Finally got a chance to play around a little. Started right off with adjusting intial timing to 11 and then to 13. Bingo, finally a difference. Now she rev's almost normal. Throttle response is fair. Even at 13 there is no knock that I can tell when accelerating. Still not what it should be. rechecked fuel pressure and readjusted to 44. Still not quite right. Seems to be pulsating over 3500. Also when reving the fuel pressure drops about 6 lb is this normal? She pulls ok. Got another new problem to. When slowing down to a complete stop the idle drops down to 500 and it wants to stall. Sitting still,it idles at 750 like it should. Is this also fuel related?

 

Doesn't sound right to me. What happens if you run her through 1st gear and tape the fuel pressure gauge to the window? How many miles on the car?

 

Are you setting the initial timing with the EST wire disconnect? You should.

Be sure to disconnect the battery when you're finished to clear the code the gets set.

With the timing set at 6 degrees (EST disconnected) once the EST has been reconnected and the code cleared, the timing should be in the range of 20 degrees at closed loop idle.

You didn't by any chance change the harmonic damper and/or timing chain cover timing tab did you. If they are mis-matched, the timing you see with the light will not be the accurate timing.

No way should the fuel pressure drop to 6 psi; middle 30s is ballpark for the lowest you should see. Where are you taking that reading? Is the engine running when you do?

Jake


[Modified by JAKE, 8:33 PM 5/6/2004]

 

I like the idea of the fuel guage being taped. That would take out some of the guessing on if it's a fuel problem. when idling I rev and it drops about 6 lb. 80,000 and change.

 

Its about that time then. :yesnod: 70k-100k is usually the die zone for those things. Its an easy 10 minute swap if you do in fact see it not holding pressure under throttle.

 

The cover and balancer are stock. The est is dissconected while setting the timing. currently I'm up to 13*. After a test run the timing seems to bounce a little. Eventually it all returns to how I set it.

 

Scorp are you saying fuel pump and filter. I put in a new AFPR.

 

Well, that's one area that has a problem. Fuel pressure is much too low. This IS a fuel injected TPI engine, right?

Fuel pressure works off vacuum. As vacuum decreases, fuel pressure increases. About 1 psi for every two inches of vacuum.

So If you open the throttle quickly, vacuum falls off and fuel pressure should increase.

As an example, if your engine pulls 20" of vacuum, at WOT, when vacuum is close to zero, fuel pressure should increase about 10 psi. So 34 psi of fuel pressure at idle would translate to 44 psi at WOT.

6 psi of fuel pressure is what carbed engines run, not FI engines.

Are taking the fuel pressure reading from the Schrader valve on the passenger side fuel rail?

Jake

 

I think he is saying it drops by an amount of 6psi, not that it is running at 6psi total.

 

OH! Now that DOES make a difference.

But the ignition timing still isn't right.

After plugging the EST back in and clearing the code, the timing shouldn't go back to 6 degrees. It should be around 20 degrees, give or take a couple.

Am I misunderstanding that too?

Jake

 

The first time I set the timing was by the book 6*. The car had no get up and go. I boosted it to as far as 10* with no difference and gave up with the timing idea and got some ideas from the forum. Went back to timing today and after getting to 13*. Finally got some progress without any knocking so far. I do not get any error codes at all.
Still knowing more tuning is needed I went back to fuel. AFPR set at 44lb at idle, it drops to 36-38 when the throttle is opened.

 

Have you verified that the ECM is taking over the ignition timing after the engine starts?

With the initial timing set at the base timing spec of 6 degrees BTDC, after the engine fires, the ECM should take over the timing and, at idle, it would advance to around 20 degrees BTDC.

Have you, by chance, been inside the timing chain cover doing a camshaft change, etc.?

Jake

 

Your balancer could have seperated and slipped giving an incorrect reading when you set base timing.

 

Im not sure if this has been checked yet, but are you confident that there is absolutely no vacuum leaks? Also make sure all the vacuum hoses are plugged into the right places.

Good luck..

 

I went back out again this morning. Without out a doubt my problems are timing related. Something is off wether it is the balancer mark or timing tab is unknown, but now with this consideration I have moved the base timing around enough to finally be able to resemble a descent driving vehicle. I never checked the timing before I did the cam change so I don't know if I distorted the tab or if the balancer slipped. I have a massive oil leak to deal with. Timing chain to oil pan. After that is fixed I'll hook up my G Tech and see where I'm at. I'm hoping for 12.9 even without headers or gears. Thanks to all. The more minds the better. :smash:

 

[SNIP] I never checked the timing before I did the cam change so I don't know if I distorted the tab or if the balancer slipped. I have a massive oil leak to deal with. Timing chain to oil pan. After that is fixed I'll hook up my G Tech and see where I'm at. I'm hoping for 12.9 even without headers or gears. Thanks to all. The more minds the better. :smash: [/SNIP]

Well, that's what is suspected!

I'm betting you misaligned the DOTS on the crankshaft gear and the camshaft gear; off by one tooth.

The symptoms you are experiencing - the need for so much initial timing to get the engine to run half-way right - is a clue that the gears are off. That's why I asked whether you had been inside the timing chain cover.

While fixing the oil leak, you can verify the position of the DOTS. Use a straight edge, ruler to make sure they're aligned.

Turn the crank until the camshaft gear DOT is at the 6 o'clock position and the crankshaft gear is at the 12 o'clock position. Those positions make it easier to verify the parts are correctly indexed.

It would be best to use a one-piece oil pan gasket instead of the four piece jobs that are prone to leaking.

To fix the leak (without chaiging the entire gasket) you'll need to loosen all the oil pan bolts just enough to allow the front of the pan to drop down about an inch or so. Install the timing chain cover, the re-tighten the oil pan bolts.

If you use a new one piece gasket, you can use short studs (hardware store) which are the same size and thread as the oil pan bolts. Hand tighten them into the block at a few places to hold the new oil pan gasket in place while you re-position the the oil pan.

Make sure the oil pan gasket at the front and rear fits into the timing chain cover properly.

Keep us posted.

Jake