Fixing over compression on a 2FE (Camshaft analysis?) (1 Viewer)

[ChaserFJ60]

Maybe you got it fixed. It’s always the little stuff. We like to go down rabbit holes here ( it’s easy to tear an engine apart behind a keyboard)

I personally would run 93 octane with your compression. Pre detonation kills main and rod bearings along with crank journals

Totally understand no money, and it being a daily driver. Ask Santa for a set of new injectors they might really pep it up!

Im guilty of the same and in all honesty the suggestions would most likely improve the lifespan of my engine.

Yeah I think especially in this Texas heat im running premium only. Not saying the problem is fixed entirely as the goal is 0 knock and I still have some knocking. but I now have a stable platform to work with a minimum intermediate knock that only occurs at hard acceleration.

This was a really strange issue, sometimes the cold idle would be perfect and others it would be terrible. I did just change my air filter and experienced no immediate effects. I think the hose was in such an orientation to where it would intermediately open and close the tear causing the issue to occur at random. The pinging would also come and go with the cold idle issue. I have a "new to me" hose in route to permanently fix this issue.

 

[OSS]

I may have missed it, but what's the status of the EGR system? If it's been disabled, the engine will ping unless the distributor got recurved.

 

[ChaserFJ60]

I may have missed it, but what's the status of the EGR system? If it's been disabled, the engine will ping unless the distributor got recurved.

I bought the engine desmogged. All thats gone. Ive never heard of re-curving a distributor

 

[F226continental]

Recurving means changing the springs and or weights inside distributor to make the mechanical advance work at different rates

 

[OSS]

I might have skipped over it but what distributor are you using?

 

[ChaserFJ60]

Recurving means changing the springs and or weights inside distributor to make the mechanical advance work at different rates

I see JIM C can do it but in 2-3 weeks? but its impossible for me to not have my car for that long. All the info I see on mud so far is to have it sent out... If its just changing some springs I cant see what the big hassle is. But then again I don't know whats involved in this yet.

I might have skipped over it but what distributor are you using?

Stock 1988 FJ62 dizzy non vacuum

 

[OSS]

The mechanical advance in the distributor is timed to the slower combustion speed of a EGR diluted mixture. When the EGR system is disabled, the stock distributor will ignite the mixture too early, causing the fuel mixture to detonate.
Re-curving the distributor is a term to describe recalibrating it's mechanical advance (with new weights & springs) so that the spark occurs at the right time. It's not something a home hobbiest can do with any accuracy or assurance it'll be right.

I'm not up to speed as to how the FJ62 ECU controls the FJ62 distributor spark timing, but I don't think the EGR system can just be disabled and everything will still be fine. The only way the ECU would know that the engine is pinging is if there's a knock sensor installed in the head. I could be mistaken though. I'm familiar with the 2F not the 3FE.

The only practical way to get the distributor recurved on a daily driver is buy another used one (if you can find one) then send yours out to get recurved. That way there's no down time waiting for it.

 

[ChaserFJ60]

The mechanical advance in the distributor is timed to the slower combustion speed of a EGR diluted mixture. When the EGR system is disabled, the stock distributor will ignite the mixture too early, causing the fuel mixture to detonate.
Re-curving the distributor is a term to describe recalibrating it's mechanical advance (with new weights & springs) so that the spark occurs at the right time. It's not something a home hobbiest can do with any accuracy or assurance it'll be right.

I'm not up to speed as to how the FJ62 ECU controls the FJ62 distributor spark timing, but I don't think the EGR system can just be disabled and everything will still be fine. The only way the ECU would know that the engine is pinging is if there's a knock sensor installed in the head. I could be mistaken though. I'm familiar with the 2F not the 3FE.

The only practical way to get the distributor recurved on a daily driver is buy another used one (if you can find one) then send yours out to get recurved. That way there's no down time waiting for it.

3F-E Desmog guide is up - https://forum.ih8mud.com/threads/3f-e-desmog-guide-is-up.47092/ In the guide here @Spook50 talks about the pinging and contemplates reinstalling the EGR system which I never had when I bought the engine. In page 4 he talks about fixing the issue by tweaking the ignition advance. I think your right on the money @OSS

Honestly I dont really care if my engine is desmogged or not. I just want it to run.

I'll have to source another distributor and have it sent out. Until then itl just have to be.

 

[fjc-man]

Thats right, One plug going into the dizzy.

I thought you said in post#42 you don’t have centrifugal ( weights and springs ) or vacuum advance on your distributor?

 

[ChaserFJ60]

Jim Chenoweth on Land Cruiser Distributors

Im not sure what to do with this thing. The ECU reads air temps and has access to AFR from the O2 sensors. SO I would hope to think that the ECU would be able to properly compensate the distributor without any external modification, Or am I giving this 1988 ECU more credit than what its capable of? Unless the EGR system shoves hot air back into the intake without measuring its temp, AFR, or whatever else; I cant imagine it doing so blindly but then again I have no idea what this ECU is doing.

I thought you said in post#42 you don’t have centrifugal ( weights and springs ) or vacuum advance on your distributor?

Man I dont know whats in that dizzy, I know theres no vacuum advance and that its done electronically.

I dont know if im getting info on FJ60 or FJ62 distributors and Ive never really had a reason to disassemble my current distributor yet so I dont know whats inside. Im taking all the info on this thread as factual without verifying it which I probably shouldn't do. I do appreciate everyone's input but we are all only human.

 

[Lead Head]

Guys, he's running 3FE engine management. There are no springs, no flyweights, no anything inside the distributor. Timing is completely controlled electronically. The only thing the distributor does is distribute the spark to the cylinders and provide the camshaft position for the computer. Rotating the distributor just offsets the computer's "frame of reference" for timing.

EGR cools and slows down combustion, allowing the use of more spark advance because of that. On this era of engine, the computer enables the EGR valve at specific times, and just sort of assumes its working. It will then advance the ignition timing. Disabling the EGR can cause pinging because of this. California 3FEs had a temperature sensor to monitor EGR operation (If the EGR is getting hot, it's probably working). Later vehicles (1996+) usually have a mechanism that actually measures EGR flow.

It doesn't really matter if the AFR is correct, because the combustion characteristics will be different without the EGR functioning.

You need to:
- Be aware that pinging is damaging to your engine. Pinging under high load is extremely hard on components and will likely lead to eventual piston failure
- Find and fix any and all vacuum hose & intake leaks. The air-flow meter needs to sample the incoming air accurately to properly fuel the engine
- Run premium fuel
- Retard ignition timing enough to preventing pinging in ANY circumstance. It may come down to you needing to run two headgaskets to drop compression back down.
- Do the responsible thing and park the rig at home if you're a broke college student. Trust me. 10 years ago I was also starting college and trying to make my FJ-62 my daily driver. They're expensive money pits that get atrocious fuel economy and will bankrupt you without a steady income of money. I get that every college kid wants a bitchin' daily, but you need reliable and thrifty transportation. You need a $2500 Camry - not a 35 year old Land Cruiser

 

[ChaserFJ60]

Guys, he's running 3FE engine management. There are no springs, no flyweights, no anything inside the distributor. Timing is completely controlled electronically. The only thing the distributor does is distribute the spark to the cylinders and provide the camshaft position for the computer. Rotating the distributor just offsets the computer's "frame of reference" for timing.

EGR cools and slows down combustion, allowing the use of more spark advance because of that. On this era of engine, the computer enables the EGR valve at specific times, and just sort of assumes its working. It will then advance the ignition timing. Disabling the EGR can cause pinging because of this. California 3FEs had a temperature sensor to monitor EGR operation (If the EGR is getting hot, it's probably working). Later vehicles (1996+) usually have a mechanism that actually measures EGR flow.

It doesn't really matter if the AFR is correct, because the combustion characteristics will be different without the EGR functioning.

You need to:
- Be aware that pinging is damaging to your engine. Pinging under high load is extremely hard on components and will likely lead to eventual piston failure
- Find and fix any and all vacuum hose & intake leaks. The air-flow meter needs to sample the incoming air accurately to properly fuel the engine
- Run premium fuel
- Retard ignition timing enough to preventing pinging in ANY circumstance. It may come down to you need to run two headgaskets to drop compression back down.
- Do the responsible thing and park the rig at home if you're a broke college student. Trust me. 10 years ago I was also starting college and trying to make my FJ-62 my daily driver. They're expensive money pits that get atrocious fuel economy and will bankrupt you without a steady income of money. I get that every college kid wants a bitchin' daily, but you need reliable and thrifty transportation. You need a $1500 Camry - not a Land Cruiser

This has been my only car ever, My other one is a 1966 Toyota Sports 800 thats cut in half.
I wonder if theres a way to trick the ECU into never over advancing the dizzy. or catch and modify the signal from the ECU to the dizzy. I bet you sombody can but not me not yet.

Regardless. pinging has been already greatly reduced and only occurs during hard load, I feel like if this was a huge issue nobody would de-smog their fj62 at all ever. Theres no economic scenario where I can entertain spending more than $300. I don't drive my FJ60 to feel cool, Its because it was a hand me down when I was in high school and I dont have the money for any decent rig that wouldn't require $1000's more in repairs. Parking this truck is not an option unfortunately

 

[Spook50]

3F-E Desmog guide is up - https://forum.ih8mud.com/threads/3f-e-desmog-guide-is-up.47092/ In the guide here @Spook50 talks about the pinging and contemplates reinstalling the EGR system which I never had when I bought the engine. In page 4 he talks about fixing the issue by tweaking the ignition advance. I think your right on the money @OSS

Honestly I dont really care if my engine is desmogged or not. I just want it to run.

I'll have to source another distributor and have it sent out. Until then itl just have to be.

Reinstalling the EGR was a briefly considered option. As it turns out I'm glad I didn't. At the time I was using 87 octane fuel. Since I became obsessive about using ethanol free fuel, 91 octane is the most common flavor available in my area and using a higher octane fuel solved my slight pinging. It was enough of an improvement that not long ago I advanced my timing to nearly the limit of the distributor adjustment. That made a considerable improvement in performance, especially up long grades, with no negative impact on my fuel economy (however the ethanol free 91 octane is typically about 60 cents more than normal 87 octane, so my fuel cost did go up considerably).

Also to confirm what @OSS stated; there is no knock sensor on the 3FE. One of these days if I get a DD car I'd love to take advantage of the downtime it would afford my 62 and attempt a fully custom ECU with distributorless ignition and more ideal tuning to how my truck is set up. Likely wouldn't gain enough to make it worth it for everyone, but I love to tinker.

 

[ChaserFJ60]

Reinstalling the EGR was a briefly considered option. As it turns out I'm glad I didn't. At the time I was using 87 octane fuel. Since I became obsessive about using ethanol free fuel, 91 octane is the most common flavor available in my area and using a higher octane fuel solved my slight pinging. It was enough of an improvement that not long ago I advanced my timing to nearly the limit of the distributor adjustment. That made a considerable improvement in performance, especially up long grades, with no negative impact on my fuel economy (however the ethanol free 91 octane is typically about 60 cents more than normal 87 octane, so my fuel cost did go up considerably).

Nice! Im glad to hear that. I think I may keep my ignition timing retard a bit to restrict its max potential spark advance and hope that it can adjust itself accordingly for cooler temps. I may try and tinker with the timing when the weather cools down some. Im going to run my current tank till its empty then just use the 93 octane.

 

[Spook50]

Nice! Im glad to hear that. I think I may keep my ignition timing retard a bit to restrict its max potential spark advance and hope that it can adjust itself accordingly for cooler temps. I may try and tinker with the timing when the weather cools down some. Im going to run my current tank till its empty then just use the 93 octane.

The best way to get your timing right is to use a vacuum gauge connected to a port in the central plenum of the intake, AFTER the throttle body. What you'll want to to is advance your timing (with the ICS disconnected) until you reach the highest idle vacuum on the gauge, and then retard it back 2 inHg. That's the most foolproof method to reach your ideal initial timing without risk of pinging. The curve, like was said earlier in the thread, is a much different beast, but since we're not really hot rodding our engines a great deal the stock setup will be just fine once you get your initial dialed in.

 

[ChaserFJ60]

The best way to get your timing right is to use a vacuum gauge connected to a port in the central plenum of the intake, AFTER the throttle body. What you'll want to to is advance your timing (with the ICS disconnected) until you reach the highest idle vacuum on the gauge, and then retard it back 2 inHg. That's the most foolproof method to reach your ideal initial timing without risk of pinging. The curve, like was said earlier in the thread, is a much different beast, but since we're not really hot rodding our engines a great deal the stock setup will be just fine once you get your initial dialed in.

Ive never heard of that method, Ill give that a try. I'm gonna wait until I go through a tank of gas to fill on premium so the operating conditions match the ignition timing as best they can!

 

[ChaserFJ60]

@Spook50 When you set the timing using the vacuum gauge do you still follow all the normal procedural steps like warming the engine and jumping the TE1 and E1 ports?

 

[Spook50]

@Spook50 When you set the timing using the vacuum gauge do you still follow all the normal procedural steps like warming the engine and jumping the TE1 and E1 ports?

I didn't jump the TE1 and E1 ports when I did, but I'm not 100% if it makes any difference using the vacuum method. If I'm not mistaken, that disables any electronic curve control that comes from the ECU (not absolutely sure in that case though). I DID make sure the engine was thoroughly warmed up though.

I have been tempted to try it with the ports jumped though, just to see if there's any difference versus not doing it.

 

[ChaserFJ60]

I didn't jump the TE1 and E1 ports when I did, but I'm not 100% if it makes any difference using the vacuum method. If I'm not mistaken, that disables any electronic curve control that comes from the ECU (not absolutely sure in that case though). I DID make sure the engine was thoroughly warmed up though.

I have been tempted to try it with the ports jumped though, just to see if there's any difference versus not doing it

I checked the timing with a light both with and without jumping the TE1 and E1 ports and the timing dot moves back about one window's length in difference. Your method makes sence as your setting (I assume) the maximum advance you want the ignition to be at when its warmed up.

 

[Spook50]

I checked the timing with a light both with and without jumping the TE1 and E1 ports and the timing dot moves back about one window's length in difference. Your method makes sence as your setting (I assume) the maximum advance you want the ignition to be at when its warmed up.

Yeah if I was going to an absolute factory spec'd engine I would definitely short the leads and use a light.