injectors too big?

[Alxsmt]

sappy - just read that link.. hmm. he has tuned a members turbo car on here and did a good job according to the member. he seems like a good guy at least, after reading some of what he told me im thinking he doesnt know everything he needs to. i dont know a lot but i have picked up a lot from this forum and bstuff and know its possable to tune on obd1. i may look into holland motorsports or maybe superdave? i know you can tune

[Alxsmt]

tried my new file, he set the idle at 1200 and it idles but its not right. he did other stuff 2 get the wot closer too. has low 10s afr idle still...

i cant afford to keep changing my oil from gas. spent easily 300+ in cheap oil and k&n filters

[SappySE107]

1 flag is all that needs to be changed, so why don't you swap in OBD2. I have tuned high compression, .500+ lift, headers, etc on OBD1 MAP.

[Alxsmt]

lol one flag??? maybe i will go thru all the flags

i believe it! i wish i could just drop my car off at your shop! i have seen many cars on this forum and bstuff heavily modified and running with tuner pro. no issues

[Alxsmt]

well i went out and played with flags that had nothing to do with a trouble code. i did it while it was running. didnt change anything. i did notice that after my car idles for a few mins the afr slowly goes up to 14s but i can rev it and when the idle goes back down the afr goes back down to 10s and slowly back up (which i didnt notice b4)... the car was warm but i have no clue if it was in open or closed loop. i still have to have my foot on the gas to start the car. and i didnt turn the car off and back on with the flag changes so i dont know if it would have given me code 51 again/limp



EDIT: vid attached of the afr at idle. it will never see 14s with daily driving.

[Guest]

The message posted on post #13 is funny.

Obviously written someone who knows very little about MAP based systems and believes that a MAF system is superior, because it's "easier to tune". While an SD system may not be perfect it has been used on MANY engines that produce VERY little vacuum at idle.

I'm currently having some minor issues with a '67 chev pick-up that I helped convert to EFI oh and this is on a 409 type engine (smaller version 365 current displacement). I am tuning it, it runs great driving along, WOT (throttle body is too small and MAP will go down to 70 KPA at higher RPM , idles fine, as long as it's not in gear. I'm switching to a 7730 from a 7747, and using S_AUJP. The reason I mention this truck, is becaus eit makes very little vacuum, and runs well. In gear idle goes screwy and the ECM tries to shorten the PW too much and the MPFI set-up can't deliver enough fuel with the short PW this is due to the firing scheme of the injectors (fires at every DRP not every other DRP like the true MPFI ECM).

I looked at your bin last night, and compared it to a known $A1 bin file I had on hand.

Your rich "idle" and the fact that it doesn't want to "idle" is likely in large part due to the spark table. There's so much timing being pulled out in the lower RPMs I'm almost surprised it's starting at all, except for the fact that the ignition module has a base 10* advance built in.

I wouldn't worry too much about what is going on with the BPC vs EGR just yet. I would scrap what ever thing guy is trying to do and start from an absolute stock bin, fire it and then you can change the BPC to get a 14.7 AFR idle. At the very least get it into the 13s, high 13s and you can work from there, that's not terribly rich at that point. I had been running my Datsun at about a 13.8 AFR idle for a while, while I worked on drivability, then I've been able to get the idle AFR closer to 14.7. Your AFRs do come down to a good AFR, they just take a little bit to get there. The AE might be a bit much, which can usually happen with larger than stock injectors. A larger injector will add more fuel with the same PW than a smaller injector. This also applies to AE. The added PW length will add more fuel with the larger injector so the added AE might need to be reduced. It can take several seconds sometimes for this fat condition to be burned off, and why the AFRs will stay fat for a while. I have the same thing going on with my Datsun, I have reduced the AE but found that my VE table wasn't close enough yet, so I put the AE back to where it was, until I get my VE table dialed in, then I'll reduce AE again. The additional fuel of AE was masking some lean spots in my VE table, which can make tuning difficult sometimes, when other factors are adding fuel, it's difficult to nail down the VE table just right.

Long steady RPM and MAP readings will help get the VE table to where it needs to be, as long as the AE and PE fuel can be burned off and the spark is back to basic advance (Main spark table), then VE tuning can be done pretty confidantly.

Don't rely solely on what the WBO2 is telling you, they can lie.
Pull the plugs, at least one from each bank, and read what the plug is telling you. I run an Innovate LC1 in a permanant install in my car, and while I believe the readings are accurate, that is only because I still pull the plugs and read them. I've had my car running for just under a month now in the current configuration, and have pulled the plugs no less than 4 times, just to make sure. The spark plugs are your best window to seeing what is going on in the combustion chamber.

Something else to consider is that the problems you're experiancing may not be entire ECM/bin/tune related.

Just yesterday I adjusted my valves on my Datsun (mechanical so they need to be set), and my idle MAP went from swinging between 29 and 32 KPA to a steady 28/29 KPA, idle also became smoother. I would suggest going through and making sure everything mechanical is within proper adjustment. An electronic tune can't tune for a mechanical failure or improper mechanical adjustment.

$A1, Speed Density, OBD-1 are not your problems, $A1 is a good bin.mask to start from, and can run some pretty healthy, low vacuum engines.

[Alxsmt]

thats kinda interisting. im also using the stock rockers so they dont need to be adjusted. everything else in my sig is on my engine.

i did attempt to get my car to idle with the bpc on my injectors but i just couldnt get it right.. it was horrible! i tried for hours and did a lot of research and asked a lot of questions on here but i still was having bad luck/no skill lol. i finally learned about gmtuners.com and heard good things about them so i had them tune it...

[Guest]

Just because you're using stock rockers DOESN'T mean that the geometry is correct.

You have swapped the heads to 3500 heads from 3400 heads, AND changed the bumpstick (cam), this can throw the geomtry of the valvetrain way off. Did you check, and measure for proper length pushrods? Did you install proper length pushrods? I don't see any listed in your sig.

[Alxsmt]

yeah ben measured on a set of 3500 heads/3400 block and got me the correct length. i hope everything else is correct

[Guest]

yeah ben measured on a set of 3500 heads/3400 block and got me the correct length. i hope everything else is correct

Did he have your cam installed when he did this? Heads and block decked the same?

There is some room for error, but I've seen too many people try and tune around mechanical problems because they assume it's correct.

As an example there was an engine that came into the machine shop I use that was "built", all very good compnments, huge cam, high compression, all sounded like a good combination, but his buddies smaller less built engine in a similar car would just walk him. Turned out the exhaust rockers weren't 1.7s like they thought they were, they turned out to be 1.2:1 break in rockers. No amount of tuning would get around the inccorect assembly of parts.

[Superdave]

^^ LOL.. i'd be pissed! ^

if the idle vacuum isn't too low and there is no mechanical ticking/knocking it's probably fine. Since you assembled it, you know for sure that everything is tightened to spec.

[Alxsmt]

yeah same everything, with my cam (it was the first he did i belive).

i didnt build the engine my self, i dont know enough of the general technical specs and dont have enough experience to trust my self with it. the guy that helped me has build a lot of engines/race engines. i dont rember what the vaccume was but it was higher than the guy expected and i was told it was really good. everything was done to spec and checked by both of us. the clutch makes noise but i dont think that counts

thanks tho, if i didnt have help i would have over looked a lot of stupid things

[3400-95-Modified]

I spent a year working on the damn A-body upgrade/conversion he was talking about and I TOLD him it doesn't work with our wiring setup, grounds aren't right so it throws codes left and right... Coolant codes, Cam codes, and crank codes... stuff just doesn't work right, and you know as well as I do a OBDII swap has been done on 94-95 cars very easily so if you were to find a full 96 harness in and out the swap would be even easier for you. I find it easier to do a whole harness than have to do the modifications to the interior harness a 94-95 guy would have to do.

BUT besides that error, I would listen to Dave and those other guys, they know what they are talking about.

[Alxsmt]

ok thanks. dave is helping me at the moment

im letting gmtuners know about the wiring andsaying i know for a fact its possable to tune. lets see what he says

[Joseph Upson]

This may not be an issue, but is it possible your INT limits are part of the problem. I realized that using the integrator value to tune relative to the BLM helps quite a bit since the BLM changes slowly. If your Integrator limits are not low enough when you add larger injectors which I did, you will prevent the ECM from pulling as much fuel as maybe needed during a rich condition to help make the engine run better, while trying to adjust the fuel tables to bring the BLM and INT into proper range.