Thanks Six-Shooter. I should have known it. I have been making other changes such as BPW right along. Haven't changed VE but will tinker around at
the idle rpms.
Bob
Thanks Six-Shooter. I should have known it. I have been making other changes such as BPW right along. Haven't changed VE but will tinker around at
the idle rpms.
Bob
Don't force it, get a bigger hammer!
With bypass open I got it running (by feel/ear) with 46 deg advance. After re-connecting by-pass timing came back to 26 deg.Originally Posted by Six_Shooter
When it warmed up and the fan came on the engine quit and I couldn't restart. Letting it cool overnight and will try again in the AM.
I changed from AHAK to ACSR that 1project2many suggested. The VE table is more in line with your suggestion to get lower near the idle RPMs.
Will I see any changes in the bin after running a while in idle?
BPW = 135 and FP = 12psi.
Last edited by uncabob; 08-23-2016 at 06:26 AM. Reason: Corrected advance fro 18 deg to 26 deg.
Requiring 46* advance to start the engine makes no sense.
The EFI backing off the timing 20* also makes no sense. Check the timing tables and find where the table specifies -20* for the timing. If you can't find that then it's not happening.
You really need to figure out this timing thing before you go further. Something is not right. Start by using a piston stop and checking the 0* timing mark.
Thanks for jumping in Lionel. Totally agree that something is not right. I first thought that my Harmonic-balancer might be off but the mark is right on at TDC.
I haven't tuned a car in over 20 years and all my tuning was by feel and ear. Never had timing more than 4 or 5 degrees. This is why I posted the thread.
I brought #1 to TDC on compression stroke and the mark is right on 0 at the indicator. Then put #1 plug wire where the point was. Used the timing order on the intake manifold in a clockwise direction from there. Disconnected the bypass and tried to start it. It finally started when I got to abot 45 deg. It ran and I got the timing light on it at 46 deg. Shut down, connected bypass wire, restarted, got code 42, shut down and cleared the code. Restarted and it idled at near 600 rpm, the timing was now at 26 deg. Have no clue what I've done wrong. I'll try anything about now (except hire a "mechanic").
Thanks mom, but I'd rather do it myself.
Thanks again. Bob
Is it a GM module, or an aftermarket? It's also possible that the pick up coil is wired backwards to the ICM, which can cause retarding of the timing. Usually seen when the engine is reved not at a static RPM just when connecting the bypass wire though.
There's no reason why you should need so much advance to start. The only time I ran across something similar was on the 283 that I just pulled out of my T-Bucket, and that had mechanical issues with the cam and likely worn piston rings. It would still start and idle with less than 10 degrees base timing though. So something is definitely off with your set-up.
Next time you try t0 start it, and it won't start at with the base timing between 0 and 10 degrees BTDC, hold the throttle all the way open and see if it does. It might be that you have too much fuel at cold start and the engine is flooding. On the flip side it may be that you don't have enough (I have found that the Crossfire system needs a little extra fuel at start than other TBI systems, and the extra advance may be getting the fuel to inject sooner causing some of the additional fuel into the engine. You could also try pouring a little bit of fuel down the TBs just before you start it and see if that helps, which would confirm that you need additional fuel at start up.
The man who says something is impossible, is usually interrupted by the man doing it.
Six-Shooter:
Q1. My first time with the HEI and I don't Know about the module, but, I think it's probably aftermarket. I'll check to see and also check the pick up coil.
I feel that I need to go back and check for vacuum leaks again. I made a thorough check last year and eliminated a couple. Maybe something has dried up?
Do you know where the MAP should be connected on these single barrel TBs? Also I am doing the initial tries with the air cleaner off. Is this a mistake?
Before doing the above, I'll try the flood clear method as you say.
On my Grandfather's Crossfire I have the MAP plumbed to a fitting in the base plate behind the driver side TB. I don't know which port on the TBs would be manifold vacuum off hand.
Air cleaner off is not an issue at this point.
The man who says something is impossible, is usually interrupted by the man doing it.
Six-Shooter
Tried starting with WOT and it started but it was still at 26 deg and it back fired a few times and quit. It idled for a few seconds at about 1100 rpm but
not solid. Checked for codes after it quit and got a "33" High TPS v which I attribute to the back firing. I'll try checking for vac leaks and double check timing tomorrow and then look into the HEI. I don't like throwing parts at it but the HEI was used and given to me.
Backfiring where? Through the exhaust or intake? I really doubt that a backfire will cause a high TPS code.
Check the TPS voltage with a DMM, make sure the TPS is working properly, this can cause problems as well if it's not.
If I were in your shoes, I think I'd try getting it to start and run on base timing and by base timing I mean down around 4 to 10 degrees BTDC, not 45 or 46. There's ZERO reason you should need that much and really doesn't make sense that you would.
The man who says something is impossible, is usually interrupted by the man doing it.
Backfired through intake (drivers side) TB. Ran TPS voltage test last week and it ran .6 to 4.7 IIRC. I'll do it again tomorrow to make sure.
It ran smooth with no breaks bottom to top. I'm going to double check timing first thing, this is crazy. Can you look at the ACSR bin and tell if there is anything that would cause a problem with timing? I've tried to start with a low base timing but it always wants more. Also need to check again for vacuum leaks.
Appreciate the time you've spent on this. Bob
Sorry Six-Shooter but I erred on the code 33 it was a high MAP voltage not TPS.
Is this a stock engine, or has it been cammed?
Bigger cam durations require more ignition timing advance. But even the biggest, nastiest cam in an SBC isn't going to need 46* to start. First thing I'd check and see if I had the distributor installed 180* out of phase. Then you MIGHT have to crank it around that far to get it to pop, might have to go a lot further than that.
Disconnect the ignition coil from the distributor cap pull the fuel pump fuse, turn the key on and slowly roll the engine over with a bar-as soon as the ignition coil fires, stop and measure your firing angle. That'll tell you exactly where the computer thinks the crankshaft is, and might give you some detail as to what the issue is.
From there, just like Six-Shooter said, check the ICM for a flipped connector to the pickup coil. Is there anything in the code that would change the ignition timing by a fixed amount? Kinda like the DIS/Distributor selection for the V660 engines?
Xnke:
The engine is original except for a mild cam. Don't believe the cam is the problem. Not following your disconnect the coil from the cap. The dis is HEI with coil in cap. Did check the coil wires and they are correct in the cap. Will check the wires out of the ICM though.
Tried to get it running long enough to check for vac leaks but no go. Tried re-timing and reversing the timing and it still back fires but doesn't run. Will run diagnostic on the HEI. But first I'm going to try another HEI today. Have 5 or 6 more. Any other suggestions (except a carb) are welcome. Will re-post with findings.
Thanks to all.
Bob.
Can you plumb it for series fuel delivery? I'm well-being of maybe one TB is not getting the fuel flow through it that the other is.
Also, so far I've assumed that everything other than what toy mentored is stock. So I'm going to ask about the intake manifold plate. Under the throttle bodies are the fans still in that plate?
The man who says something is impossible, is usually interrupted by the man doing it.
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