low end power disappeared?

Topic: low end power disappeared? (Read 21098 times) previous topic - next topic

low end power disappeared?

Reply #15 – December 24, 2014, 01:48:13 PM

I didn't install the cam or timing chain, someone else did that for me. I'll check with him. I'll pull codes as soon as I get through the Christmas craziness. thanks again for responding. everyone have blessed Christmas!

low end power disappeared?

Reply #16 – December 24, 2014, 03:01:00 PM

This from the guy who installed it.

" No it wasn't degree'd because its a stock cam in a stock block. Yes it was installed straight up on the timing marks".

low end power disappeared?

Reply #17 – December 24, 2014, 05:02:31 PM

Quote from: marianadeeps;441915

Quote from: V8Demon;441904
You DID reroute the ignition wires to the H.O. firing order, correct?

Yes I did. I've now done the TPS/idle adjustment and it no longer surges, and the IAC is working properly. Now I'm thinking that I just don't have the low end torque I used to have. My power band is way up in the 3000 rpm and above. Should I advance the timing? Trade in my x-pipe for an h-pipe? Install a higher stall torque converter? I'm hoping to find a relatively inexpensive solution. Has any had this issue with their engine upgrade?

If you were running say the TFS stage 1 cam and were saying that your low end punch disappeared then yeah, I could see that. Being that you're running a stock HO cam I would say that there is an issue. The TW heads flow more than a set of E7 heads all throughout the lift range in bench flow tests. Swapping from an x-pipe to h-pipe wouldn't make the difference enough to justify. The converter you have should be a good fit with an HO cam. No point in throwing parts at it as if it were a mismatched combo. It will compound your problem as something else is going on.

Code scanner (or test light), timing light, vacuum gauge, and some time.

low end power disappeared?

Reply #18 – December 24, 2014, 11:22:38 PM

Are you sure you've got the firing order right? You are of course aware that the HO is different. I have experience that says that an HO will still run with the SO firing order, but poorly, and will show low vacuum, causing the MAP sensor to provide data that causes the EEC to dump extra fuel. If you do it right, you can make the headers glow this way.

low end power disappeared?

Reply #19 – December 24, 2014, 11:33:03 PM

He says he did account for the new firing order of the wires...and if it's running smooth, no missing or misfires as it would with mis-routed plug wires, my gut says base timing is off.

OP, here's a quick "test fix"; loosen the distributor hold down bolt, and with engine off, but up to operating temp, rotate the dist. a little bit one way or the other, then snug the bolt down just past finger tight, start it up, and see if that made a difference.

Of course, you can also use a timing light, inhook the SPOUT connector (gray plug in the distributor harness..looks like a Lego block) and just fix your issue while you're in there....once your base timing is set, plug the spout back in...all it does it prevent the EEC from advancing timing while you're setting it via the good ole distributor twist 'n turn.

I'd think that a weak fuel pump would cause a lean out at higher RPM rather than lower, but hell, I've had worse and stranger things happen to my own engine(s) a few times.

low end power disappeared?

Reply #20 – December 24, 2014, 11:42:31 PM

Then put a light on it, pull the SpOut plug and dial it to 14 degrees btdc. Ho cams are pretty happy there. My TFS-1 likes 16, but 14 should be perfect for your setup.

low end power disappeared?

Reply #21 – December 25, 2014, 12:23:59 PM

Do a compression test that will answer all you issues one way or the other. Post the numbers and i am willing to bet they are low

low end power disappeared?

Reply #22 – December 25, 2014, 08:23:09 PM

Quote from: TheFoeYouKnow;441942

Then put a light on it, pull the SpOut plug and dial it to 14 degrees btdc. Ho cams are pretty happy there. My TFS-1 likes 16, but 14 should be perfect for your setup.

I'll give this a shot and see what happens. As far as the compression check, geeze I hope that's not an issue. The car was pretty solid before the upgrade -- spark plugs were all a perfect tan.

low end power disappeared?

Reply #23 – December 26, 2014, 07:53:03 AM

Check the compression. Even if your timing is off by lets say 6* that will not make much difference. If it is off like 16-20 then you found your issue. But i am leaning to low squeeze what is the compression numbers

low end power disappeared?

Reply #24 – December 26, 2014, 11:08:08 PM

Quote from: TOM Renzo;441983

Check the compression. Even if your timing is off by lets say 6* that will not make much difference. If it is off like 16-20 then you found your issue. But i am leaning to low squeeze what is the compression numbers

I got a few of them done before having to run and go to SCAL for a few days. 1 = 149, 2= 148, 5=150, 6=151.

The guy that installed my HO cam said that I would never get any decent low end power with those TW heads unless I went to a performance cam -- I hope that's not true. I currently have a 60mm stock EGR spacer with my explorer TB and intake -- would that be my problem? Is it worth it to upgrade to 70mm TB and spacer?

low end power disappeared?

Reply #25 – December 26, 2014, 11:47:26 PM

TW heads comment sent me back to OP to re-read combo. Issues I have: 19# injectors are usually maxed out with GT40 heads on your combo, with TW heads, 19# is inadequate. DA1 is a speed density PCM, and SD ain't exactly known to play nice with parts that alter the vacuum profile of the engine, so your cam is ok, your injectors are ok, but I'm concerned about TW heads, how big are the ports, valves and chambers? An engine is an air pump, and speed density likes to spaz out with parts that radically change the amount of air being pumped (unless you have a twEECer or similar tuning module and are a EEC tuning genius).

Sounds like your combo is underfueled, and THAT is going to start you down the road to MAF. Best recommendation: 24# injectors, MAF conversion w/70mm housing stock meter and X3Z PCM if you can find one.

I'd like to hear what some of the older 5.0 guys have to say on the subject of Cylinder Head/Speed Density compatibility.

low end power disappeared?

Reply #26 – December 27, 2014, 02:20:33 AM

X2 on the mass air setup and at least an A9l EEC, with 24# injectors. Especially with aftermarket heads....as mentioned, GT40's are close to the limit of being "good" with a SD/19 pound injector setup...though it can and has been used reliably, with some elbow grease.

low end power disappeared?

Reply #27 – December 27, 2014, 06:34:16 AM

So far the compression is ok but i would like to see a bit more. Lack of bottom end performance is directly connected to the cam and it's events. It sounds like that engine is lean down on the bottom. SD and 24 Injectors with a tune is mandatory at this point. Your Compression numbers rules out an issue with cam timing and selection. Good luck

low end power disappeared?

Reply #28 – December 27, 2014, 08:33:39 AM

There were guys running blown combos with 30 pound injectors. There used to be a bunch more f info on http://www.50tech.com the site is gone now. I have a ton of the info saved, but I gotta pull it up from my external hard drive.

low end power disappeared?

Reply #29 – December 27, 2014, 04:58:03 PM

I still think OP needs to verify his timing is where it needs to be...should've been the first thing looked at before ever touching the keyboard. :)