Need some help......What could it be, vacuum leak or timing off a tooth

[1995GTStang]

I just put a 2002 PI engine in my 97 GT.

Before Idropped it in, put new head and intake gaskets etc......I did not replace 1 intake gasket because Mustangs unlimited forgot to send me two...

The problems I having is....its fires right up idles just fine but when I tap on the throttle it bogs way down, similar to a vacuum leak. Its hard to tell if it is a vacuum leak because of the CAI setup, and the sucking of air. I have tried using carb cleaner and hitting up the intake/throttle body gaskets...but I did not notice a change in idle. I did not however change the plenum or tb gasket when did I the swap. Any ideas.....

Thanks

 

[1995GTStang]

One thing as well. There is a mark on the drivers side cam gear that the sensor in the timing cover reads as it turns. When you correctly set the timing to cylinder 1 TDC to place the chains. With the timing cover installed does that sensor line up with the cam gear?

 

[wmburns]

Can we start with the basics? Have you checked the fuses in the engine bay and passenger compartment? Confirm +12 volts on the TPS.

Do you have an ODB2 scanner? It would be handy to know the PCM operating mode (open/closed loop), Long term fuel trim (LTFT), air flow (MAF), TPS, timing, Fuel pressure to name a few.

If you suspect cam timing, disconnect the cam sensor and see if it runs better.

For base engine timing, a compression test can help give some information. Also, do both headers get hot?

It almost sounds like the PCM is not advancing the timing. Something that would happen if the PCM is operating in failure mode. Examples could include missing sensor data (check fuses).

Please describe how you set up the engine timing.

 

[1995GTStang]

I actually used this website as reference:

Timing the 4.6L SOHC Engine

These links are my end result:

http://i59.photobucket.com/albums/g287/Camarofanatic75/1997 Mustang GT/new046.jpg

http://i59.photobucket.com/albums/g287/Camarofanatic75/1997 Mustang GT/new052-1.jpg

I noticed that when I was installing the timing cover that the cam sensor was just a little off from the mark on the cam gear. That is what I am wondering if I was a tooth off. I do not have any specific tools but I do have a vacuum tester and I have a OBDII reader that does LIVE readings. The check engine does not come on.....but do scan to see if any codes pull up.

 

[1995GTStang]

What kinda vacuum PSI should I be looking for?

I disconnected the cam sensor, it does run a little better at idle.
According to the reader it says the timing at idle is 25 degrees....I do not believe that one header is getting hotter than the other, but I can not tell.

 

[nickmckinney]

Compression test driver side to pass side comparison will tell you quick if one cam is a tooth off.

 

[1995GTStang]

Ok, that is what I will do.....here is a quick question, what exactly would I see if from the compression test? Would it be weak to no compression on one side of the engine?

 

[wmburns]

Since you have the ability to monitor LIVE data, here are some checks.

Check the PCM operating mode and confirm it is in CLOSED LOOP.

Monitor the timing at idle. Increase the RPM's and note what the timing does. Post at 1k, 1.5k, 2k, 2,5k, 3k, 3.5k, and 4k. We are looking to see the timing advance as RPM's increase. Do the same for MAF and fuel pressure.

Note, if given some time, the PCM will learn to adapt for minor differences between stock motors.

The compression test will give important information. The vacuum gauge will also give clues.

On the timing. Did you fold the chain in half and MARK the end links? Did you confirm the marked links matched up with cam marks and the crank shaft marks?

The cam pictures look OK to me. Do you have pictures of the crank shaft?

What are the results of the fuse check? What is the results of the +12 volt TPS check?

How is the condition of the exhaust system? A clogged exhaust/cats can cause this symptom.

 

[1995GTStang]

I really appreciate the information given...it gives me a few steps to try tomorrow

Cats are good....car was running 14.9 in complete stock form before I started the swap.

I will also take a short vid of the car running to give you an idea of whats going on.

I believe I have a photo of the crank and gears...I will try and post tomorrow

Thanks for the above info

 

[1995GTStang]

Ok, I went out today and started it up drove it around the block.

It gave me the code PO300 cylinder misfire (x2) two counts of the code.

My scanner did not give me the TPS open/closed loop information it just said 19.6 I am assuming that is voltage.

here is a link to car running....sorry about the sound quality, its my cell phone...decent photos bad sound...:/

97' Mustang video by Camarofanatic75 - Photobucket

 

[wmburns]

P0300 is a Random Misfire. What this means is the PCM is unable to pinpont which cylinder is misfiring. For this DTC, concertrate quality of the CMP (cam) sensor, CKP signal, EGR system, or the secondary ignition system.

Look for loose/chaffed/burnt harness wires. Check the routing of the wiring harness.

Check the routing of the spark plug wires. Look for areas where the spark could cross fire to the wiring harness. If you have not followed the factory routing for the spark plug wires, this could be your problem.

Try an old racer's trick. Run the car in a totally dark location. Look for the blue spark. Inspect the wires carefully for white spots which is evidence of spark arcing.

In fact, if your spark plug wires are old, replace them. Follow the factory routing exactly including the order in the looms.

OBTW, Confirming +12 volts on the TPS is done with a Volt/Ohm (VOM) meter. Connect red to the TPS red wire the black to a known good ground. Should be +12 volts. This test is to confirm there is power to the VPWR engine buss.

If it still runs poorly, disconnect and plug the EGR solenoid vacuum line. This will throw an EGR related DTC but it's for testing. Does this improve performance? If so, there is a problem with the EGR system (excessive flow).

Based on the new engine install, my best guess is the spark plug wires or incorrect harness routing. In any case, these should be ruled out before going back to pull the timing cover to check cam timing.


>>
P0300 - Random Misfire The random misfire DTC indicates multiple cylinders are misfiring or the PCM cannot identify which cylinder is misfiring.

Camshaft position sensor (CMP)
Low fuel: less than 1/8 tank
Stuck open EGR valve
Blocked EGR passages

One or more EGR passages may be blocked or partially blocked. If this is the case the Misfire Detection Monitor will indicate the EGR port to check for possible blockage.

 

[1995GTStang]

Great information...its a start...I will pull all spark plug wires check them and rerun them to their locations. These have the cylinder marked on them as well as the coil packs. I double checked and they are going to the right locations.

Could this be the reason why I am having this type of vacuum/loss of power issues? Also could these be my coil packs? How do I test them?

Oh yeah....btw, there is a wire that is supposed to plug into something.....it is off the wiring harness back by the map sensor. Its a single elbow push on type of plug....I could not find a location for this...any suggestions?

 

[1995GTStang]

Well I am pretty sure I know what was causing the code PO300....I left the cam sensor unplugged....and I forgot to attach it before running other tests. I plugged it back in and cleared it....so far no more codes. However that did not fix the initial problem. A local mechanic swung in and says he thinks I retarded one cam......I think he is right, especially the retarded part.....

 

[wmburns]

Well I am pretty sure I know what was causing the code PO300....I left the cam sensor unplugged....and I forgot to attach it before running other tests. I plugged it back in and cleared it....so far no more codes. However that did not fix the initial problem. A local mechanic swung in and says he thinks I retarded one cam......I think he is right, especially the retarded part.....

Did you find pictures of the crank shaft? You didn't answer the question about marking the chain.

It seams to me that if a mistake was made this would be a logical place. Without the marks on the chain, there is no way to confirm the initial setting of the cams. Remember the initial setting is a just a guess. When the marked chain links are lined up with the dots, this locks in the timing.

IMO, your symptoms can be explained by the timing being off. At the very least, it can take one big item off of the list.

OBTW, if this were my car, I would want to confirm the timing error. That way you will know a change has been made. No guessing.

 

[1995GTStang]

Your absolutely right. I do have a picture of the crank gear....not the best, but it shows that the hole is at the 6 o clock position. I did all the work to the motor when it was sitting on pallet.

http://i59.photobucket.com/albums/g287/Camarofanatic75/new050.jpg

I will go hit up Napa for a new timing cover gasket and plan on taking the cover off again. I have a compression tester but its the hold in kind, not screw in. It is not long enough to make it to the spark plug hole....

BTW...the scanner unit I have does live data but does not have the option for TPS open or closed.
The LTFT was like -17...does this sound right?

The information you guys have been giving is very much appreciated. Its good to know that some of you really know your stuff. If this was an OHV V8 I would have no problems, but this is my first time tinkering with an OHC V8.

So basically all I have to do is pull the chains fold them in half and mark opposing ends? Then install the chains with a mark lining up with the crank at 6 oclock and at the corresponding cam gear marks? These chains do not have any marks other than what I made on them. But if I remember correctly as I was lining up the cam gears to attach the chains it is possible that it come off a tooth.

I will get back to you as soon as I take the cover off.....Thanks again

 

[wmburns]

For the further reference of anybody else looking at this thread, there are perhaps some lesons to be learned here.

The Ford factory service procedures call for a special purpose tool to be used to hold the cam in position. The chains are folded in half and the links on either end are marked. There are other steps to correctly align the crank prior to the cam steps.

The cam tool holds the cam in the correct position and prevents it from moving. Positive verification comes from the dots on the cam matching up with the marked links and the crank dot matching up with the marked link.

However, most ppl do not use the cam holding tool. Why? Because it's an expensive tool. But the forum is full of ppl that successfully timed their motors without the tool.

Consider when the cam tool is not used, the marked links provide a cross check just in case the cam rotates during installation.

Without the benefit of the marked chain links it is like the high wire act without a safety net.

No doubt about it. The 4.6 timing procedures are complex. Some of the procedures are arcane and it is not always apparent the purposes for each step. Nor is it obvious the possible ramifications of skipping a step.

The good news is that no damage was done (lucky). The biggest loss is the time to re-do. I suspect there is some stress from the unknown. Hopefully a corner has been turned.

Good luck.

 

[trombonedemon]

For the further reference of anybody else looking at this thread, there are perhaps some lesons to be learned here.

The Ford factory service procedures call for a special purpose tool to be used to hold the cam in possition. The chains are folded in half and the links on either end are marked. There are other steps to correctly align the crank prior to the cam steps.

The cam tool holds the cam in the correct position and prevents it from moving. Positive verification comes from the dots on the cam matching up with the marked links and the crank dot matching up with the marked link.

However, most ppl do not use the cam holding tool. Why? Because it's an expensive tool. But the forum is full of ppl that successfully timed their motors without the tool.

Consider when the cam tool is not used, the marked links provide a cross check just in case the cam rotates during installation.

Without the benefit of the marked chain links it is like the high wire act without a safety net.

No doubt about it. The 4.6 timing procedures are complex. Some of the procedures are arcane and it is not always apparent the purposes for each step. Nor is it obvious the possible ramifications of skipping a step.

The good news is that no damage was done (lucky). The biggest loss is the time to re-do. I suspect there is some stress from the unknown. Hopefully a corner has been turned.

Good luck.

Is this said tool neccesary when you are just changing the tensioners, chain-guides and chains?

 

[wmburns]

Is this said tool neccesary when you are just changing the tensioners, chain-guides and chains?

That depends on how the job is done.

First, let's assume that steps are taken to ensure that the chain does not slip off of the crank. Ford makes a special tool for the job. The tool holds the chain in place to make it possible to release the adjusters while the front timing cover is still in place.

The cam holding tool provides the positive verification that the cam remains in it's original position. If the cam holding tool is NOT used, then some other means should be taken to verify alignment. Such steps could include marking the chain link on the cam dot. Or placing some index mark on the cam that lines up with a known fixed location.

The chances of the cam moving on its own also depends wheither or not the roller follows are in place. If the roller follows have been removed, there is no spring tension on the cam that might want to move it. However, without the roller followers, there is little preventing the cam from turning on its own.

So if you are the kind of guy that doing the job right the first time is very important, then the cam holding tool should be used.

Does this make sense?

 

[bgee]

4.6 timing chain install

I'm having the same problems and need some guidance too. After replacing tensioners and tensioner arms, the idle is rough, low on power and surges. Starts great, but sometimes symptoms are worse than others. It ran great before the replacement.

I did not remove the chains when I replaced the tensioners and guide arms. To prevent the chains from slipping I wired the chains together after each gear to remove slack and prevent them from slipping a tooth. I also made reference marks on the cam gears at the valve cover surface. After installing the new tensioners I removed the wire and let the tensioner take up the slack. When I was done, the reference marks were still lined up with the valve cover surface. When I first started it, it knocked for a couple seconds until oil pressure rose then the noise went away. The idle was ok then progressively got worse. Test drives were way under powered.

I couldn't figure out why it was running so bad and decided to take it apart again to see if the chains slipped. I set the crank to TDC before taking off the cover. My chains did not have marks on them. Instead of removing the chains and marking, I counted the number of timing chain links from the crank timing mark to the cam timing mark. The number of links were the same counter clockwise or clockwise for both chains and the counts were the same from chain to chain. I counted it 4 or 5 times clockwise and counter clockwise to make sure. I also measure the chain for stretch and over 5 links it was still exactly 3/8" pitch. So I put it back together again. It ran fairly smooth, but was way down on power on the test drive. Second test drive was rough under low rpm load and rough idle. After 3 or 4 miles it started bucking and kicking badly under low rpm load.

I noticed that the cam position sensor did not line up with the gear trigger. It lines up at about 30 degrees ATDC (guessing based on the timing cover marks)

I had autozone read the codes and I got 2 new codes which weren't present before I started - P0303 "cylinder #3 misfire" and P0203 fuel injector #3 circuit condition".

Can you check timing without taking it apart again to make sure it's right?

What should I do next?

 

[trinity_gt]

First logical thing is to solve the conditions causing the two codes. The fact that both are on cylinder #3 and that cylinder #3 is located right under the throttle body is suspicious: Did you properly connect the coil and injector for that cylinder?