[chphlds]

hey guys,
trying to figure out why my ecm is for speed density,and I am running maf. no knock sensor installed,but wiring is there.runs rich till warmed up then smooths out,but pings.downloading pics. maybe somebody can see something from these.any input appreciated.

[64nailhead]

Did you get the last issue repaired - the stalling when cold/won't stay running until it's warmed up? If so, then what was the issue/repair?

If everything is working properly and the only issue you are having is the pinging, then based on that you mentioned you have no knock sensor installed, I would *** U ME that you need the knock sensor. The primary purpose of the knock sensor is to change the timing to avoid detonation/pinging. But, I'll repeat, if you are having other issues, then I would address them also.

Did you ever find anyone with a datalogger to see what is happenning while your driving?

Good luck

[chphlds]

hello,
nothing resolved.same issues.have been told that hooking up knock sensor will not solve problem as s d is set up without it.will try installing one since I have already purchased it.[my computer is 16198262,speed density,but running m a f].was told bad temp sensor could be my problem with the rough running until it warms up,so purchased one and will install both items and take out of storage and go for a test spin.will let you know how I make out.thanks for your interest.never delt with tuned port befor so all help is much appreciated.have not found any one in this area who does either.

[64nailhead]

Before I decided to go with a MegaSquirt I contacted as many people as I could about reprogramming my chip or purchasing a different ECM and/or memcal. I'd recommend contacting a couple of these guys and tell them what you have in terms of parts and ECM.

Sinister Performance, LLC. Sinister Performance

Tuned Port Injection Scott Hansen

TPI CHIPS TPI Chips

Both Sinister Performance and Scott Hansen were more than helpful. I would be relatively confident that either would be willing to help and let you know what you might have occurring that is causing some of your problem.

Also, here a couple of links with a lot of helpful info about using a stock TPI setup with a stock ECM in a non TPI chassis :

TPI Conversion Parts

Hot Rod Handbooks: Tuned Port Fuel Injection

Chevythunder

Programming PROMs for your Thirdgen Fuel Injected F-Body: Part I - ThirdGen.org

I think you'll discover that there a lot of guys on the thirdgen site that have done the conversion that is in your car. There is a bunch of great info on the ChevyThunder site and in the hot rod handbook site. You might also find that one of these guys can direct you to someone in your area that could help you out.

Spend a couple of hours reading and a week or two picking the brains of the guys that have done the conversion and you will probably figure out the problem with your car or at least find out what you have to do inorder to get your problems resolved.

As always - good luck.

PS - your car is one good looking ride with a really cool looking setup under the hood

[oldbogie]

Originally Posted by chphlds

hey guys,
trying to figure out why my ecm is for speed density,and I am running maf. no knock sensor installed,but wiring is there.runs rich till warmed up then smooths out,but pings.downloading pics. maybe somebody can see something from these.any input appreciated.

Speed Density and MAF are different air quantity measuring systems, one is not compatible with the other. Speed Density or as it's called Manifold Absolute Pressure (MAP) uses throttle position, manifold vacuum (absolute pressue) and RPM to compute the amount of air being consumed which generates a number that aligns to a look up table that has an amount of fuel with an igniiton timing advance point for that number. Changes to the engine such as a larger cam change the manifold vacuum to the throttle position to the RPMs which really screws with this system.

The Mass Air Flow (MAF) system does not compute the air consumption as MAP does, it measures it using a heated filament that changes temperature in proportion to the air flow over the it. This changes the voltage on the output side of the filament from a known standard voltage being applied to it. This replaces the manifold vacuum part of the sensing used for the MAP system. The output voltage of the MAF sensor doesn't quite track engine power settings the same as from a MAP sensor so the fuel and ignition advance points aren't quite correct if the progammed chip for the type of system (MAF or MAP) is missmatched to the system being used. The MAF system is more flexible when it comes to cam and other changes because anything that changes the air flow past the filament sensor is accomodated, within reason, it doesn't generate incompatible signals to the computer.

Bogie

[Northstar T]

^^^^^^What he said ^^^^^^

You can't run a MAF system with a MAP ecm. ain't gona happen. Because you already have the MAP based ecm, it would be simpler to convert to MAP, assuming your wiring harness is for the MAP system also, but either system will work fine. they just both need to be talking the same language.
86-89 is MAF and 90-92 is MAP btw
Russ

[chphlds]

this is what I am trying to figure out.my e c m is for map[16198262]and I am running maf.i know they are not compatable,but my car runs strong once warmed up.there must be a way I can tweek it without changing the harness and ecm.

[chphlds]

thanks for the info guys.with that I should be able to figure it out.thanks again

[LATECH]

I just looked at the photos of your MAF engine. Wheres the Mass Airflow Sensor?? I dont see it.
Isnt there a connector that isnt hooked up?

[123pugsy]

Originally Posted by LATECH

I just looked at the photos of your MAF engine. Wheres the Mass Airflow Sensor?? I dont see it.
Isnt there a connector that isnt hooked up?

I don't see a MAF sensor either.

It would be in the air intake tube something like the butchered pic below.

The second pic is of a MAP sensor. This just requires a vacuum line from the plenum and hook up the wire from the ecm and that's it. No air intake plumbing to deal with.

The only problem is as Bogie mentioned that this system is useless with a big cam.
What are your cam specs?

I added a pic showing the harness connections at the ECM. Mine is the 7730 but I understand that your ECM is a replacement for the 7730 so you should have a harness the same as mine.

You must have the knock sensor hooked up if you want to avoid pinging and the damage that will happen to your engine.


In summary:

Install the knock sensor. This is the first thing.

If you have a big cam, get yourself a MAF sensor, proper intake hose, air filter and the matching ECM.

If you have a mild cam and want to run speed density (MAP), get yourself the proper wiring harness along with the MAP sensor.

[LATECH]

The correct ECM for your application is a 1227165.
The wiring harness should have 2 connectors going to the ECM and not 3.
You probably have a harness for a TBI setup from a 1227747 which is what pugsy pictured and it wont run a TPI system correctly.
Seeing a few more pictures would help sort through this mess.

[123pugsy]

Originally Posted by LATECH

The correct ECM for your application is a 1227165.
The wiring harness should have 2 connectors going to the ECM and not 3.
You probably have a harness for a TBI setup from a 1227747 which is what pugsy pictured and it wont run a TPI system correctly.
Seeing a few more pictures would help sort through this mess.

The ECM I posted is a 7730 from a 92 T/A (speed density). OP's ECM is supposed to be a replacement for this, from what I searched.

[LATECH]

He stated in an earlier post he has 2 plugs in the harness and the ECM has 3 plug ins . Here may be the issue.
Using the later ECM would require obtaining the missing third connector, and repositioning all the wiring in the 3 plugs to coincide with the ECM pinouts .Not tough to do. Or get the correct ECM for his wiring and locating the MAF wiring and plumbing it in.
Also with the MAF MIA...........

[LATECH]

Here is apples to apples (injectors pictured in both diagrams.)
Both diagrams show injectors and ecm connectors/pinouts.
Looks like he needs an electrician