Why Does It Die??

[jhanson1750]

I had a similar prob on my 86' was dumping fuel but I had no scan tools at the time. I cleaned and changed o2 and little or no effect so I took mine to conleys and told them what all I had checked they grabbed a MAF off another car that was known good and PRESTO!!! She ran like a top again. Long way to say trade out the MAF with a known good unit and see what happens. Turns out that mine was reading within the acceptable range but at idle it was saying I was getting LOTS of air. Just my .02 Hope it helps.

 

[tenright]

I'm going to say this again even thought I hate repeating myself, the recon MAF's are no good....either get a known good MAF or upgrade to the translator and LS1 MAF....

And yes your IAC #'s are way to high, you will need to get the IAC below 30 then set the TPS again, then get the IAC down to 20-25 and do a final set on the tps .42-.44.....reset the ECM......

But all the tuning in the world ain't gonna fix a bad MAF...

 

[BRAD_PADGETT]

I just realized that RADS has an 85 ECM which our scanmaster does not read. He is probably using an OTC 4000. His reading on the MAF of 38 might not correlate to the scanmaster. Forum member JERRLY will have the answer. Solve the IAC issue and post numbers. If the problem is not IAC,the offer on the Tomco MAF for an 85ECM still stands. Brad. I also have a stock 85 MAF as well.

 

[tenright]

He's using TurboLink.....

I pretty sure he can convert to the LS1 MAF and translator with the stock setup.Wouldn't take much searching to find out....

 

[Rads]

Thanks for all the replies!! I will get started on the IAC problem. I am using Turbo Link.

Brad - Thanks for the offer on the MAF. I will let you know if I need it for a test. Would you be interested in selling one?

Is there anyway to know by the numbers if the MAF is bad?

Thanks again!!

 

[BRAD_PADGETT]

RADS- There is a way to test the MAF but I do not know what your Turbolink MAF numbers mean. I am on the 87 ECM with scanmaster. I would PM JERRYL and ask him what your reading mean WRT the MAF. The IAC screw needs to be adjusted very very slowly and reconfirm your readings. Once you get to between 20-30 at idle in park- reset the ecm and relearn the chip. Retest and adjust and adjust and retest.
I have an original 85 MAF which I most likely replaced out of my own stupidity. I had no clue as to what I was doing last summer. I also have a Tomco unit which I bought last year and it worked fine on my basically stock engine. It did not work with all my new mods in my signature. I have to have a good 87 MAF or convert to the LS1/translator. You can have both of the MAFs for $50 plus shipping. Let me know. Brad

 

[JOELO'S T-TYPE]

Newbie doubt here

I guess you guys will have to excuse my ignorance, but whats BLM?

Thanks

 

[BRAD_PADGETT]

BLM is block learn measurement. The numbers range beween 100-150 and represent long term ECM learning. Ideal is 128. Usually anything within 10 either way is OK. Brad

 

[JOELO'S T-TYPE]

Thanks,

I've seen in my car what a bad MAF can do, once my car felt as if it had concrete on its trunk, it was a whole new car after replacing it. Just my two cents.

 

[darkred87T]

Judging by the numbers, it looks like the IAC valve isn't working. I would check connections or get a new one before you go any further.

 

[tenright]

Judging by the numbers, it looks like the IAC valve isn't working. I would check connections or get a new one before you go any further.

Dont'cha think maybe trying to adjust it before you decide it's faulty would be a good idea......seen more then 1 IAC reading that high, adjusted it and it was fine.

 

[darkred87T]

Dont'cha think maybe trying to adjust it before you decide it's faulty would be a good idea......seen more then 1 IAC reading that high, adjusted it and it was fine.

Sure, and what I learned was when you adjust the idle screw for the IAC, you have to also adjust the TPS. That tripped me up when I first started messing around with trying to adjust mine.

 

[Rads]

I've tried two different IAC controllers and they both do the same thing.
What I am wondering is after each time I make an adjustment do I need to reset the ECM? Once I try to get the IAC down to 20 +/- the engine will really gallop and this usually ends with the car stalling. I have a known good MAF on the way and hopefully this will help me.

 

[tenright]

I learned was when you adjust the idle screw for the IAC, you have to also adjust the TPS.

Absolutely, the 2 go hand in hand....RADS you should take note of that. Any adjustment to the IAC also throws your TPS out of wack.

Honestly though I said it 3 times in this thread, your MAF is more then likey your problem. Its a recon and those don't work. Best advice I have for you is to move to the LS1 and translator, your going to have to do it eventually anyway....You may also find that your O2 sensor is screwed, mine was when I had a faulty MAF.....I put in the translator, LS1 MAF, and O2 sensor at the same time and everything came alive.....havent had a problem since.

and yes you need to reset the ECM after you adjust the IAC....

 

[darkred87T]

I know this is redundant but on the 86-87 cars at least, the "idle adjustment screw" (used for setting IAC) will alter the TPS setting. Once you make an adjustment for the IAC, you need to re adjust the TPS to get it back to the right parameters. (39-.42) volts with the throttle released (at idle). You should be able to adjust the TPS with the key on and engine off being that it only senses the physical position of the throttle lever. I hope my rambnling makes sense or you might already know this. If not, it might be why the car is stumbling when you try to adjust the IAC.

 

[Rads]

Well the MAF was the problem (well most of it anyway). I put on the new one and it runs alot better. I have not had time yet to do the final adjustments on the IAC but, I did drive it and it ran good until I really got in the gas. The motor really bogs down at about 3000 rpm. I am wondering if with larger injectors I need to be running more than 40 psi fuel pressure? I also need to add a boost gauge any recomandations?? Thanks for all the really good replies, if it was not for you guys I still wouldn't be able to drive this thing yet!

 

[tenright]

This is where a scanmaster or some kind of diagnostic tool comes in handy, all cars are different..some run better on low FP, some run better on higher FP, really depends on what the BLM's are telling you....I believe I also mentioned I thought you might have a bad O2 sensor along with the MAF...

Really you can't do anything without at the very least a knock gauge because at this point I would lower the FP till I saw knock at stock boost levels then come up a little till the knock was gone. You really can't tune that car without knowing exactely what it's doing.......

I am currently working on a similar problem, cold she is awesome, fishtails into second gear, churps into third...but after a couple of miles she was acting really stupid, floor it from a dead stop and it would barely move, floor it from a slow roll and it would not have anywhere near the power it had cold, also it would have all kinds of crazy issues in third gear...after pulling the spark plugs I noticed one was wet on the threads with fuel....(Bad injector) I hope. Otherwise the Fuel pump is probably on it's way out. My point is you may have several problems.....

 

[BRAD_PADGETT]

RADS- You are now at the point where you really cannot go any further without a scan tool, knock gauge and a boost gauge. You need a scan tool that can read the 85 ECM. The scan tool will give us numbers which will tell us whats going on with your car. Brad

 

[Rads]

Thanks for the info. I will get some numbers off T.L. I am out of town until Sunday so I will get the numbers out late this weekend. Thanks again to all!!