morepowerjoe

On my 91' Camaro RS, 5.0L TBI, Auto, All Stock except for high flow 3" cat and 3" to 2 1/2" dual flowmaster, it has a lot of spark knock, detonation. pre ignition, whatever you want to call it. I just bought the car a couple of weeks ago when it wasn't running. It was at a little classic car lot and was running when someone traded it in and then broke down on the car lot. A monkey that worked there could not figure out the fuel pump was out, he broke the rotor contact. put the spark plug wires back on wrong, and the shifter cable was off a gear and it wasn't in park just to name a few things wrong that I found before I got it running. I put a tank of 89 in it and some fuel treatment and ran that out. I put some more 89 in there and have been trying to adjust the timing. When I set it at zero, (esc wire diconnected) it runs very rough, almost not drivable. It only runs good around 6-8 degrees, idle cleans uppretty good. I've even tried putting it at 2-4, and it still pings like heck. Also the exhaust fumes are the kind that burn your eyes. The ses light comes on after driving for a while and then goes back off before I can check it. I am grateful for any help as always.

naf

iTrader: (7)

You can still pull the stored codes:

https://www.thirdgen.org/service-eng...ht-error-codes

Start with that.

morepowerjoe

Cool, I didn't know that. I'll check it this evening.

morepowerjoe

Pulled the code like you said, (32).
barometric pressure sensor, egr junk

I searched around the board a little and didn't find much. Any suggestions? Thanks.

naf

iTrader: (7)

Check your egr valve. With the engine idling put your fingers under the cap and pull the diaphragm up. This will manually open the valve and should cause the idle to stumble. If there is no change either your valve is bad or the passages have become clogged, or BOTH. Lack of proper EGR will cause the pinging. Your rich condition may be another matter, but chase the codes first.

morepowerjoe

Pulled up diafram and it stumbles the engine.

cIaRmOaCrZo

i believe you are suppose to start with 6* advance from the git go. zero is much to low. and you said it yourself that when you had it around 6*, it smoothed out. that may not FIX your problem, but that is what your timing should be set to start with while you look for the problem (such as egr)

morepowerjoe

I went a head and set it at 2 degrees and reset the ecu. It idles ok in park but real jerky in gear.

I read over a lot of old post here, and most everyone said leave it at zero or only go up 2 degrees. The sticker under the hood says zero, alldata says zero. It's hard to decide what to do. I'm wondering if may be the combustion chamber just has a lot of carbon build up. The car only has 139k on it.

On another thought, I wonder if the tcc is just making it ping because it kicks in so early. I think I might install a inline switch for grins, or unplug it for a drive and see what it sounds like. I have a switch on my carbed 86 and it is like night and day.

naf

iTrader: (7)

No, the TCC is not making it ping. How freely did the diaphragm move?

You've verified that the passages are not clogged and the valve is not stuck open. It still may not be opening when commanded, which is a pretty common failure as the valve clogs or the diaphragm leaks.

To test that the EGR valve opens properly you're supposed to increase rpm's at rest (no load) until there is vacuum (5") to the valve. Remove the vacuum line and the valve should be seen to close and the rpm's will increase slightly. Re-connect the line and the rpm's should drop back.

morepowerjoe

I found a little hole in the vacuum line to the map sensor. Fixed that and it ran a little smoother. Also at 2 degrees it still pings just as bad as at 6-8. But at 2 it is very sluggish. So I just put it back where it runs best at 6. Still pings there but runs a lot better. I also put some lucas fuel treatment in it and a tank of 92 octange.


So I took off the egr to take a look at it and it wasn't too bad. But what I did find was that if I blow in the vacuum port on the egr valve, the air slowly escapes from somewhere. That probably means the diaphram is bad right? Or is it supposed to have a little bleed? One other thing, when I check it on the engine like you said, should it be at operating temp or does it matter?

cIaRmOaCrZo

nvm lol. it was already answered

cIaRmOaCrZo

i have a suggestion, it seems like we are going in great detail about the egr problem (which may very well be what is wrong)(iv been digging in alldata on that problem and seems you are already doing the diagnostic precedures for c32, so ill leave that alone) but have you maby thought of thinking a bit more outside the box and possible believe that it could need a simple ignition tune-up? like the basics, cap, rotor, wires, and plugs.

cIaRmOaCrZo

The egr is controlled by a vacuum solenoid that uses "Pulse Width Modulation." The valve allows the ECM to turn ON and OFF the solenoid many times a second. The ECM varies the amount of ON time (Pulse Width) to change the amount of exhaust gas flow. The Coolant Temperature Sensor (CTS), Throttle Position Sensor (TPS), and the park/nuetral switch transmits signals to the ECM in order to regulate the EGR solenoid. During cold and idle operations, the solenoid circuit is not grounded by the ECM, which does not allow vacuum to flow to the egr valve. The amount of exhaust gas flow depends on manifold vacuum and variations in exhaust back pressure. So the cts may be bad and causing these problems, or mis-adjusted tps because those indirectly affect the egr operation..

cIaRmOaCrZo

lol sry for posting so many in a row, but even check and see if the knock sensor is bad, or unplugged! but if it was unplugged it would throw a code 42 (my rs knock sensor was unplugged and had that code) because the ecm saw an open or grounded EST or Bypassed circuit. it ran like complete **** and started knocking or pinging when it warmed up. and if it is plugged in, and happen to be bad, then it would send mixed info to the ecm and start changing timing through the EST and run like crap.

morepowerjoe

The car has a b&m ratchet shifter. And the gear selector switch is not hooked up. Well it's hooked up but not mechanically to the shifter. And another cable is just laying there beside the shifter. I figured it was a part of the P/N safety switch and back up lights. But I didn't think it did anything else. But now you have told me it does a little more than I thought. I'm gonna go out right now and figure out how to get this stuff hooked up, or just put the stock shifter back in. Thanks a lot for the info.

Also I did cap, rotor, wires, and plugs before I even drove it.

I also think you just addressed a problem of mine in another post for my 86 TPI. I think I have the wrong knock sensor in it. I built the engine form peices and used a 91 knock sensor. I bet it's not the same for a 86. It gave me a code 42 one day and I thought may be I just grounded something when I was working on it.

Damon

Before you worry about the EGR valve and it's ECM-controlled soenoid I'd check the vacuum lines. If they aren't hooked up or cracked/spilt it won't work either!

One from the TB to the solenoid, another from the solenoid to the EGR valve, and a 3rd port of the EGR solenoid that is open to atmosphere (no vacuum line attached to it- often with a little foam filter over the end of it).

Rough idle, pinging and EGR codes smells like vacuum leak issues to me.

morepowerjoe

I just put the shifter all back to stock. Everything back the way it should be. I robbed parts from my 86 carbed camaro. Seems like now I can only hear the pinging when the torque converter locks up. It sounds better, but the air just got cooler tonight as well, I don't know if that's helping it. I wonder now if I should try backing off the timing now? The ses light didn't come on but I'll drive it further tomorrow to be sure. Thanks for everyones help, I'll let you know what happens with it.

naf

iTrader: (7)

You can back off the timing or you can find and fix the problem. The test I outlined above (performed with the engine at operating temp) will check for proper operation of the EGR AND the associated vac lines.

If your TCC is locking up it's a strong indicator that the ECM is in feedback mode: meaning your CTS is probably fine. The TBI's do a self test of the KS on start up and will throw a code if it fails. It will then retard the timing and be less likely to ping. Listen to Damon, go back to the basics.

jackballs529

I read a thread once that stated the converter was installed wrong, (upside down or something). It caused similar symptoms. Was the car fine before the converter was installed?

naf

iTrader: (7)

Whoa. I usually stay away from these but do you mean torque 'converter' or catalytic 'converter'? Since the op doesn't specify I might assume (until told differently) that both were installed at the factory.

jackballs529

Sorry, I meant Torque converter. The guy said he wasn't paying attention when he swapped in the new converter and it was mis-aligned. He had similar problems. Problems you wouldn't think you could get from this... You can probably find it with a search.

Drumer919

You mean Closed Loop (ie PCM has fuel trim, using feedback from O2)

And I doubt the TQ converter is installed wrong, he says its locking up, something it usually doesnt do if installed wrong.

naf

iTrader: (7)

Yeah. Thanks. Edited my post above.

morepowerjoe

I have to wait untill saturday to finish checking that egr but I wanted to ask if the ecu goes into closed loop based on engine temperature?

naf

iTrader: (7)

yes. But like I said above the tcc won't lock until it's in closed loop.

morepowerjoe

Ok naf. You were right on. I took the vacuum line off the egr and held it with my finger as I revved the engine and I felt vacuum. Switch is good. So then I put it back on and revved the engine while I looked at the egr. It will not move. So in a couple days I will get a new one. Thanks a lot for your help.

I'm just curious though about something. You said the tcc doesn't work until closed loop. But it seems like even if I just hop in it and drive away cold it still locks up. Do you know what temp closed loop would be? Because I put in a 180 t-stat, and I just want to make sure the computer doesn't go into closed loop after that. Thanks again naf.

naf

iTrader: (7)

I don't recall exactly , but around 120 degrees comes to mind although it could be different for other models. I do remember it was much lower than I expected. Someone may chime in with something more concrete, but you'll be fine with a 180 stat.

morepowerjoe

I put a new egr valve on last night and took it for a test drive. It still pings just as much, and still ildes just as rough. I can't believe it. I don't know where to start now. I know it was bad so at least that's eleminated. When I drive it a little further I'll see if the ses light comes back on. The car has a high flow cat and a flowmaster. Could that be causing any problems with the knock sensor or something?

naf

iTrader: (7)

Recheck for vacuum leaks, not just in the EGR circuit. You may want to cap every vacuum port on the manifold and TB then reconnect them one at a time.

morepowerjoe

I caped all the vacuum lines one at a time, and all at once, and same thing still. I rebuilt the tbi unit also. When I first start it mainly in the morning, a little blue smoke comes out the tail pipe and I've just figured it's valve seals. But I'm starting to wonder if I have another problem as well like a leaky valve. I have a tpi system I was thinking about putting on it but I think I'll just carry the problem over to it if I don't fix it first. The only other thing I can think of is the injectors. The spray doesn't look to good to me but I don't have anything to compare it to. Oh and no more ses light (code 32).

cIaRmOaCrZo

Tcc doesn't lock up on closed loop btw. It locks up strictly on tha mph your running becaus the only feed back your ECM recieces for that to operate is your vss (vehicle speed sensor) and it's usually at 40 mph on a stock ECM.

morepowerjoe

Thanks.

yupitsdadsbird

not to sound stupid or anything but I had this same issue and it took me about 3 monthes to figure it out........where are u pegging ur timeing marks? as in where are u pointing ur light to see where it is at?

naf

iTrader: (7)

I will have to check that on the TBI when I get a chance. It's been a few years and I may be mis-remembering.

Have you gotten anywhere with it?

morepowerjoe

I may not really understand your question. But I'm pointing the light on the timing pointer in between the water pump and timing cover. Not for me to sound stupid but is there another way?
And no naf I haven't figured anything else out yet. I put on new shocks and struts this week and got an alignment today. But that's about it.

yupitsdadsbird

ok when I first got my car I didnt know the marks were there and added a tab next to the PS where it was on the old blocks and tried to set it that way and had the same issues ur having.

naf

iTrader: (7)

Are you disconnecting the ESC connector when setting the timing? Four wire connector to rear of distributor?

cIaRmOaCrZo

Woah lol. the esc connector you unplug to set base timing is the tan (one wire) connector inside the wire loom right above the blower motor.

yupitsdadsbird

yeah when u pull the 4 wire connector the motor goes blugh.....and dies lol

morepowerjoe

yep.

naf

iTrader: (7)

Yeah, got my models mixed up. TBI/TPI is the one wire connector. LG4/L69 is the four wire at the dist.

You changed the fuel pump, how about fuel filter. Verify your fuel pressure is good? Most of your symptoms indicate a lean condition which is most likely caused by a vacuum leak (too much air) or fuel issues (too little fuel).

morepowerjoe

Yeah, I changed the fuel filter with the pump. But I haven't rechecked the fuel pressure because it's such a pain with out a test port. I probably should though. Tomorrow I'm going to do a compression test. I almost hate to, but it has to be done I think before I keep chasing my tail.

ShiftyCapone

iTrader: (7)

+1 here. Make sure this is the wire you are dissconnecting to set the base timing. There is a picture of it in the stickies above to help you ID it.

Also, I would back the timing down to 0° advance. Even 2° can be too much for diagnosing a knock problem with a TBI set-up. The stock TBI heads are fast burn heads and do not need any initial advance like TPI/LG4 heads. The swirl port feature in essence serves as the timing advance. Start from stock and go from there. You can test your CTS sensor with a volt meter and ice/hot water. A quick search will yield the voltage readouts you should see. After you rule that out I would take another look at your EGR, double check all plugs (gap) and plug wires, and look into datalogging to monitor your spark counts. Could be a bum KS.

morepowerjoe

I did a compression test today and found the strangest numbers I have ever seen. Basically 1,3,5,7 are 100-125 psi, not very good to me. But the strange thing is 2,4,6,8 are 195-200 psi. That is way further than a new engine right? I'm thinking that's probably where the spark knock is coming from those cylinders having too much compression. May be a bunch of carbon build up? Or is there a blown head gasket on the other side? Someone please shed some light on this for me.

And I forgot to open the throttle, would that make that much of a difference?

naf

iTrader: (7)

1,3,5,7 share the O2 sensor, so it's within the realm of possibility that a problem there could result in the computer forcing a lean condition for the opposite bank.

Your compression test, how did the wet numbers compare to the dry? Valves or rings?

morepowerjoe

I just tested it dry. But it does have a puff of blue smoke when I first start it, and I assumed it is just valve seals. But now I thinking about bad valve guides but I don't understand how that would make it lose compression. I guess I need to do a wet test too, so I can rule out the rings. I would think the head gasket would have more potential to give this low of compression. Next thing I'm going to do is check valve lash. May be someone set the valves too tight on the low side and they are not sealing enough.

Does anyone know what normal compression should be on this engine? Is 200 psi too high or is that just a healthy number? I feel like I need to know that first so I know what side to look at as a problem.

morepowerjoe

Well, I drove the car yesterday to a local swap meet thinking about selling it but it started running pretty bad when I got there. I think the car knew what was coming.
So I decided not to take the car in there for sale, and just bought a few things and started home. The ses light came on and off a few times so I decided to stop at o'reailly and use thier scanner real quick. Oxygen Sensor failure. So I went home and put one in. I'll let you guys know how it runs today.

Also I moved my compression test stuff too another spot.
https://www.thirdgen.org/forums/tech...test-help.html I'm gonna redo the test pretty soon

morepowerjoe

Oxygen sensor made a improvement for sure. BUT, I redone the compression test today with bad results. Plugs out, throttle open, and engine warmed up. Number 1 had 100 psi, and with three squirts of oil had 120 psi, and number 3 had 80 psi and 90 with the oil. Rings? Head Gasket? I don't know why it doesn't smoke, only when you first start it in the morning which points to just the valve seals.

I do know I will be either selling it or putting in my olds 350 and putting the TBI stuff on it. I don't have the funds for another rebuild. The olds 350 is in my 86 right now with a carb and it is insane fast. I'm really curious on how it will run with this tbi stuff. I know it will be like an instant restrictor plate but the fuel injection will be nice. This 91 RS has a great interior and straight body so I wouldn't mind keeping it. I just have a hard time selling something without telling the buyer it's got a major issue. I'm just not like that.

stroker_SS

Did you ever figure out your problem?

Mine (lo3/in 91 caprice) is kind of doing the same thing, when i'm free revving the engine I get no knocking/pinging, but once a load is placed on the engine it will ping at anything above idle. I also got a code 32.

I know I should start a new thread, but I just want to know if you got your's fixed and how you did it.

morepowerjoe

Just that half of the cylinders had low compression. I fixed it by replacing the engine.

Check back with me in a couple weeks. I'm gonna pull the engine apart and try and figure out exactly what it was.

Here's the engine swap
https://www.thirdgen.org/forums/engi...ldsmobile.html