New to Tuning

[GNBeswick]

Hey guys, recently I converted my 85 ecm over to the 86-87 style as well as the maf. When I converted it, I hooked up a Scanmaster so I could finally see whats going on in my car. Ive recorded the values Scanmaster has given me at idle, but not my WOT values, because its reading massive knock, around 10...I let off imediatly....as I didnt wanna break anything. Before I list the values Ive recorded though, Ive got another problem I think I should adress. The car is running really rich it seems, can really smell the richness at idle, what can I do to fix that? Alright, here are the values Ive recored for idle:
02 760s AF 06 l8 42 bat 13.2 Int 128 bl 101 clt 165
Ats 94 r 800 tps .40 Iac 37

Do those values seem good? I know bl stands for block lean, but what is it exaclty? Does it have something to do with actual fuel lean values? From what Ive been able to gather, the values are all good except the BL, Im wondering if thats the cause for my high knock issues.

 

[trbodon21]

I think you are talking about the Block Learn Multiplier (BLM). This value should be around 128. A high number means the computer is increasing the injector time becasue of a lean condition and a lower number (in your case 101) the computer is decreasing injector time becasue of a rich condition. Your 101 is a little low.
What is your fuel pressure set at?
What do your spark plugs look like?

 

[GNBeswick]

My fuel pressure is 42 psi line off...spark plugs....I should probably change those, but would they really cause such a rich condition?
Im also curious what is causing me such horid knock, im getting one degree of knock for every pound of boost pretty much. At five pounds of boost, Im getting 5 degrees of knock, 10 pounds, 10 knock degrees, its friggin ridiculous. Anyone got any ideas as to the cause of this?

 

[trbodon21]

I'm not saying you need new plugs, I was saying look at your spark plugs to indicate a rich condition,
e.g... if they are black and sooty with carbon deposites then your plugs indicate a rich running motor.
As for the knock. Do you have scanmaster readings from when the motor is detonating? That would help to pinpoint problem. Also can you see your fuel pressure when driving? It should be increasing 1psi of fuel for every 1psi of boost.

 

[AZ Vic]

Too rich of an A/F can cause as much knock as being lean when you are "under pressure"...

YES the plugs can create a rich condition ---> plugs that are fouled will not burn as much fuel when combusted because of lack of proper detonation----> your o2 picks this up and retards the injectors causing your low BLM's.

I would say this is a possiblity... I am far from an expert or even that experienced... but these are my first thoughts.

Vic

 

[GNBeswick]

Thanks for the replies guys, appretiate it. When you say readings from when the car is detonating, do you mean basically WOT readings for every category? Like IAC, TPS, 02, BLM, l8 and such?

 

[bruce]

Originally posted by GNAsuka
Hey guys, recently I converted my 85 ecm over to the 86-87 style as well as the maf.

Did you hook up a MAT/IAT sensor?.

 

[GNBeswick]

Ya, I hooked up a MAT sensor, put it in front of the maf.

 

[GNBeswick]

Alright, I took some readings from the engine under detonation, a couple odd values.
02 896-902 l8 237 Tps 3.08 Iac 108 Maf 151 Int 128

That Maf one worries me....its low, I thought Maf was supposed to be 255 at WOT.

 

[AZ Vic]

your o2's show rich... your TPS is WAY low if that is WOT, it should be 4.2-4.7 I think... yes the MAF is low too...

I would change the plugs, and adjust the TPS... easy things to do and then see where you are at. Your air filter really dirty? is thier something blocking your pedal from going WOT? ie floormat?

Good Luck,

Vic

 

[trbodon21]

I agree with AZ Vic. TPS should be in that range. Also see if you can get another air filter from a friend and strap that on to see if MAF changes. The O2's should be in the 750-800 range I believe. Here is a website with some good reference tunning values. http://www.vortexbuicks-etc.com/

 

[GNBeswick]

Alright, Im gonna try cleaning my air filter (Ive got a cold air kit from BuickGN.com, so the filter sits behind the drivers side headlight, and Im sure its dirty) Im also gonna get some new plug wires as well, mine are old...real old. I also made sure the pedal can be pressed all the way, which it can, and the throttle blade is also all the way open when the pedal is depressed. As for the TPS, Ive adjusted mine before for idle, how do you go about doing that for WOT? Just have the ignition on and have someone press the pedal down all the way?

 

[AZ Vic]

Yes, it is best with two people - just like you said, turn key on but do not start the car, have your assistant floor the pedal and take your reading. You have to keep referencing your idle position to because it will change. I had to actually file the groove about a 16th to be able to move enough.

It would also be a good idea to check the difference between the actual TPS (at the connector on the throttle body)and what the computer is reading (on the scan master). If there is a loss of more than .2 VDC from the TPS to the SM, then check for a bad connection.

May I recommend the MSD set that Nick offers for your new plug wires. They are like 50-60 bucks and are an excellent fit. I am VERY happy with mine, I would bet they are the last set you ever buy.

If you do not live in a very dirty or dusty area, you may want to try a quick cruise and WOT without your air filter on...

Did you have a knock problem before the ECM swap?


Vic

 

[GNBeswick]

Well, I got my tps straight....4.02 at WOT. I went ahead and cleaned my filter as well, but that didnt do anything. I saw another post about someone who was having low maf readings, and I saw a reply about altitude and boost affecting the readings. Im wondering if that aplies to my case, as Im only running around 16 pounds of boost, and my altitude is fair. My rich situation still exists however, when I get my new plugs and wires, Ill post the results.

 

[AZ Vic]

Originally posted by AZ Vic

Did you have a knock problem before the ECM swap?


Vic

 

[GNBeswick]

I did have some knock, but I dont think I had as much. Before the conversion, I didnt have a scantool, so I had no way of knowing exactly what my knock was. I know my car ran rich before the conversion as well, but it runs richer now I believe.