Ok, to start with the engine is a 94' 350 TBI(auto). I Would have never noticed the noise if my door had been properly shut hehe.

Ok, when hitting the throttle in a high gear with low rpms (kinda boggen) I hear a tick not really a metal tick, more like a rattle. Itt's fast paced, and not alow noise more of a tin-ish type.Upon further investigation I can recreate the noise at will.

When power braking (no tire spin) rpm 1500-2000 when I get a good load on it i can hear it, sounds definetaly like it's coming from the top end of the motor.

When cruising in overdrive and I hit the gas but not enough to downshift. I feel if It were a manual and I put it in 4th early, and kind lugged 'er up to speed it would definetaly make the noise.

I don't hear it under high revs, or when the motors in it's power band.

Is this detonation or pinging possibly? I thought that detonation was a lower type sound, this seems almost like lifter rattle.

Where should I start to trouble shoot? I adjusted valves on my dunebuggys, but that's about as far as I have gone motor wise.

Pull the valve covers and look? Do these lifters need adjustment? I dont have a timing light, but judging by all the wiring, and odds and ends left I the truck the owner before me I wouldn't doubt if he adjusted some things.

It would seem to me if the timing were way avanced i'd get a hell of a lot more power than I have right now.

Last note. It idles fine, warms up, idles smooth etc. The only time I get a SES light is when I am on the freeway at a cruise and the temp stabilizes at 200 on the gauge, seems like 15 minutes on the freeway and the light comes on like clockwork, shut off the truck its gone till freeway again.


I have been lurking here (for months it seems) learning all I can for my first 350 power build when I can afford it this fall.
Any help or directioni you an point me in would be greatly appreciated

 

bump before it hits the end of the page

 

The noise description sounds like pinging, otherwise known as spark knock. Try a higher octane gasoline and see if it helps. Check the ignition timing; make sure the harmonic balancer (where the timing mark is) hasn't slipped.

What codes are stored in the ECM when the Check Engine light comes on? Those will tell you what the ECM thinks is going wrong, without them it's all just a guessing game.

 

Do you have an egr valve on that engine. That can cause problems like that if it's worn out. Especially comming down from high speeds.

 

Sure do, have an egr. Pulled codes 32 33 and 45.. any idea on those.. hitting up search now..

 

Ok figured out the codes .. got a question or two for ya guys.

#32 is a bad egr, Do i have to replace this, or is there a way to disconnect it and not get an error code. We don't have emmisions here, and I really don;t want to buy a new one anyways.. open to suggestions here. (cant burn my own proms yet)

#33 vacum to low? Did I get the right definition to this one? Is it possible that the bad egr is setting this code? or do I have a vacuum leak somewhere possibly? or both

#45 Too rich, this I belive was caused by the adjustable FPR I turned up too high I definetaly had it way rich for a day or two. Glad somone mentioned checking the codes..

Ok a few months ago I removed the battery and left it off for about 25 minutes or so and it didn't reset the codes or the computer. It did when I left the cables off over night tho.

Is there a way to reset the codes without a scan tool, or basically reset the ecm to relearn, and reset codes?

One last Q does this ecm have the "limp home mode" if so is it possible that it's been in limp mode for some time, and could that account for not getting the power I expected out of it? The ses light does not stay on, only pops on once a code is tripped, a restart takes care of the light until it pops on again.

Should I run down and buy an egr $27.99 just hate oto go get one if its not going to fix it.

Thanks for all your help, greatly appreciated

 

Ok update.

I did a lot of searching and research and figured out how to test my EGR I found that the vacuum hose that goes to the egr was plugged into the wrong outlet.

It was connected to the upper outlet that usually has a foam filter on it.

After I attached the hose to the right spot, I tested the egr by putting my hand on it, and found when I hit the throttle it opens up. So I am assuming the EGR valve works

The ping is now gone, but unfortunetaly I know why whoever did that put the hose there in the first place.

After putting the hose where it belongs it started having a rough idle. Not only does it have a rough idle, but when I let off the accelerator and it returns to idle it stumbles almost as if it is going to die.

Any suggestions as to why it would stumble onreturn to idle, and idle rough now that its all hooked up correctly? I feel like I have been chasing my tail on this one for a while.

 

OK a bad egr valve can set the codes you talked about previously a rich exhaust, a lean map sensor code, and of course an egr code. Are you still getting any codes with the hose in the right place??? It shounds like your egr valve is staying open at idle when it should be closing. It should only open when driving and close at idle, but when it stays open it's letting too much exhaust gases, (causing a rich condition) into the intake, making the engine run rough and try to stall at idle, but when you take off it seems fine again. Replace the egr.

 

Ok, ill pick up an egr and gaskets today, along with new plugs. (I want to check their color and may be fouled from running rich).

Is there a pin to short to clear th ECM codes, or do I just leave the battery cables off for a 30 minutes or so?

I would like to clear the codes, and then un for a bit see if they re pop soon or if it is just from the hose in the wrong spot.

 

On some cars you can pull the ecm fuse for a couple minutes to clear the codes. never tried it on the bird though. Only way i know is to disconnect battery for a while.

 

I'll disconnect the battery before I start, and let you guys know how it turns out after the plugs/egr.

Just on a side ntoe I hve done a lot of reading. I read in a tech article that if your spark wires are routed over your egr solenoid (the vacuum box conenected to the egr by a hose), that they could cause some electrical noise and mess up the signal going to the egr solenoid causing improper function, and a false 32 code.

Maybe a stab in the dark for those who have replaced their egr and are still havign problems. I know that I broke the little wire holders, and had my SP wires up over the egr solenoid to hold them off the manifold.

 

Ok I removed the EGR to inspect it, it doesn't look all fudged up with carbon, it actually aside from being dark doesnt look bad at all

Here's my next Q/ Don't know how to put it.

I blew in the EGR, (where the exhaust usually goes), and there is a tiny leak, blowing either way into the egr.

Is the EGR supposed to be air tight when closed (ie vacuum not applied).

Also, how fast is the egr supposed to respond once vacuum isnt there, the diaphram moves really slow when released.

 

Well it sounds like the spring that should push the diaphragm back might be weak. Mine didn't have much carbon build up but the diaphragm just didn't move as well as the new one. pull up on the new diaphragm, it will probably move with less force applied to it and return faster.

 

Ok replaced the EGR, the idle problem is way better.

However I still just dont have the power I am expecting out of a 350.

Replaced the cap and rotor today, no noticable difference all though there was a alot of burn marks/carbon on the top of the rotor.

I checked vacuum today, and it's 19 at idle, after letting off the throttle it goes right to 15, and creeps its way back up to 19 so I think I can rule out a vacuum leak (correct me if I am wrong).

So new
EGR
wires
plugs
cap
rotor

I think next in the chain of diagnosis is, CAT, and then timing. BTW I couldn't really see any timing marks on the crank pulley, or balancer I am used to a big V notch I mark with chalk, what do the timing marks look like and where are they at iof somone could be so kind.

Anything I might be overlooking?