Rebuilt motor, No power

[99chevys10]

I just fired my truck up from where I rebuilt my motor and it seems to run good when its idling but when you drive it, the thing has no power. I put a 266AHR Comp Cam and got my computer tuned by Wait4Me. You can give it all the gas you want and it just doesn't go. It sputters too and shakes when you are in the gas. I have 2 trouble codes. They are both crank/cam position sensor correlation codes. Any ideas? Oh yeah it's a 99 with the 4.3

[MikeInCtown]

Did you do a crank relearn yet? You'll need to do that for sure.

[99chevys10]

Not yet. I wouldn't think that would cause it to be this low on power would it?

[S15vortecpwr]

without the relearn it can/will not put full timing/fuel in to it. So hince no power, or you have it out of time.

[Neeseius]

Hmm my motor was swapped and I've not needed the relearn procedure. I have the same cam as you. But Wait4Me has a reputation for sending out PCMs that require crankshaft relearns. The camshaft position sensor is odd too. Have you made sure the connection on the Crank sensor and Cam sensor are secure, and the eletrical connections inside the plugs themselves haven't been tampered with?

[Neeseius]

BTW there's debate whether a crankshaft relearn is even required period, some say it's purely for GM diagnostics to detect misfires (which is its main function) whether it can cause timing and fuel to be pulled I guess we'll see.

[MikeInCtown]

Regardless of the debate, the computer does require that information, so why not do it. At least you'll get rid of a few codes and it may solve the problem.

W4M sends out the PCMs that need it because people send in PCMs not from the vehicle they are putting it on, or they buy the one directly from W4M. If you do searches on crank relearn in Google you'll find a lot of info about it.

[Yogi]

A rebuilt motor will definitely need the crank relearn ("CASE learn"). Click here for info on how it is done. CASE Learn is on page 3.

But I'm wondering if you got the dizzy in right? Did you line up both marks on the crank damper? Did the rotor point to #6 OK? The cam position sensor depends on proper dizzy installation. If you're off by one tooth it will run but run badly and throw the crank/cam code.

[99chevys10]

I'm pretty sure I've got it in right. I haven't checke dit yet. But I also read in some other forums about the gear being on wrong. It is a reman from autozone so that is a possibility.

[Yogi]

Quote: Originally Posted by 99chevys10

I'm pretty sure I've got it in right. I haven't checke dit yet. But I also read in some other forums about the gear being on wrong. It is a reman from autozone so that is a possibility.

If the gear is on wrong, then the rotor will be off by 14* at TDC when looking at the #6 tab on the dizzy housing. Not a great amount, but noticeable.

[99chevys10]

True, It's really weird... When it is idling it sounds perfectly fine. And when I rev it in neutral it sounds fine. But put it in gear and its like somebody chained an anchor to it.

[Yogi]

I hope that this helps. Note the 2 lines on the crank damper.

Quote: Originally Posted by blanz

Bill.

[99chevys10]

Thanks, I'll try it sometime this week.

[Bill Wheats]

Is the brown timing wire disconnected?
Try cheching for timing advance using a timing light and the brown wire connected. We usually add a couple of chaulk markes so that you can see the reference easy. As you higher the rpms the timing should advance.

Also check it with a vacuum gauge.

Good luck

[Yogi]

Quote: Originally Posted by Bill Wheats

Is the brown timing wire disconnected?
Try cheching for timing advance using a timing light and the brown wire connected. We usually add a couple of chaulk markes so that you can see the reference easy. As you higher the rpms the timing should advance.

Also check it with a vacuum gauge.

Good luck

It's a '99 so I don't think it has a timing wire.

[Bill Wheats]

You're right. It probably doesn't. Shows you what I know.

[99chevys10]

So I lined the crank up with the timing marks this time. I turned the dizzy a tooth but it still is low on power. Is it possible for the truck to run 2 teeth off? And I remember now that when I installed it the first time I had didn't know there were 2 marks so I believe I had what is supposed to be the bottom line lined up to the top timing mark. So it is possibly off another tooth I guess. I have no idea. It's drivable now though so I'll mess with it over the weekend.

[Bill Wheats]

The best way to check is with a timing light.

[Yogi]

Quote: Originally Posted by Bill Wheats

The best way to check is with a timing light.

On a '99?

[99chevys10]

I was actually wondering if it was possibly to to check it with a timing light. But I'm pretty sure my timing is good now. I haven't been able to get my hands on a scan tool to check for the crank/cam correlation code yet. And I'v edone some research and thinking on my own and I have determined my injectors are bad too. I ordered the upgrade kit to go to the multiport injection from gmpartsdirect.com Mine being bad would cause the rough idle, hard starts from time to time where fuel has bled out and sat in the intake, and it would explain the sputtering and feeling like it is bogging from dumping unwanted fuel into my intake. And it explains why I smell lots of fuel when I take my intake off the throttle body. I ordered it tonight. Hopefully itll get here asap so I can get back to driving my truck daily.

[99chevys10]

BTW, I've burned 3/4 of a tank and I've drove 120 miles. Terrible MPG's from the fuel problem...

[Yogi]

Quote: Originally Posted by 99chevys10

BTW, I've burned 3/4 of a tank and I've drove 120 miles. Terrible MPG's from the fuel problem...

Man! That is terrible!!

[Bill Wheats]

Quote: Originally Posted by Yogi

On a '99?

Yes, if you want to see when it's firing and if it's advancing.
The crank is 360` and every 60` it should fire the right cylinder. I've often used a cloth tape measure the crank pully and chaulked the number of the cylinder on the crank and connected the probe to each plug to track the problem down...
But I'm an idiot some times and don't have a 99. LOL
Sometimes it takes me a while to eliminate simple problems...
Could be just a crossed wire. Someone proved the engine would run I think with 4 and 2 crossed??? might have been 4 and 6???

[Yogi]

Quote: Originally Posted by Bill Wheats

Yes, if you want to see when it's firing and if it's advancing.
The crank is 360` and every 60` it should fire the right cylinder. I've often used a cloth tape measure the crank pully and chaulked the number of the cylinder on the crank and connected the probe to each plug to track the problem down...
But I'm an idiot some times and don't have a 99. LOL
Sometimes it takes me a while to eliminate simple problems...
Could be just a crossed wire. Someone proved the engine would run I think with 4 and 2 crossed??? might have been 4 and 6???

No, You're not an idiot. But you have to admit that it is somewhat unconventional to check the timing on a motor on which it is non-adjustable!

[Bill Wheats]

Quote: Originally Posted by Yogi

No, You're not an idiot...

I see you have never met my beter half.

Quote: Originally Posted by Yogi

... But you have to admit that it is somewhat unconventional to check the timing on a motor on which it is non-adjustable!

Ayy, but it is electronically adjusted and controlled. The engine just went through a rebuild and many things that can affect the timing have changed.
Given the issues posted, sometimes you need to go back to basics and prove or dis prove possible causes.

[99chevys10]

When I first fired it up 4 and 2 were crossed and it was extremly noticable. I'm going to go back and check everything soon when I put the new injectors in.

[Yogi]

Quote: Originally Posted by 99chevys10

...... I have determined my injectors are bad too. I ordered the upgrade kit to go to the multiport injection from gmpartsdirect.com Mine being bad would cause the rough idle, hard starts from time to time where fuel has bled out and sat in the intake, and it would explain the sputtering and feeling like it is bogging from dumping unwanted fuel into my intake. And it explains why I smell lots of fuel when I take my intake off the throttle body. I ordered it tonight. Hopefully itll get here asap so I can get back to driving my truck daily.

When you get the top off look for puddling of fuel and indications of "scouring" of the deposits in the lower intake manifold. The symptoms that you describe above are those of a broken fuel pressure regulator. If you ordered the "kit" from GMPartsDirect (the kit has a "PK" in front of the part #) it should come with a new FPR.

[99chevys10]

Yeah its the PK12568332... The pressure regulator was another option but I wanted to go with the upgrade anyways. So as soon as I tear into it I'll post what I find. It won't be in for a week or more and I'll be on vacation next weekend so it will be a couple of weeks until I get to install it.

[lesterl]

The shop my Uncle works at had a pickup with a v8 in it and the plug wires ended up being all crossed up, ran good, just every once in a while it would lurch when it shifted and it was a fun one.

[99chevys10]

The cylinder number is molded into the dist. cap. It's pretty fool proof as far as crossing although I've done it before.