North American Turbocoupe Organization



Being one tooth off on cam timing..will it run?
ianbfromct Offline
Senior Member
#1
Im battling some pinging issues on my TC on WOT. I currently have a stock TMIC, big fuel pump, stock injectors, and just recently installed a PIMP. I noticed even before the PIMP install when I disconnected my knock sensor I would get pinging on 93. I should have addressed it then but too late now. One of the advantages of the PIMP is being able to adjust timing on the fly and to also log everything. My air temps seem to be good and not crazy hot..its still pretty cold here. So im on 16 psi for boost and its all good until im in the upper rpm range and I hear that dreadful noise so I always back off.

I've been going back and forth with Stinger and others about this. The base tune he sent me is meant for a stock 2.3t and the timing is pretty much on point with a stock la3 I believe. So far its boiled down to the following reasons why it might be pinging..

  • Excessive blowby oil in the PCV system causing the fuel octane to drop = Will be doing a catch can very soon

  • Base timing is off = Its been checked multiple times

  • Excessive heat soak = its cold and my air temps never go over 150 F and my coolant never goes over 200 F

  • Running lean = Im actually running pig rich at WOT and still need to tune some fuel out..unless its one injector giving me problems which might not register on a wideband

  • Not stock compression = This is a possibility but the most unlikely..im not pulling this head (to check for milling and look at the pistons) until I absolutely have to since it runs quite well otherwise.

  • Lastly Cam timing is off...Now I did a head gasket last year but didnt take pics or have the head inspected (I know dumb). I've spoken to a few people who claim the car will run with it being off a tooth. Some say it will run like absolute crap and wont be drive able. Its very possible I have it one tooth off as it was my first time doing the cam timing. The funny thing is I never considered this because I always thought that being one tooth off would simply affect the power range of the cam and not have anything to do with pinging. I thought this because cam timing and distributor timing are two different things. Well I was corrected by lots of people lol.


The car runs great otherwise its just really beating on it is where it gets pingy. I actually had to drop it down on the timing table a few degrees from stingers stock tune and im even running colder NGKs to help out. But I know that's just a bandaid. For reference his stock table has me at about 18 degrees under wide open and so far it wont ping unless it's at 15 degrees or lower.
88 5 speed TC
-3" DP,lowered, 255 Walbro, Gillis valve, Cobra R's, bondo/rust, Stinger's PIMP Ecu
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Pete D Offline
Administrator
#2
Colder plugs are probably not any help in this case. As others have said you could borrow/rent a bore scope to check type of head. An N/A head could cause the problem you describe. . Are you seeing little aluminum splatter marks on the plugs?

Being off a tooth depends on which way, usually if it's only 1 tooth the engine will run smooth, show boost, even earlier than usual, but be down on power. I would start by checking cam timing. It always the place to start for diagnosis because if it isn't right, then nothing else matters until it's correct

I'm a little baffled that you only get the pinging when you cut WOT timing. Usually it works the other way. What happens if you cut back on boost?
Pete Dunham


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Sophosis Offline
Member
#3
I had similar issues not long after I got my car running decent when I first got it. I couldn't throw any timing at it and it wanted to knock if I turned the boost up. Pretty soon, I had to do a head gasket. The amount of oil/carbon buildup I ended up scraping off the piston tops was ridiculous. That lends to a bump in compression and probably a heat soak that doesn't help fend off detonation.

If you have some compression check numbers, you can compare those to similar setups and see if the numbers are comparatively high. I don't know what the normal/average psi is for stock setups without doing a search.
1988 Turbo Coupe
- 0.020 Diamonds w/stock rods, T3 w/stock IC, BoPort 1.5 cam, LA3 w/QH on MAF, water/meth
- 5-lug swap, 31-spline, 4.10s, vacuum brakes, PBR front brakes, 2000 Mustang GT 17" rims
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ianbfromct Offline
Senior Member
#4
Pete D Wrote:Colder plugs are probably not any help in this case. As others have said you could borrow/rent a bore scope to check type of head. An N/A head could cause the problem you describe. . Are you seeing little aluminum splatter marks on the plugs?

Being off a tooth depends on which way, usually if it's only 1 tooth the engine will run smooth, show boost, even earlier than usual, but be down on power. I would start by checking cam timing. It always the place to start for diagnosis because if it isn't right, then nothing else matters until it's correct

I'm a little baffled that you only get the pinging when you cut WOT timing. Usually it works the other way. What happens if you cut back on boost?

Havent gone down in boost but im pretty sure it would take away the ping. Ill have to check it though. IM currently printing out a timing belt guide right now.

If I had a borescope how would I be able to tell if I had a NA head ?
88 5 speed TC
-3" DP,lowered, 255 Walbro, Gillis valve, Cobra R's, bondo/rust, Stinger's PIMP Ecu
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ianbfromct Offline
Senior Member
#5
Sophosis Wrote:I had similar issues not long after I got my car running decent when I first got it. I couldn't throw any timing at it and it wanted to knock if I turned the boost up. Pretty soon, I had to do a head gasket. The amount of oil/carbon buildup I ended up scraping off the piston tops was ridiculous. That lends to a bump in compression and probably a heat soak that doesn't help fend off detonation.

If you have some compression check numbers, you can compare those to similar setups and see if the numbers are comparatively high. I don't know what the normal/average psi is for stock setups without doing a search.


My compression numbers we just did shown 170-170-160-170 which is pretty high compared to other people. I think the average numbers for most are around 140. I know ill be pulling the head eventually one way or another. I was just trying to see if its anything easy first..like cam timing or something else.
88 5 speed TC
-3" DP,lowered, 255 Walbro, Gillis valve, Cobra R's, bondo/rust, Stinger's PIMP Ecu
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Pete D Offline
Administrator
#6
A bore scope or even a relatively cheap fiber optic scope with a lighted tip would let you look t piston tops and see the shape of the combustion chamber so you can tell if it is an open chamber (turbo head) or a heart shaped chamber (N/A head)

I have heard of inducing small quantities of water into the intake system as the engine runs to "steam clean" the carbon out. I can't give you the details as I haven't done it myself. Might want to research it.
Pete Dunham


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ianbfromct Offline
Senior Member
#7
Pete D Wrote:A bore scope or even a relatively cheap fiber optic scope with a lighted tip would let you look at piston tops and also see the shape of the combustion chamber in the head, so you can tell if it is an open chamber (turbo head) or a heart shaped chamber (N/A head)

I have heard of inducing small quantities of water into the intake system as the engine runs to "steam clean" the carbon out. I can't give you the details as I haven't done it myself. Might want to research it.


Im working on trying to borrow a good borescope from somebody. They main issue would be visability on the head chambers since those are angled up and most cheap scopes wont curve up enough. I did run some sea foam this week but not sure if it didnt anything lol. Im not sure about running water in the engine either lol but I heard it works.
88 5 speed TC
-3" DP,lowered, 255 Walbro, Gillis valve, Cobra R's, bondo/rust, Stinger's PIMP Ecu
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Pete D Offline
Administrator
#8
I've used seafoam and have run it through a small engine, kind of like I envision for and auto engine. I run it in the gas tank periodically for injector cleaning. I feel it helps.
Pete Dunham


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Jeff K Offline
Administrator
#9
I used to decarbon carbed engines all the time with water back in the old days. I would hold the fully warmed up engines at 2500 RPM or so, and slowly dump a quart of water down the carb throats over about 2 minutes. As they started to choke, I would open the throttle more to keep the RPMs up. You would not believe all the crap that would come out the exhaust (pre cat converter days). Not sure how you would get the water in on an EFI engine? Suck it in thru the PCV hose? Other vac hose that goes directly to the vac side of the throttle plate?
Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 24 psi, forced air IC, water injection, BPV, Ranger cam, subframes, etc., etc.
86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP N2O, ignition, gears, suspension, etc., etc.
05 Taurus SEL Duratec daily driver
04 Taurus Duratec (wifes car)
02 Pontiac Grand Prix GT
95 Taurus GL Vulcan winter beater
67 Honda 450 Super Sport - completely customized
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Not B Anymore Offline
Administrator
#10
I've done it on a couple EFI engines - a corvette and a Daytona. With both of them I put the water in a jug and sucked it into the motor with one of the vacuum hoses. Good idea to use a smaller one and you definitely want to have a hand on the throttle like Jeff said.
Brian Leavitt
'86 TC 5-Speed -- MS2x w/COP | 83 lb. injectors | T3/T4 50 Trim Stage 3 .63AR | Full 3" Exhaust - No Cat | Motorsport FMIC | Ranger Roller | Ported E6 | Walbro 255HP | Kirban | 20psi | 120-amp 3G | 8.8" 3.55 rear | '03 Cobra Wheels
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