My '89 TBI auto won't stop knocking/pinging for anything. It does it loudest when it's warm--and when it's upshifting, going uphill at a low RPM, or accelerating very gently (shifting at @ 1600 rpm). It annoys the hell out of me. I'm in southern new mexico, and its starting to get warm---and my car is getting louder. Here's everything I've replaced:

-EGR valve and solenoid (got a code 32 a couple of times)
-all the rubber vacuum lines I could find that were cracked
-o2 sensor
-catalytic converter (old one was definetly clogged)
-dumped an entire can of B12 chemtool in the throttle body while running it
-tried premium gas (kind of helped--worse gas mileage and was slower)

What else should I check?? Still is knocking like it always has been. I have a new knock sensor, but I need to know where it's located--can I get to it under the hood?? I don't have a good lift or jack at home--

I should also mention that the car has 160,000 miles on it and smokes a little at start up--otherwise runs smooth now that a got a new cat.

Is this kind of knock/ping really all that bad for the engine?? can it cause a lot of damage?

Thanks any input is helpful This is driving me insane I'm thinking about trading it for a CRX!!!

 

Knock/detonation can very easily destroy a motor and the issue should be resolved ASAP before you do major damage.


The knock sensor is located in the general area of the passenger side of the block above the starter.

 

Here's a few things off top of head -

Did you get the correct EGR valve? There are 2, one is positive backpressure, one is negative backpressure - double check new one against old one - there should be a stamping on the top - most autozoners don't know this.

If it's never had it changed - might want a new fuel filter. Make sure the EST wire is connected for the timing advance (little brown wire with connector right where pass side strut tower is). Invest in a jack (you can do most everything with a $29 set from Walmart that includes jack stands). Beg/borrow/steal a timing light and check base timing with EST disconnected. Might wanna try new plug wires, new coil, and new ignition module (those are in order, from cheapest to most expensive - try one at a time). You should get better mileage with hi-test gas.

Let us know what you find.

 

After the knock sensor...160,000 miles, lots of ping (probably) as that much knock would probably have popped a hole by now... cup of water while revving the engine. Get rid of that carbon and then make sure your state of tune is good, your fans are running and your temp is proper and then start with fuel pressure and work down the list.

 

I have replaced the ignition module already---my car was dying all the time and not starting back up-- that fixed it.

I have checked the timing and the est connector- i set it at 0. I tried banging on the exhaust manifold while it was running to see if the timing would change (knock sensor kicking in)- sometimes it would change, sometimes not.

Are there two knock sensors on this engine?? on the driver's side there is something that feels like one under the exhaust manifold. I guess that could the the temp sensor or something.

I'm gonna try a new EGR valve--the one I got was From AUTOZONE! who knows if its correct. The old one was only about a year old- who knows if it was a good one to go off of. I'll get one from the dealer.

I'm also thinking of replacing the ESC MODULE--I think it's located to the right of the power brake booster. Any body reccommend this??

If worse comes to worse I'll get a new ECM. I'm not sure if it's working right cuz the only code I ever get for anything is a 32. And it always happens under the same conditions--after driving at 60 mph for about 10 minutes--when I turn it off after that, it doesn't come back on for a long time. This last time I got it was the first time in about 6 months.

Thanks for you help--this is a really nice car and I wanna keep it. It sucks because I'm a student working part time trying to buy all this stuff (ECMs and EGR valves aren't exactly cheap) but I guess its cheaper than buying another car or and engine overhaul---I hope this gets figured out soon!

 

have you looked at your spark plugs? i'd pull at least a few (probably all), and inspect, can't hurt, doesn't take long. You may find some scrapped.

I've never heard of B12, I guess it's like seafoam? That'd be along the same lines as red devil mentioned, water... When you replaced the egr, you cleaned the passage?


aside from your knock sensor (probably up on the list of things to check), i'd maybe also look into the cooling system. Does the car run very hot most of the time? maybe top up your coolant if it's low, make sure your reservoir has something in it. Try water wetter if you want.

 

Are you sure it's knock, or an exhaust leak?

 

I'm pretty sure it's pinging---It has an exhaust leak too under the hood on the driver's side. That sounds more like a lifter, and continues when I lay on it hard. This pinging I'm hearing only occurs at low rpms when upshifting or going uphill (stress) and gets louder as it gets hotter

I'm cleaned the EGR passage as well as I could. How far in do I need to go.

I ordered a new EGR from GM #17113496---this number doesn't match with anything available at autozone/checker/napa around here. The one that the previous owner put on was aftermarket, and I used it to get the new one- maybe this is the problem. The EGR and the AIR tube on the cat are somehow associated with each other right?? I messed with the cat and got a code 32 for the first time in months We'll see

I'm gonna check the plugs this weekend--they're probably fowled anyway since I'm burning a little oil
Would it make a difference to mess with the initial timing if EGR is not the problem??

thanks

 

Yea, reading plugs wil tell you a lot... if they aren't old as hell. Goes back to state of tune and it's always a good idea to make sure they are in good condition.

IIRC b12 is everything but water, and nothing that I think has the same violent property change in the combustion chamber as water does,if this is the right msds:

0105 B12 CHEMTOOL CARBURETOR CLEANER

I think that's right as it's listed for b12 chemtool and not berryman's carb cleaner. :shrug:

And look at Sonix and my posts and post up some findings on the trouble shooting.

 

Ok i'll try the water this weekend after I put on my EGR and check the plugs. I don't know how old they are, but the original owner of the car (from 1989-2005) seemed to take care of it pretty well--other than the fact that he traded it in on a V6 mustang

Oh yeah--you guys know how many knock sensors are on the 305 TBI?? some people tell me one, some two. I haven't had a chance to look at it

 

Mmm... not sure, I avoid TBI like Black Ech... er... Plauge, like Black Plauge.
I'm sure you can post that up on the TBI board and get someone to post the correct answer.

(There, some levity for the 'old timers' that are still kicking around. )

 

ok thanks i would have avoided it too but i got it for 1000 bucks with ac and one owner my 80 z28 was costing me $150 a month for gas. this one is about half. that cars gets all the chicks though---young and old.

sorry i didnt get the joke. you said old timer---i'm 22- should i be getting it?

 

Only 1 knock sensor, on the pass side, either in the head, or block, I don't remember which is knock and which is fan switch.

 

hey white80z89rs did you figure out what the problem was.mine is doing something similar and ive tried alot of the things you have but it still does it.just trying to fix it brfore my new moter goes in.thanks

 

Any luck finding the problem? Sounds exactly like the problem that I am having.

 

I was having a hell of a time last saturday.


The thing was knocking like crazy no matter what i did to the timing, i must have had a really, really bad tank of gas because it never did this before or after the weekend.

I just kept it to the floor and it would smarten up after sounding like its going to chuck parts through the hood for about 5 seconds, then off we go into second gear to catch back up to the person i was racing

Still beat everything i raced other than a 02 grand am gt

 

I put the factory EGR valve in. It seems to have made a slight difference, but I can still get it to ping when the temp. guage gets between 180 and 220 (stop and go traffic without the ac on.) I didn't get a chance to put the knock sensor in or check the plugs---I'll get back to you guys on that.

This weekend I was picking up the '85 grand am my aunt is giving me to save gas---2.5 liter Iron duke with a 5 speed---big torque for a 2500 pound car--
It looks like sh_t but has sentimental value! anybody know anything about these cars?? What should I do with it?

Hey shadygrady what is yours doing??
----------
and jmp91rs also---what is yours doing????

 

mine is knocking and pinging like crazy once it gets over 190 or so when i put my foot in it pretty good.Stop and go traffic in the summer is when it does it.Both my fans are wired to run all the time.Ive got a 160 degree thermostate.When its cool or at 185 or less it runs awesome.I dont know if its cause of my chip or what.Ive checked everything i can think of but no help.It gets very hot in Mississippi so i hope i can find out what it is cause in the summer you cant run below 200 in traffic.Im putting in a new engine in the next few weeks and changing all the sensors so ill let u know if it stops.Have yall had any luck

 

Mine is also knocking and pinging when it heats up to between 180 and 220. Does it mostly under a low rpm load especially slow take offs. If I gas it when it is knocking and pinging it will do a very quick series of knocks then quiet down completely. Usually seems to be most frequent after a shift point where the rpms drop back down. I've put a new egr valve and knock sensor on it but no changes. I'm wondering if I just have a large amount of carbon deposits on the top of the pistons causing the knocks. Any ideas on what to look for or check?

 

Hey jmp91 rs, that is exactly like my problem---every detail! It must be carbon cuz I have tried everything you have.

anybody know a sure fire way to get it all out without taking the heads off!??

jmp81rs--did you ever get a code 32 service engine soon light?---I keep getting it after about 10 mins of driving in the highway.

 

For all TBI thirdgens, its one. For the later systems that actually used a PCM rather then the ancient ECM, some of those got the dual knock sensors. From what Ive heard, it was the 4.3Ls.

 

As for the knock, the sensors seem to pick up just about everything but. So far Ive had the knock sensor diagnose for me a shredded belt from road debris, a demolished front pump and TC from misalignment, various loose exhaust components, and a blown doughnut gasket on a set of edelcrap headers. If it wasnt for the knock sensor, I would have never known about those things. What would I have ever done without it?

As for knock, well, it picks that up too, but so do my ears (granted not as early as the KS). My compressions low enough that Im probably just going to run without it soon.

 

I got the code 32 also after a few minutes of driving. Also got a code 43 one time, but it hasn't resurfaced as of yet. Haven't put many miles on it since the new egr and knock sensor, but no codes so far. I'll keep you posted on what it throws code wise.