I am lost...

EcSy#2671

EcSy#2671

Si vis pacem, para bellum
I can't figure out what the problem is. If you see my build below, my truck feels very low on power. It is slower then my SS. I have just changed the plugs, cap and rotor, valve springs, and exhaust. Afr at wot is 11.5. I reset the computer and now have 12.0 afr at idle . Like I said, lost.....

I had a tuner named zippy from the Silverado forums come out and take a look at it, he looked over the datamaster files and said it looks right but still has no power. He though it Could be low valve spring pressure with valve float. The closed pressure is now about 124. Still no power and lost......

Any pointers or ideas would help.

Thanks
 
EcSy#2671

EcSy#2671

Si vis pacem, para bellum
Re: I am lost...

NecroWolf said:
have you checked your timing?
Click to expand...

Yes, a lot. O degrees and unplugged and after plugging back in the tan wire also check to see the datamaster time adjustment match what the timing mark were saying, also to double check that the distributor is working correctly.

As a guess, I put 5 Degrees advanced on it and felled like it made more power with out making knock.

WyoSyclone said:
Can you post that DM log?
Click to expand...

I don't know how. I have files saved. How do you post the files?

TYTILIDIE said:
Any knock? What are you IAT's?
Click to expand...

Hit or miss, some knock, under 3 degrees. IAT are around 110 when it was 93 outside.
 
bezerk

bezerk

New member
Re: I am lost...

you get only 124 psi when you do a compression check? should be 150-160
 
EcSy#2671

EcSy#2671

Si vis pacem, para bellum
Re: I am lost...

bezerk said:
you get only 124 psi when you do a compression check? should be 150-160
Click to expand...

The 124 psi is the close valve seat pressure at an installed height of 1.7 in. I did a compression test and a leak down test when I changed the valve springs and everything is within spec.
 
bezerk

bezerk

New member
Re: I am lost...

EcSy#2671 said:
When I put the exhaust on I checked it and it look fine, after replacing the exhaust I also check it with a heat temp senser gun. and the operating temp was where it should be.



How would go about that??
Click to expand...

take out the plug put on 0 and check with your hand when compression stops or use a screwdriver too feel if it''s at tdc. or buy a piston stop.
 
EcSy#2671

EcSy#2671

Si vis pacem, para bellum
Re: I am lost...

Just checked it again and, It is back at 0 but I did notice that the plug location on the distributor cap is off by one, but the timing is still correct. Would this effect timing?
 
EcSy#2671

EcSy#2671

Si vis pacem, para bellum
Re: I am lost...

bezerk said:
take out the plug put on 0 and check with your hand when compression stops or use a screwdriver too feel if it''s at tdc. or buy a piston stop.
Click to expand...

I have a piston stop, and was wondering how to do it correctly.

Would I bring the motor up to 0 and install the stop and turn the motor backward to tell it stops again and mark it. and in middle of the two mark will be the true TDC. Correct??
 
NecroWolf

NecroWolf

lost marbles member
Re: I am lost...

is you added timing and it made more power you might need to add more timing to your chip, what is your overall advance
 
nello

nello

Active member
Re: I am lost...

EcSy#2671 said:
When I put the exhaust on I checked it and it look fine, after replacing the exhaust I also check it with a heat temp senser gun. and the operating temp was where it should be.



How would go about that??
Click to expand...

Nice work checking the op temp of the cat, but I gotta ask, were you able to check both ends of the cat? My old cat looked perfect on the outlet when installing an exhaust but after the cat was taken off the inlet was melted something silly. Though you'd probably notice your boost hit 14.7 and then fall down to 10psi quickly after WOT...a sure reason for loss of power obviously. G/L
 
BoostedSUV

BoostedSUV

Active member
Re: I am lost...

what are your boost levels at WOT? 14.4 degrees is about right for WOT ... Just curious, you didn't mention how much boost you're running.
 
EcSy#2671

EcSy#2671

Si vis pacem, para bellum
Re: I am lost...

nello said:
Nice work checking the op temp of the cat, but I gotta ask, were you able to check both ends of the cat? My old cat looked perfect on the outlet when installing an exhaust but after the cat was taken off the inlet was melted something silly. Though you'd probably notice your boost hit 14.7 and then fall down to 10psi quickly after WOT...a sure reason for loss of power obviously. G/L
Click to expand...

Are there any other tale tales that show a bad cat?

I some of my old Datamaster files,with a manual boost valve, show that the boost would peck the fall off about 2-4 psi.

BoostedSUV said:
what are your boost levels at WOT? 14.4 degrees is about right for WOT ... Just curious, you didn't mention how much boost you're running.
Click to expand...

Around 15 Psi I would like to run more, but there is no money for a H2o injection just yet.
 
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