IroczInOz

I have been reading up on some information and found some usefull info on what to change etc.. The only thing I am a little unsure about is the main spark advance. Looking for some input.

86 GTA 305 HSR T700r4

I have attached pictures of the tables and a graph so it is easier to see what it looks like.


Would anyone recommend it looking differently?

Grumpy

Less cruise timing, unless your using some huge chambered heads....

IroczInOz

Thanks Grumpy for looking I appreciate your comments. I will take it down in 1500-2200 rpm range and 48-112 LVE range by a little maybe 3-4 degrees and see how it goes.

Grumpy

If you're using an ARAP (oe one similiar to it), you might need to go even further.

IroczInOz

I started off with an AUJM bin.

IroczInOz

Just a thought what happens when you rev the car above 4800 rpm using $6E and say the AUJM bin. The main spark advance table only goes to 4800rpm and I know the HSR users say they can take it to 6000rpm. How does the ECM calculate what spark to use?

IroczInOz

Okay I have edited the tables even further. Would this be better suited for a Holley Stealth ram 305?

It is not my car. I am trying to help someone out that is having surging issues and backfiring issues. Unfortunately he does not have a scan tool at the moment which makes it very difficult to get anywhere. I must say I like $8D much better.

I have attached a few images of the table and graph. Does this one look better then the one above?

IroczInOz

Thought I would mention that I have read that the HSR like 39-41 spark advance at low load cruising speed?

Now is total timing calculated by having 34deg in spark table plus 6 base timing which gives you 40?

I might need to add heaps of spark to the tables if this is so so it gets the 41 that it likes. The post I am refering to is this one

https://www.thirdgen.org/forums/diy-...ottle+response

junkcltr

iTrader: (1)

Is the MAF bad? Did you try unplugging the MAF to see if it ran better? Is the SES light on?
If it is a stock engine, it sounds like a bad MAF.

It is nearly impossible to tune without a scan tool. It is doable but with take some time. The HSR will probably need a bit more AE to start with.

IroczInOz

Yeah what's happening is:
When you drive around at say 40kms in 3rd gear, it pulls you back and forth, cutting in and out. Then if you plant it, and sit in say second at 3500RPM it's back firing and breaking up. The surging only tends to get worse the longer you drive it, not so much temp wise but time wise.


Also the SES light stays on and was reving at 2000rpm.

Yes it is a MAF car. He is running a Holley Stealth ram on a 305. He could not get any codes to display the SES light just stays on. Someone else burnt him chip and must have made a bad burn possibly?

junkcltr

iTrader: (1)

First impression is that it sounds lean on fuel

That sounds like a possible bad MAF

That sounds like a bad chip and it is running off of the the MEMCAL/ECM hardware and not the chip. That bad chip could cause the bad looking MAF and the lean surge. Do you have a stock chip that you could through it to test it out. If so, try it. Second, you could still try unplugging the MAF and see if that helps. It really sounds like the chip burn is bad or not seated properly. If using an adapter board, make sure the chip is placed in it with the proper orientation.

How are you trying to get the codes? Key off, jumper ALDL pins A & B, key-off, light blinks

IroczInOz

Definitely a bad chip burnt.

I also think his surging issue might be due to the way he has the fuel pump set-up.

Anyway the owner before him, installed a 6psi fuel pump (carby pump) that pumps fuel into a canister. Then from the canister there is a 50psi pump installed that pumps the fuel to the engine.

Seems like this is the problem. The previous owner wanted to do a quick fix without doing the work on installing a new in tank pump and came up with this.

thirdgen88

Yeah, rip all that **** out and put a good in-tank pump in...