Car Prolem

[mhuckabee]

On Friday night I was driving home. I was pulling out of a parking lot I hit about 3000 RPM's and the car just fell on its face. I had to hold the pedal to the floor and it still would not go over 2000 RPM. I pulled into a parking lot right away. The car was pouring out black smoke and raw fuel and would not even idle on its own. To get it to start back up I had to hold the gas to the floor. It was obvious that the car wasnt going anywhere so I had it Flatbedded home. The next day I tried a bunch of things. Different Coil, different Distributor, checked fuel pressure. Finally I decided to reset the computer. 20 minutes later I hooked the battery back up and the car started right up and the smoke cleared. It was idling smooth but still didnt seem right. I kind of undid all of the things that I messed with in the morning, reset the timing, etc. Took the car for a ride and it just has absolutly no power at all. You rev it to 3000 RPM and it sounds like your flogging it and your foot is barely in the gas. Every once in a while it will pop through the intake. The car however is still building boost as I see it on the gauge. It just seems like the timing is not advancing as it should.

Since then, I have tried a bunch of things. I tried a different baro sensor which for a second seemed to help but it went right back to stumbling. I talked to a tech at PMAS, he told me which wires to probe on the MAF and what voltage I should be seeing. It all seems to be check out. I have tried 2 different computers, 2 distributors, 2 coils, bypassed the aftermarket ignition, checked TPS voltage, and probably other things im missing.

Later, I ran a compression test. I got 148 - 150psi on all cylinders. I checked that the balancer is not slipping giving me false timing readings.

Here is some background on the car:

Stock 30,000 mile 302
gt40p heads
F303 Cam
Holly systemax 2 intake
65MM bbk throttle body
V1 vortech SC trim with 7'' Crank Pully
38lb injectors
77mm ProM mass air meter
Car was tuned at Kauffmans and has custom SCT chip.


Right now I have the blower belt off and the chip out just to get those variables out of the way.

Any ideas would be greatly appreciated.

[wick]

Anybody? This is a buddy of mine. Belive me, we tried everything!!! It is throwing no codes. Runs like shit. Yes, the engine light does work. Its almost like the pulse length was being held open for way too long. But that was trumped by the car running allright again later. Really cant think of anything else it can be here. All the common sence items were taken care of. Has to be something in the wiring somewhere is the only thing I can come to think of. Anybody else have an idea, please chime in.

[mhuckabee]

Well I have found out what is causing the car to run like this but I have no idea why its happening. On Saturday, I was going to bump the timing up to 20 degrees and leave the spout out to see if the car would make any normal amount of power without the computer controlling timing. I put the timing light on and it was reading 0 degrees with the spout out! This is the same problem I had a year ago that eventually went away by unhooking the HEGO ground wire to the back of the head. Here is exactly what its doing. You remove spout and set timing to 10 degrees. Lock the distributor down, still leave spout out. When you rev the Engine, timing drops down to 0 degrees. Allow engine to fall back to idle, timing climbs back to 10 degrees. I bumped it up to 20 degrees and reved the engine and timing dropped to almost 5 degrees, all with the spout out. The disconnected ground that fixed the problem in the past, is still disconnected.

Here is where the problem gets really strange as if it werent bad enough. Last year when this problem started, it was in a different car with different wiring all together. I basically bought a nicer roller car and swapped the engine to the new car so 100% of the wiring has been replaced. The only things that were swapped from the old car to the new one were the engine, injectors, and sensors (MAF, 02's, EGR, ect.).


I have verified that the Balancer is not spinning at the rubber part by drawing a line on it. I drew the line on it last year and it still has not budged. I checked timing chain play by rotating the crank one direction until the rotor began to move, then turning the crank in the other direction until it moved again. Play is good and the chain only has about 1500 miles on it. Again, the distributor and coil have been changed numorous times as well as 3 different ECU's. I am completely out of options. Anyone have any ideas?

[mhuckabee]

Oh and I forgot to mention that I tested the pin on the TFI that is supposed to get hot only on startup to make sure that its not getting hot all the time. It also checked out fine.

[coralcoupe1993]

Very Odd. With the spout in - when rev'd what is happing with the timing. Advance when rev'd or retard with spout?

[mhuckabee]

With Spout in, timing advances to off of the chart on the balancer as it should. But given that somehow 10 - 15 degrees of timing is being pulled out, I have a feeling that with spout in, if timing should be say 30 degrees under a given load, it is probably more like 15 degrees causing the power loss.

[Viper_ed]

I talked to Wick last night and gave him some ideas to try. I would start by just running the car without any of your MSD stuff or your chip. Also, why are you still using a stock coil? I'd bet it is either related to your MAF being bad or something causing either a weak spark or the spark to blow out.

That ground on the injector harness that goes to the back of the head is there for a reason and by no means should disconnecting it be a fix for your problem.

[mhuckabee]

I agree that removing the ground should not be used as a fix. The problem was that I had replaced 100% of the wiring and I was simply out of options. I had spent an eitire summer or it and when the problem went away I was just happy that it was gone.

The Crane ignition box is out of the picture, the chip has been out, and the blower belt is off. I had swapped an MSD Blaster coil in from a buddys car and the problem persisted.

If I set the timing at 20 Degrees Base and put the spout back in I can get decent power out of it. I think this is because under throttle, it is pulling out the 10-15 degrees and actually ending up in the normal operating range. This, like disconnecting the ground, is not a fix, but it does show me that the fuel delivery is there. I back probed the ECU on Pins 50 (MAF) and 60 (Ground) and test drove. MAF voltage seemed to be exactly within the specs that the PMAS tech told me to look for under various loads.

HEGO Ground has been hooked back up since it was no longer helping the situation by being unhooked.

Thanks for your replies.

[mhuckabee]

Tonight I will try to unplug the MAF and recheck base timing with spout removed. I will also try it with TPS removed. Voltage somewhere has to be feeding the ignition modual to give this fluctuation. It can not be the actual increase in rpm. So its got to be either the voltage the MAF is providing or the voltage that the TPS is generating at part throttle. Although both of these voltages were confirmed to be good, they may be backfeeding a wiring problem somewhere. I will post results later this evening.

[mhuckabee]

Just did some more testing. I pulled the spout out and started the car and had 0 degrees timeing. I bumped it up to ten where it was solid for about 10 minutes until car was all the way up to temprature. Once it warned up the timing slowly climbed to 23 degrees and would fall back to 10 as I reved the engine. Let off the gas and slowly climbs right back to 23. This enire time the spout was out. Once timing started to fuctuate, I pulled off the TPS connector, reved the engine and timing still moved. I then unplugged the MAF and got the same result. I also tried disconnecting the electric fan. This didn't help either.

It seemed to be normal until something got hot. I know that TFI modules are known for acting up when they get hot and being fine when cold, but I have tried 3 other known good distributor assembiles.

Tomorow I think I am going to check it while cold and make sure it is sticking at 10 degrees. If it is I will try to heat it up a little with a heat gun or hair dryer to see if I can get it to act up before the car actually warms up.

[Martin0660]

Take this for what its worth as I'm a 2.3 guy, but this whole timing thing has me confused. With our stuff, spout out, is fixed timing, sort of like an old mechanical set-up. In other words, spout out, base timing should never move. Is there something different with the V8 stuff???? I just dont see how mechanical base timing can be moving like that without the spout to let the EEC control it.

As I was reading this, it sure sounded like timing chain to me although you basically checked that. It might be worth going back after that, is there some way the cam gear can be walking sperate from the crank?

I also saw its spitting no codes, but did not see specifically that you pulled codes with a scanner, but a reference to the CEL. I would pull codes, especially KOEO and continous memeory codes (although the battery disconnect might have cleared them).

Sorry if i'm off base, but that timing thing has me struggling to beleive it.

Bob Myers

[mhuckabee]

No you are right on the money. Timing should not move at all with the spout out. This is whats so confusing. I am going to start revisiting everything because I feel like I have tried everything. When this problem started, the timing chain probably had 700 miles on it and play was good. I cant see how the cam gear that turns the distributor could be messed up but maybe that is a possibility as well.

[wick]

It has us all struggling Bob. I just got off the phone with him. For some reason, it keeps moving. You are right about the timing being locked in. It should not move at all. I think he is going for a heat gun on the TFI tomorrow with a cold engine. I suggested a broken cam but the same problem happened in a different car, same engine. New car, problem fixed. This is a huge head scratcher. Is there any other sensors that can control timing or possibly override the SPOUT?

[Martin0660]

I dont think there is anthing in play with the spout out (at least on what I know). The PIP signal goes straight through in the base condition. I know TFI's are troublesome, but again, it should be locked out at that point as best I know. On a 2.3 there is an Octane rod that acts as an anchor for the internals of the distributor, but you said you swapped, so unless its a breakage issue, that probably out.

This smells of a mechanical issue, either the key on the crank, cam dowel pin, or something in the cam drive?? So with a SC car, there is a load on the crank for the drive right? Is it possible that when it sneezes in some way its busting a key? With that, how much play in the crank side of the timing chain would it take ot see an effective 20 degree timing shift? 0 to 10 base to +20 range of roaming there. Maybe the answer is there in what can effectively equal 20 degrees of change.

Bob Myers

[mhuckabee]

I agree that it could definitely be machanical and after only a few more tests, I will be digging back into the machanical side of it. The only thing that pushes me away from it being machanical is that snipping the HEGO ground made the problem go away for one and a half summers.

[mhuckabee]

Could there be a short somewhere that is frying the TFI modules? Could be that even though I am swapping out distributors, it is burning up each one as I put them in. Wick is going to try one of the distributors that I have in his car to see what happens.

[wick]

;)

Could there be a short somewhere that is frying the TFI modules? Could be that even though I am swapping out distributors, it is burning up each one as I put them in. Wick is going to try one of the distributors that I have in his car to see what happens.

[mhuckabee]

Tonight I tried heating up the TFI. Its got me thinking that Bob is maybe right on track with this being machanical. The car was cold, I heated up the tfi with a blowdryer, pulled spout out and started the car and it was at 20 degrees just as I left it last night. I hit the gas a little and it went down to 10 dgrees where it stayed until the car reached 180 degrees at which point it slowly climbed back to 20 degrees timing. Its almost like when its cold its stiff enough to hold at 10 but when the heat loosens it up it starts to fluctuate. What could machanically do this though? I rechecked the timing chain play and it seems good.

Im also sure that its not something moving and giving me a false timing reading. The timing is definitely actually reaching 20 degrees, I can tell by the idle speed. When I have the fluctuation occuring, I hit the gas and get it down to 10 degrees, when the idle drops it idles lower and as the timing reading increases, so does the idle. Any ideas on what could mananically cause this?

[mhuckabee]

I found the problem tonight! I removed the timing cover and cam great and found that the cam retainer was broken in half, the dial pin was broken in half, and the hole in the cam gear that accepts the dial pin was reamed to twice its original size. I was probably about a timing light test away from major valve damage if that thing would have let go. The whole thing happend because the bolts that hold the retainer in came lose. The cam must have smacked it hard enough to break it. Then the extensive cam walk broke the dial pin. Bob, you were right on the money! Thanks. half of the dial is stuck in the cam so im not sure if I am giong to try to get it out and reuse the cam or just replace it. Could the cam walking cause any cam bearing damage?

[383taman]

I found the problem tonight! I removed the timing cover and cam great and found that the cam retainer was broken in half, the dial pin was broken in half, and the hole in the cam gear that accepts the dial pin was reamed to twice its original size. I was probably about a timing light test away from major valve damage if that thing would have let go. The whole thing happend because the bolts that hold the retainer in came lose. The cam must have smacked it hard enough to break it. Then the extensive cam walk broke the dial pin. Bob, you were right on the money! Thanks. half of the dial is stuck in the cam so im not sure if I am giong to try to get it out and reuse the cam or just replace it. Could the cam walking cause any cam bearing damage?

I would say no to hurting the cam bearing cause flat tappet cams walk back and forth. Imo ill ask my machine shop guy in the morning and give you a buzz.