock but usually under 10. My exaust temp are super low now ... 1425 max at 16psi boost. Now I really do beleive exhaust temp is 80%+ all timing. I think most of my knock is because i am running rich down low and now at 16psi my inj are at 18.17ms at 6406rpm. 100% duty cycle according to http://www.taboospeedshop.com/IPW2IDC.htm . I need to bump fuel pressure up higher or get bigger injectors. I probably should have 650's anyway. Any tuning right now with this unstable fuel pressure is fruitless. Looks like i wait for the AFPR. . With the new chip I am logging about 2000 htz at 15-16psi. This motor really moves some air huh. Any recomendations on injectors or how high I can run fuel pressure when i get fpr. For all i know the factory fpr may not be rising the pressure with boost. This goes to show tuning is just as, if not more important than countless upgrades. I moved my timing back to five but this may be inducing some of the knock which i still have so i'm gonna bump it back to 1-2 next time out to see what that does.