help with pinging noise, also cooling ??

[ryanmcb]

I recently purchased an 89 Suburban for my family. Very well maintained, original owner, 73k original miles. The guy gave me a perfect service record from the time he bought it.

When I climb a hill the motor starts to ping, only on inclines under load. I have tried high octane fuel and it does not solve the problem. I thought the computer would adjust itself and time the ignition correctly over time but it continues to ping.

Are there any suggestions? Should I manually time it? If so, how do I disconnect it from the computer? Should I be looking at something else, maybe I am not identifying the right sound? I am taking a trip this week to the mountains and would love to resolve this issue.

One more thing, the truck runs a little warm, more than I like. Do you guys use 180 or 160 Tstats? I believe it has the stock 190 in it right now.

Thank you!

[rwhit57]

I would check the timing first. Also it could be carboned up. Get it up to running temp and pour a little trans fluid down the carb, crack the throttle a little don't kill it. Then drive it at speed for awhile. If it's a solid motor it might not hurt to blow the cobs out of it, if you see a bunch of smoke you just helped it.Try running a lead additive in the gas.

[ryanmcb]

sorry, I should have mentioned that this motor is TBI. I don't know if that affects your suggestions or if they apply to an injected motor as well.

thanks,

[rwhit57]

You can do that with a TBI motor, but play with the timing first. Advance it a little and see how it does. If you get it too far it will be hard to start. I would bet it's a combination of timing and carbon build up. Keep running the high octane gas. Hope this helps. Oh you might run some inj cleaner through it, it could be running lean. You can check that by pulling a plug, if it's white looking it's lean.

[camshaftgsxr]

i would run a bottle of seafoam (or bg if you have access) through a vacuum line (brake booster) and drive it some (there are instructions on the bottle)

if that doesnt clear up the ping checking the timing should be next. remember if your truck still has the timing computer it is neccasary to unplug it before adjusting the timing,

with the timing computer unpluged set timing to zero and then plug it back in, it should then adjust itself 12-14 degrees advanced

[camshaftgsxr]

Originally Posted by camshaftgsxr

timing computer---unplug it---

with the timing computer unpluged set timing to zero and then plug it back in, it should then adjust itself 12-14 degrees advanced

check before and after wards to make sure it advanced it properly, and the plug for the computer will have 4 wires on it and come out of the passenger side of the distributor

[motornut]

just wondering
on the passenger side of the block there is a knock sensor
on my 88 it broke off and this is what happened
drove me nuts trying to figure it out
it's the loose plug hanging by the starter
but it goes in the block drain plug pass side

[camshaftgsxr]

Originally Posted by motornut

just wondering
on the passenger side of the block there is a knock sensor
on my 88 it broke off and this is what happened
drove me nuts trying to figure it out
it's the loose plug hanging by the starter
but it goes in the block drain plug pass side

it took my tired mind a minute to figure that out, but thats the place to START for sure, good tip!

[ryanmcb]

Originally Posted by motornut

just wondering
on the passenger side of the block there is a knock sensor
on my 88 it broke off and this is what happened
drove me nuts trying to figure it out
it's the loose plug hanging by the starter
but it goes in the block drain plug pass side

I am going to check that. Thank you for the suggestion.

[ryanmcb]

Awesome thank you. What is BG? I am familiar with seafoam but not BG.

[camshaftgsxr]

its good stuff, we always used a misting dispenser, but its going to be cheaper and easier to use seafoam ( http://www.bgprod.com/products/fuelair.html )

[rayfinseats]

Pinging under load is usually timing too high.

[gchemist]

Normal for a SB in hot weather. If you are constantly driving on hills, back off on the timing. Reset it to zero first. It may help. Use a can of seafoam. Carbon buildup on valves may also cause premature ignition.

[ryanmcb]

I have not backed off the timing yet but I did check the timing. It appears it is nearly at Zero right now. Should I still set it and back it off even more?

I did put the seafoam in as well, I have driven about 10 miles. The truck seems to be smoking from the exhaust now which I hope clears up.

My next step is to try a hill and see if the pinging is still there. If so, I will back off the timing another degree and try again.

I will also check that Knock Sensor on the Freeze plug.

Thanks, I will get back soon.

[camshaftgsxr]

check the timing advance at 3000 rpms (with the timing computer plugged in) if its pinging and the base timing is set at 0, something is wrong

[ryanmcb]

ok, I will do that. What should the timing be showing at that RPM? 12-14?

[nate_g_2003]

on the seafoam, i'd let it smoke it self out sitting in one place, not driving. When I had a 03 Ranger, a lot of guys in the ranger community do that to the V-6 motors in them to help with carbon buildup and driveablility issues. Make sure to follow the directions on the can. You can do 1/2 a can through the booster hose, and the other half in the gas tank. For a real good cleaning, pour 1/2 a can in your oil about 500 miles before you need to change it. It helps get a lot of sludge (if you have any) broken down and out of the engine.

as for timing, I'm not too sure at that RPM.