Timing Advance on a 93 5.0 Can I?

Unplug the spout connector and adjust the timing in the usual manner. Reconnect the spout and you're good to go. The PCm takes it's timing cue from the hall effect sensor in the distributor. If the distributor has been out, it is important to align the signature PIP with #1.

The 5.0 does not have a timing belt - belt or chain, any attempts to get "creative" with sprocket/chain relationships will only result in disappointment and possible broken parts.

I suggest purchasing a service manual for your car and learning about the systems.

Thanks Jim,

The motor has a Edelbrock Performer timing chain. It is adjustable 4 degrees one way or the other. Are you saying if I advance the timing at the timing chain, the engine will be damaged or not run?

I am having trouble researching this because stock publications don't really cover after market changes. I have a service manual, but I am trying to focus on motor issues. It is more of an aftermarket problem.

You said there is no timing belt or chain. Not sure why you say this. It is not a gear drive, it is a chain drive. I am certain of this. I just want to understand what will happen if I advance the timing. Does a mechanical change in timing effect the electronic aspects of the motor?

I hope I am making more sense here.

Laws>Unplug the spout connector and adjust the timing in the usual manner.

Read Jim's post again, very carefully. You have a timing chain. Ignition timing is normally adjusted by turning the distributor. To far in either direction (retarded or advanced) will not yield the desired results. No idea what timing should be set at in a 5.0... maybe Jim can help with that one.

Carl

Aftermarket timing chain sets often have advance and retard slots, either

2* or 4* (sometimes both). Changing the gear placement changes cam/valve timing, not ignition timing. Changing the cam timing will not necessarily add or delete hp, but it does move the powere band up or down a little. On a stock engine, it's best to install it straight up. The cam timing slots also serve another purpose. Sometimes your cam timing is off from the factory. Because of variances in manufacturing, specs may be off 1-2*.

I recommend advancing the timing via the distributor. Depending on the engine I've seen timing advanced up to 14 degrees total. It just depends on the particular engine you heve in the car. The computer expects the distributor timing to be set at a standard 8 degrees (I think this is correct) and the timing curves it uses will be increases or decreased by the amount you deviate from the stock setting.

If you really want to c> If someone would be kind enough, I have a question about a 92 Mustang > motor.

I must have misread your post (though no mention was made of the Edelbrock gears). Set up properly, advamcing the cam 4 degrees will not damage the motor. Information is our friend and you need to include all pertinent data.

Advancing the camshafy 4 degrees will generally improve bottom end torque

*in most instances*.

What I said was the 5.0 does not have a timing belt.... then I went on to say (it doesn't matter if it is) belt or chain. This is the reason there was a punctuation mark in the statement. You had made mention of adjusting the timing belt even though you "are sure" it is a chain.... why would that be?

State your questions clearly, including all pertinent data. In that way, we can opffer meaningful advice.

The motor has a Edelbrock Performer timing chain. It is adjustable 4 degrees one way or the other. Are you saying if I advance the timing at the timing chain, the engine will be damaged or not run?

I am having trouble researching this because stock publications don't really cover after market changes. I have a service manual, but I am trying to focus on motor issues. It is more of an aftermarket problem.

You said there is no timing belt or chain. Not sure why you say this. It is not a gear drive, it is a chain drive. I am certain of this. I just want to understand what will happen if I advance the timing. Does a mechanical change in timing effect the electronic aspects of the motor?

I hope I am making more sense here.

Laws Unplug the spout connector and adjust the timing in the usual manner. Reconnect the spout and you're good to go. The PCm takes it's timing cue from the hall effect sensor in the distributor. If the distributor has been out, it is important to align the signature PIP with #1.

The 5.0 does not have a timing belt - belt or chain, any attempts to get "creative" with sprocket/chain relationships will only result in disappointment and possible broken parts.

I suggest purchasing a service manual for your car and learning about the systems.

If someone would be kind enough, I have a question about a 92 Mustang motor.

Can I put a 4 degree advance on a stock 5.0 mustang motor? My concern is that the computer would have no way to identify what was going on.

If I advanced the timing at the timing belt, do I have to make any adjustments, or will the car even run? I can't decide if the computer would "see" the timing problem, or in some way compensate for it. Would that cause a rich mixture and poor low torque?

Thank you for your input. My local mechanics have not had an answer for

me.

I greatly appreciate the help. I am trying to keep the question as simple as possible to not distract from the core question I have in mind. I can see where the confusion come from. Let me clarify as best I can. To be honest, I know enough to get myself in trouble, but the bigger issue is that no one seems to know the answer to my question locally.

I participate in newsgroups myself, and genuinely respect the knowledge that they generally represent. That is why I am here. My understanding for some unknown reason is that timing can be altered on an engine two ways. One by changing the electronic timing at the distributor (that's how it used to be), and Two by mechanically changing the timing at the timing chain on the camshaft. Again, my understanding is that the mechanical approach is more reliable and considered "true" timing advance. Hopefully my mind isn't melting over the years, but that is how I recall it.

The motor I am referring to was rebuilt. The man rebuilding it, knew that I wanted as much low torque as possible. We chose to use an Edelbrock Performer timing chain set-up. The gear set had the option to set a 4 degree advance to increase torque. No one I could find at the thought that would present any problems.

My concern was that engines have changed over the years, and I am unclear on what readings the computer takes off the engine, and how it uses those readings. If my engine's computer "thinks" it is using a standard timing position of 0 degrees, have I created a problem by using a mechanical timing advance?

The engine is slow at the line, runs rich, some light backfiring in the engine compartment when starting or warming up. Kind of hard to keep running that first minute or so until it stabilizes. Once the RPM's are up, the engine seems to have nice pick-up and all is satisfactory.

I replaced the Mass Air Intake, but the problem still exists. I am haunted by that decision on the timing chain advance. Is the timing creating the problem of rich, no power, or should I go back to tracking down a false sensor or something?

The engine is from a 92 mustang convertible GT. The computer unfortunately is not. It is a Mass Air set-up that uses a jumper of some sort to attach to an old school wiring harness. I would have to look up details on that, but I want to first resolve whether I can dismiss the timing as a non issue and move on to other troubleshooting.

The reason for the wiring jumper is because the engine had no wiring with it when purchased. The people who did the wiring for me used the earlier engine wiring with the later model Mass Air sensors. That apparently requires some type of jumper. I will track down more details as needed, but if timing advance is the problem, then I need to fix that.

Thank you in advance, and I am sorry for so much info here. Again I really appreciate your assistance here.

Lawson

Jim Warman wrote:

I just posted a few more details, but you are on to what I am asking. I want a resolution that doesn't require taking the engine apart. I know that there are all sorts of chips for all sorts of applications. I just want to get everything under control.

The eng> I recommend advancing the timing via the distributor. Depending on

You're using two terms interchangeably, and they are not. The distributor (and the computer) control ignition timing. That's the timing of the ignition spark in relation to piston movement. That can be changed simply by moving the distributor around. It's easy to check with a timing light at the crank shaft snout. I would start there. The Edelbrock timing gear advances or retards the valve timing in relationship to the piston movement. Advancing that by 4* will generally move the power band down a little lower in the rpm range. This is difficult to check, and requires a degree wheel and a dial indicator. Some engine disassembly is required - valve cover, spark plugs and balancer removal at the least. One changes ignition timing, and the other changes valve timing. Closely related, but very different. If I were you, I would forget about the cam timing. 4* advanced or retarded on the cam shaft isn't that big a deal. Instead, I would chase down that cobbled together wiring harness and get that straightened out.

Ahhh. So there is Ignition timing and the valve timing. You are correct, I was lumping them together. That clarifies things.

Do you have any suggestions as to where I might start to trace the wiring harness on the engine. This jumper they referred to was treated like it was a common solution. The new Mass Air (87-94?) sensors were added to the existing engine wiring. I will contact the people that did the work, but I have not been that excited with getting involved with them again.

It would make sense if I could get a visual of the wiring and something that tells what the components do. I have worked with a mechanic, and he seems to think all the sensors are fine. I may just have to bite the bullet and go back to the people that did the wiring.

Do the symptoms mean anything to you... or anybody else? starts easily, doesn't want to stay running at first, if I give gas, I get a hollow muffled mild backfiring from under the hood. The engine will smooth out after a minute or so, but continues to run very rich. Driving it is flat at low RPM's and doesn't really come into real power until about 3000 rpm. Does that give any indication as to what sensors may be bad. The engine only has 6,000 miles on it. Plugs, air and gas filters, fuel pump all new.

I'll dig in from here. Thanks to everyone for their input.

Laws> Laws>

Like boB said... additionally, you need to match the PCM and it programming to the vehicle. If the PCM isn't ready to handle MAF computations, you are in trouble from the git-go.

It would help clear the waters if you were to restate what you have and restate your problem.... leave nothing out. These are not simple systems... They are much more complex that what you are communicating on (your desktop PC).

Jim,

There is another post in this thread that details more of the question. It is included below, as well as some additional details. I hope this helps some, and thanks for your continued follow-up.

91 motor from a Mustang GT convertable. Installed in a 75 bronco (a common swap). Motor was rebuilt with 4* advance on the cam to lower torque curve. (yes a 351W would have been better, but 302 came alone first)

There was a period when mustangs used Map sensors. The engine harness is apparently from that type of car. The MAF sensor harness is from the later models that used that type of sensor. So, I will estimate I have an 86 engine harness, and a 91 MAF wiring set-up. The people that did the wiring used a "jumper" to connect the older wiring harness with the newer MAF air sensors.

This jumper was explained as a common solution to make that wiring change. The computer came from a MAF car as well. I was told that this would all work just like original. Even to the extent that someone could hook a diagnostic computer up to the system and get sensor readings. (that turned out not to be true)

The computer is an A9L. I am using stock injectors, stock fuel pump, this is not a cobra, just an HO.

The motor I am referring to was rebuilt. The man rebuilding it, knew that I wanted as much low torque as possible. We chose to use an Edelbrock Performer timing chain set-up. The gear set had the option to set a 4 degree advance to increase torque. No one I could find at the thought that would present any problems.

My concern was that engines have changed over the years, and I am unclear on what readings the computer takes off the engine, and how it uses those readings. If my engine's computer "thinks" it is using a standard timing position, have I created a problem by using a mechanical timing advance?

The engine is slow at the line, runs rich, some light backfiring in the engine compartment when starting or warming up. Kind of hard to keep running that first minute or so until it stabilizes. Once the RPM's are up, the engine seems to have nice pick-up and all is satisfactory.

I replaced the Mass Air Intake, but the problem still exists. I am haunted by that decision on the timing chain advance. Is the timing creating the problem of rich, no power, or should I go back to tracking down a false sensor or something?

The engine is from a 91 mustang convertible GT. The computer unfortunately is not. It is a Mass Air set-up that uses a jumper of some sort to attach to an old school (pre 87) wiring harness. I would have to look up details on that to be exact.

The reason for the wiring jumper is because the engine had no wiring with it when purchased. The people who did the wiring for me used the earlier engine wiring with the later model Mass Air sensors. That apparently requires some type of jumper.

The computer I used was

Jim Warman wrote: